In the composite realm, cermets have a very important place with their properties and applications. Here, we explain the general properties of cermets and applications that cermets are used in engineering.
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What Is Cermet?
Cermet is a composite material obtained with ceramics and metals. Metals are used as matrix phase and reinforcement phase is ceramic. But if we take a look at the compositions, ceramic constitutes around 965 of the whole material. Interphase bonding between ceramic and metal phases is done with relative solubility of metals and ceramics at elevated temperatures.
As you understand from its name that cermet is an acronym of CERamic-METal.
There are two types of cermets; cemented carbides and oxide-based cermets.
What Is Oxide-Based Cermet?
Aluminum oxide and magnesium oxide are used as a particulate phase in composite materials. In general, chromium is used as matrix metal, and other metals can be used as binders. The proportions of phases change with the changing material and material properties. General applications of oxide-based cermets thermocouple shields, cutting tools for machining operations, and mechanical seals.
What Is Cemented Carbide?
It is also another type of cermet that carbide is used as particulate in a metal matrix. General carbides that are used in cemented carbides are titanium carbide, tungsten carbide, and chromium carbide. General matrix metals are nickel and cobalt.
Cobalt is used for tungsten carbide and nickel is used as a matrix material for titanium carbide and chromium carbide. Like in other cermets, the composition of the matrix phase is very low compared with the particulate phase, which is around 5-15%. When the particulate phase decreases, hardness also decreases but transverse rupture strength increases.
Tungsten carbide cutting tool applications in machining operations are very common. And other applications of tungsten carbide are drill bits, mining tools, hardness test indenters, rock drilling tools. These are major applications that hardness and wear resistance is very important.
Chromium carbide material has very good corrosion resistance and chemical stability. Compared with other cemented carbides, it is much more brittle. So chromium carbide is suitable for such applications as bearing seal rings, spray nozzles, gage blocks, and vale liners.
Titanium carbides are the most important material for high-temperature applications when nickel is used as a binder or matrix. At elevated temperatures, oxidation resistance is a very important feature. In gas turbine nozzle vane production, titanium carbide materials are generally used.
Conclusion
These are the general properties and applications of cermets in engineering. Do not forget to leave your comments and questions about cermets below. Your precious feedbacks are very important for us.
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