Oxidation of NiAl and FeAl

Grabke, H. J.

doi:10.1016/s0966-9795(99)00037-0

Cited by 331 publications

(135 citation statements)

References 39 publications

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“…This can be rationalised as follows-Oxide growth kinetics as given by the parabolic rate constant, k P is significantly retarded in a-Al 2 O 3 compared with other oxides, such as NiO or CoO. [20,21] In fact, initially transitional Al 2 O 3 forms by outward cation (Al 3+ ) diffusion and eventually a-Al 2 O 3 forms by internal oxidation, which is anion (O 2À ) controlled. Therefore, as long as there is no ''continuous'' coverage of the surface by Al 2 O 3 , vaporization will occur.…”

Section: B Sequence Of Microstructure Evolution At the Surfacementioning

confidence: 99%

On the Roles of Oxidation and Vaporization in Surface Micro-structural Instability during Solution Heat Treatment of Ni-base Superalloys

D’Souza

Welton

West

et al. 2014

Metall Mater Trans A

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Micro-structural instability at the surface that develops during solution heat treatment of a typical third generation Ni-base superalloy, CMSX10N has been reported. It is shown that elemental Ni vaporizes from the surface during solutioning leading to de-stabilization of c phase. With increasing extent of vaporization, a phase mixture of b, c¢, and the refractory (W and Re-rich) precipitates occur within the surface layers resulting in the complete breakdown of the cuboidal c/c¢ phase morphology that is usually observed. It is demonstrated that the conditions at the surface have a marked effect on the vaporization kinetics and subsequent evolution of surface phases-the presence of a continuous dense oxide such as Al 2 O 3 or the presence of sacrificial Ni-foils interspersed in the furnace significantly suppresses elemental vaporization from the sample surface.

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Section: B Sequence Of Microstructure Evolution At the Surfacementioning

confidence: 99%

On the Roles of Oxidation and Vaporization in Surface Micro-structural Instability during Solution Heat Treatment of Ni-base Superalloys

D’Souza

Welton

West

et al. 2014

Metall Mater Trans A

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“…Observations of the samples surface made by a scanning electron microscope revealed that the surface areas were aluminum-containing oxides. The presence of Al 2 O 3 passive layers gave FeAl alloys very good heat resistance in an oxidizing environment [14]. The occurrence of heat-resistant layer of Al 2 O 3 , which tightly isolates the rest of the material of oxygen provides the materials high heat resistance (Figs.…”

Section: Resultsmentioning

confidence: 99%

Influence of Plastic Deformation During Extrusion Process on Heat Resistance Alloys Fe40Al

Pasek

Cebulski

2017

Archives of Metallurgy and Materials

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The article presents the results of studies on the effects wrought on the corrosion resistance of the alloy matrix phase intermetallic FeAl. Researches were carried out on the Fe40Al5Cr0.2TiB alloy and involved the oxidation of the samples after the crystallization after plastic deformation made by extrusion. The tests were performed in an oven in air at 1100°C for 100, 300 and 500 h. Determined to change the mass of the samples after corrosion research setting kinetics of corrosion processes, as well as an analysis of the microstructure of the alloy after the crystallization and after forming. The structure was examined using light microscopy and scanning electron microscopy and X-ray microanalysis with EDS chemical composition of the corrosion products. The test results revealed that plastic deformation during extrusion of intermetallic alloy led to structural changes, the effect of which was to improve the heat resistance at a temperature of 1100°C.

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“…Due to the high melting temperature, good hightemperature strength, low density, high thermal conductivity and excellent oxidation resistance 89,90) , NiAl protective coatings can be used effectively for hightemperature applications.…”

Section: Refractor Y Compoundsmentioning

confidence: 99%

“…It is known that chromium is one of the most widely used alloying elements to improve properties of nickel aluminides 93). It increases the oxidation resistance of NiAl, suppressing the formation of metastable aluminum oxides in a temperature range of 900-1000 and promoting the formation of a dense fine-grained α-Al2O3 protective film, providing high corrosion resistance 90 , and also improves the mechanical properties of NiAl by solid solution hardening and hardening by thin inclusions of α-Cr 89) . Recently, we have developed a novel SHS powder based on nickel monoaluminide alloyed with chromium and strengthened with dispersed inclusions of chromium-based solid solution (Fig.…”

Section: Refractor Y Compoundsmentioning

confidence: 99%

SHS Powders for Thermal Spray Coating

Talako

Ilyuschenko

Лецко

2009

KONA

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2009 Hosokawa Powder Technology Foundation IntroductionModern industrial technologies call for the development of novel materials with improved properties, lower costs and environmentally suitable processes. Surface engineering that attempts to create functional layers on the surface is obviously the most economical way to provide high per formance to machiner y and equipment. Among the wide range of available methods (including varieties of atomistic and par ticulate deposition, bulk coatings wetting processes and surface modification), thermal spray coatings offer the most versatile solutions. Thermal spray processes form a continuous coating by melting the consumable material (feedstock) to form droplets and impinging these droplets on the substrate. The mechanism of bonding to the substrate in thermal sprayings (TS) is the same as plating, both mechanical interlocking and atomic interaction, with the shear strength around 7 MPa 1). The thickness of the coatings can range from 10 µm to a few millimeters 2) . Other advantages of thermal spraying include a practically unlimited assortment of powders to be sprayed, high efficiency and relatively low substrate temperature (373-583 K), thus minimizing shape distortion, oxidation and phase transformations in the near-surface layer. Demanded characteristics for thermal spray feedstock powders can be very different, depending on the spraying process, the operating conditions, the desired properties of the final coating, etc. Besides the intrinsic material properties, the technical requirements for the TS feedstock powders include good flowability and sprayability. They are greatly affected by the particle size, shape and morphology as well as particle size distribution. That is why thermal spray feedstock powder production processes must be reliable and flexible, while remaining as inexpensive as possible.Self-propagating high-temperature synthesis (SHS) or combustion synthesis, discovered by A.G. Merzhanov and colleagues in 1967, is known as a ver y promising technique for processing materials (ceramics, intermetallics, cermets, etc.) with good physical and chemical properties at relatively low costs 3,4) . The main point of the process is that after localized initiation, the reaction propagates as a narrow zonecombustion wave -along a sample driven by the exothermic reaction between components of the charge mixture without the application of external heating (furnaces, etc.). Because of the extreme conditions in the SHS wave (high temperature of up to 3500 , fast heating of up to 10 6 K/s, steep temperature gradient of up to 10 5 K/cm, rapid cooling in the after-burn zone of up to 100 K/s, and fast accomplishment of reaction, 0.5 s to 1 min), chemical interaction mechanisms during the SHS are often non-equilibrium, resulting in the formation of materials with improved structure and properties, especially in multi-component composite systems [3][4][5][6] . Moreover, a product with increased purity can be obtained due to evaporation of volatile impurities at th...

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Oxidation of NiAl and FeAl

Cited by 331 publications

References 39 publications

On the Roles of Oxidation and Vaporization in Surface Micro-structural Instability during Solution Heat Treatment of Ni-base Superalloys

On the Roles of Oxidation and Vaporization in Surface Micro-structural Instability during Solution Heat Treatment of Ni-base Superalloys

Influence of Plastic Deformation During Extrusion Process on Heat Resistance Alloys Fe40Al

SHS Powders for Thermal Spray Coating

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