PURPOSE: To reduce the cost by forming a coating layer of ceramics on the surface of a substrate, sending DC, AC or microwave electric current, heating the coating layer of a ceramics by self-resistant heat generation and bonding the layer to the substrate.
CONSTITUTION: A coating layer 12 of ceramics such as glass frit powder is formed on the surface of a substrate 11 such as ALC concrete, placed on a conveyor 17 and transported in the longer direction thereof. Then an operation order signal is given to a control device 22, an electric current is sent through a current-carrying control part 14 to a heater 25 to heat the coating layer 12 of ceramics. Simultaneously electric voltage is impressed to electrodes 13 in contact with both sides of the coating layer 12. When an electric resistance value of the heated coating layer 12 is reduced and an electric current is sent between the electrodes 13, the coating layer 12 is heated by self resistant heat generation and then melted. On the other hand, when an electric current is sent to the coating layer 12, an electric current value is subjected to feedback to the control device 22 by the current-carrying control part 14 and reaches a given value, current carrying to the heater 25 is stopped. Consequently, molten part of the coating layer 12 is naturally cooled, hardened and bonded to the surface of the substrate 11.
IKOMA TOSHIAKI
YASUI ITARU
KURODA KAZUO
KAGAKU GIJUTSU JOHO KENKYUSHO