Investigation of Al2O3/TiC ceramic cutting tool materials with the addition of SiC-coated h-BN: preparation, mechanical properties, microstructure and wear resistance

SiC-coated h-BN powders ((h-BN)/SiC) were used to substitute h-BN as solid lubricant to prepare Al2O3/TiC/(h-BN)/SiC self-lubricating ceramic cutting tool materials using hot pressing. Microstructure and mechanical properties of the material were studied. Overall improvements in Vickers hardness and fracture toughness were obtained compared with that of Al2O3/TiC/h-BN. The coating of SiC blocks direct contact between h-BN and Al2O3/TiC and hence enables h-BN particles to bond more closely with Al2O3/TiC. The density of the material was dramatically improved because of the decrement of voids around h-BN particles. Dry turning tests were carried out to investigate the wear resistance of the materials when cutting 40Cr quenched and tempered steel. Enhancement in wear resistance, which may result from the improvement in mechanical properties, was observed.