2O 3-coated h-BN composite powders and as-prepared Si 3N 4-based self-lubricating ceramic cutting tool material]]>

摘要

AbstractThe surfaces of solid lubricant hexagonal boron nitride (h-BN) powders were coated with compacted and integrated Al(OH)3by heterogeneous nucleation and then the h-BN@Al2O3composite powders were prepared by calcination under vacuum at 1200°C for 2h, as determined by SEM, EDS and XRD. The Si3N4self-lubricating ceramic cutting tool material with coated h-BN was prepared by vacuum hot pressing. Microstructure analysis showed that the h-BN@Al2O3particles were dispersed homogeneously in the matrix and that the particles were tightly bound. Vickers hardness was 14.1GPa, fracture toughness was 7.2MPa·m1/2, and flexural strength was 732MPa, as determined by mechanical property testing. The hardness, fracture toughness, and flexural strength of the material were increased by 27.0%, 5.9% and 22.2%, respectively, relative to the material to which uncoated h-BN was added. Cutting tests showed that the Si3N4/TiC/(h-BN@Al2O3) self-lubricating ceramic cutting tool had better antifriction property and wear resistance than the corresponding cutting tool.Highlights?A cutting tool material with addition of metallic oxide coated solid lubricant was proposed.?Si3N4/TiC/(h-BN@Al2O3) cutting tool material was prepared by hot pressing process.?The as-prepared material has better mechanical properties and cutting performance.]]>