Amorphous and crystalline phase formation during suspension plasma spraying of the alumina–zirconia composite

Abstract

Amorphous and crystalline phase formation during suspension plasma spraying of the alumina zirconia composite Tarasi, F.; Medraj, M.; Dolatabadi, A.; Oberste-Berghaus, Jorg; Moreau, C.Contact us / Contactez nous: nparc.cisti@nrc-cnrc.gc.ca.

Thermal Cycling of Suspension Plasma Sprayed Alumina‐YSZ Coatings Containing Amorphous Phases

“…It was hypothesized that the dense alumina‐YSZ coating would tend to fail after a few thermal cycles due to the stresses induced at high temperatures generated by the crystallization of the amorphous phase in the ceramic. It should be stressed that the thermal cycles have been carried out at temperatures above the crystallization temperature of the amorphous phase in this composite, which is ~950°C . However, the stronger intersplat cohesion, as previously explained by McPherson, has supported the structure and prevented the visible delaminating of the coatings in the case of dense composite structure, irrespective of the large amorphous content in this coating.…”

“…Suspension plasma spray process was employed to produce dense and porous coatings using an axial injection plasma torch (Axial III; Northwest Mettech, North Vancouver, BC, Canada) of suspension into plasma jet, as per the details mentioned elsewhere . Two different powders were mixed to form pseudo‐eutectic composition of alumina‐8 wt% YSZ and were sprayed.…”

“…The larger sintering in YSZ coatings compared with alumina‐YSZ composite was previously observed by Dutton et al . The reason seems to be that due to limited solubility of the alumina and zirconia, the splats have a low possibility to grow by atomic diffusion through the dissimilar phases. The higher resistance to sintering process can be noted as a great advantage for TBC application, so that the amount of porosity at high temperature, as a controlling parameter on thermal conductivity can be more predictable.…”

Hot corrosion, high temperature oxidation and thermal shock behavior of nanoagglomerated YSZ–Alumina composite coatings produced by plasma spray method

“…Such a high temperature combined with the high surface energy of nanosized composite particles results in the perfect melting and the formation of solid solution [20]. Tarasi [21][22][23] showed that crystalline structures of YSZ and Alumina present an exceptionally extended solubility of both components, especially Alumina into the Zirconia lattice. The lattice parameter studies suggest that the Al atoms possibly take the substitutional sites at low ratios and interstitial sites when higher amounts of Alumina are being dissolved in Zirconia.…”

MICROSTRUCTURES, MICROHARDNESS, AND CRYSTALLIZATION BEHAVIORS OF AMORPHOUS Al2O3-YSZ COATINGS PREPARED BY AIR PLASMA SPRAYING

“…Furthermore, the composite Al 2 O 3 -YSZ has shown the potential for amorphous phase formation as well. [17][18][19][20][21] In this study, we fabricated amorphous coatings of the near-eutectic composite Al 2 O 3 -YSZ using the air plasma spraying (APS) method. The microstructural characteristics of the amorphous coatings obtained under di®erent spraying conditions were investigated.…”