A High-Temperature Dilatometer Utilizing Recrystallized Silicon Carbide Rods

Abstract

A new dilatometer which can measure thermal expansion and contraction of ceramic raw materials and refractories under oxidizing atomosphere up to the temperature range of over 1600°C was designed. The thermal behaviors of recrystallized SiC rods were examined at first. The results showed that SiC rods are very suitable for use in a high-temperature dilatometer as structural materials. The construction and mechanism of the apparatus are illustrated and a meas taken on experimental research for nearer approach to the real temperature reading was explained. Because the reading of specimen length was varied according to the methods of cooling the lower part of apparatus extending downwards from the furnace, data are given for each case to calibrate the reading of specimen length at high temperature. Procedure for correcting the experimental data obtained with the apparatus is established. Accuracy and reliability of the apparatus is demonstrated by the tests made on both sintered and bonded alumina refractories.
The features of the apparatue are summerized as follows: When textures of sampl es are homogeneous, quick and accurate measurements can be made on such a specimen smaller than 8mm×20mm. It can afford measurements on such materials which react with SiC or soften at high temperature, because of the special construction of the apparatus. Results of the measurements on various ceramic raw materials and refractories aredescribed.