The effect of hexagonal boron nitride addition on presureless sintered alumina matrix composites

Abstract

The structural ceramics use in biomaterials such as artificial teeth and bone applications because of their high strength, good chemical resistance, and abra-sion resistance. Alumina (Al2 O3) is a good candidate for artificial tooth applications due to its high strength, high chemical resistance, and white color. However, their elastic modulus and stiffness are quite high compared to human teeth and bone, so they damage the teeth and bone when used as an implant. Hexagonal boron nitride (hBN) is a white, biocompatible artificial ceramic material that is structur-ally similar to graphite. By changing the physical properties of Al2 O3 with adding hBN, it is possible to increase the potential of use in implant applications. In this study, the physical properties of the composite were investigated by adding different amounts of nano hBN into the hBN-alumina composite. The composite powders prepared by using α-Al2 O3, nano hBN and MgO as a sintering agent were shaped by the hydraulic press and pressureless sintered under a protective atmo-sphere. Physical properties (density, elastic and shear modulus, Poisson’s ratio) of sintered samples were determined. Phase analysis (XRD) and microstructure characterization (SEM) were performed. hBN showed a homogeneous distribution in the composite. It was determined that relative density decreased, porosity increased, elastic modulus and stiffness decreased with the increasing amount of hBN in the composite.