scholarly journals Crystalline Ytterbium Disilicate Environmental Barrier Coatings made by High Velocity Oxygen Fuel Spraying

Author(s):  
Markus Wolf ◽  
Daniel Emil Mack ◽  
Georg Mauer ◽  
Olivier Guillon ◽  
Robert Vaßen
Author(s):  
M.A. Cole ◽  
R. Walker

Abstract Over the past 30 years, there has been considerable interest in the development of thermally sprayed thermal barrier coatings (TBCs) for aerospace and land based turbine applications. The use of TBCs enables higher operating temperatures, resulting in significant fuel efficiency savings. This paper reports on the development of dense Yttria Stabilised Zirconia (YSZ) thermal barrier coatings produced by High Velocity Oxygen Fuel (HVOF) spraying using acetylene as the fuel gas. The use of a high temperature gas erosion rig allowed the controlled evaluation of erodent size, velocity, impact angle, and temperature on coating performance. The work also covers the optimization of process parameters, including powder morphology, stand-off distance, oxygen to fuel ratio, gas pressures, and flowrates, and their effect on coating characteristics such as deposition efficiency, microhardness, and surface roughness.


Alloy Digest ◽  
2008 ◽  
Vol 57 (7) ◽  

Abstract Colmonoy No. 43HV comprises a nickel-base alloy recommended for hard surfacing parts to resist wear, corrosion, heat, and galling. Deposits that have moderate hardness have increased ductility and slightly less resistance to abrasion than Colmonoy 53HV. Deposits can be finished by grinding or machined with carbide tooling. Colmonoy No. 43HV is supplied as an atomized powder specially sized for application with high-velocity oxygen fuel (HVOF) systems. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance and surface qualities as well as heat treating and surface treatment. Filing Code: Ni-664. Producer or source: Wall Colmonoy Corporation.


2015 ◽  
Vol 11 (2) ◽  
pp. 238-272 ◽  
Author(s):  
Mica Grujicic ◽  
Jennifer Snipes ◽  
Ramin Yavari ◽  
S. Ramaswami ◽  
Rohan Galgalikar

Purpose – The purpose of this paper is to prevent their recession caused through chemical reaction with high-temperature water vapor, SiC-fiber/SiC-matrix ceramic-matrix composite (CMC) components used in gas-turbine engines are commonly protected with so-called environmental barrier coatings (EBCs). EBCs typically consist of three layers: a top thermal and mechanical protection coat; an intermediate layer which provides environmental protection; and a bond coat which assures good EBC/CMC adhesion. The materials used in different layers and their thicknesses are selected in such a way that the coating performance is optimized for the gas-turbine component in question. Design/methodology/approach – Gas-turbine engines, while in service, often tend to ingest various foreign objects of different sizes. Such objects, entrained within the gas flow, can be accelerated to velocities as high as 600 m/s and, on impact, cause substantial damage to the EBC and SiC/SiC CMC substrate, compromising the component integrity and service life. The problem of foreign object damage (FOD) is addressed in the present work computationally using a series of transient non-linear dynamics finite-element analyses. Before such analyses could be conducted, a major effort had to be invested toward developing, parameterizing and validating the constitutive models for all attendant materials. Findings – The computed FOD results are compared with their experimental counterparts in order to validate the numerical methodology employed. Originality/value – To the authors’ knowledge, the present work is the first reported study dealing with the computational analysis of the FOD sustained by CMCs protected with EBCs.


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