Ceramic substrate and polishing method thereof

摘要

A ductile rotating body (11) containing abrasive grains is used, and the surface of a ceramic substrate (10) is polished by the circumferential portion of rotating body (11). At this time, angleθformed between the polishing direction D0 of ceramic substrate (10) and the rotating direction D1 of rotating body (11) is set in the range from 10 DEG to 80 DEG for polishing. Alternatively, the polishing process is divided into at least two steps, and the average grain size of abrasive grains is reduced stepwise for polishing. According to this method, the surface of a large-area and thin ceramic substrate can be polished without damages, and a ceramic surface having a smooth polished surface can be provided. This method is particularly suitable for polishing a ceramic substrate (10) having a thickness of at most 2.0mm, and the resulting polished ceramic substrate is suitable for a substrate for a ceramic heater in a thermal fixation device for toner image.