The proposal is for a temperature-resistant ceramic used especially as a solid electrolyte ceramic for gas sensors. The ceramic of the invention comprises at least two ceramic powders, and at least one ceramic powder is highly stabilised, i.e. contains at least 4 mol% yttrium oxide, and at least one second ceramic powder which is low-stabilised, i.e. contains between 0 and 2.5 mol% yttrium oxide, consists of grains, the surface of which has a coating, especially aluminium oxide, which inhibits the diffusion of the stabiliser oxide cations. According to the invention, a very uniform distribution of the aluminium oxide in the body of the ceramic is attained, with a concomitant improvement in the impact strength, endurance limit and temperature shock resistance without any adverse effect on the O2 ion conductivity.