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Preparation and microstructure characterization of ball‐milled ZrO 2 powder by the Rietveld method: monoclinic to cubic phase transformation without any additive
Author(s) -
Bid S.,
Pradhan S. K.
Publication year - 2002
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889802008725
Subject(s) - monoclinic crystal system , ball mill , rietveld refinement , materials science , tetragonal crystal system , crystallography , particle size , lattice constant , phase (matter) , powder diffraction , microstructure , analytical chemistry (journal) , crystal structure , mineralogy , chemical engineering , diffraction , metallurgy , chemistry , chromatography , optics , organic chemistry , physics , engineering
The phase transformation kinetics of high‐energy ball‐milled monoclinic ZrO 2 have been studied in detail by Rietveld powder structure refinement analysis. In the present study, no stabilizing compound was required to obtain the cubic phase. The fine‐grain powder was milled in a planetary ball mill for up to several hours at different BPMRs (ball to powder mass ratios): 10:1, 20:1, 35:1 and 40:1. During the process of ball milling, the monoclinic phase is gradually transformed to the cubic phase. The relative phase abundances of the respective phases, the particle sizes, the r.m.s. strains, the lattice parameter changes, etc. , have been estimated from Rietveld analysis of X‐ray powder diffraction data. It has been found that a higher BPMR exerts more influence on rapid phase transformation. In the m ‐ to c ‐ZrO 2 phase transformation, no formation of an intermediate tetragonal ZrO 2 phase has been found. The small change in the lattice volume of m ‐ZrO 2 , which is very close to the lattice volume of c ‐ZrO 2 , caused by ball milling may be attributed to this phase change. The formation of the c phase is noticed, in general, after just 1 h of ball milling, and the particle size of the m phase is reduced to a large extent at the first stage of milling and remains almost unchanged with increasing milling time. However, the particle size of the c phase increases with increasing milling time for the samples milled with higher BPMRs (35:1 and 40:1), suggesting that quenching caused by a high impact energy followed by an annealing effect may play a vital role, which is further manifested in the agglomeration of small particles.