Residual Stress Measurement of Plasma Sprayed Coating Layers in ZrO2

Plasma sprayed coatings have been widely applied in modifying surface properties of metal components. It is also useful to prevent various types of wear, corrosion, erosion and thermal. But the residual stress is still an important problem which can effect the properties of sprayed coating. So it’s necessary to find out the reason of residual stress and the relationship between plasma sprayed condition and residual stress. Plasma spray coating layers with conventional ZrO2 powder was examined to calculate residual stress by X-ray diffraction method with various coating thickness.

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Residual Stress Measurement in Plasma Sprayed Coatings by X-Ray Diffraction

Thermal Spray 1997: Proceedings from the United Thermal Spray Conference ◽

10.31399/asm.cp.itsc1997p0855 ◽

1997 ◽

Author(s):

J. Matejicek ◽

S. Sampath ◽

J. Dubsky

Keyword(s):

Residual Stress ◽

Stress Measurement ◽

Diffraction Method ◽

Precise Determination ◽

Residual Stress Measurement ◽

X Ray Diffraction ◽

X Ray ◽

Specific Position ◽

Plasma Sprayed ◽

Sprayed Coatings

Abstract Processing induced residual stresses play an important role in the performance of thermally sprayed coatings. Their precise determination is a key to influence the coating properties by modification of process variables and to understand the processing-property relationship. Among various methods for residual stress measurement, x-ray diffraction holds a specific position by being nondestructive, phase distinctive, localized and applicable for real parts. The sin2ψ method is commonly applied for bulk materials as well as coatings. However, the results are often reported without sufficient experimental details and the method is used in its simplified form without justification of certain assumptions. In this investigation, the sin2ψ x-ray diffraction method was used to measure residual macrostress in plasma sprayed Ni, NiCrAlY and ZrO2+8%Y2O3 coatings. Reproducibility of the method was tested and the assumptions allowing its use are discussed and experimentally verified. For Ni coatings, a comparison with blind hole and neutron diffraction measurements is presented. The results are discussed with respect to processing, structure and properties of the coatings.

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New Challenge of Plasma Spray Coatings in Nano Oxide Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.317-318.533 ◽

2006 ◽

Vol 317-318 ◽

pp. 533-538

Author(s):

Soo Wohn Lee ◽

Huang Chen ◽

Yi Zeng ◽

Chuan Xian Ding

Keyword(s):

Electron Microscopy ◽

Deposition Efficiency ◽

Metallic Substrate ◽

Atmospheric Plasma ◽

Ceramic Powders ◽

Plasma Sprayed Coatings ◽

Coating Layers ◽

Sprayed Coating ◽

Plasma Sprayed ◽

Sprayed Coatings

Nanostructured and conventional Al2O3, ZrO2, and TiO2 were deposited using an atmospheric plasma spraying (APS). The size of commercial nano-ceramic powders was varied from 5nm up to 150nm. The microstructure and phase composition of the plasma sprayed coatings on metallic substrate were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It was found that nano-sized ceramic powders enhanced the deposition efficiency on the metallic substrate rather than the micro-sized conventional commercial powders. Density and mechanical property such as microhardness were better in the case of the nano-sized ceramic powders than that of the conventional micro-sized ceramic powders, which are associated with the fine surface roughness and less size in pores of the coating layers. The wear rate of the nanostructured coating was lower than that of the conventional coating. The results were explained in terms of their microstructure of the coatings layers. Also, photocatalytic characterization of the plasma sprayed coatings, using nanocrystalline size TiO2 as feedstock with various powder sizes and shapes as well as adding with different photocatalytic oxides, was performed. The photocatalytic reactivity using plasma sprayed coating layers can be utilized into various applications.

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