HIGH-TEMPERATURE SILICIDES: PROPERTIES AND APPLICATION

The overview presents a historic retrospective and current state of research of structure, properties and application of hightemperature silicide materials in science and engineering. These materials, particularly construction and functional materials based on or involving silicide refractory metals, are a most important alternative class of materials which adequately complete with special alloys, intermetallic metals, and ceramics that are traditionally used at high (above 15000C) temperatures in oxidizing and other aggressive environments. The paper analyzes the data available on constitutional diagrams, particularly on molybdenum-silicon and tungsten-silicon systems. Also, it shows differences in descriptions of diagrams given by different authors and considers some crystallochemical and physical properties of some high-temperature silicides. The paper reviews areas of application of high-temperature silicide materials of various types (layered and multiple-phase composites, consolidated powders, film structure, three-dimensional materials), and presents details of the challenges encountered in the process of creation and application of high-temperature protecting silicide coatings, as well as possible ways to improve their performance. It is noted that lack of unified approach to presentation and correlation of research results as well as to description of real performance of materials is a substantial problem in creating new high-temperature silicide materials.