Diamond exhibits a large number of extreme properties, which individually or in combination make it the best performer in a whole range of industrial applications:



1. Chemical: It is chemically insert.

2. Mechanical: It is the hardest material known to man.

3. Electrical: It has certain high performance electrical properties.

4. Optical: It has unmatched optical transparency across the widest spectrum.

5. Thermal: It is the most thermally conductive material.

Chemical

Diamond is chemically inert and is highly resistant to chemical attack by acids or other chemical reagents. The only exceptions are materials that at high temperatures act as oxidizing agents - these provide the only effective way to attack diamond at normal pressures and temperatures (below about 1000'C). Salts, such as sodium nitrate, are known to attack diamond when in the molten state at temperatures as low as 450'C and, in oxygen itself, diamond starts to be oxidized at around 650'C.

The only other possible form of chemical attack is by two groups of metals. The members of the first group are strong carbide formers, and include tungsten, tantalum, titanium and zirconium. The second group of metals includes iron, cobalt, manganese, nickel and chromium (and also the platinum group of metals). In the molten state these metals are true solvents for carbon.

Mechanical

The strength of the carbon to carbon bond is the source of the exceptional mechanical properties of diamond. Dislocation of the atoms is difficult and consequently diamond is the hardest known substance.

Diamond has been recognized as being a unique material for several centuries, mainly because of its unsurpassed hardness and its unrivalled resistance against abrasion. In more recent years, this has led to the growth of diamond as a raw material for the manufacture of cutting tools for different materials such as non-ferrous metals, natural stone and concrete, wood based materials, plastics, glass and ceramics.

Electrical

Diamond has always been considered to be the ultimate material for the fabrication of active electronic devices for the most demanding high power and high frequency applications. However, until recently it has not been available in sufficient quality or purity.

The exploration of the electrical properties of diamond have only just begun, but diamond-based electronic devices could include high-voltage switching in future generation power distribution networks and high power, high frequency communication systems.

Optical

Diamond is unmatched in being transparent from near the ultra-violet cut-off at 225 nm to beyond a wavelength of 100'm, including the atmospheric infrared transmission bands.

The use of diamond materials in optical applications such as infrared laser windows, was, for a long time, restricted by the size and cost of natural diamond. The use of CVD diamond is an economic alternative to zinc selenide (ZnSe) because of its hardness and high thermal conductivity.

Thermal

Diamond's strong covalent bonds and rigid lattice result in high stress wave (phonon) velocity. This in turn gives diamond a high thermal conductivity, about five times that of copper at room temperature.

The first natural diamond heat sink for a microwave diode was manufactured in 1967 and since then, this material has been used for the thermal management for microwave and laser diode devices.