Study On Preparation And Properties Of Al₂O₃-SiC Composite Ceramics By Aluminum Dross

Aluminum dross is mainly solid waste discharged in the process of aluminum electrolysis,aluminum processing and waste aluminum recovery,but it still contains a large amount of aluminum resources,which will cause a great waste of resources if it is not well treated and recycled.In this paper,using aluminum dross as the main raw material,Al2O3-SiC composite ceramics were prepared by adding SiC particles.The roasting temperature and time of aluminum dross raw materials and the factors affecting the amount of SiC,sintering temperature and holding time affecting the preparation of Al2O3-SiC composite ceramics were studied.The apparent porosity,bulk density,room temperature compressive strength and thermal shock resistance of ceramic samples were measured by universal material testing machine and Archimedes drainage method,and the effects of various factors on material structure and properties were discussed by SEM,XRD and TG-DTA analysis.The results obtained in this paper are as follows:(1)The main phase composition of aluminum dross is(Al2O3)11(H2O)1.79、α-Al2O3、Al(OH)3 and MgAl2O4,after high temperature roasting treatment is α-Al2O3 and MgAl2O4.The optimum roasting condition is 1100℃ for 100 min.(2)The optimum technological parameters for the preparation of Al2O3-SiC composite ceramics with aluminum dross as the main raw material are as follows:The addition of silicon carbide is 15%,the sintering temperature is 1450℃ and the holding time is 180min.The volume density of the composite ceramic sample obtained under this process condition is 3.23 g/cm3,the apparent porosity is 10.16%,the room temperature resistance strength is 541.74 MPa,the thermal shock residual strength is 499.38 MPa,and the loss rate of thermal shock strength is only 7.82%.And the final thermal shock resistance results show that it can withstand 41 thermal shock cycles and has good thermal shock resistance.(3)According to the results of SEM and XRD analysis,no new phase was formed in the whole preparation process of composite ceramics,and the main phases of the materials were Al2O3,SiC and MgAl2O4.