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Composite materials are widely used for insulation and structure in superconducting magnets. The design of appropriate superconducting windings requires a knowledge of the magnitudes of all sources of local heating that might drive the superconductor normal.

The non-lubricated wear behavior of Al2O3, PSZ, and two grades of sintered alpha SiC has been studied under unidirectional sliding conditions at room temperature. Using a ring on ring geometry, the wear rates were established as a function of normal load and sliding time. Mechanistic understanding is explored by extensive microscopy and profilometry of the wear surface at specific operating regimes. Various wear mechanisms such as asperity shearing, ploughing, and brittle fracture operate at different loads depending on material properties.

The measurement of hardness is probably the most widely applied method of evaluating the mechanical properties of solids. Its usage ranges from techniques of quality control to such fundamental studies as the identification of slip systems. Nevertheless, there are still many aspects which have been neither thoroughly investigated nor properly explained. Consequently, the full potential of hardness measurement, in terms of our understanding of the behaviour of materials and their properties, is far from having been realised. In this paper we shall identify some of the aspects of hardness which are especially relevant to the hardest materials and which would benefit from further research. In particular, we shall be concerned with the implications of anisotropy for our understanding of the effects of varying normal load, temperature, and indentation creep.