WO2019059255A1 - Magnesium-lithium alloy and surface-treatment method thereof - Google Patents

Magnesium-lithium alloy and surface-treatment method thereof Download PDF

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Publication number
WO2019059255A1
WO2019059255A1 PCT/JP2018/034746 JP2018034746W WO2019059255A1 WO 2019059255 A1 WO2019059255 A1 WO 2019059255A1 JP 2018034746 W JP2018034746 W JP 2018034746W WO 2019059255 A1 WO2019059255 A1 WO 2019059255A1
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Prior art keywords
magnesium
lithium alloy
chemical conversion
solution
treatment
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PCT/JP2018/034746
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French (fr)
Japanese (ja)
Inventor
健樹 松村
朋 陳
淳 七山谷
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ミリオン化学株式会社
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Priority claimed from JP2018174452A external-priority patent/JP6553268B2/en
Application filed by ミリオン化学株式会社 filed Critical ミリオン化学株式会社
Priority to CN201880056924.XA priority Critical patent/CN111094625B/en
Publication of WO2019059255A1 publication Critical patent/WO2019059255A1/en

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
    • C23C22/34—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/78—Pretreatment of the material to be coated

Definitions

  • the present invention relates to a magnesium-lithium alloy and its surface treatment method. More specifically, the present invention relates to a magnesium-lithium alloy that can form a surface that is excellent in corrosion resistance and does not generate particles, and can reduce the surface electrical resistance value, and a surface treatment method thereof. is there.
  • Magnesium alloys are excellent in physical strength, lightness, recyclability, electromagnetic wave shielding, heat dissipation, dimensional stability and the like.
  • magnesium-lithium alloy containing lithium is used in various fields as a material which has the same ductility as iron, aluminum and the like, and can be pressed at normal temperature.
  • magnesium-lithium alloys have lower corrosion resistance than common magnesium alloys and in many cases can not withstand practical use as they are.
  • particles derived from the chemical conversion treatment may be generated on the surface of the formed chemical conversion film, and the particles inhibit the low electric resistance value. If it occurs, it is necessary to wipe off the particles after the surface treatment.
  • the magnesium-lithium alloy thus surface-treated when used in a casing of a mobile phone, a personal computer, etc., the particles are not sufficiently wiped off the particles generated on the surface of the chemical conversion film. It scatters within the case to cause contamination, which may adversely affect the electronic devices in the case.
  • the present invention has been made in view of such circumstances, and is excellent in coating base performance and bare corrosion resistance, and does not cause the problem of contamination due to particles, and forms a film capable of realizing low electrical resistance.
  • the object is to provide a method and a magnesium-lithium alloy obtained thereby.
  • the surface treatment method of magnesium-lithium alloy according to the present invention for solving the above problems is characterized in that the surface of magnesium-lithium alloy is an etching solution comprising an aqueous solution containing 150 to 500 ppm of neutral ammonium fluoride in phosphoric acid. It comprises the process to process.
  • the method may further include a step of film formation treatment by immersing in a chemical conversion treatment solution containing 1 / liter of a fluorine compound.
  • this chemical conversion treatment liquid one containing one or more selected from polyallylamine, polyallylamine partial carponylation, polyacrylic acid and polyacrylamide at a concentration of 50 to 5000 ppm in the above chemical conversion treatment liquid May be used.
  • the magnesium-lithium alloy of the present invention for solving the above problems is obtained by the above surface treatment method.
  • the magnesium-lithium alloy has 20 or more independent convex projections having a longest separation distance of 15 ⁇ m or more in plan view scattered on the surface per unit area of 310 ⁇ m ⁇ 250 ⁇ m square.
  • a tape having a strength of adhesive strength 7.02 ⁇ 1 N / cm is crimped by a crimping roller with a mass of 2 kg, a diameter of 85 mm, and a width of 45 mm, and then peeled off by 90 degrees with respect to the crimping surface When peeled off at an angle, the amount of particles transferred to the tape is made to be 2.0 mg / m 2 or less.
  • the magnesium-lithium alloy has a surface electric current of an ammeter when a cylindrical two-point probe (contact surface area 3.14 mm 2 of one needle) with a pin distance of 10 mm and a pin tip diameter of 2 mm is pressed against the surface with a load of 240 g.
  • the resistance value is 1 ⁇ or less.
  • the above magnesium-lithium alloy is coated with an epoxy-based primer to a film thickness of 12.5 ⁇ 2.5 mm on the surface of magnesium-lithium alloy, and then an acrylic top coat is formed with a film thickness of 12.5 ⁇ 2.5 mm.
  • an acrylic top coat is formed with a film thickness of 12.5 ⁇ 2.5 mm.
  • magnesium-lithium alloys to be treated according to the present invention various magnesium alloys containing lithium compatible with cold pressing can be used.
  • various magnesium-lithium alloys disclosed in the prior art can be used.
  • the size and shape of the magnesium-lithium alloy are not particularly limited.
  • Preferred magnesium-lithium alloys include those containing 5 to 20% by mass, more preferably 5 to 16% by mass of lithium, with the balance being magnesium and impurities.
  • the balance is magnesium and LZ 91 made of impurities, lithium 7%, zinc 1%, the balance is magnesium and impurities made LZ 71, lithium 7 %, Aluminum 7%, zinc 1%, the balance is magnesium and impurities LAZ 771 material, lithium 7%, aluminum 3%, zinc 1%, the balance is magnesium and impurities LAZ 731 material, lithium 7%, aluminum 4 %, Zinc 1%, the balance is magnesium and impurities LAZ741 material, lithium 14%, aluminum 1%, the balance is magnesium and impurities LA141 material, lithium 14%, aluminum 2%, the balance is magnesium and impurities LA142 material made, 14% lithium, aluminum %, LA143 material containing the balance of magnesium and impurities, an alloy containing several percent of Ca added to LZ 91 material, an alloy containing several percent of Y added to LAZ 741, and others containing magnesium and lithium as main ingredients Or various lithium-magnesium alloys to which a plurality
  • this magnesium-lithium alloy is subjected to degreasing process, water washing process, etching process, etc., as required, to remove the surface oxide layer and segregation layer, etc., as in the case of ordinary chemical conversion treatment.
  • the degreasing step can be performed by a method such as immersion in a highly alkaline solution of sodium hydroxide or the like.
  • sodium hydroxide it is preferably prepared as a highly alkaline solution at a concentration of 1 to 20% by weight.
  • the immersion time in the highly alkaline solution is preferably 1 to 10 minutes. If the concentration of the sodium hydroxide aqueous solution is less than 1% by mass, or the immersion time is less than 1 minute, the appearance will be deteriorated due to insufficient degreasing. Moreover, when the sodium hydroxide aqueous solution with a density
  • FAL free alkalinity
  • the processing step using an etching solution is an etching solution containing 150 to 500 mg / liter of neutral ammonium fluoride in an aqueous solution having a concentration of 9 to 35 g / liter of phosphoric acid as a main component, and a magnesium-lithium alloy By immersion treatment.
  • This etching solution it is possible to obtain a magnesium-lithium alloy free from particle generation, which has not been obtained conventionally.
  • the surface electrical resistance value can be lowered, and excellent coating performance and corrosion resistance can also be obtained.
  • the content of neutral ammonium fluoride in the etching solution is preferably 150 to 500 mg / liter, more preferably 150 to 400 mg / liter.
  • a chemical conversion treatment film having fine convex projections for lowering the surface electric resistance value may be formed on the surface of a magnesium-lithium alloy. If the amount exceeds 500 mg / liter, adjacent convex projections will be connected to form continuous projections, and generation of particles will be excessive.
  • the concentration of the inorganic acid in the etching solution is adjusted so that the free acidity (FA) is in the range of 9.0 to 12.0 points. If it is less than 9.0 points, insufficient treatment, appearance defect, increase in surface electric resistance value, decrease in coating film adhesion, etc. may occur, and if it exceeds 12.0 points, surface roughening due to excessive treatment, dimensional defect And corrosion resistance of the coating may occur.
  • phosphoric acid is used at a concentration of 9 to 35 g / liter in the etching solution so that phosphoric acid is the main component in the inorganic acid.
  • the particles on the surface of the magnesium-lithium alloy which are generated after the surface treatment of the magnesium-lithium alloy, are considered to be residual etching components generated by etching, and in order to prevent the generation of the particles, the excess is considered. It is necessary to limit the free fluorine component generated by the etching to a certain amount or less.
  • various influential factors such as composition near the surface, dirt, and pressing pressure can be considered, but in particular, a plurality of independent heights having a predetermined height on the surface of magnesium-lithium alloy It is effective to form a convex protrusion.
  • the free fluorine component is completely blocked to reduce the amount of particles generated on the surface of the magnesium-lithium alloy.
  • a plurality of independent convex projections having a predetermined height can be appropriately scattered on the surface of the magnesium-lithium alloy to set the surface electric resistance value low.
  • the longest separation distance ie, the linear distance between the most distant positions in a convex-shaped projection is 15 micrometers or more It is necessary to be formed so that
  • the number of convex projections needs to be 20 or more per unit area of 310 ⁇ m ⁇ 250 ⁇ m. If the number is less than 20, the surface electrical resistance can not be lowered.
  • the upper limit of the number of convex projections is not particularly limited, but if the amount of neutral ammonium fluoride is increased to increase the number of convex projections, the free fluorine component generated by excessive etching is obtained.
  • the convex projections 20 to 85, and more preferably 30 to 70, are ideally dispersed per unit area of 310 ⁇ m ⁇ 250 ⁇ m.
  • the immersion with the etching solution is preferably performed at a temperature of 35 ° C. to 70 ° C., preferably 55 ° C. to 65 ° C. If the temperature is less than 35 ° C., insufficient treatment, appearance defect, increase in surface electric resistance, decrease in coating film adhesion, etc. may occur. If it exceeds 70 ° C., surface roughening due to excessive treatment, dimensional defect, film corrosion resistance decrease, etc. May occur.
  • the immersion time is 0.5 to 2 minutes, more preferably 1 minute. If it is less than 0.5 minutes, insufficient treatment, an increase in surface electric resistance value, a decrease in coating film adhesion and the like may occur, and if it exceeds 2 minutes, the coating corrosion resistance may be reduced.
  • the alkaline aqueous solution After degreasing treatment with an alkaline aqueous solution, after performing a process for forming a convex protrusion with an etching solution having the above composition, the alkaline aqueous solution is again used to remove residual smut.
  • the surface conditioning treatment with this alkaline aqueous solution can be performed by a method such as immersion in a highly alkaline solution of sodium hydroxide or the like, as in the degreasing step.
  • sodium hydroxide it is preferably prepared as a highly alkaline solution at a concentration of 5 to 30% by weight.
  • the immersion time in the highly alkaline solution is preferably 0.5 to 10 minutes.
  • the immersion temperature is 45 to 70 ° C.
  • the concentration of the sodium hydroxide aqueous solution is less than 5% by mass, the immersion time is less than 0.5 minutes, or the temperature is less than 45 ° C., smut may remain and the coating corrosion resistance may be reduced. is there. Moreover, when the sodium hydroxide aqueous solution with a density
  • FAL free alkalinity
  • a step of film chemical conversion treatment is performed using a fluoride-containing chemical conversion solution. Corrosion resistance is enhanced by this process.
  • the step of film conversion treatment is obtained by immersing in a chemical conversion solution containing fluorine.
  • hydrofluoric acid sodium fluoride, hydrofluoric acid, sodium acid fluoride, potassium acid fluoride, ammonium acid fluoride, hydrofluoric acid and salts thereof, and fluoroboric acid
  • at least 1 sort (s) chosen from and its salt it is possible to obtain fluorine in a state of being sufficiently dissolved in the active state.
  • acid ammonium fluoride is particularly preferable.
  • the content of fluorine in the chemical conversion solution is preferably in the range of 3.33 to 40 g / liter. More preferably, it is 8.0 to 30.0 g / liter. If the content of fluorine is less than 3.33 g / liter, the amount of adhesion of the film may be insufficient, the corrosion resistance of the film may be reduced, etc., and if it exceeds 40 g / liter, the surface electrical resistance increases, and the coating film adhesion This may cause a decrease in
  • the concentration of the acid in the chemical conversion solution is adjusted so that the free acidity (FA) is in the range of 8.0 to 12.0 points. If it is less than 8.0 points, the amount of adhesion of the film may be insufficient, the corrosion resistance of the film may be deteriorated, etc. If it exceeds 12.0 points, the surface electric resistance may be increased, the adhesion of the coating film may be deteriorated, etc. It is because there is.
  • FA free acidity
  • the film conversion treatment with the chemical conversion solution can be carried out by a general method capable of bringing the treatment solution into contact with the surface of the magnesium-lithium alloy for a predetermined time, such as immersing the magnesium-lithium alloy in the chemical conversion solution.
  • the chemical conversion treatment solution is preferably performed at a temperature of 40 to 80 ° C., preferably about 55 to 65 ° C. This is to make the chemical reaction between magnesium and lithium and fluorine rapidly and favorably.
  • the immersion time is preferably 0.5 to 5 minutes, more preferably about 1.5 to 4.5 minutes. This is to produce magnesium fluoride and lithium fluoride on the surface of the magnesium-lithium alloy and to fully exert its combined action. If the immersion time is less than 0.5 minutes, the coating adhesion may be insufficient, the corrosion resistance of the film may be reduced, etc. If the immersion time is more than 5 minutes, the surface electrical resistance may be increased due to the excessive treatment, and the coating adhesion may be reduced. And so on.
  • the chemical conversion solution further contains at least one or more organic compounds selected from polyallylamine, polyallylamine partial carponylation, polyacrylic acid and polyacrylamide.
  • organic compounds selected from polyallylamine, polyallylamine partial carponylation, polyacrylic acid and polyacrylamide.
  • polyallylamine is particularly preferable. That is, in the case of a magnesium-lithium alloy, there is a concern that the coating performance (particularly the durability) may be reduced due to the components of the magnesium-lithium alloy when the film conversion treatment is performed with the above-described chemical conversion solution.
  • the adhesion performance of the coating film can be improved when painting is performed by adding at least one or more organic compounds selected from allylamine, polyallylamine partial carpenylation, polyacrylic acid and polyacrylamide. Become.
  • the amount of the organic compound added is preferably 50 to 5,000 mg / liter, more preferably 2,000 to 4,000 mg / liter, in the chemical conversion treatment solution.
  • the film conversion treatment step with the chemical conversion solution after the degreasing, the treatment step with the etching solution and the surface conditioning treatment.
  • the degreasing, the treatment process with the etching solution, the surface conditioning treatment, and the film conversion treatment are individually performed, and a water washing treatment is performed between each treatment.
  • the magnesium-lithium alloy surface-treated by the method of the present invention can maintain good adhesion to the coating film formed on the surface thereof.
  • This coating process can be performed after the process of water washing and drying after the surface conditioning process of the present invention described above.
  • the coating method can be a method such as primer treatment by epoxy cation electrodeposition coating, topcoat treatment by melamine resin or the like, general baking coating, or the like.
  • the magnesium-lithium alloy surface-treated by the method of the present invention not only provides excellent corrosion resistance, but also has a strength of adhesive strength 7.02 ⁇ 1 N / cm, weight 2 kg, diameter 85 mm, width 45 mm
  • the amount of particles transferred to the tape can be made to be 2.0 mg / m 2 or less when pressure-bonded by the pressure-bonding roller and then peeled off at a peeling angle of 90 degrees with respect to the pressure-bonded surface.
  • the magnesium-lithium alloy has 240 g of A probe (manufactured by Mitsubishi Chemical Analytech Co., Ltd.) with a cylindrical two-point probe (contact surface area 3.14 mm 2 of one needle) of 10 mm between pins and 2 mm in pin tip diameter.
  • the surface electrical resistance value of the ammeter can be made 1 ⁇ or less when pressed against the surface by a load of
  • the surface electrical resistance value of the ammeter when this probe is pressed with a load of 60 g can be 10 ⁇ or less, and can be 1 ⁇ or less when adjusted to preferable conditions.
  • the load of 240 g assumes a fixing force when grounding to a magnesium-lithium alloy by screwing
  • the load of 60 g assumes a fixing force when grounding by a tape fixing to the surface of a magnesium-lithium alloy doing.
  • magnesium-lithium alloys obtained by performing the surface treatment according to the method of the present invention have high electromagnetic wave shielding properties and substrates, such as mobile phones, laptop computers, mobile translators, video cameras, digital cameras, etc. It can be effectively used as various electronic device housing parts which are required to have a low surface electric resistance value in order to provide a ground.
  • the surface treatment according to the method of the present invention can maintain excellent corrosion resistance and low surface electric resistance even if the obtained rolled material is subjected to pressing after processing after being applied to a rolled material of magnesium-lithium alloy. it can. Therefore, the surface treatment according to the method of the present invention may be performed on the magnesium-lithium alloy in the state of parts after pressing, or on the magnesium-lithium alloy in the state of the rolled material before processing. It may be one.
  • the magnesium-lithium alloy thus obtained is to be coated in a later step, it is selected from the above-mentioned polyallylamine, polyallylamine partial carponylation, polyacrylic acid and polyacrylamide in the chemical conversion solution. If chemical conversion treatment is performed by adding at least one or more organic compounds, the adhesion of the coating film can be improved and the coating film durability can be enhanced. Therefore, in the case of the various electronic device case components as described above, it is possible to ground the inside of the case and to coat the outer surface of the case, which can be suitably used.
  • the surface treatment method of magnesium-lithium alloy of the present invention As described above, according to the surface treatment method of magnesium-lithium alloy of the present invention, independent convex projections having a longest separation distance of 15 ⁇ m or more in plan view are made 310 ⁇ m ⁇ 250 ⁇ m square on the surface of magnesium-lithium alloy. 20 or more can be scattered per unit area of Therefore, the magnesium-lithium alloy treated by this surface treatment method can be used without causing a problem of contamination even when it is used for the casing of various electronic devices.
  • the magnesium-lithium alloy treated by this surface treatment method can lower the surface electric resistance value, in addition to the advantages such as the ultra-light weight possessed by the magnesium-lithium alloy and the reduction in processing cost due to cold pressing. , It becomes possible to use for the electronic equipment case parts which electromagnetic wave shielding property is called for, or it is necessary to take the earth from a substrate. Furthermore, the magnesium-lithium alloy treated by this surface treatment method can improve the adhesion of the coating when the surface is coated.
  • Examples 1 to 7, Comparative Examples 1 to 24 A 50 mm long, 50 mm wide, and 0.8 mm thick rolled material consisting of magnesium-lithium alloy ("LZ91 material” manufactured by Nippon Metals Co., Ltd .: lithium 9% by mass, zinc 1% by mass, remaining magnesium) as an object to be treated Were prepared as test pieces.
  • LZ91 material manufactured by Nippon Metals Co., Ltd .: lithium 9% by mass, zinc 1% by mass, remaining magnesium
  • this test piece was subjected to a degreasing treatment by being immersed for 8 minutes in a strong alkaline aqueous solution (Million Chemical Co., Ltd .: 30% aqueous solution of GFMG15SX, trade name) maintained at a liquid temperature of 80 ° C.
  • a strong alkaline aqueous solution Million Chemical Co., Ltd .: 30% aqueous solution of GFMG15SX, trade name
  • test pieces after the degreasing treatment were washed with water and then subjected to an etching treatment step with an etching treatment solution in which each additive shown in Table 1 was added to an aqueous solution containing 19 g / liter of phosphoric acid.
  • This etching process was carried out by immersing the test piece for 120 seconds in each etching solution maintained at 60 ° C.
  • test piece was subjected to surface conditioning treatment by being immersed in a strong alkaline aqueous solution (manufactured by Million Chemical Co., Ltd .: 45% aqueous solution of GFMG15SX under the trade name GFMG15SX) whose liquid temperature was kept at 60 ° C. for 2 minutes after water washing.
  • a strong alkaline aqueous solution manufactured by Million Chemical Co., Ltd .: 45% aqueous solution of GFMG15SX under the trade name GFMG15SX
  • test piece was washed with water, it was immersed in a chemical conversion treatment solution consisting of an aqueous solution containing ammonium acid fluoride under conditions of 60 ° C. and 180 seconds.
  • the chemical conversion solution was used by adjusting the amount of fluorine in ammonium acid fluoride to 13.33 g / liter.
  • test pieces obtained through the water washing and drying steps were prepared for one condition, and two of them were evaluated for surface particle generation amount and surface electric resistance, respectively. Also, the appearance of the film was observed visually. The results are shown in Table 1.
  • test piece (Example 1-Example 5) which performed the etching process by the etching process liquid which used neutral ammonium fluoride in a favorable range, and the etching which used neutral ammonium fluoride out of a favorable range
  • test pieces (Comparative Examples 15 to 20) subjected to the etching treatment with the treatment liquid and the test pieces subjected to the etching treatment with the treatment liquid not containing neutral ammonium fluoride (Comparative Example 1)
  • the formation state of the convex part of the surface of the obtained test piece was evaluated.
  • each evaluation in a present Example and a comparative example was performed as follows.
  • -Evaluation of particle generation rate- A tape with a width of 12 mm having an adhesion strength of 7.02 ⁇ 1 N / cm at a 180 ° angle to a stainless steel plate according to the method defined in Japanese Industrial Standard JIS 1522 on the surface of a test piece is Japanese Industrial Standard JIS Crimping was performed using a crimping roller having a mass of 2 kg, a diameter of 85 mm, and a width of 45 mm defined in Z0237.
  • the pressure-bonded tape was peeled off at an angle of 90 degrees by the adhesion test method defined by Japanese Industrial Standard JIS Z 0237.
  • the amount of Mg adhering to the adhesive surface of the peeled tape was quantitatively measured by a fluorescent X-ray analyzer.
  • the X-ray fluorescence analyzer used was a scanning X-ray fluorescence analyzer ZSX Primusll, and a calibration curve was prepared by dusting magnesium nitrate on the adhesive surface of a specified amount of tape per a fixed area of 10 mm in diameter. The same test piece was measured three times. In addition, the 90 degree tensile strength at the time of tape peeling was also measured for reference.
  • the case where the quantified powdery particles are less than 0.5 mg / m 2 is “ ⁇ ”, and the case where 0.5 mg / m 2 to less than 20.0 mg / m 2 is “ ⁇ ”, 20.
  • the case of 0 mg / m 2 or more was regarded as “x”.
  • -Surface electrical resistance The surface electrical resistance value is determined by using Loresta EP 2 probe A probe (Mitsubishi Chemical Analytech Co., Ltd .: 10 mm between pins, pin tip diameter 2.0 mm (contact surface area of one needle 3.14 mm 2 ), spring pressure 240 g) The surface electrical resistance value was measured by pressing the pins to the central part, the upper part, and the lower part of the surface of the test piece. The measurement was performed three times for one test piece to obtain the average value.
  • the measured value of 240 g is measured by pressing the surface of the test piece until the pin of the 2-probe probe is retracted against the spring pressure. The case was marked as “x” if it became impossible to measure " ⁇ ⁇ ", 100 ⁇ or more, or even once.
  • the measured value of 240 g assumes the case where screw fixation of the earth is carried out to a member surface, and taking it.
  • -Coating film corrosion resistance test The coated test pieces were cut with a cutter knife to prepare. The solution was put into a test tank set at 35 ° C. by a salt spray test method (SST test) according to JIS Z 2371, sprayed with a 5% saline solution, and taken out after 240 hours. After the surface was washed with water and dried, a tape was attached to the dried coated film cut and peeled off, and the one-side maximum peeling width (mm) after peeling of the tape was measured.
  • SST test salt spray test method
  • -Coating film moisture resistance test The coated test piece was placed in boiling (100 ° C.) hot water and immersed for 60 minutes, then the test piece was taken out, the surface was wiped off, and left at room temperature for 1 hour. Thereafter, a 1 mm grid-like cut was made on the surface of the test piece, a tape was attached to the surface and peeled off, and the area of the peeled coating was measured.
  • the convex projections make it possible to compare an electron micrograph taken from directly above with an electron micrograph taken at an oblique 45 ° photographing angle. The number of convex projections was counted in an electron micrograph taken at an oblique 45 degree photographing angle.
  • Example 1 A chemical conversion treatment solution containing 13.33 g / l of ammonium acid fluoride for which good results were obtained in Example 1, and a chemical conversion treatment solution containing polyallylamine in the respective compounding amounts shown in Table 7 in the same chemical conversion treatment solution ( Each of the test pieces was treated in the same manner as in Example 1 using Examples 8 to 10).
  • Each test piece that has been subjected to water washing and drying steps is coated with an epoxy primer (product of Dainippon Paint Co., Ltd .: Primer MG-GUARD # 1-SP) to a film thickness of 12.5 ⁇ 2.5 mm, and then 160 ° C ⁇ After baking for 20 minutes and allowing to cool, an acrylic topcoat (made by Dainippon Paint Co., Ltd .: Topcoat Maglac # 636) is applied at a thickness of 12.5 ⁇ 2.5 mm, and then 160 ° C ⁇ 20 minutes We baked and painted.
  • an epoxy primer product of Dainippon Paint Co., Ltd .: Primer MG-GUARD # 1-SP
  • an acrylic topcoat made by Dainippon Paint Co., Ltd .: Topcoat Maglac # 636
  • test piece was immersed in a container containing tap water, and left in a thermostatic bath maintained at 60 ° C. for 24 hours. Then, after taking out the test piece and wiping off the moisture on the surface, it was allowed to stand under a room temperature atmosphere for 1 hour, and then a cross cut test of 100 squares in accordance with JIS 5400 was performed. In this test, in addition to the immersion for 24 hours, after the immersion, the surface moisture is wiped off and left for 1 month under normal temperature indoor environment atmosphere, then left for 2 months and left for 3 months. Later, a cross cut test of 100 squares in accordance with JIS 5400 was performed. After the test, the surface of each test piece was confirmed and evaluated. The details and evaluation criteria of the crosscut test are as follows.
  • test piece according to the present invention is less likely to generate particles that cause contamination, has a low surface electrical resistance value, and can provide excellent bare corrosion resistance and coating adhesion. Moreover, when polyallylamine was added to the chemical conversion treatment liquid, it has been confirmed that the durability of the coating film is improved.

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Abstract

[Problem] To provide: a method for forming a coating which exhibits excellent undercoat performance and bare corrosion resistance, does not give rise to the problem of contamination by particles, and is capable of achieving low electrical resistance; and a magnesium-lithium alloy obtained using the method. [Solution] A surface-treatment method of a magnesium-lithium alloy involves a process in which the surface of the magnesium-lithium alloy is treated with an etching solution comprising an aqueous solution of phosphoric acid containing 150-500ppm of neutral ammonium fluoride. The surface-treatment method of the magnesium-lithium alloy further involves a chemical conversion coating process in which, after surface conditioning is carried out, the alloy is dipped in an aqueous solution containing 3.33-40g/l of acidic ammonium fluoride (with polyallylamine [50-5000ppm] being further added in some instances). Provided is the magnesium-lithium alloy obtained using the above treatment method.

Description

マグネシウム－リチウム合金およびその表面処理方法Magnesium-lithium alloy and its surface treatment method
　本発明は、マグネシウム－リチウム合金と、その表面処理方法とに関するものである。より具体的には、耐食性に優れ、かつ、パーティクルの発生がない表面を形成することができ、かつ、表面電気抵抗値を低くすることができるマグネシウム－リチウム合金と、その表面処理方法に関するものである。 The present invention relates to a magnesium-lithium alloy and its surface treatment method. More specifically, the present invention relates to a magnesium-lithium alloy that can form a surface that is excellent in corrosion resistance and does not generate particles, and can reduce the surface electrical resistance value, and a surface treatment method thereof. is there.
　マグネシウム合金は、物理的強度、軽量性、リサイクル性、電磁波シールド性、熱放散性、寸法安定性などが優れている。その中でも、鉄やアルミニウム等の合金と同様に展伸性が向上し、常温でプレスが可能な素材として、リチウムを含有したマグネシウム－リチウム合金は、様々な分野で利用することが行われている。しかし、マグネシウム－リチウム合金は、一般的なマグネシウム合金よりも耐食性が低く、そのままでは実用に耐えられないケースが多い。 Magnesium alloys are excellent in physical strength, lightness, recyclability, electromagnetic wave shielding, heat dissipation, dimensional stability and the like. Among them, magnesium-lithium alloy containing lithium is used in various fields as a material which has the same ductility as iron, aluminum and the like, and can be pressed at normal temperature. . However, magnesium-lithium alloys have lower corrosion resistance than common magnesium alloys and in many cases can not withstand practical use as they are.
　そこで、従来より、マグネシウム－リチウム合金の耐食性を向上させるとともに、低電気抵抗を実現する表面処理方法として、本発明者等は、アルミニウムおよび亜鉛の金属イオンを含有する無機酸の処理液によってマグネシウム－リチウム合金の表面処理を行う方法を提案している（例えば、特許文献１、２参照）。 Therefore, conventionally, as a surface treatment method for achieving low electrical resistance while improving the corrosion resistance of magnesium-lithium alloys, the present inventors et al. Have studied magnesium- with a treatment solution of an inorganic acid containing metal ions of aluminum and zinc. A method for performing surface treatment of lithium alloy is proposed (see, for example, Patent Documents 1 and 2).
特開２０１１－５８０７４号公報JP 2011-58074 A 特開２０１１－５８０７５号公報JP 2011-58075 A
　しかし、上記従来の表面処理方法の場合、形成された化成皮膜の表面に、化成処理由来のパーティクルが発生することがあり、このパーティクルが低電気抵抗値を阻害することとなるため、当該パーティクルが発生した場合には、表面処理後にこのパーティクルの拭き取り作業をする必要があった。 However, in the case of the above-mentioned conventional surface treatment method, particles derived from the chemical conversion treatment may be generated on the surface of the formed chemical conversion film, and the particles inhibit the low electric resistance value. If it occurs, it is necessary to wipe off the particles after the surface treatment.
　また、このように表面処理したマグネシウム－リチウム合金を、携帯電話やパーソナルコンピュータ等の筐体に使用するような場合、化成皮膜の表面に発生したパーティクルを十分に拭き取りしていなければ、当該パーティクルが筐体内で飛散してコンタミネーションの原因となり、当該筐体内の電子機器に悪影響を及ぼしてしまうといった不都合を生じることとなる。 In addition, when the magnesium-lithium alloy thus surface-treated is used in a casing of a mobile phone, a personal computer, etc., the particles are not sufficiently wiped off the particles generated on the surface of the chemical conversion film. It scatters within the case to cause contamination, which may adversely affect the electronic devices in the case.
　そのため、パーティクルが発生しない表面処理条件で化成皮膜を形成することが考えられるが、パーティクルが発生しない条件の化成皮膜は、当該化成皮膜の形成も不十分となっていた。したがって、化成皮膜が十分に形成されて耐食性が良く、パーティクルの発生がなく、しかも、低電気抵抗値を達成することはできなかった。 Therefore, it is conceivable to form a chemical conversion film under surface treatment conditions in which no particles are generated, but the chemical conversion film in the condition in which particles are not generated is insufficient in the formation of the chemical conversion film. Therefore, the chemical conversion film was sufficiently formed, corrosion resistance was good, particles were not generated, and it was not possible to achieve low electric resistance value.
　本発明は、係る実情に鑑みてなされたものであって、塗装下地性能や裸耐食性に優れ、パーティクルによるコンタミネーションの問題を生じることがなく、低電気抵抗を実現することができる皮膜を形成する方法と、それによって得られるマグネシウム－リチウム合金とを提供することを目的としている。 The present invention has been made in view of such circumstances, and is excellent in coating base performance and bare corrosion resistance, and does not cause the problem of contamination due to particles, and forms a film capable of realizing low electrical resistance. The object is to provide a method and a magnesium-lithium alloy obtained thereby.
　上記課題を解決するための本発明のマグネシウム－リチウム合金の表面処理方法は、マグネシウム－リチウム合金の表面を、リン酸に１５０～５００ｐｐｍの中性フッ化アンモニウムを含有した水溶液からなるエッチング処理液で処理する工程を具備するものである。 The surface treatment method of magnesium-lithium alloy according to the present invention for solving the above problems is characterized in that the surface of magnesium-lithium alloy is an etching solution comprising an aqueous solution containing 150 to 500 ppm of neutral ammonium fluoride in phosphoric acid. It comprises the process to process.
　上記マグネシウム－リチウム合金の表面処理方法において、エッチング処理液で処理する工程の後、アルカリ系水溶液に浸漬してスマットの残留分を除去する表面調整処理を行った後、フッ素として３．３３～４０ｇ／リットルのフッ素化合物を含有する化成処理液に浸漬して皮膜化成処理する工程をさらに具備するものであってもよい。 In the above surface treatment method of magnesium-lithium alloy, after the step of treating with an etching solution, after being subjected to a surface conditioning treatment of removing the remaining portion of the smut by immersing in an alkaline aqueous solution, 3.33 to 40 g as fluorine The method may further include a step of film formation treatment by immersing in a chemical conversion treatment solution containing 1 / liter of a fluorine compound.
　この化成処理液としては、上記化成処理液に、さらに、ポリアリルアミン、ポリアリルアミン部分カルポニル化、ポリアクリル酸、ポリアクリルアミドの中から選択される１種以上が５０～５０００ｐｐｍの濃度で含有されたものを使用するものであってもよい。 As this chemical conversion treatment liquid, one containing one or more selected from polyallylamine, polyallylamine partial carponylation, polyacrylic acid and polyacrylamide at a concentration of 50 to 5000 ppm in the above chemical conversion treatment liquid May be used.
　上記課題を解決するための本発明のマグネシウム－リチウム合金は、上記の表面処理方法によって得られるものである。 The magnesium-lithium alloy of the present invention for solving the above problems is obtained by the above surface treatment method.
　上記マグネシウム－リチウム合金は、表面に平面視１５μｍ以上の最長離隔間距離を持つ独立した凸状突起が３１０μｍ×２５０μｍ四方の単位面積あたりに２０個以上散在しているものである。 The magnesium-lithium alloy has 20 or more independent convex projections having a longest separation distance of 15 μm or more in plan view scattered on the surface per unit area of 310 μm × 250 μm square.
　上記マグネシウム－リチウム合金は、粘着力７．０２±１Ｎ／ｃｍの強度を有するテープを、質量２ｋｇ、直径８５ｍｍ、幅４５ｍｍの圧着ローラにより圧着し、その後、圧着面に対して９０度の引き剥がし角度で引き剥がした際に、テープに移行したパーティクルの量が２．０ｍｇ／ｍ２以下となされたものである。 In the magnesium-lithium alloy, a tape having a strength of adhesive strength 7.02 ± 1 N / cm is crimped by a crimping roller with a mass of 2 kg, a diameter of 85 mm, and a width of 45 mm, and then peeled off by 90 degrees with respect to the crimping surface When peeled off at an angle, the amount of particles transferred to the tape is made to be 2.0 mg / m 2 or less.
　上記マグネシウム－リチウム合金は、ピン間１０ｍｍ、ピン先直径２ｍｍの円柱状２探針プローブ（１針の接触表面積３．１４ｍｍ２）を、２４０ｇの荷重で表面に押圧した時の電流計の表面電気抵抗値が１Ω以下となされたものである。 The magnesium-lithium alloy has a surface electric current of an ammeter when a cylindrical two-point probe (contact surface area 3.14 mm 2 of one needle) with a pin distance of 10 mm and a pin tip diameter of 2 mm is pressed against the surface with a load of 240 g. The resistance value is 1 Ω or less.
　上記マグネシウム－リチウム合金は、マグネシウム－リチウム合金の表面に、エポキシ系プライマーを膜厚１２．５±２．５ｍｍの厚みで焼付塗布後、アクリル系トップコートを膜厚１２．５±２．５ｍｍの厚みで焼付塗布し、６０℃の温水に２４時間浸漬した後、水分を除去し常温の室内環境雰囲気下で１時間放置した後に、ＪＩＳ５４００に準拠した１００マスのクロスカット試験を行った際に、剥離するマス目を生じないものである。 The above magnesium-lithium alloy is coated with an epoxy-based primer to a film thickness of 12.5 ± 2.5 mm on the surface of magnesium-lithium alloy, and then an acrylic top coat is formed with a film thickness of 12.5 ± 2.5 mm. After baking coating with thickness, immersing in warm water at 60 ° C for 24 hours, removing moisture and leaving it for 1 hour under a room temperature atmosphere at normal temperature, when performing a cross cut test of 100 mass according to JIS 5400, It does not produce the square which peels off.
　本発明の処理対象となるマグネシウム－リチウム合金としては、冷間プレス加工に適合するリチウムを含有する種々のマグネシウム合金を用いることができる。例えば、先行技術文献に開示している各種のマグネシウム－リチウム合金を用いることができる。このマグネシウム－リチウム合金の大きさ、形状については特に限定されるものではない。好ましいマグネシウム－リチウム合金としては、リチウムを５～２０質量％、さらに好ましくは５～１６質量％含有し、残部がマグネシウムと不純物となされたものが挙げられる。具体的なマグネシウム－リチウム合金としては、リチウム９％、亜鉛１％、残部がマグネシウムと不純物となされたＬＺ９１材、リチウム７％、亜鉛１％、残部がマグネシウムと不純物となされたＬＺ７１材、リチウム７％、アルミニウム７％、亜鉛１％、残部がマグネシウムと不純物となされたＬＡＺ７７１材、リチウム７％、アルミニウム３％、亜鉛１％、残部がマグネシウムと不純物となされたＬＡＺ７３１材、リチウム７％、アルミニウム４％、亜鉛１％、残部がマグネシウムと不純物となされたＬＡＺ７４１材、リチウム１４％、アルミニウム１％、残部がマグネシウムと不純物となされたＬＡ１４１材、リチウム１４％、アルミニウム２％、残部がマグネシウムと不純物となされたＬＡ１４２材、リチウム１４％、アルミニウム３％、残部がマグネシウムと不純物となされたＬＡ１４３材、また、ＬＺ９１材にＣａが数％添加された合金、ＬＡＺ７４１材にＹが数％添加された合金、その他、マグネシウムとリチウムを主成分として１種または複数種の金属元素が添加された各種のリチウム－マグネシウム合金が挙げられる。 As magnesium-lithium alloys to be treated according to the present invention, various magnesium alloys containing lithium compatible with cold pressing can be used. For example, various magnesium-lithium alloys disclosed in the prior art can be used. The size and shape of the magnesium-lithium alloy are not particularly limited. Preferred magnesium-lithium alloys include those containing 5 to 20% by mass, more preferably 5 to 16% by mass of lithium, with the balance being magnesium and impurities. As a specific magnesium-lithium alloy, lithium 9%, zinc 1%, the balance is magnesium and LZ 91 made of impurities, lithium 7%, zinc 1%, the balance is magnesium and impurities made LZ 71, lithium 7 %, Aluminum 7%, zinc 1%, the balance is magnesium and impurities LAZ 771 material, lithium 7%, aluminum 3%, zinc 1%, the balance is magnesium and impurities LAZ 731 material, lithium 7%, aluminum 4 %, Zinc 1%, the balance is magnesium and impurities LAZ741 material, lithium 14%, aluminum 1%, the balance is magnesium and impurities LA141 material, lithium 14%, aluminum 2%, the balance is magnesium and impurities LA142 material made, 14% lithium, aluminum %, LA143 material containing the balance of magnesium and impurities, an alloy containing several percent of Ca added to LZ 91 material, an alloy containing several percent of Y added to LAZ 741, and others containing magnesium and lithium as main ingredients Or various lithium-magnesium alloys to which a plurality of metal elements are added.
　なお、マグネシウム－リチウム合金の極表層では、リチウムが多量に偏析しているため、その表面では非常に腐食し易い状態になっている。したがって、このマグネシウム－リチウム合金は、通常の化成処理でも行われているように、必要に応じて、脱脂工程、水洗工程、エッチング工程等を経て表面酸化物層や偏析層の除去等を行ってから使用される。 In addition, in the surface layer of the magnesium-lithium alloy, since lithium is segregated in a large amount, the surface is in a state of being very easily corroded. Therefore, this magnesium-lithium alloy is subjected to degreasing process, water washing process, etching process, etc., as required, to remove the surface oxide layer and segregation layer, etc., as in the case of ordinary chemical conversion treatment. Used from
　脱脂工程は、水酸化ナトリウム等による高アルカリ溶液中に浸漬させる等の方法によることができる。水酸化ナトリウムによる場合、好ましくは１～２０質量％の濃度の高アルカリ溶液として調製される。高アルカリ溶液中への浸漬時間は、１～１０分間であることが好ましい。水酸化ナトリウム水溶液の濃度が、１質量％未満であったり、浸漬時間が１分間未満であると、脱脂不足により外観不良を生じることとなる。また、２０質量％よりも高い濃度の水酸化ナトリウム水溶液を用いると、アルカリ残が原因となる白粉が発生する。なお、上記した水酸化ナトリウム水溶液以外の高アルカリ溶液を使用する場合は、遊離アルカリ度（ＦＡＬ）が２１．０～２４．０ポイントとなるように調整したものを用いることが好ましい。 The degreasing step can be performed by a method such as immersion in a highly alkaline solution of sodium hydroxide or the like. In the case of sodium hydroxide, it is preferably prepared as a highly alkaline solution at a concentration of 1 to 20% by weight. The immersion time in the highly alkaline solution is preferably 1 to 10 minutes. If the concentration of the sodium hydroxide aqueous solution is less than 1% by mass, or the immersion time is less than 1 minute, the appearance will be deteriorated due to insufficient degreasing. Moreover, when the sodium hydroxide aqueous solution with a density | concentration higher than 20 mass% is used, the white powder which causes alkali residue will generate | occur | produce. When using a highly alkaline solution other than the above-mentioned aqueous sodium hydroxide solution, it is preferable to use one adjusted to have a free alkalinity (FAL) of 21.0 to 24.0 points.
　エッチング処理液による処理工程は、主成分としてリン酸を９～３５ｇ／リットルの濃度とした水溶液に、１５０～５００ｍｇ／リットルの中性フッ化アンモニウムを含有させたエッチング処理液で、マグネシウム－リチウム合金を浸漬処理することによって行われる。このエッチング処理液で処理することにより、従来では得られなかった、パーティクルの発生が無いマグネシウム－リチウム合金を得ることができる。しかも、表面電気抵抗値を低くすることができ、優れた塗装性能、耐食性も得られる。 The processing step using an etching solution is an etching solution containing 150 to 500 mg / liter of neutral ammonium fluoride in an aqueous solution having a concentration of 9 to 35 g / liter of phosphoric acid as a main component, and a magnesium-lithium alloy By immersion treatment. By treating with this etching solution, it is possible to obtain a magnesium-lithium alloy free from particle generation, which has not been obtained conventionally. Moreover, the surface electrical resistance value can be lowered, and excellent coating performance and corrosion resistance can also be obtained.
　中性フッ化アンモニウムのエッチング処理液中の含有率は、１５０～５００ｍｇ／リットルであることが好ましく、より好ましくは、１５０～４００ｍｇ／リットルである。中性フッ化アンモニウムの含有量が、１５０ｍｇ／リットル未満の場合、マグネシウム－リチウム合金の表面に、表面電気抵抗値を低くするための微細な凸状突起を形成した化成処理膜を形成することができず、５００ｍｇ／リットルを超える場合、隣接する凸状突起同士が繋がって連続した突起となってしまうとともに、パーティクルの発生が多くなりすぎてしまう。 The content of neutral ammonium fluoride in the etching solution is preferably 150 to 500 mg / liter, more preferably 150 to 400 mg / liter. When the content of neutral ammonium fluoride is less than 150 mg / liter, a chemical conversion treatment film having fine convex projections for lowering the surface electric resistance value may be formed on the surface of a magnesium-lithium alloy. If the amount exceeds 500 mg / liter, adjacent convex projections will be connected to form continuous projections, and generation of particles will be excessive.
　エッチング処理液における無機酸の濃度は、遊離酸度（ＦＡ）が９．０～１２．０ポイントの範囲となるように調整する。９．０ポイント未満であると、処理不足、外観不良、表面電気抵抗値の上昇、塗膜密着性の低下などを生じることがあり、１２．０ポイントを超えると、過剰処理による肌荒れ、寸法不良、皮膜耐食性低下などを生じることがある。この際、無機酸において、リン酸が主成分となるように、エッチング処理液中、９～３５ｇ／リットルの濃度でリン酸を使用する。 The concentration of the inorganic acid in the etching solution is adjusted so that the free acidity (FA) is in the range of 9.0 to 12.0 points. If it is less than 9.0 points, insufficient treatment, appearance defect, increase in surface electric resistance value, decrease in coating film adhesion, etc. may occur, and if it exceeds 12.0 points, surface roughening due to excessive treatment, dimensional defect And corrosion resistance of the coating may occur. At this time, phosphoric acid is used at a concentration of 9 to 35 g / liter in the etching solution so that phosphoric acid is the main component in the inorganic acid.
　マグネシウム－リチウム合金を表面処理した後に生じる、当該マグネシウム－リチウム合金の表面におけるパーティクルは、エッチングで発生した過剰エッチング成分が残留したものと考えられ、このパーティクルの発生を防止するためには、この過剰エッチングによって発生する遊離フッ素成分を一定量以下に制限する必要がある。一方、表面電気抵抗値を低くするためには、表面近傍の組成、汚れ、押し圧など様々な影響因子が考えられるが、特にマグネシウム－リチウム合金の表面に、所定高さがある複数の独立した凸状突起を形成することが有効である。これらのことから、中性フッ化アンモニウムを一定量の範囲の量に制御することで、遊離フッ素成分を完全に封鎖して、マグネシウム－リチウム合金の表面に発生するパーティクルの量を低減させるとともに、マグネシウム－リチウム合金の表面に、所定高さがある複数の独立した凸状突起を適度に散在した状態で形成して表面電気抵抗値を低く設定できることとなる。この際、凸状突起は、小さすぎると表面電気抵抗値を低くするために有効なものとならないので、最長離隔間距離、すなわち、凸状突起における最も離れた位置の間の直線距離が１５μｍ以上となるように形成されたものであることが必要である。また、凸状突起の数としては、３１０μｍ×２５０μｍ四方の単位面積あたりに２０個以上散在している必要がある。２０個未満の場合は、表面電気抵抗値を低くすることができなくなる。なお、この凸状突起の数の上限については、特に限定されるものではないが、凸状突起の数を増やそうとして中性フッ化アンモニウムの量を増やすと、過剰エッチングで発生した遊離フッ素成分がパーティクルとなってマグネシウム－リチウム合金の表面に発生し易くなるとともに隣接する凸状突起同士が繋がってしまい、独立した凸状突起が形成され難くなる。したがって、凸状突起としては、３１０μｍ×２５０μｍ四方の単位面積あたりに２０個～８５個、より好ましくは、３０個～７０個が理想的な散在状態となる。 The particles on the surface of the magnesium-lithium alloy, which are generated after the surface treatment of the magnesium-lithium alloy, are considered to be residual etching components generated by etching, and in order to prevent the generation of the particles, the excess is considered. It is necessary to limit the free fluorine component generated by the etching to a certain amount or less. On the other hand, in order to lower the surface electrical resistance value, various influential factors such as composition near the surface, dirt, and pressing pressure can be considered, but in particular, a plurality of independent heights having a predetermined height on the surface of magnesium-lithium alloy It is effective to form a convex protrusion. From these facts, by controlling the neutral ammonium fluoride to a certain range of amount, the free fluorine component is completely blocked to reduce the amount of particles generated on the surface of the magnesium-lithium alloy. A plurality of independent convex projections having a predetermined height can be appropriately scattered on the surface of the magnesium-lithium alloy to set the surface electric resistance value low. Under the present circumstances, since a convex-shaped projection will not become effective in lowering surface electric resistance value if it is too small, the longest separation distance, ie, the linear distance between the most distant positions in a convex-shaped projection is 15 micrometers or more It is necessary to be formed so that In addition, the number of convex projections needs to be 20 or more per unit area of 310 μm × 250 μm. If the number is less than 20, the surface electrical resistance can not be lowered. The upper limit of the number of convex projections is not particularly limited, but if the amount of neutral ammonium fluoride is increased to increase the number of convex projections, the free fluorine component generated by excessive etching is obtained. As particles are likely to be generated on the surface of the magnesium-lithium alloy and adjacent convex projections are connected to each other, it becomes difficult to form independent convex projections. Therefore, as the convex projections, 20 to 85, and more preferably 30 to 70, are ideally dispersed per unit area of 310 μm × 250 μm.
　上記エッチング処理液による浸漬は、３５℃～７０℃、好ましくは５５～６５℃の温度状態として行うのが好ましい。３５℃未満であると、処理不足、外観不良、表面電気抵抗値の上昇、塗膜密着性低下などを生じることがあり、７０℃を越えると、過剰処理による肌荒れ、寸法不良、皮膜耐食性低下などを生じることがある。また、浸漬時間は、０．５～２分間、より好ましくは１分間である。０．５分間未満であると、処理不足、表面電気抵抗値の上昇、塗膜密着性低下などを生じることがあり、２分を越えると、皮膜耐食性が低下することがある。 The immersion with the etching solution is preferably performed at a temperature of 35 ° C. to 70 ° C., preferably 55 ° C. to 65 ° C. If the temperature is less than 35 ° C., insufficient treatment, appearance defect, increase in surface electric resistance, decrease in coating film adhesion, etc. may occur. If it exceeds 70 ° C., surface roughening due to excessive treatment, dimensional defect, film corrosion resistance decrease, etc. May occur. The immersion time is 0.5 to 2 minutes, more preferably 1 minute. If it is less than 0.5 minutes, insufficient treatment, an increase in surface electric resistance value, a decrease in coating film adhesion and the like may occur, and if it exceeds 2 minutes, the coating corrosion resistance may be reduced.
　アルカリ系水溶液による脱脂処理の後、以上の組成で構成されるエッチング処理液により凸状突起を形成するための工程を行った後、スマットの残留分を除去するために、再度、アルカリ系水溶液により表面調整処理を実施する。このアルカリ系水溶液による表面調整処理は、脱脂工程と同様に、水酸化ナトリウム等による高アルカリ溶液中に浸漬させる等の方法によることができる。水酸化ナトリウムによる場合、好ましくは５～３０質量％の濃度の高アルカリ溶液として調製される。高アルカリ溶液中への浸漬時間は、０．５～１０分間であることが好ましい。また、浸漬温度は４５～７０℃である。水酸化ナトリウム水溶液の濃度が、５質量％未満であったり、浸漬時間が０．５分間未満であったり、温度が４５℃未満の場合は、スマットが残留し、皮膜耐食性が低下する可能性がある。また、３０質量％よりも高い濃度の水酸化ナトリウム水溶液を用いると、アルカリ残が原因となる白粉が発生する可能性がある。なお、上記した水酸化ナトリウム水溶液以外の高アルカリ溶液を使用する場合は、遊離アルカリ度（ＦＡＬ）が３１．５～３５．５ポイントとなるように調整したものを用いることが好ましい。 After degreasing treatment with an alkaline aqueous solution, after performing a process for forming a convex protrusion with an etching solution having the above composition, the alkaline aqueous solution is again used to remove residual smut. Implement surface conditioning treatment. The surface conditioning treatment with this alkaline aqueous solution can be performed by a method such as immersion in a highly alkaline solution of sodium hydroxide or the like, as in the degreasing step. In the case of sodium hydroxide, it is preferably prepared as a highly alkaline solution at a concentration of 5 to 30% by weight. The immersion time in the highly alkaline solution is preferably 0.5 to 10 minutes. The immersion temperature is 45 to 70 ° C. If the concentration of the sodium hydroxide aqueous solution is less than 5% by mass, the immersion time is less than 0.5 minutes, or the temperature is less than 45 ° C., smut may remain and the coating corrosion resistance may be reduced. is there. Moreover, when the sodium hydroxide aqueous solution with a density | concentration higher than 30 mass% is used, the white powder which causes alkali residue may generate | occur | produce. When using a highly alkaline solution other than the above-mentioned sodium hydroxide aqueous solution, it is preferable to use one adjusted to have a free alkalinity (FAL) of 31.5 to 35.5 points.
　この表面調整処理の後に、フッ化物を含有する化成処理液により、皮膜化成処理する工程を行う。この工程によって耐食性が強化される。 After the surface conditioning treatment, a step of film chemical conversion treatment is performed using a fluoride-containing chemical conversion solution. Corrosion resistance is enhanced by this process.
　皮膜化成処理する工程は、フッ素を含有する化成処理液に浸漬することによって得られる。 The step of film conversion treatment is obtained by immersing in a chemical conversion solution containing fluorine.
　この化成処理液中のフッ素としては、フッ酸、フッ化ナトリウム、フッ化水素酸、酸性フッ化ナトリウム、酸性フッ化カリウム、酸性フッ化アンモニウム、ケイフッ化水素酸およびその塩、ならびにホウフッ化水素酸およびその塩から選ばれる少なくとも１種から供給されることが好ましい。これらの化合物によれば、フッ素が活性状態で十分に溶け込んだものとして得ることができるからである。この中でも特に、酸性フッ化アンモニウムが好ましい。 As fluorine in this chemical conversion treatment solution, hydrofluoric acid, sodium fluoride, hydrofluoric acid, sodium acid fluoride, potassium acid fluoride, ammonium acid fluoride, hydrofluoric acid and salts thereof, and fluoroboric acid It is preferable to supply from at least 1 sort (s) chosen from and its salt. According to these compounds, it is possible to obtain fluorine in a state of being sufficiently dissolved in the active state. Among these, acid ammonium fluoride is particularly preferable.
　化成処理液におけるフッ素の含有量は、好ましくは３．３３～４０ｇ／リットルの範囲の割合である。より好ましくは８．０～３０．０ｇ／リットルである。フッ素の含有量が３．３３ｇ／リットル未満であると、皮膜付着量不足、皮膜耐食性低下などを生じることがあり、また、４０ｇ／リットルを超えると、表面電気抵抗値の上昇、塗膜密着性の低下などを生じることがあるからである。 The content of fluorine in the chemical conversion solution is preferably in the range of 3.33 to 40 g / liter. More preferably, it is 8.0 to 30.0 g / liter. If the content of fluorine is less than 3.33 g / liter, the amount of adhesion of the film may be insufficient, the corrosion resistance of the film may be reduced, etc., and if it exceeds 40 g / liter, the surface electrical resistance increases, and the coating film adhesion This may cause a decrease in
　化成処理液における酸の濃度は、遊離酸度（ＦＡ）が８．０～１２．０ポイントの範囲となるように調整する。８．０ポイント未満であると、皮膜付着量不足、皮膜耐食性低下などを生じることがあり、１２．０ポイントを超えると、表面電気抵抗値の上昇、塗膜密着性の低下などを生じることがあるからである。 The concentration of the acid in the chemical conversion solution is adjusted so that the free acidity (FA) is in the range of 8.0 to 12.0 points. If it is less than 8.0 points, the amount of adhesion of the film may be insufficient, the corrosion resistance of the film may be deteriorated, etc. If it exceeds 12.0 points, the surface electric resistance may be increased, the adhesion of the coating film may be deteriorated, etc. It is because there is.
　化成処理液による皮膜化成処理は、マグネシウム－リチウム合金を化成処理液中に浸漬する等、処理液をマグネシウム－リチウム合金の表面に一定時間接触させることができる一般的な方法によって行うことができる。 The film conversion treatment with the chemical conversion solution can be carried out by a general method capable of bringing the treatment solution into contact with the surface of the magnesium-lithium alloy for a predetermined time, such as immersing the magnesium-lithium alloy in the chemical conversion solution.
　上記した浸漬する方法による場合、化成処理液は、４０～８０℃、好ましくは約５５～６５℃の温度状態で行われるのが好ましい。マグネシウム及びリチウムと、フッ素との化学反応を迅速かつ良好に行わせるためである。また、浸漬時間は、好ましくは０．５～５分間、より好ましくは約１．５～４．５分間である。マグネシウム－リチウム合金の表面にフッ化マグネシウム及びフッ化リチウムを生じさせると共に、その複合作用を十分に発揮させるためである。浸漬時間が０．５分間未満であると、皮膜付着量不足、皮膜耐食性低下などを生じることがあり、５分間を超えると、過剰処理のため表面電気抵抗値の上昇、塗膜密着性の低下などを生じることがある。 In the case of the above-described immersion method, the chemical conversion treatment solution is preferably performed at a temperature of 40 to 80 ° C., preferably about 55 to 65 ° C. This is to make the chemical reaction between magnesium and lithium and fluorine rapidly and favorably. The immersion time is preferably 0.5 to 5 minutes, more preferably about 1.5 to 4.5 minutes. This is to produce magnesium fluoride and lithium fluoride on the surface of the magnesium-lithium alloy and to fully exert its combined action. If the immersion time is less than 0.5 minutes, the coating adhesion may be insufficient, the corrosion resistance of the film may be reduced, etc. If the immersion time is more than 5 minutes, the surface electrical resistance may be increased due to the excessive treatment, and the coating adhesion may be reduced. And so on.
　なお、上記した化成処理液による皮膜化成処理において、化成処理液には、ポリアリルアミン、ポリアリルアミン部分カルポニル化、ポリアクリル酸、ポリアクリルアミドの中から選択される少なくとも1種以上の有機化合物が、さらに加えられることが好ましい。この中でも特にポリアリルアミンが好ましい。すなわち、マグネシウム－リチウム合金の場合、上記した化成処理液によって皮膜化成処理を行うと、マグネシウム－リチウム合金の成分により、塗装性能（特に耐久性）が低下することが懸念されるが、上記したポリアリルアミン、ポリアリルアミン部分カルポニル化、ポリアクリル酸、ポリアクリルアミドの中から選択される少なくとも1種以上の有機化合物を加えることで、後に塗装を行う場合、塗膜の密着性能を向上させることができることとなる。この場合、上記有機化合物の添加量としては、化成処理液中に、５０～５０００ｍｇ／リットルの量で含有されることが好ましく、２０００～４０００ｍｇ／リットルの量で含有されることがより好ましい。 In the film conversion treatment with the above-mentioned chemical conversion solution, the chemical conversion solution further contains at least one or more organic compounds selected from polyallylamine, polyallylamine partial carponylation, polyacrylic acid and polyacrylamide. Preferably it is added. Among these, polyallylamine is particularly preferable. That is, in the case of a magnesium-lithium alloy, there is a concern that the coating performance (particularly the durability) may be reduced due to the components of the magnesium-lithium alloy when the film conversion treatment is performed with the above-described chemical conversion solution. The adhesion performance of the coating film can be improved when painting is performed by adding at least one or more organic compounds selected from allylamine, polyallylamine partial carpenylation, polyacrylic acid and polyacrylamide. Become. In this case, the amount of the organic compound added is preferably 50 to 5,000 mg / liter, more preferably 2,000 to 4,000 mg / liter, in the chemical conversion treatment solution.
　本発明のマグネシウム－リチウム合金の表面処理方法においては、脱脂、エッチング処理液による処理工程、および表面調整処理を行った後に、この化成処理液による皮膜化成処理工程を行うことが好ましい。なお、脱脂、エッチング処理液による処理工程、および表面調整処理、皮膜化成処理は、それぞれ個別に行われ、各処理の間に水洗処理が施される。 In the surface treatment method of magnesium-lithium alloy according to the present invention, it is preferable to carry out the film conversion treatment step with the chemical conversion solution after the degreasing, the treatment step with the etching solution and the surface conditioning treatment. Note that the degreasing, the treatment process with the etching solution, the surface conditioning treatment, and the film conversion treatment are individually performed, and a water washing treatment is performed between each treatment.
　本発明の方法により表面処理したマグネシウム－リチウム合金は、その表面に形成した塗装膜に密着性を良好に保持させることができる。この塗装処理は、上記した本発明の表面調整処理後に、水洗、乾燥の過程を経た後に行うことができる。塗装方法としては、エポキシカチオン電着塗装によるプライマー処理、さらにはメラミン樹脂等による上塗り処理、一般焼付け塗装等の方法によることができる。 The magnesium-lithium alloy surface-treated by the method of the present invention can maintain good adhesion to the coating film formed on the surface thereof. This coating process can be performed after the process of water washing and drying after the surface conditioning process of the present invention described above. The coating method can be a method such as primer treatment by epoxy cation electrodeposition coating, topcoat treatment by melamine resin or the like, general baking coating, or the like.
　また、本発明の方法により表面処理したマグネシウム－リチウム合金は、優れた耐食性が得られるだけでなく、粘着力７．０２±１Ｎ／ｃｍの強度を有するテープを、質量２ｋｇ、直径８５ｍｍ、幅４５ｍｍの圧着ローラにより圧着し、その後、圧着面に対して９０度の引き剥がし角度で引き剥がした際に、テープに移行したパーティクルの量を２．０ｍｇ／ｍ２以下にすることができる。また、上記マグネシウム－リチウム合金は、ピン間１０ｍｍ、ピン先直径２ｍｍの円柱状２探針（１針の接触表面積３．１４ｍｍ２）のＡプローブ（株式会社三菱化学アナリテック社製）を、２４０ｇの荷重で表面に押圧した時の電流計の表面電気抵抗値を１Ω以下とすることができる。また、このプローブを６０ｇの荷重で押圧した時の電流計の表面電気抵抗値でも１０Ω以下、好ましい条件に整えると１Ω以下とすることができる。２４０ｇの荷重は、ビス固定によってマグネシウム－リチウム合金にアースを取る場合の固定力を想定しており、６０ｇの荷重は、マグネシウム－リチウム合金の表面にテープ固定によってアースを取る場合の固定力を想定している。 Moreover, the magnesium-lithium alloy surface-treated by the method of the present invention not only provides excellent corrosion resistance, but also has a strength of adhesive strength 7.02 ± 1 N / cm, weight 2 kg, diameter 85 mm, width 45 mm The amount of particles transferred to the tape can be made to be 2.0 mg / m 2 or less when pressure-bonded by the pressure-bonding roller and then peeled off at a peeling angle of 90 degrees with respect to the pressure-bonded surface. The magnesium-lithium alloy has 240 g of A probe (manufactured by Mitsubishi Chemical Analytech Co., Ltd.) with a cylindrical two-point probe (contact surface area 3.14 mm 2 of one needle) of 10 mm between pins and 2 mm in pin tip diameter. The surface electrical resistance value of the ammeter can be made 1 Ω or less when pressed against the surface by a load of In addition, the surface electrical resistance value of the ammeter when this probe is pressed with a load of 60 g can be 10 Ω or less, and can be 1 Ω or less when adjusted to preferable conditions. The load of 240 g assumes a fixing force when grounding to a magnesium-lithium alloy by screwing, and the load of 60 g assumes a fixing force when grounding by a tape fixing to the surface of a magnesium-lithium alloy doing.
　したがって、本発明の方法による表面処理を行って得られるマグネシウム－リチウム合金は、例えば、携帯電話、ノートパソコン、携帯翻訳機、ビデオカメラ、デジタルカメラなどのように、高い電磁波シールド性や、基板からのアースをとるために表面電気抵抗値が低いことを要求される、各種の電子機器筐体部品として有効利用することができる。 Therefore, magnesium-lithium alloys obtained by performing the surface treatment according to the method of the present invention have high electromagnetic wave shielding properties and substrates, such as mobile phones, laptop computers, mobile translators, video cameras, digital cameras, etc. It can be effectively used as various electronic device housing parts which are required to have a low surface electric resistance value in order to provide a ground.
　さらに、本発明の方法による表面処理は、マグネシウム－リチウム合金の圧延材に施した後、得られた圧延材をプレス加工などで加工しても優れた耐食性と表面電気抵抗値を低く保つことができる。したがって、本発明の方法による表面処理は、プレス加工した後の部品の状態になったマグネシウム－リチウム合金に行うものであってもよいし、加工前の圧延材の状態のマグネシウム－リチウム合金に行うものであってもよい。 Furthermore, the surface treatment according to the method of the present invention can maintain excellent corrosion resistance and low surface electric resistance even if the obtained rolled material is subjected to pressing after processing after being applied to a rolled material of magnesium-lithium alloy. it can. Therefore, the surface treatment according to the method of the present invention may be performed on the magnesium-lithium alloy in the state of parts after pressing, or on the magnesium-lithium alloy in the state of the rolled material before processing. It may be one.
　さらに、このようにして得られるマグネシウム－リチウム合金に、後工程で塗装を行う場合には、化成処理液に上記したポリアリルアミン、ポリアリルアミン部分カルポニル化、ポリアクリル酸、ポリアクリルアミドの中から選択される少なくとも1種以上の有機化合物を加えて化成処理を行えば、塗膜の密着性を向上させ、塗膜耐久性を高めることができる。したがって、上記したような、各種の電子機器筐体部品の場合、筐体内でアースを取り、筐体外面に塗装を行うことができ、好適に利用することができる。 Furthermore, when the magnesium-lithium alloy thus obtained is to be coated in a later step, it is selected from the above-mentioned polyallylamine, polyallylamine partial carponylation, polyacrylic acid and polyacrylamide in the chemical conversion solution. If chemical conversion treatment is performed by adding at least one or more organic compounds, the adhesion of the coating film can be improved and the coating film durability can be enhanced. Therefore, in the case of the various electronic device case components as described above, it is possible to ground the inside of the case and to coat the outer surface of the case, which can be suitably used.
　以上述べたように、本発明のマグネシウム－リチウム合金の表面処理方法によると、マグネシウム－リチウム合金の表面に、平面視１５μｍ以上の最長離隔間距離を持つ独立した凸状突起を、３１０μｍ×２５０μｍ四方の単位面積あたりに２０個以上散在している状態にすることができる。したがって、この表面処理方法によって処理したマグネシウム－リチウム合金は、各種電子機器の筐体に使用するような場合であっても、コンタミネーションの問題を生じることなく、使用することができる。 As described above, according to the surface treatment method of magnesium-lithium alloy of the present invention, independent convex projections having a longest separation distance of 15 μm or more in plan view are made 310 μm × 250 μm square on the surface of magnesium-lithium alloy. 20 or more can be scattered per unit area of Therefore, the magnesium-lithium alloy treated by this surface treatment method can be used without causing a problem of contamination even when it is used for the casing of various electronic devices.
　しかも、この表面処理方法によって処理したマグネシウム－リチウム合金は、表面電気抵抗値を低くすることができるので、マグネシウム－リチウム合金が有する超軽量、常温プレス加工による加工コストの低下などの利点に加えて、電磁波シールド性が求められたり、基板からのアースを取る必要がある電子機器筐体部品に用いることが可能となる。
　さらに、この表面処理方法によって処理したマグネシウム－リチウム合金は、その表面に塗装を行う場合には、塗膜の密着性を向上させることができる。 Moreover, since the magnesium-lithium alloy treated by this surface treatment method can lower the surface electric resistance value, in addition to the advantages such as the ultra-light weight possessed by the magnesium-lithium alloy and the reduction in processing cost due to cold pressing. , It becomes possible to use for the electronic equipment case parts which electromagnetic wave shielding property is called for, or it is necessary to take the earth from a substrate.
Furthermore, the magnesium-lithium alloy treated by this surface treatment method can improve the adhesion of the coating when the surface is coated.
（実施例１～７、比較例１～２４）
　被処理対象物として、マグネシウム－リチウム合金（日本金属株式会社製「ＬＺ９１材」：リチウム９質量％、亜鉛１質量％、マグネシウム残部）からなる縦５０ｍｍ、横５０ｍｍ、厚さ０．８ｍｍの圧延材を試験片として用意した。 (Examples 1 to 7, Comparative Examples 1 to 24)
A 50 mm long, 50 mm wide, and 0.8 mm thick rolled material consisting of magnesium-lithium alloy ("LZ91 material" manufactured by Nippon Metals Co., Ltd .: lithium 9% by mass, zinc 1% by mass, remaining magnesium) as an object to be treated Were prepared as test pieces.
　まず、この試験片は、液温を８０℃に保った強アルカリ水溶液（ミリオン化学株式会社製：商品名ＧＦＭＧ１５ＳＸの３０％水溶液）中に、８分間浸漬して脱脂処理を行った。 First, this test piece was subjected to a degreasing treatment by being immersed for 8 minutes in a strong alkaline aqueous solution (Million Chemical Co., Ltd .: 30% aqueous solution of GFMG15SX, trade name) maintained at a liquid temperature of 80 ° C.
　脱脂処理後の試験片は、水洗後、リン酸１９ｇ／リットルを含有する水溶液に、表１に示す各添加剤を添加したエッチング処理液によって、エッチング処理工程を行った。このエッチング処理工程は、液温を６０℃に保った各エッチング処理液中に、試験片を１２０秒間、浸漬することによって行った。 The test pieces after the degreasing treatment were washed with water and then subjected to an etching treatment step with an etching treatment solution in which each additive shown in Table 1 was added to an aqueous solution containing 19 g / liter of phosphoric acid. This etching process was carried out by immersing the test piece for 120 seconds in each etching solution maintained at 60 ° C.
　次いで、試験片は、水洗後、液温を６０℃に保った強アルカリ水溶液（ミリオン化学株式会社製：商品名ＧＦＭＧ１５ＳＸの４５％水溶液）中に、２分間浸漬して表面調整処理を行った。 Next, the test piece was subjected to surface conditioning treatment by being immersed in a strong alkaline aqueous solution (manufactured by Million Chemical Co., Ltd .: 45% aqueous solution of GFMG15SX under the trade name GFMG15SX) whose liquid temperature was kept at 60 ° C. for 2 minutes after water washing.
　次に、試験片は、水洗後、酸性フッ化アンモニウムを含有する水溶液からなる化成処理液に６０℃、１８０秒の条件で浸漬した。この化成処理液は、酸性フッ化アンモニウム中のフッ素が、１３．３３ｇ／リットルとなるように調整して使用した。 Next, after the test piece was washed with water, it was immersed in a chemical conversion treatment solution consisting of an aqueous solution containing ammonium acid fluoride under conditions of 60 ° C. and 180 seconds. The chemical conversion solution was used by adjusting the amount of fluorine in ammonium acid fluoride to 13.33 g / liter.
　水洗および乾燥工程を経て得られた試験片は、一つの条件につき複数枚用意しておき、そのうち２枚は、表面のパーティクル発生量、表面電気抵抗値をそれぞれ評価した。また、目視により皮膜の外観状態を観察した。結果を表１に示す。 A plurality of test pieces obtained through the water washing and drying steps were prepared for one condition, and two of them were evaluated for surface particle generation amount and surface electric resistance, respectively. Also, the appearance of the film was observed visually. The results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１の結果から、良好な使用範囲が広かった中性フッ化アンモニウムのエッチング処理液で処理した試験片については、以下の試験を行った。すなわち、良好な範囲で中性フッ化アンモニウムを使用したエッチング処理液（実施例１～実施例５）と、良好な範囲外で中性フッ化アンモニウムを使用したエッチング処理液（比較例１５～比較例２０）と、中性フッ化アンモニウムを含んでいない処理液（比較例１）とによってエッチング処理を行った各試験片に、マグネシウム合金用一般焼き付け塗装を下記の要領で行った後、塗膜耐食性試験、塗膜耐湿性試験を行った。また、酸性フッ化アンモニウムの量を変更した化成処理液で皮膜化成処理を行った各試験片（実施例６，７、比較例２３、２４）についても、マグネシウム合金用一般焼き付け塗装を下記の要領で行った後、塗膜耐食性試験、塗膜耐湿性試験を行った。なお、マグネシウム合金用一般焼き付け塗装は、下塗りをエポキシ樹脂系塗料プライマーにより塗装後、１５０℃、２０分間焼き付け、上塗りをアクリル系塗料により１５０℃、２０分間焼き付け、総合膜厚を４０～５０μｍとした。 From the results of Table 1, the following tests were conducted on the test pieces treated with the etching solution of neutral ammonium fluoride which had a wide usable range. That is, etching solutions using neutral ammonium fluoride (Examples 1 to 5) in a good range and etching solutions using neutral ammonium fluoride outside a good range (Comparative Example 15 to Comparative) After performing general baking coating for magnesium alloy in the following manner on each of the test pieces etched by Example 20) and the processing solution (Comparative Example 1) not containing neutral ammonium fluoride, Corrosion resistance test and coating film moisture resistance test were conducted. In addition, for each test piece (Examples 6, 7 and Comparative Examples 23, 24) subjected to film conversion treatment with a chemical conversion solution in which the amount of ammonium acid fluoride was changed, general baking coating for magnesium alloy was as follows. The coating film corrosion resistance test and the coating film moisture resistance test were conducted. In general baking coating for magnesium alloy, the primer is coated with an epoxy resin paint primer, then baked for 20 minutes at 150 ° C, and the top coating is baked for 20 minutes at 150 ° C with an acrylic paint to a total film thickness of 40 to 50 μm. .
　これら各試験片の塗装耐食性試験、塗膜耐湿性試験の結果を表２に示す。 The results of the coating corrosion resistance test and the coating moisture resistance test of these test pieces are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　また、良好な範囲で中性フッ化アンモニウムを使用したエッチング処理液によってエッチング処理を行った試験片（実施例１～実施例５）と、良好な範囲外で中性フッ化アンモニウムを使用したエッチング処理液によってエッチング処理を行った試験片（比較例１５～比較例２０）と、中性フッ化アンモニウムを含んでいない処理液によってエッチングを行った試験片（比較例１）とについて、表面処理後に得られた試験片の表面の凸部の形成状態を評価した。 Moreover, the test piece (Example 1-Example 5) which performed the etching process by the etching process liquid which used neutral ammonium fluoride in a favorable range, and the etching which used neutral ammonium fluoride out of a favorable range After the surface treatment, the test pieces (Comparative Examples 15 to 20) subjected to the etching treatment with the treatment liquid and the test pieces subjected to the etching treatment with the treatment liquid not containing neutral ammonium fluoride (Comparative Example 1) The formation state of the convex part of the surface of the obtained test piece was evaluated.
　試験片の表面の凸部の形状状態の評価結果は、表３ないし表６に示す。 The evaluation results of the shape state of the convex portion on the surface of the test piece are shown in Tables 3 to 6.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
なお、本実施例および比較例における各評価は以下のように行った。
－パーティクルの発生量評価－
　試験片の表面に、日本工業規格ＪＩＳ　１５２２に規定された方法による、ステンレス板への１８０度における粘着力が７．０２±１Ｎ／ｃｍの密着強度を有する幅１２ｍｍのテープを、日本工業規格ＪＩＳ　Ｚ　０２３７に規定された材質の質量２ｋｇ、直径８５ｍｍ、幅４５ｍｍの圧着ローラにより、圧着した。圧着したテープを、日本工業規格ＪＩＳ　Ｚ　０２３７により規定された粘着力試験法により、９０度の角度で剥離した。そして、剥離したテープの粘着面に付着したＭｇ量を蛍光Ｘ線分析装置により定量測定した。蛍光Ｘ線分析装置は、走査型蛍光Ｘ線分析装置　ＺＳＸ　Ｐｒｉｍｕｓｌｌを用い、検量線は１０ｍｍの直径の一定面積当たりに硝酸マグネシウムを規定量テープの粘着面にまぶして作成した。同じ試験片につき３回測定した。なお、テープ剥離の際の９０度引っ張り強度も参考に測定した。評価については、定量された粉状のパーティクルが、０．５ｍｇ／ｍ２未満の場合を「○」、０．５ｍｇ／ｍ２～２０．０ｍｇ／ｍ２未満の場合を「△」、２０．０ｍｇ／ｍ２以上の場合を「×」とした。
－表面電気抵抗値－
　表面電気抵抗値は、ロレスターＥＰ２探針Ａプローブ（株式会社三菱化学アナリテック社製：ピン間１０ｍｍ、ピン先直径２．０ｍｍ（１針の接触表面積３．１４ｍｍ２）、バネ圧２４０ｇ）を用い、試験片表面の中央部、上部、下部に、それぞれピンを押圧して表面電気抵抗値を測定した。測定は一枚の試験片につき３回測定してその平均値を求めた。 In addition, each evaluation in a present Example and a comparative example was performed as follows.
-Evaluation of particle generation rate-
A tape with a width of 12 mm having an adhesion strength of 7.02 ± 1 N / cm at a 180 ° angle to a stainless steel plate according to the method defined in Japanese Industrial Standard JIS 1522 on the surface of a test piece is Japanese Industrial Standard JIS Crimping was performed using a crimping roller having a mass of 2 kg, a diameter of 85 mm, and a width of 45 mm defined in Z0237. The pressure-bonded tape was peeled off at an angle of 90 degrees by the adhesion test method defined by Japanese Industrial Standard JIS Z 0237. Then, the amount of Mg adhering to the adhesive surface of the peeled tape was quantitatively measured by a fluorescent X-ray analyzer. The X-ray fluorescence analyzer used was a scanning X-ray fluorescence analyzer ZSX Primusll, and a calibration curve was prepared by dusting magnesium nitrate on the adhesive surface of a specified amount of tape per a fixed area of 10 mm in diameter. The same test piece was measured three times. In addition, the 90 degree tensile strength at the time of tape peeling was also measured for reference. For the evaluation, the case where the quantified powdery particles are less than 0.5 mg / m 2 is “○”, and the case where 0.5 mg / m 2 to less than 20.0 mg / m 2 is “Δ”, 20. The case of 0 mg / m 2 or more was regarded as “x”.
-Surface electrical resistance-
The surface electrical resistance value is determined by using Loresta EP 2 probe A probe (Mitsubishi Chemical Analytech Co., Ltd .: 10 mm between pins, pin tip diameter 2.0 mm (contact surface area of one needle 3.14 mm 2 ), spring pressure 240 g) The surface electrical resistance value was measured by pressing the pins to the central part, the upper part, and the lower part of the surface of the test piece. The measurement was performed three times for one test piece to obtain the average value.
　２４０ｇの測定値は、２探針プローブのピンがバネ圧に抗して引っ込むまで試験片の表面に押圧して測定し、１．０Ω未満の場合を「○」、１．０～１００Ω未満の場合を「△」、１００Ω以上、または一回でも測定不能になれば「×」とした。 The measured value of 240 g is measured by pressing the surface of the test piece until the pin of the 2-probe probe is retracted against the spring pressure. The case was marked as "x" if it became impossible to measure "一 回", 100 Ω or more, or even once.
　なお、２４０ｇの測定値は、部材表面にアースをビス固定して取る場合を想定している。
－塗膜耐食性試験－
　塗装を施した試験片にカッターナイフで切り込みを入れたものを用意した。これを、ＪＩＳ  Ｚ  ２３７１に準じた塩水噴霧試験方法（ＳＳＴ試験）によって、３５℃に設定した試験槽に入れ、５％食塩水を噴霧して２４０時間後に取り出した。表面を水洗いして乾燥した後、乾燥した塗膜カット部にテープを貼って剥離し、テープ剥離後の片側最大剥離幅（ｍｍ）を測定した。２．０ｍｍ未満の場合を「◎」、２．０ｍｍ～３．０ｍｍ未満の場合を「○」、３．０ｍｍ～６．０ｍｍ未満の場合を「△」、６．０ｍｍ以上の場合を「×」とした。
－塗膜耐湿性試験－
　沸騰（１００℃）しているお湯の中に、塗装を施した試験片を入れ、６０分間浸漬後、試験片を取り出し、表面の水を拭いて常温で１時間放置した。その後、試験片の表面に１ｍｍの碁盤目状の切り込みを入れ、その表面にテープを貼って剥離し、剥離された塗膜の面積を測定した。０％の場合を「◎」、５％以下の場合を「○」、５％を超え、３０％未満の場合を「△」、３０％以上の場合を「×」とした。
－表面の凸部の形成状態評価－（赤字部分不要）
　試験片の表面を電子顕微鏡で拡大し、３１０μｍ×２５０μｍ四方の面積に占める、凸状突起の数をカウントした。凸状突起は、当該凸状突起における最も離れた位置間の直線距離が１５μｍ以上の長さとなる独立した凸部の数をカウントした。評価については、独立した凸部の数が２０個以上の場合を「○」、２０個未満または隣接する凸状突起同士が繋がって測定不能の場合を「×」とした。なお、凸状突起は、当該凸状突起の隆起具合を、より確認し易くするため、真上から撮影した電子顕微鏡写真と、斜め４５度の撮影アングルで撮影した電子顕微鏡写真とを照らし合わせながら、斜め４５度の撮影アングルで撮影した電子顕微鏡写真で、凸状突起の数をカウントした。 In addition, the measured value of 240 g assumes the case where screw fixation of the earth is carried out to a member surface, and taking it.
-Coating film corrosion resistance test-
The coated test pieces were cut with a cutter knife to prepare. The solution was put into a test tank set at 35 ° C. by a salt spray test method (SST test) according to JIS Z 2371, sprayed with a 5% saline solution, and taken out after 240 hours. After the surface was washed with water and dried, a tape was attached to the dried coated film cut and peeled off, and the one-side maximum peeling width (mm) after peeling of the tape was measured. "◎" for less than 2.0 mm, "○" for less than 2.0 mm to 3.0 mm, "△" for less than 3.0 mm to 6.0 mm, "× for greater than 6.0 mm ".
-Coating film moisture resistance test-
The coated test piece was placed in boiling (100 ° C.) hot water and immersed for 60 minutes, then the test piece was taken out, the surface was wiped off, and left at room temperature for 1 hour. Thereafter, a 1 mm grid-like cut was made on the surface of the test piece, a tape was attached to the surface and peeled off, and the area of the peeled coating was measured. In the case of 0%, "◎", in the case of 5% or less is "○", in the case of more than 5%, less than 30% is "Δ", and in the case of 30% or more is "X".
-Evaluation of the formation of convexes on the surface-
The surface of the test piece was magnified with an electron microscope, and the number of convex projections occupying an area of 310 μm × 250 μm was counted. The convex projections were counted as the number of independent convex portions in which the linear distance between the most distant positions of the convex projections was 15 μm or more. About evaluation, when the number of independent convex parts is 20 or more, "(circle)" and the case where less than 20 or adjacent convex projections were connected and measurement was impossible were made into "x". In order to make it easier to confirm the degree of protrusion of the convex projections, the convex projections make it possible to compare an electron micrograph taken from directly above with an electron micrograph taken at an oblique 45 ° photographing angle. The number of convex projections was counted in an electron micrograph taken at an oblique 45 degree photographing angle.
（実施例１、８～１０）
　実施例１で良好な結果が得られた酸性フッ化アンモニウムを１３．３３ｇ／リットル含む化成処理液と、同化成処理液に、表７に示す各配合量でポリアリルアミンを添加した化成処理液（実施例８～１０）とを用いて、上記実施例１と同様に各試験片の処理を行った。
　水洗および乾燥工程を経た各試験片は、エポキシ系プライマー（大日本塗料株式会社製：プライマー　MG-GUARD#1-SP）を膜厚１２．５±２．５ｍｍの厚みで塗布後、１６０℃×２０分の焼付を行って放冷後、アクリル系トップコート（大日本塗料株式会社製:トップコート　マグラック#636）を膜厚１２．５±２．５ｍｍの厚みで塗布後、１６０℃×２０分の焼付を行って塗装を施した。 (Example 1, 8 to 10)
A chemical conversion treatment solution containing 13.33 g / l of ammonium acid fluoride for which good results were obtained in Example 1, and a chemical conversion treatment solution containing polyallylamine in the respective compounding amounts shown in Table 7 in the same chemical conversion treatment solution ( Each of the test pieces was treated in the same manner as in Example 1 using Examples 8 to 10).
Each test piece that has been subjected to water washing and drying steps is coated with an epoxy primer (product of Dainippon Paint Co., Ltd .: Primer MG-GUARD # 1-SP) to a film thickness of 12.5 ± 2.5 mm, and then 160 ° C × After baking for 20 minutes and allowing to cool, an acrylic topcoat (made by Dainippon Paint Co., Ltd .: Topcoat Maglac # 636) is applied at a thickness of 12.5 ± 2.5 mm, and then 160 ° C × 20 minutes We baked and painted.
　このようにして得られた各試験片は、塗膜耐温水試験を行った。結果を表７に示す。 Each test piece obtained in this manner was subjected to a coating warm water resistance test. The results are shown in Table 7.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
－塗膜耐温水試験－
　水道水を入れた容器内に各試験片を浸漬し、６０℃に保った恒温槽で２４時間放置した。
　その後、試験片を取り出し表面の水分を拭き取った後、１時間常温の室内環境雰囲気下で放置した後、ＪＩＳ５４００に準拠した１００マスのクロスカット試験を行った。
　この試験は、上記２４時間の浸漬後の他に、浸漬後に表面の水分を拭き取って常温の室内環境雰囲気下で１カ月放置後、同２カ月放置後、同３カ月放置後についても、それぞれ放置後にＪＩＳ５４００に準拠した１００マスのクロスカット試験を行った。試験後、各試験片の表面を確認して評価を行った。クロスカット試験の詳細および評価基準は以下の通りです。 -Coating water resistance test-
Each test piece was immersed in a container containing tap water, and left in a thermostatic bath maintained at 60 ° C. for 24 hours.
Then, after taking out the test piece and wiping off the moisture on the surface, it was allowed to stand under a room temperature atmosphere for 1 hour, and then a cross cut test of 100 squares in accordance with JIS 5400 was performed.
In this test, in addition to the immersion for 24 hours, after the immersion, the surface moisture is wiped off and left for 1 month under normal temperature indoor environment atmosphere, then left for 2 months and left for 3 months. Later, a cross cut test of 100 squares in accordance with JIS 5400 was performed. After the test, the surface of each test piece was confirmed and evaluated. The details and evaluation criteria of the crosscut test are as follows.
（クロスカット試験詳細）
(1)塗装面の中央一か所に規定するすきま間隔（1mm）のカッターガイドなど用い、碁盤　目状の切傷を付ける。
(2)切傷を付ける時のカッターナイフの刃先は常に新しいものを用い、塗面に対して35～45度の範囲の一定の角度に保つようにする。
(3)切傷は、塗膜を貫通して試験片の素地に届くように、切傷1本につき　約0.5秒間かけて等速で引く。
(4)幅24mm巻状セロハンテープ（幅24mmのNICHIBAN製を使用のこと）の一端を碁盤目状にカットした塗装面に長さ約50mmを張付ける。更に、張付けたセロハン粘着テープの上を指の腹（約1500g以上の力）で3往復以上擦りながら押し付けた後、その部分から約80mmの位置でセロハン粘着テープの巻き芯又は、端を持って、約45°の角度で手前に素早く引張り、セロハン粘着テープを引き剥がす。この時、塗装面に剥がれが発生しないかどうかを確認する。 (Crosscut test details)
(1) Use a cutter guide with a gap distance (1 mm) specified at one central position on the painted surface, etc., and make a grid-like cut.
(2) When making a cut, always use a new cutting edge of the cutter knife and keep it at a constant angle in the range of 35-45 degrees with respect to the coated surface.
(3) The cuts are taken at a constant speed for about 0.5 seconds per cut so as to penetrate the coating and reach the substrate of the test piece.
(4) Attach a length of about 50 mm to a coated surface of one end of a 24 mm wide cellophane-shaped cellophane tape (made by NICHIBAN with a width of 24 mm) cut in a grid pattern. Furthermore, after rubbing and pressing 3 times or more with finger pad (force more than about 1500 g) and pressing on cellophane adhesive tape stuck, hold the core or edge of cellophane adhesive tape at about 80 mm from that part Quickly pull it forward at an angle of about 45 °, and pull off the cellophane adhesive tape. At this time, it is checked whether peeling occurs on the coated surface.
（評価基準）
「１０」：切傷1本ごとが細くて両側が滑らかで、切り傷の交点と正方形の一目一目に剥がれがない。
「８」：切り傷の交点にわずかなはがれがあって、正方形の一目一目に剥がれがなく、欠損部の面積は全正方形面積の５％以内。
「６」：切り傷の両側と交点とにはがれがあって、欠損部の面積は全正方形面積の5～15%。
「４」：切り傷によるはがれの幅が広く、欠損部の面積は全正方形面積の15～35%。
「２」：切り傷によるはがれの幅は4点よりも広く、欠損部の面積は全正方形面積の35～65%。
「０」：はがれの面積は、全正方形面積の65%以上。 (Evaluation criteria)
"10": Each cut is thin and smooth on both sides, and there is no peeling at the intersection of the cut and the square at a glance.
"8": There is slight peeling at the intersection of cuts, no peeling at a first glance at a square, and the area of the defect is within 5% of the total square area.
"6": There is peeling at both sides of the incision and at the intersection, and the area of the defect is 5 to 15% of the total square area.
"4": Peeling width is wide, and the area of the defect is 15 to 35% of the total square area.
"2": The width of peeling from cuts is wider than 4 points, and the area of the defect is 35 to 65% of the total square area.
"0": The area of peeling is 65% or more of the total square area.
　上記の結果から、本発明に係る試験片は、コンタミネーションの原因となるパーティクルを生じ難く、表面電気抵抗値が低く、優れた裸耐食性、塗膜密着性が得られることがわかる。また、化成処理液にポリアリルアミンを添加した場合、塗膜の耐久性が向上することが確認できた。 From the above results, it can be seen that the test piece according to the present invention is less likely to generate particles that cause contamination, has a low surface electrical resistance value, and can provide excellent bare corrosion resistance and coating adhesion. Moreover, when polyallylamine was added to the chemical conversion treatment liquid, it has been confirmed that the durability of the coating film is improved.
　なお、実施例８～１０に係る各試験片は、パーティクル発生量評価および表面電気抵抗値評価ともに「○」であった。 In each of the test pieces according to Examples 8 to 10, both of the particle generation amount evaluation and the surface electric resistance value evaluation were “o”.
　本発明は、その精神または主要な特徴から逸脱することなく、他のいろいろな形で実施することができる。そのため、上述の実施例はあらゆる点で単なる例示に過ぎず、限定的に解釈してはならない。本発明の範囲は特許請求の範囲によって示すものであって、明細書本文には、なんら拘束されない。さらに、特許請求の範囲に属する変形や変更は、全て本発明の範囲内のものである。
  The present invention can be embodied in other various forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely illustrative in every point and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not limited at all by the text of the specification. Furthermore, all variations and modifications that fall within the scope of the claims fall within the scope of the present invention.

Claims (10)

  1. 　マグネシウム－リチウム合金の表面を、リン酸に１５０～５００ｐｐｍの中性フッ化アンモニウムを含有した水溶液からなるエッチング処理液で処理する工程を具備することを特徴とするマグネシウム－リチウム合金の表面処理方法。 A method of treating a surface of a magnesium-lithium alloy, comprising the step of treating the surface of the magnesium-lithium alloy with an etching solution comprising an aqueous solution containing 150 to 500 ppm of neutral ammonium fluoride in phosphoric acid.
  2. 　請求項１記載のエッチング処理液で処理する工程の後、アルカリ系水溶液に浸漬してスマットの残留分を除去する表面調整処理を行った後、３．３３～４０ｇ／リットルのフッ素化合物を含有する化成処理液に浸漬して化成皮膜を形成する工程をさらに具備するマグネシウム－リチウム合金の表面処理方法。 After the step of treating with the etching solution according to claim 1, after the surface conditioning treatment of removing the remaining portion of the smut by immersion in an alkaline aqueous solution, 3.33 to 40 g / liter of a fluorine compound is contained. A surface treatment method of magnesium-lithium alloy, further comprising a step of forming a chemical conversion film by immersing in a chemical conversion treatment solution.
  3. 　化成処理液として、３．３３～４０ｇ／リットルのフッ素化合物を含有する化成処理液に、さらに、ポリアリルアミン、ポリアリルアミン部分カルポニル化、ポリアクリル酸、ポリアクリルアミドの中から選択される１種以上が５０～５０００ｐｐｍの濃度で含有されたものを使用する請求項２に記載のマグネシウム－リチウム合金の表面処理方法。 In the chemical conversion solution containing 3.33 to 40 g / liter of the fluorine compound as the chemical conversion solution, one or more selected from polyallylamine, polyallylamine partial carponylation, polyacrylic acid and polyacrylamide are further added. The method for surface treatment of a magnesium-lithium alloy according to claim 2, wherein one contained at a concentration of 50 to 5000 ppm is used.
  4. 　請求項２に記載の表面処理方法によって得られるマグネシウム－リチウム合金。 A magnesium-lithium alloy obtained by the surface treatment method according to claim 2.
  5. 　請求項３に記載の表面処理方法によって得られるマグネシウム－リチウム合金。 A magnesium-lithium alloy obtained by the surface treatment method according to claim 3.
  6. 　表面に平面視１５μｍ以上の最長離隔間距離を持つ独立した凸状突起が３１０μｍ×２５０μｍ四方の単位面積あたりに２０個以上散在している請求項４または５に記載のマグネシウム－リチウム合金。 The magnesium-lithium alloy according to claim 4 or 5, wherein independent convex projections having a longest separation distance of 15 μm or more in plan view on the surface are scattered 20 or more per unit area of 310 μm × 250 μm.
  7. 　粘着力７．０２±１Ｎ／ｃｍの強度を有するテープを、質量２ｋｇ、直径８５ｍｍ、幅４５ｍｍの圧着ローラにより圧着し、その後、圧着面に対して９０度の引き剥がし角度で引き剥がした際に、テープに移行したパーティクルの量が２．０ｍｇ／ｍ２以下となされた請求項４または５に記載のマグネシウム－リチウム合金。 A tape with a strength of adhesive strength 7.02 ± 1 N / cm is crimped by a crimping roller with a mass of 2 kg, a diameter of 85 mm, and a width of 45 mm, and then peeled off at a peeling angle of 90 degrees with respect to the crimped surface. The magnesium-lithium alloy according to claim 4 or 5, wherein the amount of particles transferred to the tape is 2.0 mg / m 2 or less.
  8. 　ピン間１０ｍｍ、ピン先直径２ｍｍの円柱状２探針プローブ（１針の接触表面積３．１４ｍｍ２）を、２４０ｇの荷重で表面に押圧した時の電流計の表面電気抵抗値が１Ω以下となされた請求項４または５に記載のマグネシウム－リチウム合金。 The surface electrical resistance of the ammeter is 1 Ω or less when a cylindrical two-point probe (contact surface area 3.14 mm 2 of one needle) with a pin distance of 10 mm and a pin tip diameter of 2 mm is pressed against the surface with a load of 240 g. The magnesium-lithium alloy according to claim 4 or 5.
  9. 　マグネシウム－リチウム合金の表面に、エポキシ系プライマーを膜厚１２．５±２．５ｍｍの厚みで焼付塗布後、アクリル系トップコートを膜厚１２．５±２．５ｍｍの厚みで焼付塗装し、
    　６０℃の温水に２４時間浸漬した後、水分を除去し常温の室内環境雰囲気下で１時間放置した後に、ＪＩＳ５４００に準拠した１００マスのクロスカット試験を行った際に、剥離するマス目を生じない請求項４または５に記載のマグネシウム－リチウム合金。     After baking the epoxy primer to a film thickness of 12.5 ± 2.5 mm on the surface of magnesium-lithium alloy, baking coating with an acrylic top coat at a film thickness of 12.5 ± 2.5 mm
    After immersing in warm water at 60 ° C for 24 hours, after removing moisture and leaving it for 1 hour under a room temperature atmosphere at normal temperature, a cross cut test of 100 squares in accordance with JIS 5400 is performed to generate squares to be peeled off. The magnesium-lithium alloy according to claim 4 or 5.
  10. 　マグネシウム－リチウム合金の表面に、エポキシ系プライマーを膜厚１２．５±２．５ｍｍの厚みで焼付塗布後、アクリル系トップコートを膜厚１２．５±２．５ｍｍの厚みで焼付塗装し、
    　６０℃の温水に２４時間浸漬した後、水分を除去し常温の室内環境雰囲気下で２カ月放置した後に、ＪＩＳ５４００に準拠した１００マスのクロスカット試験を行った際に、剥離するマス目を生じない請求項５に記載のマグネシウム－リチウム合金。
          After baking the epoxy primer to a film thickness of 12.5 ± 2.5 mm on the surface of magnesium-lithium alloy, baking coating with an acrylic top coat at a film thickness of 12.5 ± 2.5 mm
    After immersing in warm water at 60 ° C for 24 hours, after removing the moisture and leaving it for 2 months under a room temperature atmosphere at normal temperature, a cross cut test of 100 squares in accordance with JIS 5400 produces a peeling off mass The magnesium-lithium alloy according to claim 5.
PCT/JP2018/034746 2017-09-20 2018-09-20 Magnesium-lithium alloy and surface-treatment method thereof WO2019059255A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003171776A (en) * 2001-12-07 2003-06-20 Million Kagaku Kk Surface treatment method for lithium based magnesium alloy material
JP2012097340A (en) * 2010-11-04 2012-05-24 Mitsui Mining & Smelting Co Ltd Magnesium alloy surface treatment method
JP2014084500A (en) * 2012-10-24 2014-05-12 Knowledge Management Technology Co Ltd Method of treating surface of magnesium or magnesium alloy, acid cleaning agent, conversion treatment agent and conversion-treated structure of magnesium or magnesium alloy
JP2015203135A (en) * 2014-04-14 2015-11-16 富士通株式会社 Component and production method of component, and surface treatment method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003171776A (en) * 2001-12-07 2003-06-20 Million Kagaku Kk Surface treatment method for lithium based magnesium alloy material
JP2012097340A (en) * 2010-11-04 2012-05-24 Mitsui Mining & Smelting Co Ltd Magnesium alloy surface treatment method
JP2014084500A (en) * 2012-10-24 2014-05-12 Knowledge Management Technology Co Ltd Method of treating surface of magnesium or magnesium alloy, acid cleaning agent, conversion treatment agent and conversion-treated structure of magnesium or magnesium alloy
JP2015203135A (en) * 2014-04-14 2015-11-16 富士通株式会社 Component and production method of component, and surface treatment method

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