HEAT-INSULATING MATERIAL FOR HEAT TREATMENT OVEN, ELECTRICAL HEATING UNIT FOR HEAT TREATMENT OVEN, AND HEAT TREATMENT OVEN

摘要

A heat-insulating material (10) for heat treatment ovens and an electrical heating unit (20) for heat treatment ovens which each comprises a base material (1) made of ceramic fibers comprising alumina and silica and a coating layer (2) formed by applying a coating material comprising a base ingredient comprising water and a water-soluble aluminum phosphate and a pigment comprising silicon carbide to that surface of the base material (1) which serves as an oven-wall inner side and thenmatériau drying the coating material. Since the aluminum phosphate contained in the coating layer (2) has a high affinity for the alumina as a component of the base material (1), the coating layer (2) formed on the surface of the base material (1) is adherent thereto at high bond strength. The surface of the base material (1) is hence prevented from generating dust in the oven over long.