Synthesis and sintering of MAX phases in the Zr–Al–C system

Abstract

In this paper synthesis and sintering of MAX phases in the Zr–Al–C system is described. Different mixtures of initial Zr/Al/C and Zr/Al/ZrC powders were used to synthesize the MAX phases of Zr₂AlC and Zr₃AlC₂ compositions by a combined method (high‐temperature sintering followed by spark plasma sintering). The highest content of the Zr₃AlC₂ MAX‐phase was obtained using initial Zr/Al/ZrC powders in a component ratio of 1:1.5:2 – 51.1 vol. %. The optimal temperature for the synthesis of a material based on the Zr₂AlC MAX phase is 1525°C, and a material based on Zr₃AlC₂ is 1575°C. During subsequent spark plasma sintering at a temperature of 1500°C, a pressure of 50 MPa, within 5 min, it was obtained a material containing up to 71.1 vol. % Zr₃AlC₂. The relative density of the samples synthesized and consolidated by the SPS method reaches 98.9 %. The structure of the obtained synthesized MAX materials includes elongated grains of the composition Zr₂AlC and Zr₃AlC₂, which determines their high strength. The influence of the sintering time and temperature on the formation of the MAX phase of Zr₃AlC₂ from the initial powders of Zr/Al/ZrC is shown. Zirconium carbide, as an intermediate phase, is always present in the final products. Due to the large evaporation of aluminum, the ZrAl₂ phase is also present in the synthesis products. An excess of aluminum contributes to the greatest formation of the Zr₂AlC and Zr₃AlC₂ phases during the combined synthesis.

This article is protected by copyright. All rights reserved