Preparation of SiC_w-ZTA Composites by Two-Step Sintering or Spark Plasma Sintering

Abstract

Alumina materials are widely used in the industry as cutting tool inserts. In order to improve mechanical properties of the Al2O3 matrix, different reinforcing phases are introduced. In the presented work, reinforcements in the form of ZrO2 particles and SiC nanofibres have been used. ZTA-SiC composites were obtained from 0.5%MgO-20%(3Y2O3)ZrO2-79.5%Al2O3 powder and 15% of SiC whiskers. Tested materials have been prepared by means of the two-step sintering (TSS) and spark plasma sintering (SPS). TSS method permits to obtain dense materials with fine-grained microstructure. TSS has been carried out for two different sintering times: 1 hour 20 minutes and 8 hours. Due to the reactivity of the components, the SPS method has been used to shorten sintering times. SPS has been performed at two different temperatures: 1500 °C and 1550 °C.