JP2006200041A - High strength alloy, metal material coated with the high strength alloy and micro structure obtained by using the high strength alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high strength alloy with a satisfactory toughness which can be used suitably as a material for a micro structure, and also to provide a metal coated with the high strength alloy and a micro structure obtained by using the high strength alloy. <P>SOLUTION: The high strength alloy is obtained by depositing metals electrolytically at a bath temperature of 40 to 80°C using an electrolyte of a composition in which the total of Ni ion or Co ion and W ion or Mo ion is in the range of 0.1 to 0.3 mol/L and in which a content ratio of Ni ion or Co ion in the above metal ions is in the range of 20 to 40%. The high strength alloy has an amorphous structure or a nanocrystal structure with an average crystal grain size of ≤100 nm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a high-strength alloy suitable as a material for a microstructure that can be obtained by applying specific electrolytic conditions, a metal formed by coating the high-strength alloy, and a microstructure using the high-strength alloy It is about.

  Electrodeposited alloys have been used mainly as surface coating materials for the purpose of imparting functions such as corrosion resistance and wear resistance to a material that becomes a substrate. However, in recent years, as represented by the LIGA process (micro-molding technology combining lithography using synchrotron radiation, electrolytic deposition and mold molding, developed at the Karlsruhe Research Center in Germany) Development of manufacturing technology for complex microstructures using analyzed alloys is underway.

  In addition, with the development of semiconductor integrated circuit technology, electronic devices are required to have higher density and more functions. In particular, in the portable electronic device, the mounting density of electronic components is required to have a wiring density of 100 μm or less. As a means for repairing, replacing, or expanding the functions of these minute electronic circuit components, the soldering connection method is extremely difficult to work, and may have an unacceptable thermal effect on the peripheral board. . In order to solve this problem, a connector using the microstructure is provided. However, the metal materials that have been used for the microstructures so far are limited to soft materials such as nickel, copper, and gold that are easily electrodeposited. These materials include micro mold materials and drive sliding functions. In other words, it is too soft to be used as a material for micro parts that requires a large amount of material, and does not have sufficient strength and toughness as a structural material.

  On the other hand, various hard electrodeposited alloys represented by Ni-P alloys have been proposed, but any of these alloys is very brittle and cannot be used as a material for a microstructure.

  The present invention has been made in view of such problems of the prior art, and its purpose is to provide a high-strength alloy having sufficient toughness that can be suitably used as a material for a microstructure, and its The object is to provide a metal material coated with a high-strength alloy and a microstructure using the high-strength alloy.

  In order to achieve the above object, the present invention uses an electrolytic aqueous solution having a specific composition containing a specific amount of Ni ions or Co ions and W ions or Mo ions. In the electrolytic aqueous solution of this specific composition, the eutectoid of hydrogen on the cathode substrate is suppressed, and it has high strength with ultrafine crystal grain structure or amorphous structure that is electrolytically deposited under high electrolytic deposition efficiency. Ni-W, Ni-Mo, Co-W or Co-Mo alloys can be provided.

  That is, the present invention comprises the following first to fifth inventions.

  The high-strength alloy of the first invention is such that the sum of Ni ions or Co ions and W ions or Mo ions is in the range of 0.1 to 0.3 mol / L, and the content ratio of Ni ions or Co ions in the metal ions A high-strength alloy obtained by electrolytic deposition using an electrolytic bath having a composition (molar concentration) in the range of 20 to 40% at a bath temperature of 40 to 80 ° C., having an amorphous structure or an average crystal grain size Has a nanocrystal structure of 100 nm or less.

  The high-strength alloy of the second invention has a composition containing 8 to 30 atomic% of W or Mo, a hydrogen atom content of 1.00 atomic% or less, and an oxygen atom content of 0.50 atomic% or less. And the balance is made of Ni or Co.

  The third invention is the high-strength alloy of the second invention, wherein the total of Ni ions or Co ions and W ions or Mo ions is in the range of 0.1 to 0.3 mol / L, and the Ni ions in the metal ions Alternatively, it is characterized in that it is obtained by electrolytic deposition at a bath temperature of 40 to 80 ° C. using an electrolytic bath having a composition with a Co ion content ratio (molar concentration) in the range of 20 to 40%.

  The metal material of the fourth invention is characterized by being coated with the high-strength alloy of the first, second or third invention.

  The microstructure of the fifth invention is characterized by using the high-strength alloy of the first, second or third invention.

  According to the first, second, and third aspects of the invention, it is possible to provide an ultra high strength alloy having sufficient toughness. Moreover, according to the invention of Claim 4, the metal material coat | covered with the ultra high strength alloy can be provided. Furthermore, according to the invention described in claim 5, it is possible to provide a microstructure suitable as a material for a micro component.

In the first invention, the total content of Ni ions or Co ions and W ions or Mo ions is in the range of 0.1 to 0.3 mol / L (liter), and the content ratio of Ni ions or Co ions in the metal ions ( A high strength alloy obtained by electrolytic deposition using an electrolytic bath having a composition in the range of 20 to 40% at a bath temperature of 40 to 80 ° C., having an amorphous structure or an average crystal grain size. Although it is a high-strength alloy having a nanocrystal structure of 100 nm or less, the reason for limiting the numerical values in the present invention is as described below.
(B) When the bath temperature of the electrolytic bath is lower than 40 ° C. or higher than 80 ° C., the efficiency of electrolytic deposition of metal atoms is reduced, and hydrogen elements are easily generated on the cathode plate. Due to hydrogen embrittlement, no high strength is exhibited.
(B) When the sum of Ni ions or Co ions and W ions or Mo ions is less than 0.1 mol / L, the metal ion concentration is too low, so that the rate of electrolytic deposition is too low and the thickness exceeds a certain level. For example, in the case of the LIGA process, it is difficult to form an alloy film having a thickness of 100 μm or more, and a burn-in phenomenon is observed, which is not preferable. On the other hand, if the sum of Ni ions or Co ions and W ions or Mo ions exceeds 0.3 mol / L, the tensile residual stress of the electrodeposited alloy increases, and a severe embrittlement state is exhibited.
(C) When the content ratio (molar concentration) of Ni ions or Co ions in metal ions composed of Ni ions or Co ions and W ions or Mo ions is less than 20%, the concentration of Ni ions or Co ions is too low. The electrolytic deposition rate is too low, and it becomes difficult to form an alloy film having a certain thickness (for example, a thickness of 100 μm or more in the case of the LIGA process). On the other hand, when the content ratio (molar concentration) of Ni ions or Co ions in the metal ions composed of Ni ions or Co ions and W ions or Mo ions exceeds 40%, the tensile residual stress of the electrodeposited alloy increases, which is severe. An embrittled state is exhibited, which is not preferable.

  And by having a nanocrystal structure with an amorphous structure or an average crystal grain size of 100 nm or less, the strength can be dramatically improved. On the other hand, in the case of an alloy having a nanocrystal structure, the average crystal grain size of the high-strength alloy may be 15 nm or less from the viewpoint that the hard nanoparticles do not collide with each other and the grain boundary slip occurs and high toughness can be expressed. Further preferred.

  The second invention has a composition containing 8 to 30 atomic% of W or Mo, a hydrogen atom content of 1.00 atomic% or less, and an oxygen atom content of 0.50 atomic% or less, and the balance Is a high-strength alloy made of Ni or Co. The reasons for limiting the numerical values of the W or Mo content, the hydrogen atom content, and the oxygen atom content are as described below.

  That is, when the hydrogen atom content is 1.00 atomic% or less, so-called hydrogen embrittlement does not occur and toughness can be improved. The cause of this hydrogen embrittlement is said to be due to the formation of hydrides at the grain boundaries, and the decrease in grain boundary bonding force due to hydrogen adsorbed on the grain boundaries or hydrogen carried to the grain boundaries by dislocation during plastic deformation. However, when oxygen is present at the same time as hydrogen, severe hydrogen cracking occurs. This is because oxygen adsorbed on metal atoms during electrolytic deposition and heat treatment generates a stable compound with hydrogen, thereby significantly reducing the bonding force at the grain interface, and as a result, generating microcracks. This is because embrittlement cannot be avoided even after dehydrogenation. In this respect, the oxygen atom content is preferably 0.50 atomic% or less. In order to avoid such embrittlement due to the presence of hydrogen and oxygen and improve toughness, it is more preferable that the hydrogen atom content is 0.20 atomic% or less and the oxygen atom content is 0.20 atomic% or less. Most preferably, it does not contain hydrogen and oxygen at all. However, it is inevitable that hydrogen atoms and oxygen atoms are contained in an amount of about 0.01 atomic% by the principle of electrolytic deposition. As a result, the strength and toughness are not adversely affected.

  Also, when obtaining a high-strength alloy with W or Mo exceeding 30 atomic%, the electrolytic bath temperature and the electrolytic current density are increased, the electrolytic deposition efficiency of metal atoms is lowered, and hydrogen atoms are likely to be generated on the cathode plate. The obtained alloy does not show high strength due to hydrogen embrittlement. When W or Mo is less than 8 atomic%, Ni or Co is electrodeposited at a low electrolysis current density before W or Mo is electrodeposited, and the content of W or Mo in the alloy is reduced. The strength cannot be secured.

  Therefore, a composition containing 8 to 30 atomic% of W or Mo, the balance being made of Ni or Co, a hydrogen content of 1.00 atomic% or less, and an oxygen content of 0.50 atomic% or less. The alloy formed by electrolytic deposition has high strength and high toughness.

  The third invention is the high-strength alloy of the second invention, wherein the total of Ni ions or Co ions and W ions or Mo ions is in the range of 0.1 to 0.3 mol / L, and the Ni ions in the metal ions Alternatively, it is obtained by electrolytic deposition at a bath temperature of 40 to 80 ° C. using an electrolytic bath having a composition with a Co ion content ratio (molar concentration) in the range of 20 to 40%. Reasons for limiting the numerical values of the bath temperature, the sum of Ni ions or Co ions and W ions or Mo ions, and the content ratio (molar concentration) of Ni ions or Co ions in the metal ions are as described above in (a), (b), (c) ).

  The fourth invention is a metal material coated with the high-strength alloy of the first, second or third invention. In this specification, “coating” is synonymous with “plating” and includes electroplating, chemical plating, hot dipping, and the like. If the high strength alloy having the above characteristics is coated on, for example, a metal frame of an electrical product or the inner surface of an oil transportation metal pipe, the metal frame or It can prevent cracks and corrosion of metal pipes.

  In the first or third aspect of the invention, by performing baking following electrolytic deposition, eutectoid hydrogen generated along with electrolytic deposition is released (hereinafter referred to as “baking effect”), and hydrogen embrittlement is prevented. Therefore, the strength can be further improved, which is preferable.

  The baking temperature is preferably 50 to 200 ° C. If the baking temperature is less than 50 ° C., the baking effect is not sufficient. If the baking temperature exceeds 200 ° C., the baking effect is not improved and extra energy is required, which is economically disadvantageous. Therefore, by heating to 50 to 200 ° C. following electrolytic deposition, it is possible to efficiently enjoy the baking effect and obtain an ultra-high strength alloy. However, if the baking time becomes long, the alloy may be brittle due to the progress of the formation reaction of oxygen and hydrogen compounds in the alloy and the entry of oxygen from the atmosphere. In the system, it is preferably 1 to 3 hours, and more preferably 1.5 to 2.5 hours. Since the bond strength between nickel and hydrogen is stronger than the bond strength between iron and hydrogen, the baking time of the alloy system based on Ni is preferably longer than the baking time of the alloy system based on iron.

  The fifth invention is a microstructure using the high-strength alloy of the first, second or third invention. By using such an alloy, a high-strength microstructure suitable as a material for a micro component can be provided.

Examples of the present invention will be described below.
1. Preparation of Ni-W alloy (1) When the composition of the electrolytic bath is A as described below The composition of the electrolytic bath is nickel sulfate (NiSO ₄ ) with a concentration of 0.06 mol / L, and the concentration is 0.14-0. Sodium citrate (Na ₃ C ₆ H ₅ O ₇ -2H ₂ O) varied in the range of 5 mol / L and sodium tungstate (Na ₂ WO ₄ -2H ₂ O) at a concentration of 0.14 mol / L In the case of the composition A mainly composed of ammonium chloride (NH ₄ Cl) at a concentration of 0.5 mol / L, a platinum anode plate having a size of 0.5 mm × 30 mm × 40 mm and 0.2 mm × 30 mm × Electrolysis was performed using a copper cathode plate having a size of 40 mm. Moreover, the electrolysis current density was changed in the range of 5 to ²⁰ A / dm ² , thereby changing the W content of the alloy. A CFC mask was applied to one side of the copper cathode plate, and the alloy was deposited only on one side without the mask. The copper cathode plate was subjected to an electropolishing treatment using a phosphoric acid: water = 2: 1 solution as a pretreatment. In addition, during electrolytic deposition, the electrolytic bath is constantly stirred using a hot stirrer so that the bath temperature during each experiment shown below is constant, and at the same time, the pH during electrolytic deposition using a pH controller is maintained. Was kept constant (about 7.4-7.5). The electrolytic deposition time was 0.5 hour.

  After electrolytic deposition, the copper cathode plate (hereinafter also referred to as copper plate) is dissolved and removed with a chromic acid-sulfuric acid mixed aqueous solution (mixed liquid of chromic acid 250 g / L and sulfuric acid 15 cc / L), so that only the Ni-W alloy is obtained. Was left on the copper plate.

Hereinafter, the experimental results will be sequentially described.
(A) Bath temperature and alloy deposition rate when the electrolytic bath composition is A Bath temperature (° C.) and electrodeposition rate (mg / cm) when the bath temperature of the electrolytic bath is changed in the range of 20 to 90 ° C. ² hr) is shown in FIG. The electrolytic current density at this time was 5 A / dm ² . In FIG. 1, “Δ”, “●”, and “◯” indicate sodium citrate concentrations of 0.50 mol / L, 0.25 mol / L, and 0.14 mol / L, respectively. For the rate of electrolytic deposition, the weight (mg) per hour deposited on 1 cm ^{2 of the} copper plate was calculated from the difference in weight of the copper plate before and after electrolytic deposition.

  In each reference numeral, what is indicated by the symbol t indicates “high toughness” that does not break even after complete adhesion bending. As shown in FIG. 2, the bending test for evaluating the toughness is performed as follows: a test piece having a thickness d (a copper cathode plate obtained by electrolytically depositing a Ni—W alloy) between transparent quartz flat plates 1, 1. ) 2 is bent and sandwiched so that the flat plates 1 and 1 are brought into close contact with each other, the distance L between the flat plates 1 and 1 when the test piece 2 is broken is measured with a micrometer, and curved. If the strain amount at the center of the test piece 2 is zero, the surface strain ε of the curved test piece is ε = d / (L−d) (hereinafter referred to as “expression of ε”). The toughness was evaluated by the value. “No breakage even after complete contact bending” means that the test piece that contacts the upper flat plate 1 and the test piece that contacts the lower flat plate 1 are in complete contact with each other without breaking. , L = 2d, and ε = 1.0.

  That is, in the Ni-W alloy, the bath temperature is 75 ° C. when the sodium citrate concentration is 0.5 mol / L, and the bath temperature is 60 when the sodium citrate concentration is 0.25 mol / L. When the concentration of sodium citrate is 0.14 mol / L, the Ni-W alloy having extremely excellent toughness can be obtained by electrolytic deposition at bath temperatures of 40 ° C and 50 ° C, respectively. it can.

As apparent from FIG. 1, when the concentration of sodium citrate is increased, the point showing high toughness (pointed by the symbol t) is shifted to a higher bath temperature side.
(B) Bath temperature and crystal grain size when the electrolytic bath composition is A The bath temperature (° C.) and the average crystal of the Ni—W alloy when the sodium citrate concentration shown in FIG. 1 is 0.14 mol / L FIG. 3 shows the relationship with the particle size (× 10 ⁻⁹ m), and the bath temperature (° C.) and the average of the Ni—W alloy when the sodium citrate concentration shown in FIG. 1 is 0.25 mol / L. FIG. 4 shows the relationship with the crystal grain size (× 10 ⁻⁹ m). In FIG. 3, those exhibiting high toughness (pointed by the symbol t) have crystal grain sizes of about 5.15 × 10 ⁻⁹ m and about 7.0 × 10 ⁻⁹ m. Those exhibiting toughness (pointed by the symbol t) have a crystal grain size of about 6.1 × 10 ⁻⁹ m and are all fine crystals. The crystal grain size was determined by the method described below.
(C) Bath temperature and W content when the electrolytic bath composition is A The bath temperature (° C.) when the sodium citrate concentration shown in FIG. 1 is 0.14 mol / L and the W in the Ni-W alloy. FIG. 5 shows the relationship with the content (atomic%), and the bath temperature (° C.) and the W content in the Ni—W alloy when the sodium citrate concentration shown in FIG. 1 is 0.25 mol / L. The relationship with (atomic%) is shown in FIG. 5 and 6, the W content of the Ni—W-based alloy exhibiting high toughness (pointed by the symbol t) is about 10 to 12 atomic%. In addition, W content was calculated | required by the quantitative analysis method by ZAF correction | amendment using the angle dispersion | distribution type EPMA (X-ray microanalyzer) analyzer (JXA-8900R by the JEOL datum company).
(D) X-ray diffraction pattern when the electrolytic bath composition is A The structure of the Ni-W alloy was calculated and the crystal grain size was calculated using an X-ray diffraction measurement device (RINT-1500) manufactured by Rigaku Denki. . Measurement conditions were 40 kV-200 mA, and a Cu counter cathode (Cu-Kα ray) was used as a target. The crystal grain size (c _dia ) was determined from the half width of the diffraction peak using the Scherrer equation shown below.

c _dia = 0.9λ / (B cos θ) where λ is the wavelength (nm), B is the half width (radian), and θ is the diffraction angle (degrees).

  FIG. 7 shows an X-ray diffraction pattern of the Ni—W alloy in the case where the concentration of sodium citrate shown in FIG. 1 is 0.14 mol / L, and the concentration of sodium citrate shown in FIG. An X-ray diffraction pattern of the Ni—W alloy in the case of L is shown in FIG. In FIG. 7, “bath temperature, W content in alloy, average grain size of alloy” of lines a, b, c, and d are “40 ° C., 10.6 atomic%, 10.6 nm (nanometer), respectively. ”,“ 50 ° C., 12.3 atomic%, 5.2 nm ”,“ 60 ° C., 15.1 atomic%, 3.3 nm ”,“ 70 ° C., 12.8 atomic%, 5.4 nm ”. Similarly, in FIG. 8, “bath temperature, W content in alloy, average grain size of alloy” of lines e, f, g, h are “40 ° C., 7.2 atomic%, 9.9 nm”, respectively. ”,“ 50 ° C., 9.1 atomic%, 8.0 nm ”,“ 60 ° C., 11.7 atomic%, 6.3 nm ”,“ 70 ° C., 9.4 atomic%, 13.2 nm ”.

FIG. 7 shows that an amorphous structure having a wide X-ray diffraction peak with a W content of about 12 atomic% or more is shown. 7 and 8, it can be seen that when the W content is about 15 atomic% or less, a nanocrystal structure having an average crystal grain size of 15 × 10 ⁻⁹ m or less is shown.
(2) When the composition of the electrolytic bath is the following B: Nickel ammonium sulfate ((NH ₄ ) ₂ Ni (SO ₄ ) in which the concentration of the electrolytic bath was changed in the range of 0.06 to 0.12 mol / L. ) and ₂ -6H ₂ O), and sodium citrate with varying concentrations in the range of 0.10-0.16 mol _{/ L (Na 3 C 6 H} 5 O 7 -2H 2 O), a concentration of 0. Sodium tungstate (Na ₂ WO ₄ -2H ₂ O) changed in a range of 08 to 0.14 mol / L, ammonium sulfide ((NH ₄ ) ₂ SO ₄ ) having a concentration of 0.25 mol / L, In the case of the composition B mainly composed of sodium bromide (NaBr) having a concentration of 0.15 mol / L, a copper cathode plate having the same size as a platinum anode plate having a size of 0.1 mm × 30 mm × 40 mm is used. Electrolysis was performed. Also, the electrolytic current density was 5A / dm ^2. Other conditions are the same as when the electrolytic bath composition is A.

Hereinafter, the experimental results will be sequentially described.
(A) Bath temperature and alloy deposition rate when electrolytic bath composition is B Bath temperature (° C.) and electrodeposition rate (mg / cm) when bath temperature of electrolytic bath is changed in the range of 10 to 80 ° C. ² hr) is shown in FIGS. At this time, the concentration of sodium citrate was 0.14 mol / L. For the rate of electrolytic deposition, the weight (mg) per hour deposited on 1 cm ^{2 of the} copper plate was calculated from the difference in weight of the copper plate before and after electrolytic deposition. In FIG. 9, the symbols “◯” and “●” indicate “a liquid having a composition of nickel ammonium sulfate having a concentration of 0.06 mol / L and sodium tungstate having a concentration of 0.14 mol / L” and “concentration of 0. FIG. 10 shows a “liquid having a composition of 08 mol / L nickel ammonium sulfate and a sodium tungstate having a concentration of 0.12 mol / L”. In FIG. / Liquid having a composition of nickel ammonium sulfate at a concentration of 0.10 mol / L and sodium tungstate at a concentration of 0.10 mol) ”,“ a nickel ammonium sulfate at a concentration of 0.12 mol / L and sodium tungstate at a concentration of 0.08 mol / L "Liquid having the composition".

As apparent from FIGS. 9 and 10, the higher the bath temperature, the higher the precipitation rate of the alloy, and the more the Ni ion content increases (the more the ratio of Ni ions to all metal ions), the more the precipitation occurs. Although the rate is increased, even when the bath temperature is 20 ° C. and the Ni ions are 0.06 mol / L (the ratio of Ni ions to all metal ions is 30%), the deposition rate is sufficiently practical.
(B) Concentration of sodium citrate and alloy deposition rate when electrolytic bath composition is B When the bath temperature of the electrolytic bath is 30 ° C. or 40 ° C., the concentration of sodium citrate is 0.10 to 0.16 mol / L. FIG. 11 shows the relationship between the concentration of sodium citrate (mol / L) and the rate of electrodeposition (mg / cm ² hr) when changed in the range of. The electrolytic deposition rate was calculated by the method described above.

  In FIG. 11, symbols “◯” and “●” each have a composition of “ammonium nickel sulfate having a concentration of 0.10 mol / L and sodium tungstate having a concentration of 0.10 mol / L at a bath temperature of 30 ° C. Liquid "and" liquid having a composition of nickel ammonium sulfate having a concentration of 0.08 mol / L and sodium tungstate having a concentration of 0.12 mol / L ". The symbols" △ "and" ▲ " At 40 ° C., “a liquid having a composition of nickel ammonium sulfate at a concentration of 0.10 mol / L and sodium tungstate at a concentration of 0.10 mol / L”, “a nickel ammonium sulfate at a concentration of 0.08 mol / L and a concentration of 0 "Liquid having a composition of 12 mol / L sodium tungstate".

As is apparent from FIG. 11, the rate of electrodeposition is highest when the concentration of sodium citrate is 0.12 mol / L. This is considered to be because the amount of the complexing agent is optimal with respect to the amount of metal ions.
(C) X-ray diffraction pattern when the electrolytic bath composition is B The structure of the Ni-W alloy was calculated and the crystal grain size was calculated using the same X-ray diffraction measurement apparatus (RINT-1500) as above.

  FIG. 12 shows an X-ray diffraction pattern of a liquid Ni—W alloy having a concentration of nickel ammonium sulfate shown in FIG. 9 of 0.08 mol / L. In FIG. 9 and FIG. 13 ”shows the X-ray diffraction pattern of the Ni—W-based alloy having a nickel ammonium sulfate concentration of 0.08 mol / L, 0.10 mol / L, and 0.12 mol / L. Shown in

  In FIG. 12, “bath temperature, W content in alloy, average grain size of alloy” of lines i, j, k, m, n, and p are “30 ° C., 10.7 atomic%, 10. “5 nm (nanometer)”, “40 ° C., 13.7 atomic%, 9.3 nm”, “50 ° C., 13.7 atomic%, 9.3 nm” “60 ° C., 15.4 atomic%, 10.1 nm” , “70 ° C., 15.9 atomic%, 16.7 nm”, “80 ° C., 11.9 atomic%, 25.5 nm”. In FIG. 13, “Ni ion concentration, W content in alloy, and average crystal grain size of alloy” of lines q, r, and s are “0.08 mol / L, 10.7 atomic%, and 10.5 nm, respectively”. "0.10 mol / L, 12.2 atom%, 10.9 nm" "0.12 mol / L, 3.3 atom%, 13.4 nm".

The following points can be understood from FIGS. That is, it can be seen that as the bath temperature increases and the Ni ion concentration increases, the crystal grain size increases, and the W content significantly decreases as the Ni concentration increases.
2. Mechanical properties of Ni-W alloy A Mechanical properties In composition A of the above electrolytic bath, the concentration of sodium citrate is 0.5 mol / L, and the bath temperature of the electrolytic bath is 60 to 90 ° C. (333 to 363 K). Thus, the W content was changed by performing electrolytic deposition for 1 hour under the condition of an electrolytic current density of 20 A / dm ² , and the results shown in Table 1 were obtained. As is apparent from Table 1, when the bath temperature is 75 ° C. (348 K), the micro Vickers hardness HV is as high as 685, and the breaking strain (according to the equation of ε) is 1.0, that is, complete adhesion It shows the property of “ultra high toughness” that does not break even after bending. Further, a bath temperature of 80 ° C. (353 K) has a fracture strain (according to the equation of ε) of 0.416, indicating good toughness.

In the electrolytic bath composition A, the concentration of sodium citrate is 0.14 mol / L, the bath temperature of the electrolytic bath is 30 to 80 ° C. (303 to 353 K), and the electrolytic current density is 5 A / dm ² . Under the conditions, the W content was changed by performing electrolytic deposition for 1 hour, and the results shown in Table 2 were obtained. As is apparent from Table 2, those having bath temperatures of 40 ° C. (313 K) and 50 ° C. (323 K) have a high micro Vickers hardness HV of 696 to 702, and the fracture strain (according to the equation of ε). 1.0, that is, the characteristic of “ultra high toughness” that does not break even after complete adhesion bending.

(B) Increase in strength due to heat treatment (baking after alloy formation) In composition A of the above electrolytic bath, the concentration of sodium citrate is 0.5 mol / L, the bath temperature of the electrolytic bath is 75 ° C., and the electrolysis current density is 10 A / The thickness of the Ni—W alloy layer is changed by performing electrolytic deposition at dm ² or 5 A / dm ² for 1 to 4 hours. After heating (baking) at 348 K) for 2 hours and then cooling in the furnace, the hydrogen generated along with the electrolytic deposition was released to improve the strength, and the results shown in Table 3 were obtained. As is apparent from Table 3, the tensile strength of the Ni-W alloy before heating has already been as high as 438-583 MPa, but by heating this alloy at 75 ° C. (348 K) for 2 hours, An ultra-high strength of 1047 MPa could be achieved.

C Increase in strength due to heat treatment (annealing after alloy formation) (Increase in micro Vickers hardness HV (load 25 g, holding time 15 seconds))
In the electrolytic bath composition A, by performing electrolytic deposition under the conditions of a sodium citrate concentration of 0.14 mol / L, an electrolytic bath temperature of 50 ° C., and an electrolytic current density of 5 A / dm ² . An alloy of Ni-12.3 atomic% W was obtained. This Ni—W alloy is heated in vacuum at a temperature in the range of 300 ° C. (573 K) to 600 ° C. (873 K), and then cooled in a furnace to remove internal strain associated with electrolytic deposition, thereby reducing the grain size. (Maximum hardness is shown at about 15 × 10 ⁻⁹ m) to further increase the strength. As a result, as shown in Table 4, when the heating temperature was 400 to 600 ° C., an ultrahigh strength of about 850 to 921 was achieved as the micro Vickers hardness HV, but the heating temperature was 600 If it exceeds ℃, since the micro Vickers hardness HV has decreased, it can be estimated that the coarsening of crystal grains proceeds. That is, by heating (annealing) a Ni—W alloy to about 400 to 600 ° C. after electrolytic deposition, an ultrahigh strength alloy can be obtained without coarsening of crystal grains.

Effect of Ni ion concentration and bath temperature on fracture strain When the concentration of sodium citrate is 0.14 mol / L in the composition B of the electrolytic bath, the effect of Ni ion concentration and bath temperature on the fracture strain is shown in FIG. As shown in FIG. In FIG. 14, the symbols “◯” and “●” respectively indicate “a liquid having a composition of nickel ammonium sulfate having a concentration of 0.06 mol / L and sodium tungstate having a concentration of 0.14 mol / L”, “concentration of 0.3. FIG. 15 shows a liquid having a composition of 08 mol / L nickel ammonium sulfate and 0.12 mol / L sodium tungstate. / Liquid having a composition of nickel ammonium sulfate at a concentration of 0.10 mol / L and sodium tungstate at a concentration of 0.10 mol / L ”,“ a solution of nickel ammonium sulfate at a concentration of 0.12 mol / L and sodium tungstate at a concentration of 0.08 mol / L “Liquid having composition”.

As shown in FIG. 14, the fracture strain value is improved in a liquid having a composition (symbol ●) in which the concentration of nickel ammonium sulfate is 0.08 mol / L and the concentration of sodium tungstate is 0.12 mol / L. An alloy is obtained that has a tendency (i.e. improved toughness) and has a fracture strain (according to the ε equation) of 1.0 even at a bath temperature of 30 ° C. However, the fracture strain value decreases (toughness decreases) when the bath temperature increases due to the eutectoid of hydrogen or the like due to a decrease in electrolytic deposition efficiency.
E. Effect of sodium citrate concentration on fracture strain In the above electrolytic bath composition B, when the bath temperature of the electrolytic bath is 30 ° C. or 40 ° C., the concentration of sodium citrate is 0.10 to 0.16 mol / L. FIG. 16 shows the relationship between the concentration (mol / L) of sodium citrate and the strain at break when changing within the range. The electrolytic current density at this time is 5 A / dm ² . In FIG. 16, symbols “◯” and “●” each have a composition of “ammonium nickel sulfate having a concentration of 0.10 mol / L and sodium tungstate having a concentration of 0.10 mol / L at a bath temperature of 30 ° C. Liquid ”),“ liquid having a composition of nickel ammonium sulfate having a concentration of 0.08 mol / L and sodium tungstate having a concentration of 0.12 mol / L ”, and the symbols“ Δ ”and“ ▲ ”indicate the bath temperature. At 40 ° C., “a liquid having a composition of nickel ammonium sulfate with a concentration of 0.10 mol / L and sodium tungstate with a concentration of 0.10 mol / L”, “a nickel ammonium sulfate with a concentration of 0.08 mol / L and a concentration "Liquid having a composition of 0.12 mol / L sodium tungstate".

As is apparent from FIG. 16, when the concentration of sodium citrate is 0.14 mol / L (when the concentration of citrate ions is higher than the concentration of tungsten ions), the fracture strain value tends to improve (that is, Toughness is improved), and an alloy having a fracture strain (according to the equation of ε) of 1.0 even at a bath temperature of 30 ° C. is obtained. However, the toughness may decrease if the concentration of citrate ions is too high due to the decrease in the electrolytic deposition efficiency of the alloy and the eutectoid of hydrogen or the like.
3. Physical properties of Ni-W alloys (hydrogen content and oxygen content and toughness)
a. In the case where the current density is 5 A / dm ² Basically, the composition A of the electrolytic bath is used, and the other plating conditions are the results of electrolytic deposition under the conditions shown in the upper part of Table 5. As a result, the Ni—W alloy As the physical characteristics, the results shown in the lower part of Table 5 were obtained. As shown in Table 5, sample no. 2 to 4, the strain at break (according to the equation of ε) is 0.1 or more and has good toughness. Sample No. of toughness 3 has a hydrogen atom content of 0.12 atomic%, an oxygen atom content of 0.18 atomic%, and zero strain at break (cannot be bent at all). 5 and sample no. It is much less than the hydrogen atom content and oxygen atom content of 6. Both the hydrogen atom content and the oxygen atom content were measured by an inert gas melting method.

  In addition, sample No. 2 and Sample No. 4 was subjected to baking (dehydrogenation gas treatment) at 75 ° C. for 2 hours in a vacuum, so that the fracture strain (according to the equation of ε) was greatly improved to 1.0.

b. When the current density is 10 A / dm ² Basically, the composition A of the electrolytic bath is used, and the other plating conditions are the results of electrolytic deposition under the conditions shown in the upper part of Table 6. As a result, the Ni—W alloy As the physical characteristics, the results shown in the lower part of Table 6 were obtained. When Table 5 and Table 6 are compared, Sample No. with the same bath temperature of 50 ° C. is used. 3 and sample no. When the current density is increased, the hydrogen atom content in the alloy is slightly increased. 7 has a breaking strain (according to the equation of ε) of 1.0, which indicates ultra high toughness. As shown in Table 6, Sample No. with a bath temperature of 75 ° C was used. 8 has a breaking strain (according to the equation of ε) of 1.0, and sample No. Although the ultra-high toughness similar to 7 is shown, the difference in oxygen atom content is notable. That is, sample no. No. 8 had a hydrogen atom content of 0.20 atomic%. 7 but same as sample no. The oxygen atom content of 8 is extremely small at 0.03 atomic%. Thus, in the Ni-W alloy, even if the electrolysis current density is increased, if the citric acid concentration is increased and the bath temperature is increased, both the hydrogen atom content and the oxygen atom content are small. It suggests that it is possible to obtain tough alloys. It is also effective to keep the dissolved oxygen concentration in the electrolytic bath very low as a method for further reducing the oxygen concentration in the alloy.

Sample No. Although the oxygen atom content of No. 8 is very low and it has extremely excellent toughness, this sample no. The tensile strength immediately after the electrolytic deposition of No. 8 had already shown a very high value of 670 MPa. The sample was heated (baked) at 75 ° C. (348 K) for 24 hours in an Ar atmosphere, and then cooled in the furnace. The hydrogen generated along with the electrolytic deposition was released to improve the strength, and an extremely high tensile strength of 2333 MPa was achieved. In addition, sample No. No. 8 is a nanocrystalline structure having a particle size of 2 to 3 nm, and has a structure including an amorphous phase at the grain boundary portion. 2 has a particle size of about 5 nm. The tensile strength immediately after electrolytic deposition of No. 2 was as extremely high as 1100 MPa. That is, the strength is generally improved as the particle size is reduced, but if the particle size is an amorphous phase or an extremely fine particle size of about 5 nm or less, the strength may be slightly reduced.
4). Production of Micro Structure An example of a method for producing a micro structure using the high-strength alloy according to the present invention will be described with reference to FIG.
(1) Irradiation of radiated light The radiated light 4 is irradiated to the photosensitive resin 3 coated on the conductive substrate 2 through the photomask 1 (FIG. 17A).
(2) Development of photosensitive resin The portion 5 labeled “IMT” in the photomask 1 is composed of a light absorber that absorbs radiation, and the radiation that has passed through the portion of the photomask 1 other than the light absorber 5 is transmitted. The molecular chain of the photosensitive resin 3 in the portion exposed to the radiated light is broken by the light, and is selectively dissolved in a specific developer. By this development processing, a photosensitive resin microstructure 6 is formed on the conductive substrate 2 (FIG. 17B).
(3) Metal deposition by electrolytic deposition The high-strength alloy according to the present invention is electrolytically deposited according to the electrolytic deposition method at the portion where the photosensitive resin is dissolved (FIG. 17 (c)).
(4) Peeling of remaining photosensitive resin By removing the remaining photosensitive resin with a solvent, a microstructure 7 of a high-strength alloy can be obtained (FIG. 17D). According to this method, it is possible to form a micrometer-sized fine metal structure, which is difficult to form by a machining method, and by changing the shape of the light absorber of the photomask, the microstructure of any structure The body can be molded.
5). Others According to the present invention, a high-toughness high-strength alloy can be obtained as described above. However, in order to obtain an electrodeposited alloy with good adhesion, attention should be paid to the conditions described below. Further preferred.
(1) Current density In order to shorten the electrolytic deposition time and obtain a dense alloy film, it is generally preferable that the current density is large. However, when the current density increases, the amount of hydrogen generated increases and causes hydrogen embrittlement. Therefore, it is not preferable that the current density is too large.
(2) pH
In strong acid baths or strong alkalis, the electrolytic properties are not very sensitive to pH, but the high strength alloys according to the invention preferably use weakly alkaline baths. The structure of the metal ion and the complex changes depending on the pH, and when the electrolytic deposition potentials of Ni (or Co) and W (or Mo) are almost the same, the Ni—W alloy is precipitated, and Fe When the electrolytic deposition potential of W and W (or Mo) becomes substantially the same, the Fe—W alloy is deposited.
(3) Additive The purpose of the additive is to smoothen, brighten, refine crystals, improve uniform electrolytic precipitation, reduce residual stress, prevent pits, etc. In the present invention, it is preferable to add an appropriate amount of a known surfactant for preventing pits and to add an appropriate amount of saccharin for the above purpose other than preventing pits.
(4) Pretreatment In order to obtain a smooth electrolytically deposited film with good adhesion, pretreatment for cleaning the electrolytically deposited surface is important, and a known pretreatment method can be employed.

It is a figure which shows the change of the electrolytic deposition rate with respect to the change of the electrolytic bath temperature in a Ni-W type alloy. It is a figure explaining the method of a bending test. It is a figure which shows the change of the crystal grain diameter with respect to the change of the electrolytic bath temperature in a Ni-W type alloy. It is another figure which shows the change of the crystal grain size with respect to the change of the electrolytic bath temperature in a Ni-W type alloy. It is a figure which shows the change of W content with respect to the change of the electrolytic bath temperature in a Ni-W type alloy. It is another figure which shows the change of W content with respect to the change of the electrolytic bath temperature in a Ni-W type alloy. It is a figure which shows the change of the X-ray diffraction pattern with respect to the change of the electrolytic bath temperature in a Ni-W type alloy. It is another figure which shows the change of the X-ray diffraction pattern with respect to the change of the electrolytic bath temperature in a Ni-W type alloy. It is another figure which shows the change of the electrodeposition rate with respect to the change of the electrolytic bath temperature in a Ni-W type alloy. It is another figure which shows the change of the electrolytic deposition rate with respect to the change of the electrolytic bath temperature in a Ni-W type alloy. It is a figure which shows the change of the electrolytic deposition rate with respect to the change of the density | concentration of sodium citrate in a Ni-W type alloy. It is another figure which shows the change of the X-ray diffraction pattern with respect to the change of the electrolytic bath temperature in a Ni-W type alloy. It is a figure which shows the change of the X-ray-diffraction pattern with respect to the change of Ni density | concentration in a Ni-W type alloy. It is a figure which shows the change of the fracture | rupture distortion with respect to the change of the electrolytic bath temperature in a Ni-W type alloy. It is another figure which shows the change of the fracture | rupture distortion with respect to the change of the electrolytic bath temperature in a Ni-W type alloy. It is a figure which shows the change of the fracture | rupture distortion with respect to the change of the density | concentration of sodium citrate in a Ni-W type alloy. It is a figure which shows an example of the flow of the manufacturing method of a microstructure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Photomask 2 ... Conductive substrate 3 ... Photosensitive resin 4 ... Radiated light 5 ... Light absorber 6, 7 ... Micro structure

Claims (5)

  Composition in which the sum of Ni ions or Co ions and W ions or Mo ions is in the range of 0.1 to 0.3 mol / L, and the content ratio of Ni ions or Co ions in the metal ions is in the range of 20 to 40%. A high-strength alloy obtained by electrolytic deposition using an electrolytic bath at a bath temperature of 40 to 80 ° C., and having an amorphous structure or a nanocrystalline structure with an average crystal grain size of 100 nm or less High strength alloy.   It has a composition containing 8 to 30 atomic% of W or Mo, a hydrogen atom content of 1.00 atomic% or less, and an oxygen atom content of 0.50 atomic% or less, with the balance being Ni or Co. A high-strength alloy characterized by   Composition in which the sum of Ni ions or Co ions and W ions or Mo ions is in the range of 0.1 to 0.3 mol / L, and the content ratio of Ni ions or Co ions in the metal ions is in the range of 20 to 40%. The high-strength alloy according to claim 2, obtained by electrolytic deposition at a bath temperature of 40 to 80 ° C using an electrolytic bath.   A metal material coated with the high strength alloy according to claim 1, 2 or 3.   A microstructure using the high-strength alloy according to claim 1, 2 or 3.

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