Preparation and characterization of cordierite ceramic from coal series kaolin for electronic application

Abstract

Coal series kaolin (CSK) is used as the raw material to prepare CSK cordierite electronic ceramics. Sintering process is analyzed by a heating microscope. The microstructure of green body, phase transformation, and microstructure evolution during sintering process is elucidated by scanning electron microscope (SEM) and X-ray diffraction (XRD). Comprehensive evaluations of our product are made for physical properties, electrical properties, and coefficient of thermal expansion (CTE), respectively. According to test results of the obtained CSK cordierite ceramic, the sintering temperature range is 1280~1420 °C, synthetic temperature is 1160~1280 °C, densification process is 1360~1420 °C, and large deformations of cordierite ceramic happen above 1420 °C. The optimum performance of the obtained CSK cordierite ceramics is summarized as follows: volume density is 1.81 g·cm3, apparent porosity is 28%, bending strength is 65 MPa, CTE is 1.41 × 10−6 °C−1 (600 °C), and dielectric constant is 4.6 (100 Hz). As a result, this cordierite electronic ceramics from CSK have great potential to do with applications in electric heater supports, such as electric stove, ceramic heater base, and electric heater cooling plate.