The Properties of Diamond

Diamond is composed of the element carbon and only nitrogen and boron with atomic radii smaller than carbon are known, with certainty, to be incorporated in the diamond lattice. Almost every diamond is different, but the following general elassification based principally on optical properties (Table 2.1) can be applied. 

Diamond and graphite cannot be positively identified using electron diffraction techniques alone, but Raman spectroscopy will, however, clearly differentiate the sp bonding of graphite and the sp bonding of diamond. 

Diamond does have impurities which impair the optical performance. These impurities can be either a form of inclusion, or a lattice impurity such as nitrogen or boron, which are adjacent to carbon in the periodic table, have similar atomic radii and therefore, easily fit into the diamond structure. Nitrogen tends to form a nitrogen pair where the nitrogen atoms are adjacent within a unit cell or, alternatively, the nitrogen could form platelets. 

Diamond is anisotropic material with a density of 3.515 gcm and is more compact than graphite, which has a density of 2.26 g cm . Diamond is unique, having the highest atom 

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Not all of the properties of diamond are considered here, and additional information and qualifications are available (9,14—19). 

It is outside the scope of this Chapter to undertake a comprehensive review of structure-property relationships for the different forms of carbon. However, a limited comparison of properties is useful for illustrating the influence of chemical bonding upon the properties of diamond, graphite and Buckminsterfullerene, Qo, Table 4. Carbynes are omitted from the comparison since insufficient is known of their properties. 

A. R. Lang, Internal structure, in The Properties of Diamond, ed. J. E. Field, London,... 

Because diamond like materials contain a mixture of both sp and sp sites and hydrogen, they can therefore be considered to be an intermediate between diamond, graphite and polymeric hydrocarbon. The mixed bonding means that the properties of diamond like materials are generally inferior to those of diamond. However, these materials have certain advantages that make them competitive to diamond coatings in a number of applications. These advantages are listed below. 

Table 3 lists the properties of diamond like materials prepared by different techniques in comparison with diamond and graphite. ... 

The excellent properties of the diamond like materials combined with the low deposition temperature and high deposition rate, make these coatings very promising materials for the future. They have many potential applications as protective coatings for industrial products. Of course the properties of diamond like films never match those of diamond. The films are intrinsically smooth and amorphous, and can be used in coating applications where a plane, mechanically hard and wear/corrosion resistant surface is desirable. 

Berman, R. (1979) in The Properties of Diamond, edited by J.E. Field, Academic Press, London, p. 3. Discusses the thermal conductivity of diamond and the effect different impurities have on this property. Kingery, W.D., Bowen, H.K., and Uhlmann, D.R. (1976) Introduction to Ceramics, 2nd edition, Wiley, New York, pp. 583-645. A very detailed chapter on thermal properties. The discussion of photon conductivity and the thermal properties of glasses are covered in more depth than we do. 

The polycrystalline derivatives of diamond and cBN, normally referred to as pcD and pcBN respectively, provide engineers with materials which have many of the properties of diamond and cBN, notably hardness and abrasion resistance, but in the form of relatively large isotropic pieces, usually in the form of flat discs. These materials have a wide variety of uses, both as a defined edge cutting tool... 

A term that refers to the various different forms of amorphous carbon materials that exhibit some of the properties of diamond. 

A number of useful books on the properties of diamond have been published [4-8],... 

Field JE ed.. The Properties of Diamonds, Academic Press, London, 1979. 

The properties of diamond require many superlatives to describe them as diamond exhibits a unique set of physical and chemical properties, among those the most remarkable characteristics are ... 

The properties of diamond anda-graphite are compared in the following tabulation ... 

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