The results of the measurement of Vickers microhardness of {100} faces of synthetic lead sulphide crystals are reported. It was found that, for loads lower than ∼60g, the microhardness value depends on the applied load, the duration of indentation, and on the density of dislocations in the crystals, but that at higher loads the microhardness is independent of the applied load and is dependent on the dislocation density in the crystals. Furthermore, an influence of the adsorption of water on the microhardness of the crystals was observed. The observations are discussed in terms of the existence of a distorted zone near the crystal-medium interface, a concept originally advanced by Berzinaet al. Finally, this concept of the distorted zone is briefly compared with more recent approaches of microhardness.

Yu.S. Boyarskaya

Papers

Dislocation distributions produced by indentation and scratching in lead sulphide grown from the vapour and the melt