Plasmachemical deposition of polycrystalline diamond films on functionally graded diamond-containing materials produced by SHS

摘要

Multilayer functionally graded hard composites with TiB_2+TiSi_2+Si or TiC+SiC+Si matrix have been used as substrates for diamond film deposition by microwave plasma enhanced CVD technique. The substrates produced by self propagating high-temperature synthesis (SHS) contain 8/16 #mu#m HPHT diamond particles of gradually changing concentration to minimize the residual stress in the SHS product. The impregnated diamond particles in the composite carry out several functions: (a) increase the matrix strength, (b) act as nucleation centers upon CVD diamond growth, and (c) improve adhesion of diamond coating because of the anchor effect. The structure of the substrate and coatings were characterized with Raman spectroscopy, SEM, and XRD analysis. Being under thermal (compressive) stress of about 1 GPa the diamond films yet exhibit a good adhesion. No significant difference in growth and properties of diamond films on the composities with different matrix was noted. The diamond-based composites coated with CVD diamond may be of practical interest primarily in tool manufacturing.