Influence of solids concentration on the microstructure of suspension plasma sprayed Y-TZP/Al2O3/SiC composite coatings

SURFACE & COATINGS TECHNOLOGY

卷:371

Article; Proceedings Paper

Carnicer, V.¹  Orts, M. J.¹  Moreno, R.²  Sanchez, E.¹ 

[1] UJI, ITC, Castellon de La Plana, Spain

[2] CSIC, ICV, Madrid, Spain

关键词: Thermal barrier coatings;    Suspension plasma spraying;    SPS;    Suspensions;    Self-healing;   

DOI  :  10.1016/j.surfcoat.2019.01.078

来源: Elsevier

【 摘 要 】

The present research focuses on the effect of feedstock suspension solid concentration on the microstructure of suspension plasma sprayed Y-TZP/Al2O3/SiC composite coatings. For this purpose, concentrated aqueous suspensions were prepared at 10, 20 and 30 vol% and characterised in terms of zeta potential, rheological behaviour and sedimentation trend. The optimised suspensions were plasma sprayed, and the thickness, porosity, amount of resolidified particles and SiC content remaining in the coatings were evaluated by optical microscopy, scanning electron microscopy and X-ray diffraction. T The results revealed that spray distance and suspension solid content show a strong influence on the coating microstructure due to the great impact that these two parameters have on the energy that particles and substrate receive from the plasma jet. Cauliflower-like microstructure develops in some of the coatings, particularly for longer distances and lower solids contents. These microstructural features were discussed on the basis of the theory of columnar microstructure development in SPS coatings. Porosity and amount of resolidified particles in the coatings are favoured by increasing the spray distance and decreasing the solids content, while thickness is strongly affected by solids content variation. On the other hand, Rietveld method from X-ray diffraction showed that large amount of the initial SiC was preserved in the final coatings whereas this amount remains almost constant for the three suspension feedstock tested.

【 授权许可】

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