A method for preparing an electrodeposited layer on the surface of a superalloy using a neutral platinum plating solution

Abstract

The invention aims to provide an electrolyte solution which is relatively high in current efficiency and neutral in pH value and also provides a method for preparing electro-deposited platinum on high-temperature alloy surface by utilizing the electrolyte solution, wherein the prepared electro-deposited platinum is semi-pervious to light, bright in metallic luster, relatively good in bonding force, relatively good in compactness and uniform in thickness. The neutral platinum plating solution is an electrolyte solution formed by an H2PtCl6.H2O water solution and a mixed solution of Na2HPO4 or K2HPO4 and deionized water; the pH value of the neutral platinum plating solution is controlled to be 7.0 to 7.5; in comparison with a conventional acidic or alkaline platinum plating solution, the neutral electrolyte solution is capable of preparing an electro-deposited platinum layer which has the compactness and metal luster of a platinum layer prepared by an acidic platinum plating solution and also has the characteristic of good bonding force of the platinum layer prepared by an alkaline platinum plating solution. The electrolyte solution is simple in preparation method and suitable for popularization and application.

Description

technical field [0001] The invention belongs to the field of surface processing and coating, and in particular relates to the preparation of a coating containing platinum element in an anti-oxidation coating on the surface of a high-temperature alloy. Background technique [0002] Platinum, which has a high melting point, is used in high-temperature alloys and can form a solid solution with other metal elements as a surface coating or bonding layer for high-temperature components, thereby effectively increasing the service temperature of the components, while strengthening the substrate and other coatings the cohesion between them. In the process of preparing platinum-containing high-temperature anti-oxidation coating, a layer of platinum needs to be electroplated on the surface of the substrate first. [0003] According to the traditional pH value to classify the platinum plating solution, it can be divided into acidic and alkaline. The surface porosity of the platinum la...

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Problems solved by technology

The surface porosity of the platinum layer prepared by the acidic plating solution (pH range between 0.2 and 3.0) is low and relatively bright. This is because the reduced platinum atoms grow densely on the surface of the substrate during the deposition process. However, this It also increases the internal stress between the deposition layer and the substrate. The internal stress becomes larger with the increase of the thickness of the deposition layer, and it is easy to cause cracks in the deposition layer, resulting in a certain limitation in the thickness of the deposition layer during deposition. At the same time, it also reduces the binding force between the deposited layer and the substrate; the platinum layer prepared by alkaline plating solution (pH range between 9.0 and 13.5) has a better binding force with the substrate, which is due to the reduced The growth of platinum atoms on the surface of the substrate is relatively dispersed, resulting in certain pores on the surface of the deposition layer. The existence of these pores can release the internal stress between the deposition layer and the substrate. However, the surface color of the deposition layer prepared by alkaline plating solution darker, no metallic luster

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