An electroplating process that can improve the surface finish of the voltage equalizing electrode probe of a high-voltage direct current converter valve

Abstract

The invention discloses an electroplating process capable of improving surface smoothness of a pressure-equalized electrode probe of a high-voltage direct-current converter valve. The pretreated pressure-equalized electrode probe is put in an electroplating liquid for platinum plating treatment, the electroplating liquid is prepared from ingredients as follows: 0.001-6 mol / L of sodium tetrachloroplatinate or sodium chloroplatinate, 0.1-10 mol / L of ethylenediamine tetraacetic acid disodium salt or ethylenediamine tetraacetic acid tetrasodium salt; the pressure-equalized electrode probe serves as a work electrode, an annular platinum sheet serves as a counter electrode, and the pressure-equalized electrode probe is placed in the middle of the annular platinum sheet; the temperature of the electroplating liquid is 5-75 DEG C, the pH value of the electroplating liquid is 6-7.5, the electroplating current is 0.01-10 mA / cm<2>, and the plating layer on the surface of the pressure-equalized electrode probe is 0.1-5 mu m. The electroplating process is simple and easy to control, the activity of platinum ions and the diffusion coefficient of the platinum ions in the electroplating liquid are limited, so that the reduction reaction speed of platinum is controlled, and the surface smoothness of a platinum deposition layer is further controlled to reach the mirror surface.

Description

technical field [0001] The invention relates to the technical field of platinum electroplating, in particular to an electroplating process capable of improving the surface finish of a voltage equalizing electrode probe of a high-voltage direct current converter valve. Background technique [0002] The HVDC converter valve is the most important primary equipment in the DC transmission project, and it completes the core function of the mutual conversion between AC and DC in DC transmission. In the normal commutation process, the converter valve will generate a lot of heat, and with the development of the high-voltage direct current transmission system and the increase of the transmission capacity, the heat generated by the thyristor will be greater, which requires the auxiliary system of the converter valve - the valve The cooling system is used to maintain the temperature of the inlet and outlet water within a reasonable range to ensure the normal operation of the diverter va...

AI Technical Summary

Problems solved by technology

Although the voltage equalizing electrode probe will not corrode, when the concentration of aluminum ions (or aluminate) and hydroxide in the internal cooling water system reaches the solubility product on its surface, due to the surface of the equalizing electrode probe If the finish is not high enough, it will nucleate and grow aluminum hydroxide crystal nuclei on the unevenness of its surface, and then generate aluminum hydroxide deposition samples. With the further accumulation of deposition samples, it will cause scaling on the entire voltage equalizing electrode

[0005] Therefore, in order to slow down the scaling of the voltage equalizing electrode, the method of improving the surface finish of the voltage equalizing electrode probe can be adopted, because the higher the surface finish of the voltage equalizing electrode probe, the greater the adsorption force of the aluminum hydroxide crystal nucleus on the probe surface. becomes larger, resulting in higher nucleation activation energy and multiplied nucleation difficulty, which makes it impossible for aluminum hydroxide deposits to form on the surface of the voltage equalizing electrode probe.