High-Pressure synthesis of Al2O3-cBN-hBN Self-lubricating ceramic

Al2O3-based self-lubricating ceramics are cutting tool materials that meet the extreme working conditions of dry cutting. However, due to the soft lubricating components, the mechanical properties of composites are dramatically reduced. In this paper, Al2O3-cBN-hBN self-lubricating material was designed. High density, fine grain ceramics were synthesized by high-pressure technology. The influence of thermodynamic condition, cBN/hBN addition on mechanical and thermal properties of sintered composites was analyzed. Friction and wear tests were carried out. It is found that the addition of cBN particles can significantly improve the mechanical and thermal properties of the composites. However, the truss effect caused by excessive volume fraction of cBN can reduce the pressure transfer efficiency, and then affect the properties of sintered composites. The different hBN content can change the wear mechanism of the composites. The release efficiency of hBN particles in composites was enhanced due to the large modulus difference between cBN and hBN. The well-sintered Al2O3-cBN-hBN bulks present an excellent mechanical property. The hardness of the composites is improved at least by 54% compared with the traditional self-lubricating material on the premise of ensuring fracture toughness and lubrication performance. (c) 2022 The Authors. Published by Elsevier Ltd.

Automated summary

In this paper, Al2O3-cBN-hBN self-lubricating material was designed and the mechanical and thermal properties of the composites were improved by adding cBN particles. However, excessive volume fraction of cBN can lead to a truss effect that reduces pressure transfer efficiency. Different hBN content can change the wear mechanism, and the large modulus difference between cBN and hBN enhances the release efficiency of hBN particles.