WO2023090234A1 - 複合硬質クロムめっき - Google Patents

複合硬質クロムめっき Download PDF

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Publication number
WO2023090234A1
WO2023090234A1 PCT/JP2022/041825 JP2022041825W WO2023090234A1 WO 2023090234 A1 WO2023090234 A1 WO 2023090234A1 JP 2022041825 W JP2022041825 W JP 2022041825W WO 2023090234 A1 WO2023090234 A1 WO 2023090234A1
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Prior art keywords
plating film
alumina
plate
chromium plating
composite hard
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PCT/JP2022/041825
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English (en)
French (fr)
Japanese (ja)
Inventor
僚 神田
義之 佐野
圭介 松浦
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DIC Corp
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DIC Corp
Dainippon Ink and Chemicals Co Ltd
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Application filed by DIC Corp, Dainippon Ink and Chemicals Co Ltd filed Critical DIC Corp
Priority to US18/710,922 priority Critical patent/US20250019854A1/en
Priority to JP2023514034A priority patent/JP7384317B2/ja
Priority to MX2024005432A priority patent/MX2024005432A/es
Priority to CN202280062430.9A priority patent/CN117940615A/zh
Priority to DE112022005520.0T priority patent/DE112022005520T5/de
Publication of WO2023090234A1 publication Critical patent/WO2023090234A1/ja
Priority to JP2023149179A priority patent/JP7670095B2/ja
Anticipated expiration legal-status Critical
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D15/00—Electrolytic or electrophoretic production of coatings containing embedded materials, e.g. particles, whiskers, wires
    • C25D15/02—Combined electrolytic and electrophoretic processes with charged materials
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/04—Electroplating: Baths therefor from solutions of chromium
    • C25D3/06—Electroplating: Baths therefor from solutions of chromium from solutions of trivalent chromium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J9/00—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction
    • F16J9/26—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction characterised by the use of particular materials

Definitions

  • the present invention relates to a composite hard chromium plating film that uses trivalent chromium in the composite hard chromium plating film, and a sliding member such as a piston ring coated with the film.
  • chromium plating is widely used as decorative plating because it can maintain its metallic luster for a long time due to its excellent corrosion resistance and discoloration resistance.
  • chromium plating has a high hardness of about 800 to 950 Hv, excellent wear resistance, and a low coefficient of wear.
  • harmful hexavalent chromium is used as a main component in the plating solution used for these platings.
  • Hexavalent chromium is designated as a substance of high concern from the viewpoint of health and environmental protection, and development of chromium plating that does not use hexavalent chromium is required.
  • Trivalent chromium plating is practically used as decorative plating because it is excellent in color tone and corrosion resistance in a relatively thin plating with a film thickness of 5 ⁇ m or less.
  • wear resistance wear coefficient
  • Patent Document 1 a method of incorporating 10 to 30% by volume of a plurality of ceramic particles having excellent wear resistance in chromium plating has been proposed.
  • Patent Document 2 a method of containing plate-like and/or fibrous alumina particles to suppress the expansion and progress of cracks during heat treatment and improve hardness is proposed. It has been proposed (Patent Document 4).
  • the composite plating film formed by these methods has a low affinity between the ceramic particles used and the deposited plating film, so that the particles peel off from the plating film during treatment, and the amount of ceramic particles taken in is insufficient.
  • the formation of the composite plating film was sometimes incomplete due to the exfoliation of the particles.
  • a non-adhesive portion was observed between the plating film and the ceramic particles, and the composite plating film did not have sufficient hardness and wear resistance.
  • An object of the present invention is to provide a hard chromium plating film and a sliding member coated with the film.
  • the present inventors have made detailed studies on the state of the ceramic particles during the formation of the composite hard chromium plating film. As a result of intensive research, it was found that a plate-like material having a ratio A/B of acid adsorption amount A per surface area ( ⁇ mol/m 2 ) to base adsorption amount B per surface area ( ⁇ mol/m 2 ) was 0.5 or more and 1.5 or less.
  • alumina particles to chromium plating that uses trivalent chromium as a chromium source, the affinity between the alumina particles and the plating film is ensured, and a plating film in which non-adhesive parts are suppressed between the particles and the plating metal is obtained. As a result, it was found that cracks were suppressed and a plating film having excellent hardness and wear resistance was obtained.
  • the present invention provides a composite hard chromium plating film containing plate-like alumina, wherein the chromium source of the composite hard chromium plating film is trivalent chromium, and the plate-like alumina has an acid adsorption amount A per surface area ( ⁇ mol/m 2 ) and a base adsorption amount B per surface area ( ⁇ mol/m 2 ), wherein the ratio A/B is 0.5 or more and 1.5 or less.
  • the composite hard chromium plating film of the present invention has excellent affinity between the plating film and alumina particles, suppresses the occurrence of non-adhered parts, and as a result, leads to suppression of cracks, and the formed film has excellent hardness and wear resistance. , piston rings and other sliding members.
  • FIG. 1 is a cross-sectional SEM image of an alumina-dispersed Cr plating film obtained in Example 1.
  • FIG. 4 is a cross-sectional SEM image of an alumina-dispersed Cr plating film obtained in Comparative Example 2.
  • FIG. 1 is an image obtained by 3D observation with a laser microscope of polishing marks of an alumina-dispersed Cr plating film obtained in Example 1.
  • FIG. 4 is an image obtained by 3D observation with a laser microscope of polishing marks of an alumina-dispersed Cr plating film obtained in Comparative Example 1.
  • a composite hard chromium plating film is a plating film formed by adding ceramic particles, which are hard particles, to a chromium plating solution and co-precipitating with chromium.
  • the purpose of the ceramic particles is to improve the wear resistance of the plating film, and examples thereof include alumina, silicon carbide, and diamond.
  • the plating film according to the present embodiment contains plate-like alumina particles. Since the shape of the alumina particles is plate-like, when the plating film is formed on the base material, the alumina particles are oriented along the base material, so that the damage to the mating material that becomes the friction partner can be reduced. can.
  • a chromium plating solution uses trivalent chromium as a chromium source. By using trivalent chromium, it becomes unnecessary to use highly harmful hexavalent chromium.
  • the trivalent chromium plating solution may be appropriately prepared according to a known composition and used, or a commercially available trivalent chromium plating solution may be used.
  • Commercially available products include Top Fine Chrome SP, Top Fine Chrome LG (manufactured by Okuno Chemical Industry Co., Ltd.), JCUTRICHROM JTC series (manufactured by JCU Co., Ltd.), Envirochrome and CP series (MacDermid Performance Solutions Japan Co., Ltd. made), etc.
  • the method for forming a composite hard chromium plating film of the present invention involves preparing a chromium plating bath containing the chromium plating solution and plate-like alumina particles described later, and forming a plating film on an object by a known and commonly used electroplating method. do.
  • the “alumina” in the present invention is aluminum oxide, and is particularly limited if it satisfies the ratio A/B of the acid adsorption amount A per surface area ( ⁇ mol/m 2 ) and the base adsorption amount B per surface area ( ⁇ mol/m 2 ).
  • it may be transition alumina in various crystal forms such as ⁇ , ⁇ , ⁇ , ⁇ , or may contain alumina hydrate in the transition alumina, but it is more stable and is preferably in the ⁇ crystal form.
  • Plate-like indicates that the aspect ratio obtained by dividing the average particle size by the thickness is 2 or more.
  • the value measured using a scanning electron microscope (SEM) shall be adopted as the "thickness of the plate-like alumina particles”.
  • the "average particle size of plate-like alumina particles” is a value calculated as a volume-based median diameter D50 from a volume-based cumulative particle size distribution measured by a laser diffraction/scattering particle size distribution analyzer.
  • the average particle size of the plate-like alumina particles can be appropriately selected according to the application of the plated product, the thickness of the plated film, etc., but it is preferably 0.5 ⁇ m or more and 20 ⁇ m or less, and particularly preferably 1 ⁇ m or more and 10 ⁇ m. It is below.
  • the average particle diameter of the plate-like alumina particles is 0.5 ⁇ m or more, aggregation of the particles is suppressed, and when it is 20 ⁇ m or less, the area of the alumina particles functioning as an insulator becomes small, which is preferable because the growth of the plating film is improved.
  • the aspect ratio of the plate-like alumina particles can be appropriately selected according to the application of the plated product, the thickness of the plating film, etc., but is preferably 5 or more and 100 or less, and particularly preferably 10 or more and 50 or less. .
  • the aspect ratio of the plate-like alumina particles is within the above range, the surface of the plated film formed is smooth, the abrasion resistance is excellent, and the aggressiveness to the mating material is suppressed, which is a preferred embodiment.
  • the ratio A/B between the acid adsorption amount A ( ⁇ mol/m 2 ) per surface area of the plate-like alumina particles and the base adsorption amount B ( ⁇ mol/m 2 ) per surface area is 0.5 or more and 1.5 or less, It is particularly preferable that it is 0.7 or more and 1.3 or less. Within the above range, the affinity between the plated film and the plate-like alumina particles is enhanced, and non-adhered portions between the plated film and the plate-like alumina particles are suppressed in the formed plated film.
  • the acid adsorption amount A per surface area ( ⁇ mol/m 2 ) is 0.5 ⁇ mol/m 2 or more and 3.5 ⁇ mol/m 2 or less from the viewpoint of adhesion to the plated film after film formation. .
  • the amount of acid and base adsorption per surface area of the plate-like alumina particles affects the adhesion between the alumina particles and the plating film
  • the amount of acid adsorption per particle surface area reflects the surface potential of the particles. That is, particles with a high acid adsorption amount are particles that are more negatively charged.
  • the negatively charged particles basically migrate toward the positive electrode side, but the stirring and shaking of the plating solution causes negative charging. particles are easily incorporated into the plating film formed on the negative electrode side.
  • the negatively charged particles attract cations and become positively charged colloidal particles.
  • general ceramic particles have a positive zeta potential.
  • commercially available alumina particles, which are said to be negatively charged also had a zeta potential of about +20 mV in a pH 2 solution when measured.
  • the metal cations are accumulated in layers due to the electrode potential, and even if the positively charged colloidal particles can approach, they have poor affinity with the cation layer. a state arises.
  • the eutectoid mechanism of composite plating consists of a mechanism in which metal ions and ceramic particles are individually deposited on the negative electrode as described above, and a composite structure in which metal ions are adsorbed to ceramic particles dispersed in the plating.
  • the mechanism of precipitation on the negative electrode is presumed as follows.
  • the alumina particles which have a large amount of acid adsorption, form positively charged colloidal particles in a strongly acidic solution. It is thought that the particles repel the ions and are deposited in a state in which they are not in close contact with each other.
  • alumina particles which have a large amount of base adsorption, do not form positively charged colloidal particles.
  • the method for producing the plate - like alumina particles is not particularly limited, and known and commonly used techniques such as a hydrothermal method and a flux method can be applied as appropriate.
  • a molybdenum compound and a shape control agent are preferably used from the viewpoint of being able to suitably control alumina particles having a base adsorption amount B ( ⁇ mol/m 2 ) ratio A/B of 0.5 or more and 1.5 or less.
  • a manufacturing method using a flux method can be applied.
  • a preferred method for producing plate-like alumina particles includes a step of firing an aluminum compound in the presence of a molybdenum compound and a shape control agent.
  • the firing step is a step of firing the aluminum compound in the presence of the molybdenum compound and the shape control agent.
  • the aluminum compound is a raw material for the plate-like alumina particles used in the present invention, and is not particularly limited as long as it becomes alumina by heat treatment.
  • Examples include aluminum chloride, aluminum sulfate, basic aluminum acetate, aluminum hydroxide, and boehmite. , pseudoboehmite, transition alumina ( ⁇ -alumina, ⁇ -alumina, ⁇ -alumina, etc.), ⁇ -alumina, mixed alumina having two types of crystal phases, etc. can be used, and the shape and particle size of the aluminum compound as these precursors can be used. Physical forms such as diameter and specific surface area are not particularly limited.
  • the shape of the plate-like alumina particles hardly reflects the shape of the raw material aluminum compound. , ribbons, tubes, etc.), sheets, etc., can be suitably used.
  • the particle size of the aluminum compound is hardly reflected in the plate-like alumina particles, so it is possible to suitably use aluminum compound solids of several nanometers to several hundreds of micrometers.
  • the specific surface area of the aluminum compound is also not particularly limited. Since molybdenum acts effectively, it is preferable to have a large specific surface area, but by adjusting the firing conditions and the amount of molybdenum used, any specific surface area can be used as a raw material.
  • shape control agent In order to form the plate-like alumina particles suitable for the present invention, it is more preferable to use a shape control agent.
  • the shape control agent affects the surface properties of the produced alumina particles, and promotes plate-like crystal growth of alumina by firing the alumina compound in the presence of molybdenum.
  • the state of existence of the shape control agent is not particularly limited as long as it can come into contact with the aluminum compound.
  • a physical mixture of a shape control agent and an aluminum compound, a composite in which a shape control agent is uniformly or locally present on the surface or inside of an aluminum compound, and the like can be preferably used.
  • the shape control agent may be added to the aluminum compound, or may be included as an impurity in the aluminum compound.
  • shape control agent if molybdenum oxide can suppress selective adsorption on the [113] plane of ⁇ -alumina during high-temperature firing in the presence of a molybdenum compound and can form a plate-like shape, it is particularly desirable. Not restricted. It is preferable to use a metal compound other than a molybdenum compound and an aluminum compound because it has a higher aspect ratio, better dispersibility, and better productivity.
  • specific shape control agents include silicon atom, sodium atom, germanium atom, potassium atom, and compounds thereof, but the shape control agent contained in the present invention is limited to the above elements and compounds. It is not something that can be done.
  • the silicon atom or silicon compound is not particularly limited, and known ones can be used. Specific examples include artificially synthesized silicon compounds such as metal silicon, organic silane, silicon resin, silica fine particles, silica gel, mesoporous silica, SiC and mullite; and natural silicon compounds such as biosilica. Of these, organic silanes, silicon resins, and fine silica particles are preferably used from the viewpoint of more uniform formation of composites and mixtures with aluminum compounds.
  • the silicon atoms or silicon compounds may be used alone or in combination of two or more.
  • the shape of the silicon atom or silicon compound is not particularly limited, and for example, spherical, amorphous, structures with aspect (wires, fibers, ribbons, tubes, etc.), sheets, etc. can be suitably used.
  • the amount of silicon atom or silicon compound used is not particularly limited, but it is preferably 0.0001 to 1 mol, more preferably 0.001 to 0.5 mol, per 1 mol of aluminum metal in the aluminum compound. more preferred.
  • the amount of silicon atoms or silicon compound used is within the above range, it is preferable because plate-like alumina particles having a high aspect ratio and excellent dispersibility can be easily obtained.
  • the sodium atom or sodium compound is not particularly limited, and known ones can be used.
  • Specific examples of sodium atoms or sodium compounds include sodium carbonate, sodium molybdenum, sodium oxide, sodium sulfate, sodium hydroxide, sodium nitrate, sodium chloride, sodium metal and the like.
  • sodium carbonate, sodium molybdate, sodium oxide, and sodium sulfate are preferably used from the viewpoint of industrial availability and ease of handling.
  • a sodium atom or a sodium compound may be used individually or may be used in combination of 2 or more types.
  • the shape of the sodium atom or sodium compound is not particularly limited, and for example, spherical, amorphous, structures with aspect (wires, fibers, ribbons, tubes, etc.), sheets, etc. can be suitably used.
  • the amount of sodium atom or sodium compound used is not particularly limited, but it is preferably 0.0001 to 2 mol, more preferably 0.001 to 1 mol, per 1 mol of aluminum metal in the aluminum compound. .
  • amount of sodium or the compound containing a sodium atom is within the above range, plate-like alumina particles having a high aspect ratio and excellent dispersibility are easily obtained, which is preferable.
  • germanium atom or germanium compound is not particularly limited, and known ones can be used. Specific examples of germanium atoms or germanium compounds include germanium metal, germanium dioxide, germanium monoxide, germanium tetrachloride, and organic germanium compounds having a Ge—C bond. Germanium atoms or germanium compounds may be used alone or in combination of two or more.
  • germanium atoms or germanium compounds is not particularly limited, and for example, spherical, amorphous, structures with aspect (wires, fibers, ribbons, tubes, etc.), sheets, etc. can be suitably used.
  • the potassium atom or potassium compound is not particularly limited, but potassium chloride, potassium chlorite, potassium chlorate, potassium sulfate, potassium hydrogensulfate, potassium sulfite, potassium hydrogensulfite, potassium nitrate, potassium carbonate, potassium hydrogencarbonate, acetic acid Potassium, potassium oxide, potassium bromide, potassium bromate, potassium hydroxide, potassium silicate, potassium phosphate, potassium hydrogen phosphate, potassium sulfide, potassium hydrogen sulfide, potassium molybdate, potassium tungstate and the like.
  • the potassium compound includes isomers.
  • potassium carbonate, potassium hydrogen carbonate, potassium oxide, potassium hydroxide, potassium chloride, potassium sulfate, and potassium molybdate are preferably used, and potassium carbonate, potassium hydrogen carbonate, potassium chloride, potassium sulfate, and potassium molybdate are preferably used. It is more preferable to use, the above-mentioned potassium compounds may be used alone or in combination of two or more.
  • molybdenum compound As will be described later, the molybdenum compound functions as a flux for alpha crystal growth of alumina at relatively low temperatures.
  • molybdenum compounds include, but are not limited to, molybdenum oxide and compounds containing an acid root anion (MoOx n-) formed by combining molybdenum metal with oxygen.
  • the acid radical anion (MoOx n-)-containing compound is not particularly limited, but molybdic acid, sodium molybdate, potassium molybdate, lithium molybdate, H 3 PMo 12 O 40 , H 3 SiMo 12 O 40 , NH 4Mo7O12 , molybdenum disulfide and the like.
  • the molybdenum compound may contain silicon atoms and/or silicon and/or potassium compounds, in which case the molybdenum compound containing the silicon atoms and/or silicon and/or potassium compounds is both a fluxing agent and a shape control agent. play a role.
  • molybdenum oxide it is preferable to use molybdenum oxide from the viewpoint of cost. Moreover, the above molybdenum compounds may be used alone or in combination of two or more.
  • the amount of the molybdenum compound used is not particularly limited, but is preferably 0.01 to 3.0 mol, more preferably 0.03 to 0.7 mol, per 1 mol of aluminum metal in the aluminum compound. more preferred. When the amount of the molybdenum compound used is within the above range, it is preferable because plate-like alumina particles having a high aspect ratio and excellent dispersibility can be easily obtained.
  • the firing method is not particularly limited, and can be carried out by a known and commonly used method.
  • the firing temperature exceeds 700°C
  • the aluminum compound and the molybdenum compound react to form aluminum molybdate.
  • the firing temperature reaches 900° C. or higher
  • the aluminum molybdate is decomposed to form tabular alumina particles by the action of the shape control agent.
  • the plate-like alumina particles are obtained by incorporating a molybdenum compound into the aluminum oxide particles when aluminum molybdate decomposes to form alumina and molybdenum oxide.
  • the states of the aluminum compound, the shape control agent, and the molybdenum compound are not particularly limited as long as they exist in the same space where the molybdenum compound and the shape control agent can act on the aluminum compound. Specifically, it may be simple mixing of powders of a molybdenum compound, a shape control agent and an aluminum compound, mechanical mixing using a grinder or the like, mixing using a mortar or the like, and dry conditions. , may be mixed in a wet state.
  • the condition of the sintering temperature is not particularly limited, and can be appropriately determined according to the target average particle size, aspect ratio, etc. of the plate-like alumina particles.
  • the firing temperature should be 900° C. or higher, which is the decomposition temperature of aluminum molybdate (Al 2 (MoO 4 ) 3 ).
  • the calcination temperature can be as high as over 2000° C., but even at a temperature of 1600° C. or less, which is considerably lower than the melting point of ⁇ -alumina, the ⁇ crystallization rate is maintained regardless of the shape of the precursor. It is possible to form ⁇ -alumina having a plate-like shape with a high surface area and a high aspect ratio.
  • the maximum firing temperature is 900 ° C. to 1600 ° C., it is possible to efficiently form plate-like alumina particles having a high aspect ratio and an ⁇ crystallization rate of 90% or more at low cost. Firing at a temperature of 950 to 1500°C is more preferred, and firing at a maximum temperature in the range of 980 to 1400°C is most preferred.
  • the heating time to the predetermined maximum temperature is in the range of 15 minutes to 10 hours, and the holding time at the maximum firing temperature is in the range of 5 minutes to 30 hours.
  • the firing and holding time is about 10 minutes to 15 hours.
  • the firing atmosphere is not particularly limited as long as the effects of the present invention can be obtained.
  • an oxygen-containing atmosphere such as air or oxygen
  • an inert atmosphere such as nitrogen or argon
  • is preferable, and when cost is taken into consideration. is more preferably an air atmosphere.
  • the device for firing is not necessarily limited, and a so-called firing furnace can be used.
  • the firing furnace is preferably made of a material that does not react with the sublimated molybdenum oxide, and it is preferable to use a firing furnace with a high degree of airtightness so as to efficiently use the molybdenum oxide.
  • the method for producing plate-like alumina particles may further include a molybdenum removing step of removing at least part of molybdenum after the firing step, if necessary.
  • Molybdenum can adhere to the surface of plate-like alumina particles.
  • the molybdenum can be removed by washing with water, an aqueous ammonia solution, an aqueous sodium hydroxide solution, and an acidic aqueous solution.
  • the molybdenum content can be controlled by appropriately changing the concentrations and amounts of the water, ammonia aqueous solution, sodium hydroxide aqueous solution, and acidic aqueous solution used, as well as the cleaning sites and cleaning time.
  • the acid adsorption amount and base adsorption amount per surface area of the alumina particles can be further controlled.
  • the calcined product aggregates plate-like alumina particles and does not satisfy the particle size range suitable for the present invention. Therefore, the plate-like alumina particles may be pulverized so as to satisfy the particle size range suitable for the present invention, if necessary.
  • the method of pulverizing the fired product is not particularly limited, and conventionally known pulverizing methods such as ball mill, jaw crusher, jet mill, disc mill, spectromill, grinder and mixer mill can be applied.
  • the plate-like alumina particles may preferably be classified in order to adjust the average particle size suitable for the present invention.
  • Classification refers to an operation of grouping particles according to their size. Classification may be either wet or dry, but dry classification is preferred from the viewpoint of productivity. Dry classification includes classification by sieve, air classification based on the difference between centrifugal force and fluid drag force, etc., but from the viewpoint of classification accuracy, air classification is preferable. It can be carried out using a classifier such as a swirling airflow classifier, a forced vortex centrifugal classifier, and a semi-free vortex centrifugal classifier.
  • the pulverization process and the classification process described above can be performed at necessary stages including before and after the organic compound layer forming process described below.
  • the average particle size of the obtained plate-like alumina particles can be adjusted by the presence or absence of pulverization and classification and the selection of conditions for them.
  • Plate-like alumina particles that are less agglomerated or not agglomerated are more likely to exhibit their original properties and have better handleability themselves, and when used by being dispersed in a medium to be dispersed, they are more dispersed. It is preferable from the viewpoint of excellent properties.
  • the method for producing plate-like alumina particles if particles with little or no agglomeration can be obtained without performing the pulverization step or classification step described above, there is no need to perform the above steps, and the intended excellent properties can be obtained. It is preferable because the plate-like alumina having can be produced with high productivity.
  • the obtained plating film was measured with a load of 100 gf ⁇ 14 sec using a Shimadzu dynamic ultra-micro hardness tester DUH211Y (manufactured by Shimadzu Corporation).
  • ⁇ Body abrasion test of plating film> The obtained plating film was evaluated for abrasion coefficient and polishing marks using a Tribometer (manufactured by CSM Instruments). SUJ2 (ball shape, size 9.00 mm) was used as a friction partner material. The measurement conditions were a contact load of 2.00 N, a friction speed of 5.00 cm/s, and a friction time of 600 seconds. The polishing marks were evaluated by 3D observation of the polishing marks after the measurement with a laser microscope.
  • the temperature was lowered to room temperature at 5° C./min, and the crucible was taken out to obtain 34.2 g of pale blue powder.
  • the resulting powder was ground in a mortar until it passed through a 106 ⁇ m sieve.
  • the obtained pale blue powder was dispersed in 150 mL of 0.5% aqueous ammonia, the dispersion solution was stirred at room temperature (25 to 30° C.) for 0.5 hours, filtered to remove the aqueous ammonia, and washed with water. and drying to remove molybdenum remaining on the surface of the particles to obtain 33.5 g of pale blue powder.
  • the obtained powder had a plate-like shape, contained extremely few aggregates, and had plate-like particles with excellent handleability. Furthermore, when XRD measurement was performed, a sharp peak scattering derived from ⁇ -alumina appeared, no alumina crystal system peak other than the ⁇ crystal structure was observed, and it was confirmed that the plate-like alumina particles had a dense crystal structure. bottom. In addition, the ⁇ conversion rate was 99% or more (almost 100%). Furthermore, from the results of fluorescent X-ray quantitative analysis, it was confirmed that the obtained particles contained 0.8% molybdenum in terms of molybdenum trioxide and 1.9% silicon in terms of silicon dioxide. .
  • the acid adsorption amount was measured using potentiometric titration COM-1700 (manufactured by Hiranuma Sangyo Co., Ltd.). 15 mL of 0.001 mol/L p-toluenesulfonic acid (PTSA)/n-propyl acetate (NPAC) solution was added to 1 g of alumina particles and mixed with a rotation-revolution stirrer (2000 rpm, 3 minutes). The alumina particles were then sedimented by centrifugation (8000 rpm, 20 minutes).
  • PTSA p-toluenesulfonic acid
  • NPAC n-propyl acetate
  • ⁇ Measurement of base adsorption amount of alumina particles The amount of base adsorption on alumina particles was measured using potentiometric titration COM-1700 (manufactured by Hiranuma Sangyo Co., Ltd.). 15 mL of a 0.001 mol/L tetrabutylammonium hydroxide (TBAH)/NPAC solution was added to 1 g of alumina particles and mixed with a rotation-revolution stirrer (2000 rpm, 3 minutes). The alumina particles were then sedimented by centrifugation (8000 rpm, 20 minutes).
  • TBAH 0.001 mol/L tetrabutylammonium hydroxide
  • the specific surface area can be obtained as a surface area per 1 g of plate-like alumina particles measured by a nitrogen gas adsorption/desorption method according to the BET method, such as JIS Z 8830: BET 1-point method (adsorbed gas: nitrogen). More specifically, a sample of alumina particles was pretreated at 300° C. for 3 hours, and then the specific surface area of the pretreated sample was measured using TriStar 3000 manufactured by Micromeritics. The specific surface area was 1.7 m 2 /g.
  • the plate-like alumina particles obtained in Synthesis Example 1 were measured using a laser diffraction particle size distribution analyzer HELOS (H3355) & RODOS (manufactured by Japan Laser Co., Ltd.) under the conditions of a dispersion pressure of 3 bar and a suction pressure of 90 mbar to obtain a median diameter of D50 ( ⁇ m). was determined and defined as the average particle size L ( ⁇ m).
  • the average particle size L was 9.5 ⁇ m.
  • the aspect ratio L/D of plate-like alumina particles was obtained using the following formula.
  • the aspect ratio L/D was 15.
  • Aspect ratio average particle size L of plate-like alumina particles / average thickness D of plate-like alumina particles
  • the ⁇ conversion rate and Mo content of the plate-like alumina particles obtained in Synthesis Example 1 were analyzed by the following methods.
  • the prepared sample is placed on a measurement sample holder with a depth of 0.5 mm, filled so as to be flat with a constant load, and set in a wide-angle X-ray diffractometer (Rint-Ultma manufactured by Rigaku Co., Ltd.), Cu / K ⁇ . Measurement was performed under the conditions of line, 40 kV/30 mA, scan speed of 2 degrees/minute, and scan range of 10 to 70 degrees. The ⁇ -conversion rate was obtained from the ratio of the strongest peak heights of ⁇ -alumina and transition alumina.
  • Example 1 The tabular alumina of Synthesis Example 1 was added to a commercially available trivalent chromium plating solution Top Fine Chrome LG (manufactured by Okuno Chemical Industry Co., Ltd.) at a concentration of 20 g/L.
  • Top Fine Chrome LG manufactured by Okuno Chemical Industry Co., Ltd.
  • the washed iron plate is immersed in the above plating bath, the iron plate is used as the negative electrode, the counter electrode is used as the positive electrode, and the current density is 20 A / dm 2 , the plating bath temperature is 35 ° C. to 40 ° C., and the application time is 40 minutes while stirring the plating bath.
  • a composite hard chromium plating treatment was performed to form a composite hard chromium plating film having a film thickness of about 10 ⁇ m on the iron plate. From the obtained composite hard chromium plating film, the adhesion between the plating film and the filler and polishing marks were evaluated (Figs. 1 and 3).
  • Example 1 A composite hard chromium plating film having a thickness of about 10 ⁇ m was formed on an iron plate in the same manner as in Example 1, except that commercially available plate-like alumina particles YFA10030 (manufactured by Kinseimatec Co., Ltd.) were used as the plate-like alumina particles. From the obtained composite hard chromium plating film, the adhesion between the plating film and the filler and polishing marks were evaluated (Fig. 4).
  • Example 2 A chromium plating film having a film thickness of about 10 ⁇ m was formed on an (iron plate) in the same manner as in Example 1, except that plate-like alumina particles were not added. From the obtained composite hard chromium plating film, the adhesion between the plating film and the filler and polishing marks were evaluated (Fig. 2).

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  • General Engineering & Computer Science (AREA)
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  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
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MX2024005432A MX2024005432A (es) 2021-11-18 2022-11-10 Cromado duro compuesto.
CN202280062430.9A CN117940615A (zh) 2021-11-18 2022-11-10 复合硬质铬镀覆
DE112022005520.0T DE112022005520T5 (de) 2021-11-18 2022-11-10 Verbund-hartverchromung
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01246398A (ja) * 1988-03-28 1989-10-02 Sumitomo Metal Ind Ltd 複合分散粒子の製造方法及び複合めっき方法
JPH05148691A (ja) * 1991-11-25 1993-06-15 Mitsubishi Heavy Ind Ltd アルミナ／高分子物質複合微粒子
JP2014196533A (ja) * 2013-03-29 2014-10-16 株式会社リケン 複合硬質クロムめっき皮膜、及びかかる皮膜を被覆した摺動部材
WO2021131339A1 (ja) * 2019-12-23 2021-07-01 ディップソール株式会社 亜鉛－ニッケル－シリカ複合めっき浴及び該浴を用いるめっき方法

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JP6055611B2 (ja) 2012-05-22 2016-12-27 日本化学工業株式会社 クロムめっき物及びクロムめっき皮膜
JP6240274B2 (ja) 2016-08-08 2017-11-29 日本化学工業株式会社 クロムめっき物及びクロムめっき皮膜
JP6417438B2 (ja) 2017-03-22 2018-11-07 株式会社リケン 複合クロムめっき皮膜、及び当該皮膜を有するピストンリング

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01246398A (ja) * 1988-03-28 1989-10-02 Sumitomo Metal Ind Ltd 複合分散粒子の製造方法及び複合めっき方法
JPH05148691A (ja) * 1991-11-25 1993-06-15 Mitsubishi Heavy Ind Ltd アルミナ／高分子物質複合微粒子
JP2014196533A (ja) * 2013-03-29 2014-10-16 株式会社リケン 複合硬質クロムめっき皮膜、及びかかる皮膜を被覆した摺動部材
WO2021131339A1 (ja) * 2019-12-23 2021-07-01 ディップソール株式会社 亜鉛－ニッケル－シリカ複合めっき浴及び該浴を用いるめっき方法

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