Premium
Estimate of the Activation Energies for Boundary Diffusion from Rate‐Controlled Sintering of Pure Alumina, and Alumina Doped with Zirconia or Titania
Author(s) -
Wang Jenqdaw,
Raj Rishi
Publication year - 1990
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.1151-2916.1990.tb05175.x
Subject(s) - sintering , activation energy , materials science , cubic zirconia , zirconium , diffusion , grain boundary diffusion coefficient , grain growth , titanium , chemical engineering , grain boundary , doping , kinetics , grain size , metallurgy , ceramic , microstructure , chemistry , thermodynamics , physics , optoelectronics , engineering , quantum mechanics
Sintering experiments at constant heating rates were employed to estimate the activation energy for sintering in alumina and in alumina containing 5 vol% zirconia or 5 vol% titania. Grain growth, which can complicate the analysis of sintering kinetics data, was suppressed by using uniformly and densely packed grain compacts prepared by colloidal processing. Grain‐boundary diffusion is believed to have been the dominant sintering mechanism. The activation energies were 440 ± 40 kJ/mol for pure alumina, 585 ± 40 kJ/mol for alumina (titania), and 730 ± 60 kJ/mol for alumina (zirconia). The alumina and alumina (titania) results are in agreement with the values reported in the literature. The possibility that the higher activation energies for doped alumina reflect a stronger bonding at alumina interfaces in the presence of zirconium and titanium is discussed.