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Two‐Step Sintering of Ceramics with Constant Grain‐Size, I. Y 2 O 3
Author(s) -
Wang XiaoHui,
Chen PeiLin,
Chen IWei
Publication year - 2006
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2005.00763.x
Subject(s) - sintering , materials science , grain boundary , grain size , grain growth , grain boundary diffusion coefficient , ceramic , isothermal process , condensed matter physics , mineralogy , metallurgy , composite material , thermodynamics , microstructure , chemistry , physics
Isothermal and constant‐grain‐size sintering have been carried out to full density in Y 2 O 3 with and without dopants, at as low as 40% of the homologous temperature. The normalized densification rate follows Herring's scaling law with a universal geometric factor that depends only on density. The frozen grain structure, however, prevents pore relocation commonly assumed in the conventional sintering models, which fail to describe our data. Suppression of grain growth but not densification is consistent with a grain boundary network pinned by triple‐point junctions, which have a higher activation energy for migration than grain boundaries. Long transients in sintering and grain growth have provided further evidence of relaxation and threshold processes at the grain boundary/triple point.