Study On Densification Of Al₂O₃-Cr₂O₃ Solid Solution Sintering

Aluminum chromium solid solution is widely used as a refractory material due to its excellent corrosion resistance.In order to make up for the defects of high cost and poor thermal shock resistance of the fused material and increase the Cr₂O₃ content in the material,this paper uses a sintering method to study the preparation of aluminum-chromium solid solution with a molar ratio of 1:1,and promote the densification of aluminum-chromium solid solution Analytical research.Using Archimedes method,XRF,XRD,SEM and other methods to analyze the density,chemical composition,phase composition,microstructure,etc.of the sample,in order to produce and research the aluminum-chromium solid solution provide a certain reference.First,nano-η-Al₂O₃ powder,industrialγ-Al₂O₃ powder and activeα-Al₂O₃powder are used as raw materials,Cr₂O₃ is provided by chrome green.The solid-phase sintering method was used to prepare Al₂O₃-Cr₂O₃ solid solution.The effects of these different raw materials on the preparation of Al₂O₃-Cr₂O₃ solid solution,and two different sintering aids Ti O₂ and chromium concentrate were used to prepare Al₂O₃-Cr₂O₃ solid solution by nano-η-Al₂O₃.The sintering activation energy of nano-η-Al₂O₃ prepared Al₂O₃-Cr₂O₃ solid solution in different atmospheres and the influence of the introduction of Ti O₂ in air atmosphere on the sintering activation energy of nano-η-Al₂O₃ prepared Al₂O₃-Cr₂O₃ solid solution were calculated.Concluded as follow:（1）After calcination at 1400℃-1600℃for 2-4 h,the Al₂O₃-Cr₂O₃ solid solution sample prepared byη-Al₂O₃ powder has the best compactness,but after holding at 1600℃for 6 hours,the density of the sample prepared withα-Al₂O₃powder is better,and the average grain size of the fracture of the sample after being kept at 1600℃for 6 hours is greater than 10μm;（2）Al₂O₃ and Cr₂O₃ have formed a complete solid solution within the experimental temperature range,and the unit cell parameters gradually approach the theoretical value as the temperature rises.Theη-Al₂O₃ powder andγ-Al₂O₃ powder samples have better crystallinity;（3）The addition of Ti O₂ can promote the densification of Al₂O₃-Cr₂O₃ solid solution and make the grains more tightly bonded;（4）The addition of chromium concentrate can also promote the densification of Al₂O₃-Cr₂O₃ solid solution,and the density of the sample under the buried carbon atmosphere is better than that under the air atmosphere;（5）During the sintering process,the grain growth index of the Al₂O₃-Cr₂O₃ and Al₂O₃-Cr₂O₃-2%Ti O₂ sintering systems with two different atmospheres decreases with the increase of temperature,and with the increase of sintering temperature,the activation energy of grain growth Show an overall downward trend;（6）The air atmosphere is more conducive to the growth and development of the grains of Al₂O₃-Cr₂O₃ solid solution,but when the temperature is too high,the effect of the volatilization of Cr O₃ on the grain growth should be considered.At the same time,the addition of Ti O₂ under the air atmosphere can make the grain growth index and crystal growth of the sample The activation energy of grain growth decreases,which promotes grain growth and development.