Xrd Pattern Zirconium Silicide

Sintering Behavior, Microstructure, and Mechanical Properties: A ...

. Increasing the amount of sintering aid, the final density increased too, thanks to the formation of small amounts of liquid phase constituted by M-Mo-Si-O-C, where M is either Zr, Hf, or Ta. The matrices of the composites obtained with the standard procedure showed faceted squared grains; when an ultrasonication step was introduced in the powder treatment, the grains were more rounded and no exaggerated grains growth occurred. Other secondary phases observed in the microstructure were SiC and mixed silicides of the transition metals. Among the three carbides prepared by pressurless sintering, TaC-based composites had the highest mechanical properties at room temperature (strength 590 MPa, Young's modulus 480 GPa, toughness 3.8 MPa·m 1. Introduction

The carbides of the group IV–VI transition metals have extremely high melting points (3000–4000°C) and are commonly referred to as “refractory carbides”. Beside their stability at high temperatures, these compounds possess extremely high hardness, thus finding industrial use in cutting tools and wear-resistant parts [ 1 – 3 ]. They also have good corrosion resistance, as they are attacked only by concentrated acid or base in the presence of oxidizing agents, and retain good corrosion resistance to high temperatures. The refractory carbides are stiff, with Young’s modulus values competing with those of SiC. In addition, they have good thermal conductivity, permitting heat to be drawn away from the superheated surfaces. This gives them a benefit over other refractory materials, such as AlN, SiC, and Si μ m) with trapped porosity and poor mechanical properties [ 6 , 7 ].

The purpose of this study is to develop carbide-based materials which can be consolidated by pressureless sintering at temperatures lower than 2000°C. From the technological point of view, with this technique, complex-shaped components can be achieved at competitive costs of production. Moreover, by keeping the temperature below 2000°C it is hoped for the achievement of a fine and homogeneous microstructure which displays good mechanical properties.

Zirconium

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