ABSTRACT
Diamond is an allotrope of carbon, joining graphite and the fullerenes as the major pure carbon structures. Diamond has a unique combination of properties: hardness, thermal conductivity, chemical and thermal inertness, and abrasion resistance. Natural diamond is produced at high pressures and temperatures in volcanic shafts. In the field of tribology synthetic diamond film technology looks promising and could edge into tribological and tooling applications. In diamond each tetrahedron of the hybridized carbon atom combines with four other hybridized atoms to form a strongly bonded, three-dimensional, entirely covalent lattice structure. Knowledge of the fracture stress and crack patterns produced in diamond is important in understanding tribological phenomena, such as wear, erosion, and abrasion. Diamond has the highest thermal conductivity of any material at room temperature, cracking due to thermal shock is not likely to be a problem, in contrast to alumina.
