TWI243856B - Method for reducing internal stress of electroplated layer made of nickel-based alloy material - Google Patents

Abstract

Provided is one kind of method for reducing the internal stress of electroplated layer made of nickel-based alloy material (such as nickel-tungsten electroplated layer) which comprises steps of: adding ceramic particles into an electroplating solution containing a nickel salt; and put a base material in the electroplating solution to carry on the pulse electric-current electroplating. The method for reducing the internal stress of the electroplated layer made of nickel-based alloy material can reduce the internal stress of the electroplated layer made of nickel-based alloy material, decrease or eliminate the crack lines of the electroplated layer, and further increase the durability of the electroplated layer made of nickel-based alloy material.

Description

1243856 丨 V. Description of the invention (1) -----, [Field of the invention] The method for reducing the internal stress of the nickel-based alloy coating of the present invention, θ ,,-Fine particles in a plating solution containing nickel ions and tungsten ions or phosphorus ions = Plus f porcelain pulse electroplating and low temperature heat treatment steps to reduce the internal force of f ^ layers (such as nickel quay alloy coating, nickel scale alloy coating), ^ [Background of the invention] ~ ° Ni-based alloy coating A nickel-tungsten alloy bell layer has excellent properties such as high melting point, high hardness, and good abrasion resistance. Therefore, nickel-tungsten alloys are commonly used in the industry at present. After heat treatment at 6,000 ° C for 1 hour, the hardness value can be increased to more than 1000HV. Therefore, nickel-tungsten alloy coating is often used in cylinders, pistons, shafts, The money on compressors, rollers, or forming molds is also suitable for containers, centrifuge screens, and susceptible to industrial equipment such as petroleum, chemical, salt, and pharmaceuticals because of their excellent money resistance. Corrosion of parts However, due to the excessive stress of the nickel-tungsten alloy plating layer 'limits its scope of application and durability. The hardness and wear resistance of the nickel-tungsten alloy coating will increase with the increase of the crane content in the key layer, and the internal stress of the coating will also increase relatively. If the mirror layer is too thick, it will cause cracks in the coating or adhesion to the substrate. The force becomes worse, because reducing the internal stress of nickel-tungsten alloys has become the focus of nickel-tungsten alloy coatings. At present, there are two main methods to reduce the internal stress of nickel-tungsten alloy coatings. One of the more commonly used is to add it to the plating solution. Stress relief agents to control internal stresses, such as USpatent 5 8 5 3 556 and USpatent 6 045 6 8 2 etc., all use organic compounds as stress relief agents to reduce the internal stress of nickel-tungsten alloy coatings, but by 1243856

V. Description of the invention (2) The organic compound components in the stress relief agent will be decomposed into too many products under the action of the electric field. When the products are too much, the money layer will be degraded. It is necessary to use activated carbon or similar substances regularly to generate too much Material removal will increase the load of money management; and the stress relief agent will cause the structure and composition of the nickel-tungsten alloy coating to change, and reduce the hardness of the ore layer. Another known method to reduce the internal stress of nickel-tungsten alloy ore layers is to reduce the internal stress by using pulse current (pu 1 se current) electroplating. Although this method does not cause the above problems, it can improve the uniformity and hardness of the coating. However, its effect of reducing internal stress is limited. The so-called pulse current plating is that during the plating process, the power is applied for a period of time and the power is not applied for a period of time. Similar to the output method of AC current, an asymmetric waveform is output. The parameters of general pulse current electroplating are: energization time (Ton), no power Time (Toff), load cycle [Duty Cycle.

Ton / (Ton + Toff)], pulse frequency [frequency = l / (Ton + Toff)], and current density (peak current density), etc. In order to increase the hardness of nickel-tungsten alloy coatings, it is known to manufacture nickel-cast alloy coatings, It is heat-treated at a high temperature of 600 ° C for about 1 hour. Although the nickel-tungsten alloy plating layer can cause the micro hardness of the bond layer to be higher than 1000 Hv due to the precipitation of nickel tungsten (N i 4 W), due to the high heat treatment temperature, it is easy to soften and deform some substrates. As a result, the plating layer is separated from the substrate. [Objective of the Invention] The first object of the present invention is to uniformly add ceramic particles such as silicon carbide and tungsten carbide to a nickel-based alloy ore layer (such as a nickel-iron alloy coating) to reduce internal stress so as to reduce or eliminate cracks in the coating. It does not reduce its hardness.

Page 6 1243856 V. Description of the invention (3) The second object of the present invention is to provide a low temperature heat treatment step so that the substrate will not be softened and deformed, and the hardness of the nickel-tungsten alloy coating will be slightly increased. At the same time, the hydrogen embrittlement caused by hydrogen in the plating layer can be eliminated, thereby reducing the internal stress of the bond layer. [Inventive Features] A method for reducing the internal stress of a nickel-based alloy plating layer, the steps of which include adding ceramic particles to a plating solution containing a nickel salt; and placing a substrate in the plating solution to perform pulse current plating. In order to enable your reviewing committee to further understand the features and technical contents of the present invention, please refer to the following detailed contents and drawings of the present invention, and the preferred and feasible embodiments and comparative examples are described in detail below with reference to the drawings. It is believed that the purpose, features, and advantages of the present invention can be obtained through a deep and specific understanding. [Detailed description of the invention] The present invention provides a method for reducing the internal stress of nickel-based alloy coatings (such as nickel-tungsten alloy coatings). The method is to add ceramic particles such as carbides, metal nitrides, or metal oxides to a plating solution, and Pulse plating and low temperature heat treatment steps are used to reduce the internal stress of the nickel-tungsten alloy coating. 1M / L-0. 5M / L, The tungsten salt is a tungsten salt such as sodium tungstate, etc. The nickel salt used in the plating solution of the present invention is generally nickel sulfate or nickel sulfamate. Type, and the tungsten ion concentration is preferably 0.2M / L-0.5M / L, and the complexing agent generally uses citrate, tartrate or other organic acid salts, and the concentration is generally controlled between 0.2M / L-0.6M / L between. In addition, some ammonium ions can be added to the plating solution, such as amine chloride. This ammonium ion can stimulate tungsten in the plating solution.

1243856 V. Description of the invention (4) Electroplating, which is conducive to the stable precipitation of metal ions during the plating process, and improves the precipitation rate. At the same time, the chloride ions also help the anode nickel block to dissolve effectively. However, too much chloride ion concentration can easily increase the internal stress of the nickel-tungsten alloy coating, so the concentration of amine chloride is preferably 0.5M / L-1.5M / L. When the plating temperature is 40-70 ° C, the pH value of the plating solution is 8-10, the pulse current density is 5-30A / dm2, the load cycle is 0.1-0. 5. When the frequency is 1-1000, it can be reduced ' The internal stress value of the nickel-tungsten alloy coating increases the coating hardness. 1 ～ 1 // m。 Ceramic particles used in the present invention, can be used with better conductivity of carbonaceous materials such as carbonized particles, carbonized carbon, or carbonized crane's particle diameter of the ceramic free particles is 0. 1 ~ 1 // m. Because ceramic particles are adsorbed and embedded on the surface of the cathode, hydrogen ions can be discharged on the surface of the ceramic particles. At the same time, because the position of the ceramic particles is often protruding from the surface of the cathode, and the ceramic particles have poor hydrogen absorption and hydrogen permeability capabilities, they can The precipitated hydrogen is easily discharged, so that the amount of hydrogen absorption and hydrogen permeation of the coating can be reduced, and the crystal defects of the bond layer can also be reduced. Therefore, the internal stress of the nickel-tungsten alloy coating formed by the ceramic particles with strong conductivity, The particles are much smaller than the weaker ceramics. The ceramic particles need to be treated with about 50% hydrochloric acid, 70 ° C for 15 minutes, and washed with pure water before adding the plating solution. Generally, the content of ceramic particles added to the plating solution is lg / L-50g / L °. The low-temperature heat treatment step used in the present invention is mainly performed in a high-temperature furnace through various temperatures (such as 200 ° C, 300 ° C). , 400 ° C) and different time treatments to improve the hardness of the nickel-tungsten alloy coating without causing deformation of the substrate under the coating. During the heat treatment, the heating rate is 5 ° C per second.

1243856 i. Invention ^ [5)-"~~ '' '-------- To the optimal temperature for heat treatment, jade is within ° C, to ensure different temperatures; The accuracy needs to be controlled in the soil. Batch = uniform example of the quality of nickel-tungsten alloy coatings (such as ^ 2:: ^ T-thickness of the method of internal stress of the alloy plating layer of 130-130), the steps include: 25 ~ 35 g of sulfuric acid Nickel and ammonium are mixed to form 1 ~ 1 20g of sodium citrate and 20 ~ 30g of chlorinated silicon carbide particles = ^ 'The pH of the plating solution is 9 ~ 10; 10 ~ 20g is added at a concentration of 0% 〇〇1 ^ solution mixed and stirred to form the nickel ion sodium barium citrate in the plating solution: Lu / L 'The concentration of tungsten ions is 0.34 ~ 0.49M / L, 7M / L, silicon carbide = ~ 〇 · 47M / L, the concentration of gasified ammonium is 0.5 ~ 5 ~ placed in the plating solution, and the concentration is 10 ~ 20 g / L; and a clean iron block is taken to 12 5A / dm2 order pulse electricity money 'The current density of the pulse electricity ore is adjusted to the electric current load of the present invention is 0.2, and the current frequency is 100 Hz, and the crane nickel alloy on the iron substrate for electroplating scraps is obtained. Electroplated layer, the result of the tungsten nickel alloy and magnification with & a 0 times electron microscope is shown in the second figure 'Long Shi, the thickness of the tungsten nickel alloy electroplated layer was measured by a suspected stress measurement within 10 0 # m 2 Stress value is 2ikg / mm2, hardness is 7 9 2HV. Comparative example of the method for reducing the internal stress of the nickel-based alloy plating layer (only (eg, galvanic current plating, but without adding ceramic particles), the steps include the second picture shown): will be 2 5 ~ A mixture of 35 g of nickel sulfate, 130 to 150 g of tungstic acid, 100 to 120 g of sodium citrate, and 20 to 30 g of ammonium chloride is mixed, and the concentration of nickel ions during the night is 0. · 10 ~ 〇23M / L, the concentration of tungsten ions is 4: 49 · 49M / L, the concentration of sodium citrate is 0.39 ~ 0.47M / L, and the concentration of chlorination is 0.5 ~ 〇 · 7M / L, the pH value of the plating solution is 9 ~ 10; and take a dry

1243856 V. Description of the invention (6) A clean iron block is placed in the plating solution for pulse plating, and the current density of the pulse plating is adjusted to 12. 5A / dm2, the load cycle is 0.2, and the current frequency is 1 0 0 At 0 Hz, a nickel-tungsten alloy plating layer that is conventionally manufactured using only pulsed current plating is obtained. This nickel-tungsten alloy electroplated layer was magnified by an electron microscope at a magnification of 100 times as shown in the fourth figure, and the nickel-tungsten alloy electroplated layer of the comparative example was measured by spiral stress. When the thickness was 100 // m, the internal stress was The value is 42kg / mm2, and the hardness is 745Hv. The experimental results show that the method for reducing the internal stress of the nickel-based alloy coating (such as nickel-tungsten alloy coating) of the present invention, the produced tungsten alloy plating layer has finer cracks and lower Internal stress and high hardness, so the present invention can effectively reduce the internal stress of the tungsten alloy coating. Of course, the above is only a preferred embodiment of the present invention, and it should not be used to limit the scope of implementation of the present invention. Any modification made by those skilled in the art without departing from the spirit of the present invention should fall within the scope of the present invention. Therefore, the protection scope of the present invention should be based on the patent application scope described below.

Page 10 1243856 Brief description of the drawings [Simplified description of the drawings] The first figure is a flowchart of the steps of the method for reducing the internal stress of the nickel-based alloy plating layer of the present invention. The second figure is an electron micrograph of a tungsten nickel alloy electroplated layer manufactured by the method for reducing the internal stress of a nickel-based alloy electroplated layer at a magnification of 1000 times. The third figure is a flowchart showing the steps of a conventional method for reducing the internal stress of a nickel-based alloy plating layer. The fourth figure is an electron micrograph of a tungsten nickel alloy plating layer produced by a conventional method for reducing the internal stress of a nickel-based alloy plating layer by a factor of 100.

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Claims (1)

1243856 6. Scope of patent application • 1 · A method for reducing the internal stress of the base alloy coating, the steps include: adding ceramic particles to a plating solution containing nickel salt; and placing a substrate in the plating solution for pulse current plating. 2. The method for reducing the stress in the nickel-based alloy plating layer as described in item 1 of the scope of the patent application, wherein the concentration of the nickel salt is 0.1M / L to 0.5M / L. 3. The method for reducing the stress in the nickel-based alloy plating layer as described in item 2 of the scope of the patent application, wherein the nickel salt is nickel sulfate or nickel aminosulfonate. 4 · The method for reducing the internal stress of the nickel-based alloy coating as described in the scope of the patent application No. 1 'wherein the composition of the electric ore liquid further comprises 0.2M / L ~ 0. 5M / L tungsten salt, 0.2M / L ~ 0. 6M / L complexing agent and 0.3M / L ~ 1.5M / L ammonium chloride. 5. The method for reducing the internal stress of the nickel-based alloy coating as described in item 4 of the scope of the patent application, wherein the salt is sodium crane acid. 6. The method for reducing the stress in the nickel-based alloy coating as described in item 4 of the scope of the patent application, wherein the complexing agent is citrate, tartrate or organic acid salt. 7. The method for reducing the stress in the nickel-based alloy coating as described in the first item of the patent application scope, wherein the ceramic particles are carbides, metal nitrides or metal oxides. 8 · The method for reducing stress in a nickel-based alloy coating as described in item 7 of the scope of the patent application, wherein the carbide is silicon carbide, tungsten carbide or titanium carbide Page 1243856 VI. Patent application scope • 1 0 · The method for reducing the internal stress of the nickel-based alloy coating as described in item 1 of the patent application scope, wherein the current density of the pulse current plating is 5 ~ 3 0 A / dm2, The load cycle is from 0.1 to 1.5, and the pulse frequency is from 1 to 1000 Hz. 1 1 The method for reducing the internal stress of the nickel-based alloy coating as described in the first patent application scope, wherein a substrate is placed on the plating After the step of performing pulse current plating in the liquid, a step of low-temperature heat treatment is further included. Page 13