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CN-121977987-A - Nickel priming layer porosity test method for researching influence of porosity on nickel alloy combined plating layer

CN121977987ACN 121977987 ACN121977987 ACN 121977987ACN-121977987-A

Abstract

The application relates to the technical field of nickel alloy plating layers, in particular to a nickel priming layer porosity testing method for researching the influence of porosity on a nickel alloy combined plating layer. The method comprises the steps of obtaining nickel priming layer types and nickel priming layer thickness data of a plurality of test pieces, wherein the nickel priming layer types comprise chemical nickel, nickel sulfate and nickel sulfamate, analyzing the corresponding relation between the porosity data and the nickel priming layer thickness to determine the critical thickness meeting a target porosity threshold, obtaining porosity change data of the test pieces after a porosity test is carried out by adopting a combination of the nickel priming layer and a gold plating layer, analyzing the relevance between the porosity reduction amplitude after gold plating and the nickel priming layer types, analyzing the porosity change data, and determining corrosion test results and the like of the test pieces. The porosity problem can be better represented.

Inventors

  • WANG TAO
  • ZHAO XIA
  • LIU GENYING
  • WANG CHAO
  • YANG SHAOTING

Assignees

  • 西安创联电镀有限责任公司

Dates

Publication Date
20260505
Application Date
20260211

Claims (10)

  1. 1. The method for testing the porosity of the nickel primer layer for researching the influence of the porosity on the nickel alloy combined plating layer is characterized by comprising the steps of obtaining nickel primer layer types and nickel primer layer thickness data of a plurality of test pieces, wherein the nickel primer layer types comprise chemical nickel, nickel sulfate and nickel sulfamate; Analyzing the corresponding relation between the porosity data and the nickel priming layer thickness, and determining the critical thickness meeting the target porosity threshold; Acquiring porosity change data of the test piece after a porosity test is carried out by adopting a combination of a nickel priming layer and a gold plating layer, and analyzing the relevance between the porosity reduction after gold plating and the type of the nickel priming layer; analyzing the porosity variation data to determine a corrosion test result of the test piece; determining porosity degradation according to the relevance and the corrosion test result; And determining the optimal technological parameter combination of the nickel alloy combined plating layer according to the critical thickness, the porosity reduction and the corrosion test result.
  2. 2. The method of claim 1, wherein the obtaining of the porosity variation data of the test piece after the porosity test is performed by adopting the combination of the nickel primer layer and the gold coating layer comprises the steps of executing a filter paper pasting method test according to the GB5935 standard, setting the concentration of potassium ferricyanide to be 8-12 g/L, the concentration of sodium chloride to be 18-22 g/L, the infiltration time to be 15-25 minutes, and determining the ratio of the number of corrosion spots of the test piece to the area of the coating layer after the infiltration is completed; The ratio of the number of corrosion spots to the area of the plating layer was taken as the porosity variation data.
  3. 3. The method of claim 1, wherein analyzing the correspondence of the porosity data to the nickel primer layer thickness to determine a critical thickness that meets a target porosity threshold comprises: Dividing the chemical nickel, the nickel sulfate and the nickel sulfamate into three groups of <2 mu m, 2-4 mu m and >4 mu m respectively, and determining the critical thickness according to the porosity abrupt change point of each group of test pieces.
  4. 4. A method according to claim 3, wherein said determining the critical thickness from the abrupt inflection points of the porosity of each group of test pieces comprises: When the porosity abrupt change point of the nickel sulfate appears at the thickness of more than or equal to 4 mu m, the porosity is less than or equal to 0.2, and the critical thickness of the nickel sulfate priming layer type is determined to be 4 mu m; When the porosity abrupt change inflection point of the nickel sulfamate appears at the thickness of more than or equal to 4 mu m, the porosity is less than or equal to 1, and the critical thickness of the nickel foundation layer type of the nickel sulfamate is determined to be 4 mu m; When the porosity mutation turning point of the chemical nickel appears at the thickness of more than or equal to 7 mu m, the porosity is less than or equal to 0.5, and the critical thickness of the nickel primer layer type of the chemical nickel is determined to be 7 mu m.
  5. 5. The method of claim 1, wherein said determining a porosity reduction based on said correlation and said corrosion test results comprises: according to the porosity reduction of the nickel sulfate/gold combined coating in the correlation of more than or equal to 30 percent and the porosity reduction of the nickel sulfamate/gold combined coating of less than or equal to 10 percent, determining a porosity reduction threshold corresponding to the type of the nickel primer layer by combining the oxidation diffusion data of the coating in the corrosion test result; And constructing the porosity amplitude reduction according to the corresponding relation between the porosity amplitude reduction threshold value and the nickel priming layer type.
  6. 6. The method of claim 1, wherein analyzing the porosity variation data to determine corrosion test results for the test piece comprises: According to the fact that the color change rate of the chemical nickel/gold combined coating in a wet heat test is higher than that of the nickel sulfate/gold combined coating by more than or equal to 50%, positive correlation between the porosity and the oxidation diffusion rate of the coating is determined; Wherein, the color change rate is quantified by a delta E value of a color difference meter, and the color change is judged to be obvious when the delta E difference value is more than or equal to 3.0.
  7. 7. The method of claim 5, wherein determining the optimal combination of process parameters for the nickel alloy composite plating layer based on the critical thickness, the porosity degradation, and the corrosion test results comprises: when the nickel priming layer is nickel sulfate and the thickness is more than or equal to 4 mu m, the porosity reduction is more than or equal to 30 percent, the qualification rate of the salt spray test is more than or equal to 95 percent, and the porosity threshold value of the nickel-gold combined plating layer is less than or equal to 0.2.
  8. 8. The method of claim 5, wherein the method further comprises: According to the fact that the porosity of the burr area on the surface of the base material of the test piece is more than or equal to 200% of that of the flattening area, the surface roughness Ra of the pretreatment process is determined to be less than or equal to 0.8 mu m.
  9. 9. The method of claim 5, wherein the method further comprises: And establishing a quantitative relation model of pickling solution concentration and porosity fluctuation according to the fact that the abnormal porosity value of the incomplete pickling test piece exceeds a standard value by more than or equal to 80 percent.
  10. 10. The method of claim 5, wherein said determining an optimal combination of process parameters comprises: When the thickness of the nickel sulfamate priming layer is more than or equal to 10 mu m, the porosity reduction is less than or equal to 10 percent, the damp-heat test discoloration rate is less than or equal to 5 percent, and the porosity threshold value of the nickel-gold combined plating layer is less than or equal to 0.5.

Description

Nickel priming layer porosity test method for researching influence of porosity on nickel alloy combined plating layer Technical Field The application relates to the technical field of nickel alloy plating layers, in particular to a nickel priming layer porosity testing method for researching the influence of porosity on a nickel alloy combined plating layer. Background Studies show that the intrinsic cause of the discoloration of the gold plating layer is closely related to the porosity of the underlying nickel plating layer. The porosity is characterized by the density of tiny holes on the surface of the plating layer, and high porosity can form a corrosive medium permeation channel to accelerate electrochemical corrosion of bottom metal, and meanwhile, promote bottom oxidation products (such as nickel oxide and nickel sulfide) to diffuse to the surface of the gold layer through the pores, so that the surface of the gold layer finally shows local color change. Currently, nickel sulfamate, chemical nickel (middle phosphorus) and nickel sulfate are commonly used as gold plating bottom layers in the industry. The influence rule of the thickness of the nickel bottom layer on the porosity is not systematically researched by the traditional process. For example, the porosity of nickel sulfamate with the thickness of <4 mu m is more than 1, the discoloration risk is obviously increased, but the prior art lacks scientific definition on critical thickness, the porosity of a part of combined plating layers (such as nickel sulfamate/gold) after gold plating is reduced by less than or equal to 10 percent, the penetration of corrosive medium cannot be effectively blocked, and the problems of burrs, incomplete acid washing and the like of a substrate lead to abnormal increase of local porosity (more than 200 percent of a leveling area), so that the failure of the plating layer is further aggravated. Although the prior art verifies the corrosion resistance of the coating through a salt spray test, a wet heat test and the like, the methods can only reflect macroscopic performance and cannot accurately quantify the dynamic influence of the porosity on the protective capability of the coating. In addition, the porosity difference of different nickel bottom layer types (such as nickel sulfate and nickel sulfamate) under the same thickness and the synergistic effect of the nickel sulfate and the gold plating process are not fully disclosed, so that the process parameter selection depends on experience, and the severe requirement of high-end application scenes (such as military industry and 5G communication) on a 'zero-discoloration' coating is difficult to meet. Disclosure of Invention The application provides a nickel primer layer porosity testing method for researching the influence of porosity on a nickel alloy combined plating layer, so as to solve the problems. The application provides a nickel primer layer porosity test method for researching the influence of porosity on a nickel alloy combined plating layer, which comprises the steps of obtaining nickel primer layer types and nickel primer layer thickness data of a plurality of test pieces, wherein the nickel primer layer types comprise chemical nickel, nickel sulfate and nickel sulfamate; Analyzing the corresponding relation between the porosity data and the nickel priming layer thickness, and determining the critical thickness meeting the target porosity threshold; Acquiring porosity change data of the test piece after a porosity test is carried out by adopting a combination of a nickel priming layer and a gold plating layer, and analyzing the relevance between the porosity reduction after gold plating and the type of the nickel priming layer; analyzing the porosity variation data to determine a corrosion test result of the test piece; determining porosity degradation according to the relevance and the corrosion test result; And determining the optimal technological parameter combination of the nickel alloy combined plating layer according to the critical thickness, the porosity reduction and the corrosion test result. Optionally, the porosity change data of the test piece after the porosity test is carried out by adopting the combination of the nickel priming layer and the gold coating layer comprises the steps of executing a filter paper pasting method test according to the GB5935 standard, setting the concentration of potassium ferricyanide to be 8-12 g/L, the concentration of sodium chloride to be 18-22 g/L, the infiltration time to be 15-25 minutes, and determining the ratio of the number of corrosion spots of the test piece to the area of the coating layer after the infiltration is completed; The ratio of the number of corrosion spots to the area of the plating layer was taken as the porosity variation data. Optionally, analyzing the correspondence between the porosity data and the nickel primer layer thickness to determine a critical thickness meeting a targe