Preparation And Properties Of ZrO₂/Al₂O₃ Composite Al₂O₃ Composite

ZrO₂/Al₂O₃composite ceramics is widely used in many fields such as machinery,defense and biology because of their high hardness,high strength of Al₂O₃ and high toughness of ZrO₂ ceramic.However,the melting point of Al₂O₃ and ZrO₂ is very high,and the ZrO₂/Al₂O₃ composite ceramics with high density and good mechanical properties can be prepared at the sintering temperature above 1700 degrees.Therefore,many researchers through the addition of sintering aids,to reduce the sintering temperature,to improve performance.In this study,the Al₂O₃-SiO₂-CaO composite sintering aids with small average particle size and uniform composition were firstly prepared by polymer network.he order of primary and secondary factors affecting the mechanical properties of ZrO₂/Al₂O₃ composites was studied by orthogonal test.The effects of sintering temperature,ZrO₂ dosage,additive amount of sintering aids,and holding time on the mechanical properties of ZrO₂/Al₂O₃ composites were investigated.Preparation of ZrO₂/Al₂O₃ Composite Ceramics by Control Variable Method.The effects of calcination temperature,addition amount of ZrO₂,addition amount of sintering aids and holding time on the relative density,microstructure and mechanical properties of Zr O₂/Al₂O₃ composite ceramics were analyzed in detail.The sintering properties of the composite sintering aids prepared by mechanical method were compared.The main research contents and results are as follows:1 Al₂O₃-SiO₂-CaO composite sintering aids precursor were prepared by olyacrylam-ide gel method.The gel precursor distribution of each element is very uniform,when the mono-mer and network agent to add the ratio of 6:1,the amount of water is 160ml,the initiator of ammonium persulfate is added 0.1g.The Al₂O₃-SiO₂-CaOcomposite sintering additive with high phase purity,average particle size of 1570nm can be obtained after calcination at 600?.2 Based on the orthogonal design of L₁₆?4⁴?,the data obtained are analyzed.The order of the main factors is the sintering temperature,the content of zirconia,the amount of sintering aids,the holding time.3 The effects of sintering temperature,zirconia content,addition amount of sintering aid and holding time on the relative density,mechanical properties and microstructure of ZrO₂/Al₂O₃ composite ceramics were studied in detail.The best preparation process of ZrO₂/Al₂O₃ composite ceramics is:1450?,ZrO₂ addition amount of 15%,the composite sintering additives addition amount of 5%,heat hoding time of 4 h.The optimum relative density,hardness,bending strength and fracture toughness of ZrO₂/Al₂O₃ composite ceramics were 93.1%,1204MPa,321MPa4.52MPa·m^1/2.4 In this study according compared the relative density,mechanical properties and microstructure of ZrO₂/Al₂O₃ composite ceramics prepared by macromolecule network method and mechanical mixing method.The relative density,Vickers hardness,flexural strength and fracture toughness of ZrO₂/Al₂O₃ composite ceramics prepared by macrom-olecule network method were improved by 5.6%,40%,24%,24.5%.