Effect of hBN Content on Property and Microstructure of Si$lt;inf$gt;3$lt;/inf$gt;N$lt;inf$gt;4$lt;/inf$gt;-hBN Composite Ceramics

Si 3 N 4 -hBN composites were prepared using hot-press method with nano-scaled powder, the influence of hBN content on density, mechanical properties, tribological properties, microstructure of Si 3 N 4 -hBN composites were investigated.The density and mechanical properties of composites were measured by Archimedes method, three point bending method and Vickers indentation method.The tribological properties of composites were measured by friction and wear tester.The phase composition and microstructure of composites were analyzed and observed by XRD, EDAX and SEM, LSCM.The results showed that with increase of hBN content the composites' density gradually decreased, the composites' porosity increased at first and then stable gradually, the composites' mechanical performance gradually decreased.The friction tests indicated that the tribological properties of Si 3 N 4 -hBN and GCr15, with pair under dry friction, increased at first and then decreased sharply with the increase of hBN content.The friction coefficient and wear coefficient decreased gradually when hBN content was less than 20%, and then increased sharply when the hBN content was more than 20%.The friction coefficient reaches the lowest value of 0.31 when the hBN content