(EP163143-B)      Fine-grained ceramic formed body of ZrO2 containing 0.5 to mole-% rare earth oxide and 0.6 to 7 mole-% MgO, characterised in that its cubic granules are coated with Mg-Al spinel particles. (5pp)d    (US4900492-A)      A formed body is produced by pressing a powder comprising a ZrO2 powder alloyed with 0.5-4 mol % rare earth oxide or SrO, which contains 0.1-5 vol.% of Al2O3, in the presence of MgO to form a pressed body (I). (I) is then sintered at 1400-1600 deg.C in an atmos. contg. MgO. Pref. the rare earth oxide is Y2O3.    ADVANTAGE -   Formed bodies are provided which are more fine-grained than the PSZ ceramics but display, in comparison with the TZP ceramics, improved thermal stability in the range 200-500 deg.C in moist surroundings, and improved high temp. strength. (4pp)y    (EP163143-B2)      Fine-grained ceramic formed body of ZrO2 containing 0.5 to mole-% rare earth oxide and 0.6 to 7 mole-% MgO, characterised in that its cubic granules are coated with Mg-Al spinel particles. (5pp)d    (JP92075188-B)      Small grained ceramic articles are made of ZrO2, with 0.5-4 mol% of a rare-earth oxide, e.g. Y2O3 and/or CeO2, Gd2O3, La2O3 or SrO, 0.5-7 mol% of MgO and small quantities of Al2O3 and processed to form a sintered part of cubic grains coated with MgAl-spinel particles.    The processing is also claimed. This consists of mixing ZrO2 with rare earth oxide, e.g. Y2O3, and a small amt. of Al2O3, pressing and sintering at 1400-1600 deg.C, pref. 1500 deg.C. In the presence of MgO either mixed in with the powders or provided in the ambient. The sintered part is then annealed at 1200-1350 deg.C. During the high temp. sintering cubic grains are formed while during the annealing tetragonal grains grow inside the cubic grains.    USE/ADVANTAGE -   The material has a much smaller grain-size than conventional cubic ZrO2 ceramic and shows a much higher strength. It also has a greater temp. stability than conventional large grained cubic material and, though contg. tetragonal crystals, has excellent resistance to damp heat. The processing can be carried out at a lower temp. The material can be used as construction material in steam-engines and as solid electrolyte. (J60235763-A)