Mechanical Properties of ZTA-Cr2O3 Ceramic Composites Prepared with Nano and Micron Sized of Cr2O3 Powder on Different Ratios

Abstract

In this study, the effect of Cr2O3 addition in different powder sizes on the densification and mechanical properties (elastic modulus, hardness and flexural strength) of ZTA composites were investigated. Nano and micron sized of Cr2O3 powder were added to the ZTA composite separately in different weight ratios (0.3, 0.6, 1%) and uniaxially dry pressing right after pressureless sintering at 1650°C/2 h in the air used as processing procedure. The relative density values of all the composites were close to each other for the Cr2O3 containing composites. A slight decrease in both densification and elastic modulus was observed with the addition of Cr2O3 due to the evaporation problem. Also, the addition of Cr2O3 did not have a serious effect on the hardness of the ZTA composites. The main effect of Cr2O3 addition on ZTA composites was seen for flexural strength. Compared to the ZTA, a nearly 7% increase in strength was obtained for 0.6%Cr2O3 containing composite prepared with micron sized Cr2O3 powder due to the generated compressive stresses in the grain boundary caused by solid solution formation.