Research On Nano-alumina, Zirconia Composite Ceramic Material Preparation And Performance

Alumina-based ceramic has good performance and widely used because of its highmechanical strength, insulation resistance, high hardness, wear resistance, corrosionresistance and high temperature resistance, and now becomes the most widely usedand largest production ceramic new materials in oxide ceramic. In some industries,such as the material used to replace the joint head of the body, due to its highdemands in flexural strength and fracture toughness, so while ensuring thebiocompatibility, its strength and toughness also should be improved. Adding acertain amount of zirconium oxide to alumina prepared ZTA ceramic can improvestrength and toughness to some extent.In this experiment, high purity nano α-Al2O3powder was used as matrix material,ZrO2(Y2O3) as a toughening phase. MgO [added in form of Mg (NO3)2·6H2O] wasadded as an additive, and PAA as dispersant. In order to make every component canbe distributed evenly, the powders were mixed in NH3·H2O and then dispersed inultrasound machines. Afterwards, centrifuge and dry into powders. The powders werecalcined at1280℃so that the resulting hydroxide [Mg(OH)2and Y(OH)3] cancompletely decompose into its corresponding oxide. Use molding method at thepressure of10MPa and packing10minutes to obtain certain shape. Put the samplesinto cold isostatic pressing machine applying200MPa pressure and packing10minutes to eliminate the unevenness of stress and density that caused in the process ofmolding, at the same time improve the compactness of the body. To meet theprocessing requirements of the green body before sintering, the green body after thepress molding was first calcined at1150℃. After this process,the body obtainedcertain processing strength. Then ground them into strip specimens of certainspecification. Put them into silicon molybdenum furnace exposing to atmosphericpressure. Elevate temperature to1600℃with a appropriate rate and incubate for2.5hours. After this process, do not move those samples and cool the furnace to roomtemperature.Raw materials, mixed powders after calcinations and the fracture surface of thesintered ceramics were tested by Scanning electron microscopy, X-ray analyzer and TG-DSC. Ceramic flexural strength, fracture toughness, phase composition, hardnessand other properties were also tested in this experiment. Finally, We analyzed thefactors affecting every performance and found the ZTA ceramic formulations of bestoverall performance.