Synthesis of Nb2O5-doped ZrO2 and the effect of calcination on the powder characteristics

Full text: Zirconia is a popular engineering material because of their excellent properties, such as high strength, chemical stability, high melting temperature, ionic, electrical and optical properties and high fracture toughness. These qualities are obtained with the addition of oxide dopants for the stabilization, at room temperature, of tetragonal and cubic high temperature zirconia phases. CaO, CeO2, MgO, and mainly Y2O3 are some dopants used for this function and they have been widely studied. In the present study, it was prepared a zirconia powder using niobium oxide as a dopant with aim to promote the stabilization of the zirconia crystalline phases. The stabilizing effect of niobium oxide has not yet been properly explored. The Nb2O5-ZrO2 powder was prepared from precipitation technique. The calcination process was carried out at different conditions using microwave heating and conventional heating method. The developments of particle size and particle agglomeration as well as the formation of the crystalline phases of zirconia were investigated. Powder characteristics were evaluated by thermal analysis (DTA-TG) and specific area (BET technique). The X-ray diffraction results and SEM observations assisted to characterize the resulting zirconia powder. (author)