Dipankar Mandal1, S.K. Manik1, S.K. Pradhan1
1Department of Physics, The University of Burdwan, Golapbag, Burdwan 713104, West Bengal, India
Tóm tắt
High-energy ball milling of a monoclinic ZrO2–10 mol% anatase TiO2mixture results in the formation of a nanocrystalline cubic ZrO2polymorphic phase with equimolar fraction of the starting materials. The cubic phase is presumed to have formed from them-ZrO2solid solution based on the (001) plane of them-ZrO2phase. In the course of milling, the most dense (111) plane of the cubic lattice became parallel to the most dense (\bar{1}11) plane of the monoclinic lattice due to an orientation effect. Annealing of a 12 h milled sample at 773, 873 and 973 K for 1 h results in almost complete transformation of them-ZrO2to thec-ZrO2phase. At 1273 K annealing temperature (1 h), the nanocrystalline sample decomposed into individual starting phases. This suggests that the cubic phase is a metastable one and its stability depends on particle size as well as the working temperature. Formation of the cubic phase at such a low temperature using anatase TiO2as a phase stabilizer has not been reported previously. The microstructures of the unmilled, all the ball-milled and the annealed samples have been characterized by employing Rietveld's X-ray powder structure refinement methodology. The particle size, root mean square (r.m.s.) lattice strain, lattice parameters, molar fraction,etc., of individual phases have been estimated from Rietveld analysis and are utilized to interpret the results.
