Antimony-doped tin oxide thin films have a range of technical applications as conductive coatings, and sol–gel processing seems to offer some advantages over other coating techniques. In this study, undoped and antimony-doped tin oxide (ATO) thin films were prepared by sol–gel process in the solution of metal salts of tin (II) chloride dehydrate and antimony tri-chloride. It has been found that the heat-treatment temperature and doping level had strong influences on the microstructure and composition of Sb:SnO2 films. The microstructure of the thin films was analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). The SnO2 crystals existed mainly as tetragonal rutile structure in the present work. The optimum heat-treatment temperature was about 450–500 ◦C, and the film was composed with nano-crystals and nano-pores. Compared with undoped tin oxide, doped antimony tin oxide films coated glass substrate were homogenenous in composition and morphology after being sintered at different temperatures. Electrical behavior of the doped films was discussed in terms of sheet resistance measured by four point probe. From the experimental data, the sheet resistance of the films could be as low as 100Ω/□.

In the present paper, the research on the sintering mechanism of BaTiO3-based Positive Temperature Coefficient of Resistance (PTCR) semiconductive ceramics was carried out. According to the mechanisms of surface diffuse and volume diffuse, the comprehension acting mechanism was suggested, the kinetic equation was proposed at the initial stage of sintering, and the initial stage of sintering process was simulated by a computer. We obtained the object illustrations about the relationships between the grain growth of the initial stage of sintering on BaTiO3-based PTCR ceramics and sintering temperatures, as well as the particle sizes of raw materials.

This paper presented a novel modified Q-states Potts Monte-Carlo computer simulation procedure applied to simulate the grain growth of intermediate and final stages of sintering and Ostwald ripening process of BaTiO3 Positive Temperature Coefficient of Resistance (PTCR) ceramics, and the effects of liquid-phases on the grain growth of BaTiO3-based PTCR ceramics. The computer simulating models of the grain growth of the sintering process were established by the theory of the grain growth. The simulating results indicated that (1) the liquid-phase would hinder the motion of the grain-boundary, and the ratio of the grain growth was limited so that the size of the grains was smaller than those of the single-phase system; (2) the shrinkage of a BaTiO3 PTCR ceramics almost ceased at the temperature of 1513 K or so in the two-phase system, and the soaking stage involved the densification and grain growth of ceramics controlled by liquid-phases.

The failure behaviors, by the action of ac electric field, of commercial BaTiO3-based positive-temperature-coefficient (PTC) current-limiting ceramic thermistors coated with electroless Ni electrodes were investigated. We observed five failure behaviors, namely, (1) comminuted cracking; (2) the rise of resistance value at room temperature; (3) the burnout of electrodes; (4) delamination of ceramic; and (5) the melting of ceramic. Indeed, these phenomena were correlated to the stress (including thermal and internal stresses), electric field distribution, temperature distribution, production and expansion of micro-cracks, and voltage effect. In addition, the ac shock characteristics of BaTiO3-based PTCR ceramic were related to the content of phosphorus in the electroless nickel-phosphorus alloy and thickness of the nickel electrodes. According to the experiments, the thickness of the electroless nickel alloy shoud be <1um and the phosphorus content, 4 wt.% in the alloy.