There are bunch of refractory metals that some kinds of high temperature applications can be possible with them. In this article, we will explain the types of refractory metals, types of refractory metals and applications of refractory metals.
Actually refractory means, material has superior properties at elevated temperatures. One of the most important examples of refractory metals are Molybdenum(Mo) and Tungsten(W). These materials show very good hardness and stregth characteristic at elevated temperatures.
If we talk about Molybdenum(Mo), Mo has very high melting temperature and relatively dense and stiff material. In such applications, Molybdenum can be used as pure material. Also small amounts of alloying elements can be added to Molybdenum like titanium and zirconium (less than 1% total). This alloy is named as TMZ. Because of Molybdenum’s high temperature strength, it has very important applications such as heat shield applications, heating elements, electrodes for resistance welding etc. Also Molybdenum can be used as alloying element in steels and superalloys.
Tungsten(W) also has very superior characteristics compared with other metals. The melting temperature of Tungsten is the highest one in pure metals. Tungsten is the densest and strongest pure metal. As you know that Tungsten is used in incandescent light bulbs as wire. Typical applications of Tungsten are rocket and jet engines and electrodes for arc welding. Tungsten is also widely used as an element in tool steels, heat resistant alloys, and tungsten carbide.
The most important disadvantage of Tungsten and Molybdenum is oxidizing at high temperatures such as 550-600 degrees. If these materials are oxidized, they lost their high temperature properties. Because of that, some kinds of protective coatings must be applied to Tungsten and Molybdenum parts. Also they can be used in vacuumed atmosphere such as use of Tungsten wire in incandescent light bulbs.
Also there are other minor refractory metals such as Colombium(Cb) and Tantalum(Ta).
The most common refractory metals can be summarized as above. Do not forget to leave your comments and questions about ‘Refractory metals and types’ below!