Using infiltration and self-propagating high-temperature synthesis processes for manufacturing cermets. Review

Abstract

Cermets are ceramic-metal composite materials (composites) with a relatively high content of ceramic phases from 15 to 85 % by volume. In the 20th century cermets were considered mainly as composites of high-temperature carbide, oxide, nitride, boride and silicide ceramic phases with metallic phases of the iron group, but in the 21st century the concept of cermets has significantly expanded due to the appearance of composites made of ceramic and metal phases with lower melting points including sulfides and MAX phases, as well as light and low-melting metals (Al, Mg, Cu, Ag, Pb, Sn). Therefore, cermets began to be considered not only as tool, heat-resistant and wear-resistant heavy structural materials, but also as light, strong structural materials for the production of vehicles, and as functional materials for various purposes. However, quite often cermets are characterized by such disadvantages as a tendency to brittle destruction, the difficulty in achieving structural uniformity and reproducibility, as well as fault detection, and the high cost of cermet manufacturing. It determines the need in their further development, research to improve the composition, structure and properties of cermets, searching for new applications, developing new manufacturing methods and reducing the cost of their production. Various cermet manufacturing methods are discussed such as solid-phase, liquid-phase, gas-phase, and in-situ methods. The methods of infiltration with molten metals, the effect of wetting, and the conditions for spontaneous infiltration are considered in more detail. The results of using the method of self-propagating high-temperature synthesis (SHS) are also described in detail including a new cermet manufacturing method proposed by the authors of this review based on the use of the SHS of a porous ceramic skeleton followed by spontaneous infiltration with molten metal.