Thermal Corrosion Behavior of NiCoCrAlY Coatings Prepared by Different Thermal Spraying Methods

2011 ◽  
Vol 686 ◽  
pp. 686-691 ◽  
Author(s):  
Jie Sun ◽  
Dan Zhao ◽  
Li Li Zhang ◽  
Yong Tan
Keyword(s):  
High Velocity ◽  
Thermal Spraying ◽  
Weight Ratio ◽  
Isothermal Oxidation ◽  
Atmospheric Plasma ◽  
Nickel Base Superalloy ◽  
Detonation Spraying ◽  
Nickel Base ◽  
Low Pressure Plasma Spraying ◽  
Base Superalloy

The protection of thermal parts has become one of the most important techniques with the development of high capability and high thrust-weight ratio for advanced aeroengine. In this paper, using the nickel base superalloy as the substrate, the thermal corrosion performances of NiCoCrAlY coatings using different thermal spraying methods, which consisted of high velocity oxy-fuel (HVOF), detonation spraying (DS), atmospheric plasma praying (APS) and low pressure plasma spraying (LPPS), were studied. The thermal oxidation experiments, which consisted of isothermal oxidation and cycling oxidation experiments were performed to character the thermal performances. From the results, it was shown that the NiCoCrAlY coatings prepared by high velocity oxy-fuel method were slight for 100 hours at 1100°C. The surface of the NiCoCrAlY coatings prepared by HVOF had a dense, continued Al2O3 oxide layer. Among all the methods to prepare NiCoCrAlY coatings, the method of high velocity oxy-fuel showed excellent performance.

Development of a NiW In Situ Diffusion Barrier on a Fourth Generation Nickel-Base Superalloy

2008 ◽  
Vol 595-598 ◽  
pp. 23-32 ◽  
Author(s):  
Eric Cavaletti ◽  
Sebastien Mercier ◽  
Denis Boivin ◽  
Marie Pierre Bacos ◽  
Pierre Josso ◽  
...  
Keyword(s):  
Diffusion Barrier ◽  
Isothermal Oxidation ◽  
Oxidation Behaviour ◽  
Fourth Generation ◽  
Nickel Base Superalloy ◽  
Electrolytic Coating ◽  
Nickel Base ◽  
Base Superalloy

A diffusion barrier based on a NiW electrolytic coating has been developed to limit interdiffusion between a Ni-base superalloy (MCNG) and a β-NiAl bondcoating. Isothermal oxidation tests of 50h at 1100°C confirmed that W-rich layer formed with NiW coating modifies the oxidation behaviour of the bondcoat and limits interdiffusion. The diffusion barrier reduced β-NiAl  γ’-Ni3Al transformation in the bondcoating and prevented SRZ formation.

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Characterization of Coherent, Ordered Precipitates in Nickel-Base Alloys

1973 ◽  
Vol 31 ◽  
pp. 144-145
Author(s):  
B. H. Kear ◽  
J. M. Oblak
Keyword(s):  
Stable Phase ◽  
Nickel Base Superalloy ◽  
Alloy 718 ◽  
Commercial Alloy ◽  
Precipitate Morphology ◽  
Continuous Precipitation ◽  
Nickel Base ◽  
Base Superalloy ◽  
Strengthening Precipitate

A nickel-base superalloy is essentially a Ni/Cr solid solution hardened by additions of Al (Ti, Nb, etc.) to precipitate a coherent, ordered phase. In most commercial alloy systems, e.g. B-1900, IN-100 and Mar-M200, the stable precipitate is Ni3 (Al,Ti) γ′, with an LI2structure. In A lloy 901 the normal precipitate is metastable Nis Ti3 γ′ ; the stable phase is a hexagonal Do2 4 structure. In Alloy 718 the strengthening precipitate is metastable γ″, which has a body-centered tetragonal D022 structure.Precipitate MorphologyIn most systems the ordered γ′ phase forms by a continuous precipitation re-action, which gives rise to a uniform intragranular dispersion of precipitate particles. For zero γ/γ′ misfit, the γ′ precipitates assume a spheroidal.

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