Journal of Thermal Spray Technology

, Volume 16, Issue 5, pp 798-803

First online:

Effects of Impurity Content on the Sintering Characteristics of Plasma-Sprayed Zirconia

  • S. PaulAffiliated withDepartment of Materials Science & Metallurgy, Cambridge University Email author 
  • , A. CipitriaAffiliated withDepartment of Materials Science & Metallurgy, Cambridge University
  • , I.O. GolosnoyAffiliated withDepartment of Materials Science & Metallurgy, Cambridge University
  • , L. XieAffiliated withSulzer Metco (US) Inc.
  • , M.R. DorfmanAffiliated withSulzer Metco (US) Inc.
  • , T.W. ClyneAffiliated withDepartment of Materials Science & Metallurgy, Cambridge University

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Yttria-stabilized zirconia powders, containing different levels of SiO2 and Al2O3, have been plasma sprayed onto metallic substrates. The coatings were detached from their substrates and a dilatometer was used to monitor the dimensional changes they exhibited during prolonged heat treatments. It was found that specimens containing higher levels of silica and alumina exhibited higher rates of linear contraction, in both in-plane and through-thickness directions. The in-plane stiffness and the through-thickness thermal conductivity were also measured after different heat treatments and these were found to increase at a greater rate for specimens with higher impurity (silica and alumina) levels. Changes in the pore architecture during heat treatments were studied using Mercury Intrusion Porosimetry (MIP). Fine scale porosity (<50 nm) was found to be sharply reduced even by relatively short heat treatments. This is correlated with improvements in inter-splat bonding and partial healing of intra-splat microcracks, which are responsible for the observed changes in stiffness and conductivity, as well as the dimensional changes.


apparent Young’s modulus plasma spray coatings porous material sintering thermal conductivity