EXPERIMENTAL INVESTIGATIONS ON PRECISION MACHINING OF THERMAL BARRIER COATINGS AND APPLICATION OF THE GREY RELATION APPROACH TO DETERMINE THE OPTIMUM PROCESS PARAMETERS

2016 ◽  
Vol 20 (4) ◽  
pp. 333-354 ◽  
Author(s):  
Mohammed Yunus ◽  
Mohammad S. Alsoufi
Keyword(s):  
Thermal Barrier Coatings ◽  
Process Parameters ◽  
Precision Machining ◽  
Experimental Investigations ◽  
Optimum Process ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Relation Approach ◽  
Grey Relation

Optimization of the process parameters in generic thermal barrier coatings using the Taguchi method and grey relational analysis

2015 ◽  
Vol 231 (7) ◽  
pp. 600-610 ◽  
Author(s):  
Dipak Kumar ◽  
KN Pandey
Keyword(s):  
Taguchi Method ◽  
Plasma Spraying ◽  
Thermal Barrier Coatings ◽  
Process Parameters ◽  
Grey Relational Analysis ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Relational Analysis ◽  
Grey Relational

The purpose of this paper is to develop 7 wt% yttria stabilized zirconia (7YSZ) thermal barrier coatings by optimization of the atmospheric plasma spraying process parameters. Multiple-performance characteristics, such as coating thickness and surface roughness were considered for optimization. Eighteen experimental runs based on the L18 orthogonal arrays of the Taguchi method were used to show the best conditions among the plasma spraying parameters. Thereafter, best possible process parameters were obtained by the analysis of variance using grey relational analysis as the quality guide. Results signify the application possibility of the grey-based Taguchi technique for continuous development of quality coating in the area of advanced manufacturing technology.

Investigation of Thermo-Mechanical Properties of Slurry Based Thermal Barrier Coatings under Repeated Thermal Shock

2009 ◽  
Vol 417-418 ◽  
pp. 197-200 ◽  
Author(s):  
Phuc Nguyen ◽  
Andrei G. Kotousov ◽  
Sook Ying Ho ◽  
Stuart Wildy
Keyword(s):  
Thermal Shock ◽  
Thermal Barrier Coatings ◽  
Gas Turbines ◽  
Nuclear Power ◽  
Thermal Stresses ◽  
Low Cost ◽  
Industrial Applications ◽  
Experimental Investigations ◽  
Thermal Barrier ◽  
Barrier Coatings

Thermal Barrier Coatings have existed for over 40 years, and with in the last 15 years their use in industrial applications has dramatically increased. Thermal Barrier Coatings (TBCs) are currently used in gas turbines, diesel engines, throughout aerospace and nuclear power industries. The purpose of TBC is to reduce temperature and thermal stresses, and, as a result, increase the reliability and life of load-bearing components subjected to high temperature or temperature flux. However, TBCs often fail under thermal cyclic loading with reliability still being the major issue impeding their wide-spread applications. The focus of this work is on experimental investigations of zirconia/nickel graded TBC system, subject to thermal shock loading. The graded TBC systems were fabricated utilising a recently developed slurry spray manufacturing technique. This is a robust technique, and is able to cover large and curved surfaces at low cost, and provides many advantages in comparison with its alternatives. This paper describes the developed technique and presents selected results of thermo-mechanical and fracture testing of the TBCs including graded coatings fabricated using this new technique.

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

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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