Influence of sintering temperature on the microstructure, mechanical and tribological properties of ZrO2 reinforced spark plasma sintered Ni–Cr

Abstract

The microstructure, mechanical and tribological properties of Ni–Cr–ZrO2 composites, manufactured by using the spark plasma sintering technique with different sintering temperatures, were investigated. The individual powder was measured and mixed thoroughly in a tubular mixer for 8 h before being transferred to the sintering machine. The sintering temperatures of: 800, 900, 950 and 1000 °C with a pressure of 50 MPa, a holding time of 5 min and heating rate of 100 °C/min were used as the process parameters in order to develop four compositional composite systems, used in this investigation. Wear tests were, performed on the sintered composites at 10 N, 15 N and 20 N loads. The microstructural analyses of the sintered sample revealed the associated compositional homogeneities, formation of phases and pores. The results showed that the sintering temperature influenced the mechanical and tribological properties of the sintered composites, such that the increasing sintering temperature led to an increase in the relative density. The microhardness and wear resistance increased with the increasing sintering temperature, which showed that the composites developed, possessed improved properties by using high sintering temperature. Thus, the sample sintered at 1000 °C maintained the least wear rate and consequently, the best hardness property.

Keywords

• Sintering temperature
• Ni–Cr–ZrO2 composites
• Microstructure
• Hardness
• Wear