Microstructure and mechanical property characterization of multilayer free-standing Diamond/Mo films

The monolayer diamond film and free-standing diamond/Mo multilayer films were prepared by combining microwave plasma chemical vapor deposition (MPCVD) and double glow plasma surface alloying (DGPSA) techniques. The result shows that the film grain size decreases from 70-80 mu m to similar to 10-20 mu m with the layer number increasing from the monolayer diamond film with a columnar crystal structure to the seven-layer diamond/Mo films, indicating that the Mo interlayer can effectively reduce the grain size. The Mo2C is formed between the Mo and diamond layers, which can improve the bonding strength. The internal stress of these films depends on the number of Mo interlayers and the Mo2C content. Moreover, the fracture strength and abrasion ratio of multilayer diamond films are effectively improved by adding the Mo interlayer. The four-layer diamond/Mo film system has the highest fracture strength and the seven-layer film system has the highest abrasion ratio.