Molybdenum is a refractory metal typically used in high...

Molybdenum is a refractory metal typically used in high temperature applications. Key properties include:

· Low co-efficient of thermal expansion (5.1x10-6 m/m/°C) which is about half that of most steels

· Good thermal conductivity

· Good electrical conductivity

· Good stiffness, greater then that of steel (Young’s Modulus 317MPa)

· High melting point (2615°C)

· Good hot strength

· Good strength and ductility at room temperature

· High density (10.2 g/cm3)

Its ability to withstand high temperatures and maintain strength under these conditions are responsible for the fact that molybdenum finds most of its application at elevated temperatures. In fact, it can work at temperatures above 1100°C (in non-oxidising conditions), which is higher than steels and nickel-based superalloys.

When exposed to temperatures in excess of 760°C in air rapid oxidation can result. Under these conditions, the oxide layer sublimes and the base metal is attacked. Thus, molybdenum performs best in inert of vacuum environments.

Applications
Molybdenum Metal
Molybdenum metal is used in:

· Alloying agent – contributing hardenability, toughness to quenched/tempered steels. It also improves the strength of steels at high temperatures (red-hardness).

· In nickel-based alloys (such as Hastelloys®) and stainless steels it imparts heat-resistance and corrosion-resistance to chemical solutions.

· Electrodes for electrically heated glass furnaces and forehearths.

· Nuclear energy applications, as missile and aircraft parts (where high temperature resistance is vital).

· As a catalyst in the refining of petroleum.

· As a filament material in electronic/electrical applications.

· As a support members in radio and light bulbs.

· Arc resistant electric contacts.

· Thermocouple sheaths

· Flame- and corrosion-resistant coatings for other metals (generally arc deposited for metallising).