Erosive wear of CVD ceramic coatings exposed to particulate flow

Erosion wear of boiler components in power plant industry is a critical factor in predicting the life and durability of such components. In the aggressive environment, failure of components is accelerated by erosion wear. Various erosion resistant coatings have been developed in the recent past to improve the life of such components subjected to erosive wear. Among the various types of coatings, the development of WC-Co ceramic coatings for the protection against erosion wear require understanding of their complex failure mechanisms occurring during solid particle impact. Many experimental works have been done to find the effect of different parameters on the erosion wear of the WC-Co coatings however such data is insufficient as newer composition and processing methods are being developed every day. Further, experimentation requires a lot of human effort, machine hours, sophisticated equipment and is time consuming. The simulation of the erosion process parameters in available finite element modelling software enables the prediction of erosion behavior of different combination of materials. The factors affecting the erosion wear of WC-Co coating such as the particle size, the velocity of impacting particles, the coating thickness, angle of impact and the coating composition are considers in this work. The results for erosion wear are obtained and analysed using the Hashish model for erosion wear.

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Erosive wear resistance of dimpled ceramic coatings on mild steels

Industrial Lubrication and Tribology ◽

10.1108/ilt-09-2016-0221 ◽

2017 ◽

Vol 69 (3) ◽

pp. 404-408 ◽

Cited By ~ 1

Author(s):

Mariyam Jameelah Ghazali ◽

Ahmad Firdaus Shamsul Baharin ◽

Juyana A. Wahab ◽

Andanastuti Muchtar

Keyword(s):

Ceramic Coating ◽

Surface Texturing ◽

Erosive Wear ◽

Ceramic Coatings ◽

Substrate Material ◽

Laser Surface Texturing ◽

Content Type ◽

Spray Method ◽

Erosion Test ◽

Foreign Materials

Purpose The purpose of this study is to determine the effect of dimpled texture on ceramic coating towards erosion wear. Design/methodology/approach The methodology of this experiment is based on ASTM G73, which is for erosion test for rotating apparatus. Mild steels samples were coated with alumina titania via the plasma spray method, and surface modification was done by producing different dimple densities using laser surface texturing. Two mediums were used: seawater environment and slurry environment. Findings Dimples of 150 μm diameter and 50 μm depth have proved to be successful in entrapping wear debris and other foreign materials during the erosion test. It was clearly noted that coatings with the highest number of dimples with 43 per cent had significantly improved the microhardness of the coated mild steels by twofold. Originality/value All this while, texturing was done only on substrate material. None was done on ceramic coating.

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Solid Particle Erosive Wear Behaviour of Flame Sprayed Ceramic Coatings

Acta Physica Polonica A ◽

10.12693/aphyspola.135.895 ◽

2019 ◽

Vol 135 (5) ◽

pp. 895-899

Author(s):

E. Altuncu ◽

K. Güzel

Keyword(s):

Solid Particle ◽

Erosive Wear ◽

Ceramic Coatings ◽

Wear Behaviour

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Electron microscopy studies of plasma-sprayed materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074276 ◽

1983 ◽

Vol 41 ◽

pp. 70-71

Author(s):

K.R. Subramanian ◽

A.H. King ◽

H. Herman

Keyword(s):

Plasma Spraying ◽

Substrate Surface ◽

Flame Temperature ◽

Ceramic Coatings ◽

Metallic Substrates ◽

Hot Plasma ◽

Almost All ◽

Plasma Sprayed ◽

Hostile Environments ◽

Plasma Spraying Process

Plasma spraying is a technique which is used to apply coatings to metallic substrates for a variety of purposes, including hardfacing, corrosion resistance and thermal barrier applications. Almost all of the applications of this somewhat esoteric fabrication technique involve materials in hostile environments and the integrity of the coatings is of paramount importance: the effects of process variables on such properties as adhesive strength, cohesive strength and hardness of the substrate/coating system, however, are poorly understood.Briefly, the plasma spraying process involves forming a hot plasma jet with a maximum flame temperature of approximately 20,000K and a gas velocity of about 40m/s. Into this jet the coating material is injected, in powder form, so it is heated and projected at the substrate surface. Relatively thick metallic or ceramic coatings may be speedily built up using this technique.

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Characterization of thermal barrier coatings formed by electon-beam physical vapor deposition (EB-PVD)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015410x ◽

1989 ◽

Vol 47 ◽

pp. 426-427

Author(s):

Ozer Unal

Keyword(s):

Thermal Barrier Coatings ◽

Physical Vapor Deposition ◽

Ceramic Coating ◽

High Vacuum ◽

Ceramic Coatings ◽

High Energy ◽

Thermal Barrier ◽

Protective Oxide ◽

Barrier Coatings ◽

Energy Beam

Interest in ceramics as thermal barrier coatings for hot components of turbine engines has increased rapidly over the last decade. The primary reason for this is the significant reduction in heat load and increased chemical inertness against corrosive species with the ceramic coating materials. Among other candidates, partially-stabilized zirconia is the focus of attention mainly because ot its low thermal conductivity and high thermal expansion coefficient.The coatings were made by Garrett Turbine Engine Company. Ni-base super-alloy was used as the substrate and later a bond-coating with high Al activity was formed over it. The ceramic coatings, with a thickness of about 50 μm, were formed by EB-PVD in a high-vacuum chamber by heating the target material (ZrO2-20 w/0 Y2O3) above its evaporation temperaturef >3500 °C) with a high-energy beam and condensing the resulting vapor onto a rotating heated substrate. A heat treatment in an oxidizing environment was performed later on to form a protective oxide layer to improve the adhesion between the ceramic coating and substrate. Bulk samples were studied by utilizing a Scintag diffractometer and a JEOL JXA-840 SEM; examinations of cross-sectional thin-films of the interface region were performed in a Philips CM 30 TEM operating at 300 kV and for chemical analysis a KEVEX X-ray spectrometer (EDS) was used.

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