Effect of Composite Sintering Aids on the Thermal and Mechanical Properties of Hot-Pressed Aluminum Nitride

Abstract

The aim of this work was to determine the effect of composite additives on the thermal and mechanical properties of aluminum nitride (AlN) in detail. The composite system has not been studied in depth before. The hot-pressed AlN was prepared with Y2O3-Dy2O3-YF3 and Y2O3-Dy2O3-CaO as the composite sintering additives. As the result, the thermal conductivities for the sintered body with two composite additives were 171 W/m.K and 152 W/m.K, respectively. The fracture toughness values calculated by the Evans & Clarkes’s equation for both of the samples were 2.34±0.09 MPa.m1/2and 2.63±0.13 MPa.m1/2 at 10 kg load. The toughness difference is the result of comprehensive effect of the grain size, the properties of the boundary phase, its distribution, and also the interactions between different phases.