Study On Preparation And Performance Of SnO₂-ZnO-CuO-Sb₂O₃ System Electrode Ceramics

Dense SnO₂-based electrode ceramics with excellent conductive property and goodcorrosion resistance to molten glass is the very important component of glasselectric-melting industry. In this paper, SnO₂ based electrode ceramics of highperformances doped with ZnO, CuO and Sb₂O₃ were prepared by pressurelesssintering, then the relative performances were studied.ZnO and CuO are good for sintering, a little of ZnO and CuO can greatly increasethe density of SnO₂ ceramics. Density of SnO₂ ceramics increases at first and thendecreases with increasing of ZnO and CuO. Optimal concentration of ZnO is 1.0mol%, the densification mechanism is that the reaction of ZnO and SnO₂ produces asolide solution, while optimal concentration of CuO is 0.5mol%～1.0mol%, thedensification mechanism is the liquid phase emerged at grain boundary. Sb₂O₃ Can'timprove sintering character of the material.ZnO and CuO do no good to resistivity of SnO₂ ceramics. Sb₂O₃ is oxided to Sb₂O₅at high temperatures, extra electrons produced by the substitution reaction of Sb⁵⁺ forSn⁴⁺ are able to lower the resistivity and the effect is obvious.Strength of materials is relevant to density of the bulk and the size of grains. ZnOand CuO can improve the density, while Sb₂O₃ can improve the resistivity, soco-doping SnO₂ ceramics have high strength.Corrosion rates of SnO₂ based electrode ceramics were measured after materialscorroded by soda-lime glass at 1200℃for 100 hours. Results indicate that moltenglass easily enters intergranular pores and corrodes the thick phase layer at grainboundary, while it is very difficult to infiltrate into transgranular pores and to corrodethe very thin layer at grain boundary.SnO₂ based electrode ceramics with excellently comprehensive property have beenobtained. The properties are arrive to or even exceed the present oversea SnO₂ basedelectrode products. Compositions and performance parameters are as follows: (1)98.5SnO₂-1ZnO-0.5Sb₂O₃, whose relative density is 97%, resistivity at roomtemperature is 7.139×10^-2 ohm·cm, bend strength is 163.35MPa and corrosion rate ofmolten glass is 3.633×10^-4mm/h; (2) SnO₂-0.75ZnO-0.25CuO-1.0Sb₂O₃, whose relative density is 96.5%,resistivity at room temperature is 6.48×10^-3 ohm·cm, bendstrength is 205.43MPa and corrosion rate is 4.367×10^-4mm/h.