ELECTRICAL HEATING UNIT FOR HEAT TREATMENT OVEN AND HEAT TREATMENT OVEN

摘要

An electrical heating unit (10) for heat treatment ovens which comprises: a base material (1) which is a ceramic fiber molding 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 then 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.