Surface Modification Of Zirconia Powder

Zirconia has been widely used to produce functional ceramics and structuralceramics for its excellent properties, such as high strength, high hardness, fine heatresistance, fine corrosion resistance, insulation at normal temperature and conductivityat high temperature. As a result, zirconia powder with high performance at low cost isvery popular in the market. At present, although domestic zirconia powder isinexpensive, its performance is poor and can’t meet the requirements to produce highperformance zirconia ceramic products. Imported zirconia granulated powders can meetthe high requirements but is much more expensive than domestic powder, whichprevents it from being wildly used.In this article, we use domestic zirconia powder as raw materials and modify thesurface of it. In this way, we can improve the performance of domestic powder and atthe same time lower the production costs of it. In this article, surface modificationincludes milling and spray granulation. Domestic zirconia powder is mostly obtained bycoprecipitation method，so there is more hard agglomeration in it, which is unfavorablefor pressing and sintering. So it is necessary to milling the powder to reduce the particlesize to less than200nm. Then add different binders and plasticizers to the milledpowder and spray granulation with it. We press the different groups of granulatedpowder and sinter them in the same condition. Finally, we test the relative density,bending strength and phase composition of the sintered bodies and observe themorphology of the fracture part.The result shows that the spray granulation powder to which is added PVP andPEG performs the best. The relative density of its sintered body at1450℃reaches99.67%approaching that of imported powders and its bending strength is also higherthan raw powder. So we achieve the goal and the method can be directly used inproduction.