Abstract: Corundum-zirconia abrasive grains containing more than 50 wt % of an alumina-zirconia eutectic mixture. The grains contain 0.3 to 3% nitrogen, and more than 75% of the zirconia crystals are cubic in shape. The abrasive grains are of particular use for making grinding wheels, abrasive fabrics and papers, polishing compounds and sprayed abrasives.

Abstract: A plasma processing apparatus includes an evacuatable processing vessel; a workpiece mount base for mounting thereon an object to be processed; a microwave transmitting plate provided in an opening of a ceiling of the processing vessel; a planar antenna member for supplying a microwave into the processing vessel via the microwave transmitting plate; a shield lid grounded to cover a top of the planar antenna member; a waveguide for guiding the microwave to the planar antenna member; a member elevating mechanism for relatively varying a vertical distance between the planar antenna member and the shield lid; a tuning rod insertable into the waveguide; a tuning rod driving mechanism for moving the tuning rod to adjust an insert amount thereof; and a matching control section for controlling an elevation amount of the planar antenna member and the insert amount of the tuning rod to obtain a matching adjustment.

Abstract: The invention concerns a refactory material based on corundum treated by electrofusion consisting of beads of diameter ranging between 50 ?m and 5 mm, having a total pore ratio ranging between 10 and 50 % of the volume of the beads, the sealed porosity representing from 80 to 98% of the total porosity. The inventive material is in particular designed for spray-applied refractory concrete.