Comments on "Thermal shock resistance of yttria-stabilized zirconia with Palmqvist indentation cracks" by G. Fargas, D. Casellas, L. Llanes, M. Anglada [J. Eur. Ceram. Soc. 23 (2003) 107-114]

In a recent paper, Fargas et at. [Fargas, G., Casellas, D., Llanes, L. and Anglada, M., Thermal shock resistance of yttria-stabilized zirconia with Palmqvist indentation cracks. J. Eur Ceram. Soc., 2003, 23, 107-114] make use of the Vickers indentation technique to characterise the thermal shock resistance of brittle materials exhibiting the Palmqvist indentation crack system. They claim that their approach can provide a measurement of Hasselman's R"" thermal shock resistance parameter. It is here demonstrated that the obtained parameter is in fact different from R"". In parallel, it is shown that a previously developed approach, which is both consistent with the concepts of R'"' and of the critical quenching temperature differences, Delta T-C, call be used in the case of the Y-TZP ceramics of Fat-gas et al. This approach also allows all estimation of the maximum thermal stresses and of the coefficient of heat transfer at the fluid-solid interface as a function of the quenching temperature difference. (c) 2005 Elsevier Ltd. All rights reserved.