Ceramic sheet and process for producing the same

Abstract

A ceramic sheet has a burr height on the periphery of the sheet of ±100 μm or less and/or a dimple height on the sheet surface of 100 μm or less, as determined by irradiating the sheet with a laser beam to measure reflected light, and three-dimensionally analyzing the reflected light with a laser optical three-dimensional profiling instrument. This sheet is highly resistant to stacking-induced loads and thermal stresses. Further, when the ceramic sheet includes a zirconia ceramic partially stabilized with 2.8 to 4.5% by mole of yttria and containing 0.1 to 2% by mass of at least one dispersed reinforcing oxide, in which the grain size of the surface of the sheet has an average of 0.1 to 0.4 μm, a maximum of 0.4 to 0.8 μm, and a coefficient of variation of 30% or less, which grain size is determined by scanning electron microscopic observation, the ceramic sheet has satisfactory strength at room temperature and at high temperatures and satisfactory durability of strength at high temperatures. The ceramic sheet is very useful as, for example, a solid-electrolyte film of a solid oxide fuel cell.