Effect of diffusion coatings on the high temperature properties of nickel-chromium-superalloys

2018 ◽  
Vol 32 (19) ◽  
pp. 1840056 ◽  
Author(s):  
Byeong Woo Lee
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Aluminide Coating ◽  
Pure Aluminum ◽  
Protective Layer ◽  
Nitrogen Atmosphere ◽  
Silicide Coating ◽  
Diffusion Coatings ◽  
Aluminide Coatings ◽  
Negative Role

The halide-activated pack cementation method was utilized to deposit aluminide or silicide coatings on Inconel 617 and Hastelloy X superalloys. Aluminide and silicide diffusion coatings were formed at 850[Formula: see text]C for 2 h in nitrogen atmosphere, using a pack mixture containing pure aluminum (Al) or silicon (Si) and aluminum oxide (Al2O3) powders with activators of NH4Cl and AlF3. Aluminide-coated alloys showed homogeneous and uniform microstructures. Al diffused into the alloy inwards and aluminide diffusion coatings of [Formula: see text]17 [Formula: see text]m thick were formed inside the alloy. It was shown that the Al coatings played a key role in blocking off the excessive corrosion products at a high temperature for the alloys. The enhanced thermal stability and improved wear resistance were achieved in the aluminide coatings. In contrast to the aluminide coating, the silicide coating played a negative role, unable to provide the protective layer. The microstructural evolution and thermal stability of the aluminide- and silicide-coated alloys have been elucidated.

Aluminide Coating Formation on Internal Passages of GTD-111 Superalloy by Slurry Technique

2008 ◽  
Vol 595-598 ◽  
pp. 185-190 ◽  
Author(s):  
K. Shirvani ◽  
Amir Firouzi
Keyword(s):  
High Temperature ◽  
Aluminide Coating ◽  
Air Cooling ◽  
Diffusion Coatings ◽  
Aluminide Coatings ◽  
Internal Surfaces ◽  
Nial Phase ◽  
The Matrix ◽  
Coating Formation ◽  
Cooled Blade

The diffusion aluminide coatings are widely used in the air-cooling passages to protect their surfaces against high temperature corrosion. In this study plain and Si-modified aluminide coatings were applied by slurry technique on internal surfaces of Ni-base GTD-111 superalloy cylindrical specimens derived from a gas turbine air-cooled blade. The slurries containing Al or Al plus Si powders were applied on internal surfaces by injection method. Then, the samples were heated to high temperature (800-1000°C) to form the coatings. Optical, SEM-EDS, and XRD were utilized for characterizing microstructures and phase compositions of the coatings. The thicknesses of applied coatings on internal surfaces were in the range of 30-50 μm that meets specifications for diffusion coatings in such application (i.e. 25-756m). The examinations demonstrated that both coating types were contained β-NiAl phase as the matrix. The uniformities of coatings applied on different surface positions of passageway were determined. In addition, the effects of time and temperature of coating process as well as mass of dried slurry on the coating thickness were also discussed.

Effect of Hf Addition on High Temperature Properties of Ir-Containing Alloy Coatings

2007 ◽  
Vol 546-549 ◽  
pp. 1689-1694 ◽  
Author(s):  
Hideyuki Murakami ◽  
K. Kamiya ◽  
Akihiro Yamaguchi ◽  
Ying Na Wu ◽  
Seiji Kuroda
Keyword(s):  
High Temperature ◽  
Cyclic Oxidation ◽  
Flat Surface ◽  
Small Difference ◽  
Aluminide Coating ◽  
High Temperature Properties ◽  
Aluminide Coatings ◽  
Cyclic Oxidation Test ◽  
Hf Addition ◽  
Pack Cementation Process

In the present study, high temperature properties of Ir-modified and Ir-Hf-modified aluminide coatings on Ni-based single crystal superalloy TMS-82+ were discussed. They were prepared by depositing pure Ir and Ir-Hf alloys on TMS-82+ using magnetron sputtering and EB-PVD, followed by a conventional Al-pack cementation process. The effects of Hf addition on the oxidation resistance and top-coat spallation resistance were investigated. Cyclic oxidation test at 1423K for 1h as one heating cycle revealed that while there is a small difference in oxidation kinetics and spallation lives between Ir and Ir-Hf coatings, drastic difference in surface morphology was observed. After 50 oxidation cycles the Ir-modified aluminide coating showed surface rumpling whereas the Ir-Hf modified aluminide coatings kept the flat surface. It was also revealed that excessive addition of Hf promoted the internal oxidation, resulting in the deterioration of substrates. These results agree with the conventional Pt-modified aluminide coatings and Ni-Al-Hf alloys.

Formation, Characterization, and Wear Behavior of Aluminide Coating on Mirrax® ESR Steel by Low-Temperature Aluminizing Process

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Tuba Yener ◽  
Azmi Erdogan ◽  
Mustafa Sabri Gök ◽  
Sakin Zeytin
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Low Temperature ◽  
Room Temperature ◽  
Wear Behavior ◽  
Aluminide Coating ◽  
Pure Aluminum ◽  
Dry Sliding Wear ◽  
Thickness Variation ◽  
Wear Tests

Abstract The aim of this study was to investigate the effect of low-temperature aluminizing process on the microstructure and dry sliding wear properties of Mirrax steel. Low-temperature aluminizing process was applied on Mirrax steel at 600, 650, and 700 °C for 2, 4, and 6 h. The packs for the process were prepared using pure aluminum powder as aluminum deposition source. Ammonium chloride NH4Cl and Seydisehir Al2O3 powder were used as the activator and the inert filler, respectively. Scanning electron microscope (SEM)/energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis were applied for characterization of the coating surfaces. The through-thickness variation in the layer microstructure was determined and it was found to vary between 1 µm and 45 µm which increased with higher process temperature and time. After the deposition process, the coating layer hardness increased to 1000 HVN, whereas the hardness of the matrix was 250 HVN. The wear tests were performed using a ball-on-disc tribometer under 5 N load at room temperature and 500 °C on aluminized and untreated Mirrax steel. In both room temperature and high-temperature wear tests, it was determined that the aluminizing process increased the wear resistance of Mirrax steel. Increasing aluminizing time and temperature also increased the wear resistance. The uncoated and thin-coated samples generally exhibited wear in the form of plastic deformation and adhesion related ruptures. A high degree of tribological layer was observed on the wear trace on samples with high coating thickness, especially in high-temperature tests. Therefore, the volume losses in these samples were induced by fatigue crack formation and delamination.

Thermal Stability of NiAl-Base Coatings for High Temperature Application

2005 ◽  
Vol 237-240 ◽  
pp. 709-714
Author(s):  
Robert Filipek ◽  
Marek Danielewski ◽  
E. Tyliszczak ◽  
M. Pawełkiewicz ◽  
S. Datta
Keyword(s):  
Thermal Stability ◽  
Gas Turbines ◽  
Inverse Method ◽  
Critical Role ◽  
Diffusion Coatings ◽  
Aluminide Coatings ◽  
Wide Range ◽  
Industrial Energy ◽  
Temperature Application ◽  
Thermal Stability Of

Aluminide diffusion coatings act as a remedy against the aggressive environments in which modern aero-gas turbines operate. Platinum addition to basic aluminide coatings significantly improves the oxidation resistance of these coatings. The increase in operating temperatures of industrial energy systems and gas turbines, has led to the extensive use of coatings capable of providing improved service life. Interdiffusion plays a critical role in understanding the integrity of such coatings. The Danielewski-Holly model of interdiffusion which allows for the description of a wide range of processes (including processes stimulated by reactions at interfaces) is employed for studying of interdiffusion in the Pt-modified β-NiAl coatings. Using the inverse method the intrinsic diffusivities of Ni, Al and Pt were calculated. Such obtained diffusivities were subsequently used for modelling of thermal stability of Pt-modified aluminide coatings in air and in argon atmosphere.

A Low Temperature CVD Process for Aluminum and Aluminide Coatings

2000 ◽  
Author(s):  
J. Liburdi ◽  
P. Lowden ◽  
V. Moravek
Keyword(s):  
Low Temperature ◽  
Aluminide Coating ◽  
Pure Aluminum ◽  
Turbine Blades ◽  
Chemical Vapour ◽  
Thin Layers ◽  
Internal Diameter ◽  
Temperature Oxidation ◽  
Aluminide Coatings ◽  
Internal Surfaces

A novel, low temperature Organometallic Chemical Vapour process (LOM), developed by Liburdi Engineering is presented in this paper. The process, which is widely used in the electronics industry to apply thin layers of pure aluminum, has been successfully scaled from a 3″ (75 mm) diameter quartz reactor to a production hot wall metal retort with an internal diameter of 18″ (0.45m) and a height of 60″ (1.5m). The capability for simultaneously coating external and internal surfaces is discussed. The aluminum layer can be used directly for low temperature atmospheric corrosion protection in place of IVADIZING or diffusion heat treated to produce an oxidation resistant aluminide coating for superalloys. Results of cyclic oxidation and salt fog corrosion testing are presented. The potential for alloying with modifying elements such as platinum to further enhance its high temperature oxidation resistance and to use the process in conjunction with thermal barrier coatings are presented. Potential applications ranging from coating of heat exchangers and automotive catalytic converters to the coating of industrial and aero turbine blades with complex cooling passages are presented.

Elaboration of Nickel Aluminide Diffusion Coatings: Application to Oxidation Resistance

2008 ◽  
Vol 595-598 ◽  
pp. 41-49 ◽  
Author(s):  
Céline Choux ◽  
Sébastien Chevalier ◽  
Yannik Cadoret
Keyword(s):  
High Temperature ◽  
Nickel Aluminide ◽  
Diffusion Mechanism ◽  
Alumina Scale ◽  
Organic Chemical ◽  
Material Surface ◽  
Protective Oxide ◽  
Diffusion Coatings ◽  
Aluminide Coatings ◽  
Α Al2o3

Aluminide diffusion coatings are widely used in aeronautic domain. Nickel based superalloys present good mechanical properties and creep resistance at high temperature but their corrosion resistance is somewhat poor. In order to enhance their lifetime at high temperature, aluminide coatings can be applied on alloy surface. Aluminium present on material surface can form, at high temperature, alumina scale which is a protective oxide scale. In the present study, nickel aluminide coatings were carried out by aluminisation in a single step pack cementation process on nickel based superalloys 600 and AM1. Ni-Al intermetallic was obtained in each case. Oxidation tests were carried out at 900°C in air under atmospheric pressure. At this temperature, transient alumina as γ-Al2O3 and θ-Al2O3 appear on surface and are less protective than the stable α- Al2O3. Reactive elements can enhance α-Al2O3 nucleation and change diffusion mechanism during oxidation leading to a better adherence of alumina scale. In the present work, yttria was introduced by Metal-Organic Chemical Vapour Deposition (MOCVD) prior to the aluminisation. Yttria doped and undoped sample behaviours were compared under oxidising atmospheres.

Effect of Polishing Treatment on Rumpling of Oxide Scales on NiPtAl Coatings with Different Pt-Content

2013 ◽  
Vol 662 ◽  
pp. 383-386
Author(s):  
Peng Song ◽  
Jian Sheng Lu
Keyword(s):  
High Temperature ◽  
Nickel Aluminide ◽  
Aluminide Coating ◽  
Temperature Cycling ◽  
Oxide Surface ◽  
Temperature Oxidation ◽  
Aluminide Coatings ◽  
Temperature Exposure ◽  
Engine Components ◽  
Surface Morphologies

Pt-modified nickel aluminide coatings have been more widely used for protection of jet-engine components against high-temperature oxidation. The coating rumpling of two Pt-content NiPtAl coatings was studied in this paper during high temperature exposure. The results indicated that the NiPtAl coating grains size made a great contribution to the oxide surface morphologies, especially rumpling. Smaller grain size within high-Pt coating indicated a denser rumpling compared to low-Pt coating due to PtAl2 formation in the earlier coating. The failed local alumina at the ridges was also found on the low-Pt coating after cyclic oxidatioin. It was found that polished treatment resulted a comparatively flat and homogeneous oxide layer compared to as-received coatings. The temperature cycling could promote the aluminide coating rumpling, however, the polished treatment could not completely eliminate the roughening.

Improvement of Slurry Aluminide Coating on Ferritic Stainless Steel AISI430 for High-Temperature Oxidation Resistance

2015 ◽  
Vol 658 ◽  
pp. 86-90
Author(s):  
Piyorose Promdirek ◽  
Mack Boonpensin ◽  
Thanapon Rojasawasatien
Keyword(s):  
High Temperature ◽  
Surface Morphology ◽  
Oxidation Resistance ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Aluminide Coating ◽  
Protective Layer ◽  
Growth Effect ◽  
Effect Of Temperature ◽  
Temperature Oxidation

One of the surface modification processes for high-temperature oxidation resistance is slurry aluminizing process, forming protective layer of alumina (Al2O3). However, several important parameters such as annealing times and temperatures should be intensively considered. The objective of this study is to improve the process of slurry aluminide coating of ferritic stainless steels type AISI430 (16%Cr) combat to high-temperature oxidation. The specimens were cut, then ground, and finally sprayed with slurry mixture (Al powder + polyvinyl alcohol (PVA)). They were annealed in Ar at 1100°C for 15 minutes in order to eliminate PVA and form aluminide on their suface. The protective layer Al2O3 was finally formed in the temperature range of 900-1100 °C for 15-60 minutes. The cyclic oxidation tests were performed at 1000 °C for 24 hours. The surface morphology were then examined by XRD, SEM equipped EDS. The results showed that all oxidation kinetics of coated specimens were parabolic. The oxidation rate of uncoated specimens was apparently higher than that of coated specimens. Comparing with all coated specimens, the oxidation rate decreased with the increasing temperature and annealing time. In this study, the coating process at 1100°C for 60 minutes exhibited the lowest oxidation rate due to the most complete layer of Al2O3. The surface morphology showed the formation of continuous layer of Fe2Al5 and Al2O3, acting as barrier layer to oxide growth. Effect of temperature and time on oxidation resistance were discussed in this study.

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

ALUMINUM 1100

Alloy Digest ◽  
1974 ◽  
Vol 23 (2) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Shear Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Pure Aluminum ◽  
Heat Treating ◽  
Industrial Applications ◽  
Temperature Performance ◽  
Commercially Pure

Abstract ALUMINUM 1100 is commercially pure aluminum and is characterized by its excellent ability to be drawn, spun, stamped or forged. It has good weldability, excellent resistance to corrosion and many home, architectural and industrial applications. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-44. Producer or source: Various aluminum companies. Originally published October 1956, revised February 1974.

Sign in / Sign up

Export Citation Format

Share Document