Hardness and fracture toughness are important factors typically used used for characterising armour ceramics. Their values depend on composition and microstructure of the ceramics, on the features of testing methods, and on the sample preparation procedure. Vickers and Rockwell indentation commonly used for hardness testing and fracture toughness Kic determined by the indentation method have been studied for different armour ceramics. The sample preparation procedure for Vickers hardness testing has been optimised in order to increase the accuracy of measurement and to reduce stresses occurring at indentation. The influence of microstructure for different alumina and carbide-based armour ceramics, as well as the influence of an indentation load, on hardness and fracture toughness have been analysed.
