Mechanical properties and microstructure of Al^sub 2^O^sub 3^/TiC based self-lubricating ceramic tool with CaF^sub 2^@Al (HO)^sub 3

The CaF2@Al2O3 coated powder with shell-core structure was prepared by liquid-phase non-uniform nucleation method. Based on the successful preparation of Al(OH)3 coated CaF2 powder, Al2O3/TiC self-lubricating tool was prepared by wet dispersion mixing and vacuum hot pressing sintering process. The microstructure and performance of the self-lubricating ceramic tool with different volume content of CaF2@Al(OH)3 coated powders were investigated. The results show that when the CaF2@Al2O3 content is 10 vol%, the comprehensive mechanical properties of Al2O3/TiC/CaF2@Al2O3 tool materials is the best, the hardness is 16.86 GPa, the flexural strength is 662 MPa, and the fracture toughness is 6.34 MPa·m1/2. Compared with the traditional Al2O3/TiC/10 vol%CaF2 self-lubricating ceramic cutting tools, Al2O3/TiC/10 vol% CaF2@Al2O3 ceramics in flexural strength, fracture toughness and hardness were increased 19.06%, 36.9%, 12.25%, of which the most obvious increase in fracture toughness.