Introduction of black chrome bright gold embossed sign plating Shi Lei (Department of Materials, Shandong Institute of Architecture and Engineering, Jinan 250014, Shandong, China) 3 Main plating formula and maintenance (1) Cyanide copper plating formula and process bath maintenance: 1 free sodium cyanide content The content of free sodium cyanide is high, the coating crystal is fine, the covering ability is good, the anode is normally dissolved, but the current efficiency is low; the free sodium cyanide content is low, the anode is easy to passivate, the plating solution coverage is poor, the plating layer is rough, but the current efficient. Generally, on-site observation, if the deposition of the coating is slow, a large amount of bubbles are generated on the cathode, indicating that the content of free sodium cyanide in the plating solution is too high. If the bath coverage is low, it is very important to reduce the tensile stress and improve the bonding strength between the coating and the base material for a good transition layer. In the multi-arc ion plating TiN coating process, increasing the target current and negative bias is beneficial to the formation of the transition layer. Both increase the energy of the bombardment ions and increase the temperature of the matrix material, so that the surface re-evaporation rate, surface mobility, diffusion and atomic chemical activity of the matrix material are improved. 16. Conclusion In the multi-arc ion plating TiN coating During the deposition process, the presence of tensile stress seriously affects the performance of the coating. According to the formation theory of tensile stress and the factors affecting the tensile stress, attention should be paid to the selection of the matrix material and the actual coating process: (1) selecting a material with the same crystal lattice and similar lattice constant and thermal expansion coefficient as the base material. In order to reduce the mismatch, reduce the interface energy and reduce the tensile stress; during the actual coating process, increase the target current and the negative bias as much as possible to increase the energy of the bombardment ions and increase the temperature of the matrix material, which is beneficial to the formation of the transition layer. Reduce the tensile stress.
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