Microstructure and Mechanical Properties of Spark Plasma Sintered Amorphous AlPO۴ Ceramics

The main objective of this study is to assess the structure and mechanical properties of amorphous aluminum phosphate (AlPO۴) ceramic specimens prepared through Spark Plasma Sintering (SPS) method. To this end, AlPO۴ powder was synthesized through sol-gel process and consolidated by SPS at the sintering temperature range of ۸۰۰-۱۳۰۰ °C. Ceramic specimens were characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses. Bulk density of the samples was measured using Archimedes’ principle. In addition, hardness and indentation fracture toughness of the samples were determined to identify the mechanical properties. The results from XRD analysis, SEM images, and density measurement revealed that the sintered sample was characterized by an amorphous structure with the porosity of ~ ۳ % and relative density of ۹۷ % after SPS at ۱۰۰۰ °C for ۱۵ min. Increasing the temperature to ۱۳۰۰ °C made the amorphous AlPO۴ crystallized. The fracture toughness was obtained to be ۵.۷۵ MPa.m۱/۲ under this sintering condition. Crack deflection around porosities was identified as the main toughening mechanism involved.

Keywords:

Amorphous AlPO۴ , Spark Plasma Sintering , Mechanical properties , Fracture toughness