Cosintering Simulation and Experimentation: Case Study of Nanocrystalline Zirconia

Abstract

Laminates consisting of two different nanocrystalline zirconia materials (undoped and 3Y-TZP doped) were sintered, and their densification and curvature were quantified using optical dilatometry. The experimental results agreed well with a continuum-mechanical description for the cosintering of laminates with diffusion coefficients and activation energies determined using densification of the free-sintering materials. The comparison covered various relative layer thicknesses and heating rates, but was developed only for the intermediate and late stages of sintering. Sintering stresses and compatibility stresses also were determined from the model.

Constrained sintering: A delicate balance of scales

“…(4) and (5) are very useful as they show which factors control stress evolution and distortion in layered structures and, thereby indicate routes for their mitigation by microstructural design changes. Using a different approach, Kanters et al 55 argued that a bi-layer geometry can be described using Kirchhoff thin plate theory description under the assumption that the global thickness remains small compared to the radius of curvature and that edge effects can be neglected. No stress develops in the thickness direction, z, and the bi-layer is under a biaxial stress state.…”

Constrained sintering of YSZ/Al2O3 composite coatings on metal substrates produced from eletrophoretic deposition

“…The constrained sintering leads to a reduction in the densification rate. 13,15,16,19,37 Therefore, the sintering of the supported YSZ/Al 2 O 3 coatings took a long time at 1250 • C.…”

“…Constraint sintering models [36][37][38] have been proposed by assuming the material followed a viscous behaviour during sintering. For the free-sintering case, the densification rate of the free sintering body can be expressed as 37,38 …”

Uniaxial viscosity of gadolinium-doped ceria determined by discontinuous sinter forging

“…[18][19][20][21][22][23][24][25] By characterizing properties, such as bulk and shear viscosities (K p and G p , respectively) or uniaxial viscosity E p and viscous Poisson's ratio ν p , the sintering behaviour of bilayer components used in SOFC can be predicted. [26][27][28] In order to determine the viscosities, optical dilatometry, 20 cyclic loading 19,20 as well as discontinuous sinter forging [23][24][25] studies have been carried out. Using the viscoelastic analogy for the isotropic sintering bodies, the uniaxial viscosity can be determined from the free and axial strain rates (ε f andε z , respectively) measured along the direction of the applied stress σ z :…”