The Research Of Corundum-mullite Multiphase Kiln's Stability Of Thermal Shock Resistance And Design Optimization

Corundum-mullite multiphase ceramic not only possesses many excellent properties such as high melting point ,high thermal shock resistance ,high creep resistance,oxidation resistance ,but also is abundant in raw materials with high price performance ratio, corundum-mullite multiphase ceramic is widely used as high-temperature kiln furniture materials. The domestic corundum-mullite multiphase kiln's propertities,such as the stability of thermal shock resistance,the useful time etc,are lower than those of foreign corundum-mullite multiphase kiln.At present,the researches on corundum-mullite multiphase kiln mainly focus on its macroscopic properties .However ,the results obtained by various researchers showed great differences, the stability of thermal shock resistance is not very good , the useful time is not long.Consequently,it is necessary to carry out a systematic and thorough research on corundum-mullite multiphase kiln.In this paper, the categories of kiln the formation methods of kihn the firing methods of kiln the characteristic and present situation of corundum and mullite, the characteristic and present situation of corundum-mullite multiphase kiln have been systematically reviewed.Furthermore, the relationships between the factors such as the preparation ,binder,grain composition ,mixture ratio of raw materials etc and the stability of thermal shock resistance of corundum-mullite multiphase kiln,the guidelines of the kiln's dimension designing have been studied.The follow conclusions can be generalized:According to the researches on the formation methods of kilns, it has been found that by changing mixing method , the stability of thermal shock resistance of corundum-mullite multiphase kilns can be improve prominently.the method that silicon power packaged on mullite grains first,then mixed with (X-Al₂O₃ and cordundum, is better than the method that mullite grains, corundum grains ,silicon power, α-Al₂O₃ mixed at the same time.The reason is that the silicon power packaged on the mullite grains synthesizes mullite with α-Al₂O₃ at high temperature,on onehand, it can improve corundum-mullite multiphase kilns'porosity,on the other hand ,it can decrease the number of microcrack,which caused by the difference between mullite's expansion coefficient and alumina's expansion coefficient.According to the researches on the binders ,it has been found that uses silicon-alumina gel as the binder, the stability of thermal shock resistance of corundum-mullite kiln , is higher than that ,which uses kaolin as the binder.when uses silicon-alumina gel as the binder, mullite synthesizes prominently at 1154 .In additional,the impurity content in silicon-alumina gel is lower,the glass phase is fewer during firing. Uses kaolin as the binder ,mullite synthesizes prominently at 1500 . The impurity content in kaolin is higher,the glass phase is more during firing,which does harm to the stability of thermal shock resistance of corundum-mullite multiphase kiln.so it is better to choose silicon gel-alumina gel as the binder .According to the researches on grain composition, it has been found that with the content of large grain decreasing, the content of medium grain increasing,the flexural strength at room-temperature and the flexural strength after 1100^water(3 times) are increasing,but the conservation rate of the flexural strength after 1100^water(3 times) varies as increasing- decreasing- increasing- decreasing,when the content of medium grain is 35% or 45%, the conservation rate of the flexural strength after 1100^water(3 times) is superior.This result can direct select recipe.According to the researches on mixture ratio of raw materials, it has been found thatwhen 15%water(3 times) and the conservation rate of the flexural strength after 1100 ^water(3 times) are superior.By means of nunmeric value fitting, the function[w(Biot)] of maximum surface cooling rate vs Biot is established.Considerations in the maximum tolerance cooling rate V,carried out the...