Advantages of Diamond

Diamond exhibits a rare combination of physical, optical and thermal properties that make it an attractive material for many applications. It is the hardest material known to man, has the highest thermal conductivity at room temperature of any material, yet is electrically insulating and transparent from 225 nm through and beyond the IR region of the electromagnetic spectrum (except for a second order absorption at 5 μm). Some of diamond’s basic properties are listed in Table 1.

Table 1. Properties of diamond compared to other selected materials.

Material


Thermal Conductivity (W.m-1.K-1)


Electrical Resistivity (Ω.cm)


Hardness (GPa)

Diamond


2000


1 x 1014


110

Copper


380


1.7 x 10-8


0.04

Alumina


30


3.3 x 108


20

Silicon


168


3.2 x 105


11.5

ZnSe


140


-


1.7
Disadvantages of Diamond

However, those same excellent properties such as hardness and chemical inertness are a major disadvantage when it comes to processing diamond, and, as would be expected, it is expensive. Small, artificial, single crystal diamonds are produced, but this requires extremely high temperatures and pressures. Diamond grit is also produced commercially, and is used in the manufacture of cutting tools and for abrasive applications.
Production of Diamond by Chemical Vapour Deposition (CVD)

In the 1980s reports emerged from Russia suggesting that diamond could be formed from the vapour phase at relatively low temperatures and pressures. Although greeted at first with some scepticism, these reports generated a large amount of research into chemical vapour deposition (CVD) of polycrystalline diamond.