Ceramics, sintered zinc oxide

Zinc oxide (ZnO) can exhibit a wide range of electrical properties depending on minor constituents and sintering conditions. It is also remarkable for the ease with which high-density ceramics can be achieved over a wide range of sintering temperatures and for its excellent resistance to thermal shock. 

Kim J, Kimura T, Yamaguchi ET. Sintering of zinc oxide doped with antimony oxide and bismuth oxide. J Tto Ceram Soc. 1989 72 1390-1395. DOI 10.1111/]. 1151-2916.1989.tb07659.x... 

For the range up to 170 °C, most sensors are based on NTCs. These resistors are made of powder mixtures of metal oxides such as iron, zinc, cobalt, manganese, copper, and nickel. These powder mixtures are formed into discs or wafers and sintered at high temperatures between 1000 and 1400 °C. The cured product is a ceramic material. 

Systems in which two simple oxides react to form a complex oxide are usefiil models for investigating the production of single-phase ceramics by reaction sintering because of the available data on the reaction mechanisms (91) and the relative simplicity of the reactants and product. Two examples are the formation of zinc ferrite by Eq. (11.67) and the formation of zinc aluminate spinel by the reaction between ZnO and AI2O3 powders. 

---