Kenji Yano

Temperature measurement of ceramics in furnaces by 3-color thermograph

Temperature control in the sintering process is important to secure the quality of ceramics. We have usually controlled the sintering process indirectly by making use of the temperature of the inside of a furnace. It has been a general understanding that infrared radiometric thermograph is not suitable for measuring directly the temperature of the targets such as ceramics placed in the furnace because of emissivity dependence of the targets and because of the effect of reflection from the furnace wall. The same can be said to 2-colored thermometers because of them, too, it has been impossible to eliminate the effect of reflection for correct temperature measurement. Recently we, however, contrive two new methods for direct measurement of the surface temperature of ceramics using a 3-colored thermograph. One is to measure the indefinite emissivity of the inside of a furnace and the effect of reflection from the furnace wall. The other is to eliminate such indefinite emissivity and effect of reflection. We will report the new methods of 3-colored thermograph and the result of inspecting the said methods.