A galvanic-chemical method for preparing diamond containing coatings

• A new method to prepare diamond containing coating is presented.
• The material is dipped in CuSO4 and diamond particles are sprayed on the surface.
• Phosphine is used to convert CuSO4 into copper phosphide.
• The diamonds are finally enclosed in a copper matrix through electroplating.

The formation of a diamonds containing coating on the surface of tools is a way of increasing hardness and wearability of the working surfaces. We have developed a new process to prepare these composite coating.The surface is initially wetted with copper sulphate solution and then diamonds powder is sprayed onto the surface. Upon subsequent exposure to gaseous phosphine, a surface layer of solid copper phosphide, firmly holding the diamond particles, is formed. Copper phosphide has sufficient electrical conductivity, allowing conventional metal electro-plating. The effect of process parameters such as duration of the exposure to phosphine gas, concentration of the CuSO4 solution and thickness of the electro-deposited copper layer have been investigated and the surface roughness of the prepared samples increased about 50 BHN (Brinell hardness number).

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