Mechanical Properties of Alumina Composite Hardened by Ultra Dispersed Diamonds

Structure and mechanical properties of composite coatings that contain of 5 to 25% (vol.) of ultra-dispersed diamonds, different alumina phases, and components of SiC, AlN have been investigated. Structure, grains morphology, presence of pores and their distribution, interaction zones were investigated with SEM, X-ray-phase analysis and micro-X-ray-spectral analysis. Material was formed by impulse pressing. It is revealed that the material has variable-porosity, high density, microhardness up to 25 GPa and load rating. XRD analysis shows that the structure includes the diamond phase. To investigate load rating of the material Hertzian contact was used. Ultra-dispersed diamonds strength the structure in general as well as mechanical properties and quality of composite coatings.