Effect Of Host Material Minuteness And Additives On Microstructure And Properties Of Al₂O₃-ZrO₂-C Slide Plate

Al₂O₃-ZrO₂-C slide plate is a kind of functional refractory, which is built in the bottom of ladle to control the outflow of liquid steel from the ladle. So it requires champion strength, thermal shock resistance, corrodibility resistance, antioxidation and abradability and so on. According to the requirements above, this paper studied carbon materials, silicon additives and silicon size, superfine Al₂O₃ and burnt factors, which could influence the structure and properties of Al₂O₃-ZrO₂-C materials in lab conditions. In addition, boron compound additives and definite Al powder were blended into the materials to review their effect on the properties of sintered materials.All specimens were sintered for different experimental intentions. During all sintering process, precaution was taken to avoid oxidation of the specimens by placing them in sagger filled with coke breeze. When the sintered specimens had been cooled to room temperature, their apparent porosity, bulk density, cold crushing strength and high temperature bending strength were determined, respectively. Besides properties above, mercury intrusion method was used to determine the aperture distribution, and antioxidation were tested in thermogravimetric furnace, and SiC whisker grown in specimens during sintering were observed by SEM, so did the micro structure of the specimens after oxidation test. And erosion resistant was examined by induction furnace. Then, conclusions are obtained as follows:1) Carbon black plays an important role in improving the properties of Al₂O₃-ZrO₂-C materials. It has smaller granularity and better dispersion property, leading to easier in-situ reaction with silicon to SiC crystal whisker which is well-grown and can fill in the pore so well that the rate of micro-pore less than 1μm increases apparently.2) In the range of choosed sintering temperatures, a number of SiC crystal whiskers with better quality were observed in the specimens sintered in relative lower sintering temperature, which make the physical properties of the specimens sintered in lower temperature are better than that in higher temperature. In addition, the longer the soaking time, the better the physical properties when specimens are sintered in the lower temperature. However, the properties are not improved obviously once soaking time exceeds 8 hours.3) Silicon powder with relatively muchness and smaller size, can react effectively with normal carbon forming more and better SiC crystal whisker. Consequently the physical properties, antioxidation and abradability after oxidated are more superior along with more Si powders added in the materials.4) Al₂O₃ micro powder can fill pores and accelerate sintering process remarkably. When a kind of superfine Al₂O₃ is added into the stuff, the specimens'apparent porosity gets decreased, bulk density and strength enhanced, and the rate of micro pore increased. Moreover, contrast...