Influence of Sintering on the Development of Alumina-Toughened Nanocomposites: Conventional Versus Microwave

Abstract

In this research paper, the physical properties, mechanical properties and microstructural characteristics of 3 mol% Yttria-Stabilized-Zirconia (3YSZ) matrix reinforced with 10 volume percent of alumina (Al2O3) are presented and briefly discussed. The composites were developed using the techniques of conventional sintering [1600 ℃, 5 ℃/min and held for 6 h] and microwave sintering [1600 ℃, 25 ℃/min and held for 1 h] under pressure-less condition. The sintered powders were subsequently compacted using a uniaxial cold isostatic press at a pressure of 200 MPa. The relative density, average grain size, microhardness and fracture toughness of both the conventional sintered samples and microwave sintered samples were determined and found to be [conventional sintered: density: 98.16 ± 0.15, grain size: 600 nm, microhardness: 16.81 ± 0.7 GPa and fracture toughness: 4.9 MPa m0.5) and [microwave sintered density:99.29 ± 0.10, grain size: 421 nm, microhardness: 19.65 ± 0.5 GPa and fracture toughness: 5.2 MPa m0.5], while the thermal conductivity was determined to be 2.3 W/mK for the conventional sintered sample and 2.6 W/mK for the microwave sintered sample. A near uniform microstructure was observed for both the conventional sintered and microwave sintered samples. The microwave sintered samples were observed to have superior properties when compared one-on-one with the conventional sintered counterpart. This study provides useful information specific to the development of a material for use as a thermal barrier coating and for its selection and use in dental applications.