The microstructure and oxidation resistance of the aluminide coatings deposited by the CVD method on pure nickel and hafnium-doped nickel superalloys

The aim of the present work was to determine the influence of chemical composition of the protective coating on the oxidation resistance of the protected alloy. Zirconium modified and nonmodified aluminide coatings were deposited on the MAR M200 nickel superalloy by the CVD method. The oxidation tests were conducted at 1100°C into 23 hour in the air. The chemical composition (EDS) analysis was performed. The kinetic of oxidation of zirconium modified and nonmodified aluminide coatings was similar. Oxides inclusions called pegs were observed on the surface of oxidized aluminide coating. HfO2 oxide is more stable than Al2O3 oxide, hafnium atoms can replace aluminum atoms in Al2O3 oxides. This phenomena let to stabilize NiAl phase and increase of oxidation resistance of aluminide coating.

Download Full-text

The Influence of Pd and Zr Co-Doping on the Microstructure and Oxidation Resistance of Aluminide Coatings on the CMSX-4 Nickel Superalloy

Materials ◽

10.3390/ma14247579 ◽

2021 ◽

Vol 14 (24) ◽

pp. 7579

Author(s):

Jolanta Romanowska ◽

Jerzy Morgiel ◽

Maryana Zagula-Yavorska

Keyword(s):

Oxidation Resistance ◽

Chemical Vapor ◽

Nickel Superalloy ◽

Aircraft Industry ◽

Co Doping ◽

Cvd Method ◽

Aluminide Coatings ◽

Refractory Elements ◽

Nial Phase ◽

Better Than

Pd + Zr co-doped aluminide coatings were deposited on the CMSX-4 nickel superalloy, widely used in the aircraft industry, in order to investigate their microstructure and improvement of oxidation resistance. Palladium was deposited by the electrochemical method, whereas zirconium and aluminum by the chemical vapor deposition (CVD) method. Coatings consist of two zones: the additive and the interdiffusion one. The additive zone contains β–(Ni,Pd)Al phase with some zirconium-rich precipitates close to the coating’s surface, whereas the interdiffusion zone consists of the same β–(Ni,Pd)Al phase with inclusions of refractory elements that diffused from the substrate, so called topologically closed-packed phases. Palladium dissolves in the β–NiAl phase and β–(Ni,Pd)Al phase is being formed. Pd + Zr co-doping improved the oxidation resistance of analysed coatings better than Pd mono-doping. Mechanisms responsible for this phenomenon and the synergistic effect of palladium and zirconium are discussed.

Download Full-text

The Influence of Surface Preparation Method on Microstructure of HF-Modified Aluminide Coatings Deposited by CVD Method on Rene 80 and MAR M-247 Nickel Superalloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.844.177 ◽

2016 ◽

Vol 844 ◽

pp. 177-180

Author(s):

Ryszard Filip ◽

Maciej Pytel ◽

Andrzej Nowotnik

Keyword(s):

Vapour Deposition ◽

Base Alloy ◽

Aluminide Coating ◽

Chemical Vapour ◽

Surface Preparation ◽

Substrate Thickness ◽

Nickel Superalloys ◽

Average Amount ◽

Cvd Method ◽

Aluminide Coatings

In the article the hafnium modified aluminide coatings deposited using chemical vapour deposition (CVD) method were analyzed. The influence of surface treatment (grinding, sandblasting with different pressures) on microstructure of coatings were described. The Re 80 and M-247 nickel superalloys were used as substrate. Thickness of the obtained aluminide coating was in the range 32-45 mm on Re 80 and 40-45 mm on M-247 respectively. The average amount of Al in the additive layer was 22-24 wt% on Re 80 and about 21 wt % on M-247 base alloy. The total amount of hafnium in coatings did not exceed 2.5 wt % - usuallly below 0.5 wt %. The conducted research has shown that there is no strong influence of surface preparation methodology on microstructure of aluminide coatings obtained by CVD method.

Download Full-text

The influence of deposition technique of aluminide coatings on oxidation resistance of different nickel superalloys

Materials Today Proceedings ◽

10.1016/j.matpr.2020.04.863 ◽

2020 ◽

Vol 33 ◽

pp. 1746-1751

Author(s):

Marek Goral ◽

Kamil Ochal ◽

Tadeusz Kubaszek ◽

Marcin Drajewicz

Keyword(s):

Oxidation Resistance ◽

Nickel Superalloys ◽

Deposition Technique ◽

Aluminide Coatings

Download Full-text

Oxidation Resistance of Modified Aluminide Coatings

MATEC Web of Conferences ◽

10.1051/matecconf/201925303006 ◽

2019 ◽

Vol 253 ◽

pp. 03006

Author(s):

Jolanta Romanowska ◽

Maryana Zagula-Yavorska ◽

Łukasz Kolek

Keyword(s):

Beneficial Effect ◽

Oxidation Resistance ◽

Noble Metals ◽

Aluminide Coating ◽

Pure Nickel ◽

Scale Growth ◽

Aluminide Coatings ◽

Cyclic Oxidation Test ◽

Nial Phase ◽

Better Than

The application of protective aluminide coatings is an effective way to increase the oxidation resistance of the treated parts and prolongs their lifetime. The addition of small amount of noble metals (platinum or palladium) or reactive elements such as: hafnium, zirconium, yttrium and cerium has a beneficial effect on oxidation behavior. This beneficial effect includes an improvement of adhesion of alumina scales and reduction of oxide scale growth rate. Platinum and hafnium or zirconium modified aluminide coating were deposited on pure nickel using the electroplating and CVD methods. The coatings consisted of two layers: an outer, β-NiAl phase and the interdiffusion γ’-Ni3Al phase. Palladium dissolved in the whole coating, whereas hafnium and zirconium formed inclusions on the border of the layers. Samples were subjected to cyclic oxidation test at 1100 °C for 200h. Oxidation resistance of the palladium, Hf+Pd and Zr+Pd modified coatings deposited on pure nickel does not differ significantly, but is better than the oxidation resistance of the non-modified one.

Download Full-text

Rhodium influence on the microstructure and oxidation behaviour of aluminide coatings deposited on pure nickel and nickel based superalloy

High Temperature Materials and Processes ◽

10.1515/htmp-2019-0008 ◽

2019 ◽

Vol 38 (2019) ◽

pp. 621-627

Author(s):

Maryana Zagula-Yavorska

Keyword(s):

Oxidation Resistance ◽

Layer Structure ◽

Thick Layer ◽

Xrd Analysis ◽

Pure Nickel ◽

Nickel Based Superalloy ◽

Aluminide Coatings ◽

Refractory Elements ◽

Main Components ◽

Main Component

AbstractThe rhodium 0,5 μm thick layer was deposited on pure nickel and CMSX 4 Ni-based superalloy using the electroplating method. The rhodium coated substrates were aluminized by the CVD method. Oxidation resistance of nonmodified and rhodium modified coatings deposited both on nickel and CMSX 4 superalloy was compared. The triple-layer structure of rhodium modified coatings deposited on pure nickel was found. The β-(Ni,Rh)Al, rhodium doped γ'-Ni3Al and rhodium doped γ-Ni(Al) phases were the main components of the coatings on pure nickel. Two layers – additive and interdiffusion ones were identified in coatings deposited on CMSX 4 superalloy. TEM, SEM and XRD analysis revealed that β-(Ni,Rh)Al phase was the main component of the additive layer. Moreover Topologically Closed-Pack σ phases containing refractory elements in the β-(Ni,Rh)Al matrix of the interdiffusion layer were found. The rhodium modified aluminide coatings have better oxidation resistance than the nonmodified ones both on the pure nickel and CMSX 4 superalloy.

Download Full-text