Effect of Sr addition on thermal conductivity and mechanical properties of Y-α′-SiAlON

Abstract

α′-SiAlON containing Sr, having a large ionic radius, was obtained by hot-pressing. Sr was accommodated in α′-SiAlON in conjunction with Y. The effect of adding Sr to Y-α′-SiAlON on thermal conductivity and mechanical properties was studied. Thermal conductivity decreased from 11.9 W/m · K to 6.2 W/m · K with increasing addition of Sr, due to increasing of phonon scattering both in the lattice and at the grain boundary. Bending strength increased from 460 MPa to 860 MPa with increasing addition of Sr. The increase in bending strength can be associated with grain size refinement and fracture toughness. Fracture toughness also increased with increasing addition of Sr.