The effect of fe on high temperature oxidation of NiAl

Jeong, Sanghoon; Lee, Dongbok

doi:10.1007/bf03025979

Cited by 7 publications

(1 citation statement)

References 34 publications

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“…Some authors assume that in the process of oxide scale growth on nickel at temperatures lower than 1000 °C, apart from the core network diffusion of cations, the core diffusion of oxygen across grain boundaries is involved [ 36 ]. At higher temperatures, it is assumed that the core diffusion of the metal plays a decisive role, but there is no agreement as to the degree of ionization of defects [ 37 ].…”

Section: Resultsmentioning

confidence: 99%

High-Temperature Corrosion of Flame-Sprayed Power Boiler Components with Nickel Alloy Powders

et al. 2023

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The development trends in the energy sector clearly indicate an increase in the share of biomass and alternative fuels fed for combustion in power boilers, which results in the imposition of many unfavourable factors and a demanding working environment. During the operation of the energy system, this means a sharp increase in corrosion of the gas-tight pipe walls and coils by the destructive action of chlorine and sulphur. Implementing advanced surface protection in addition to the selection of materials of better quality and resistance to difficult working conditions would significantly reduce their wear by high temperature corrosion. Thermally sprayed coatings offer a great opportunity to protect machine components and energy systems against corrosion, erosion, impact load and abrasive wear. This article presents the test results of high-temperature corrosion resistance of coatings made with Ni-Cr-B-Si and Ni-B-Si alloy powders on a boiler steel substrate. Samples with sprayed coatings were exposed to an atmosphere with a composition of N2 + 9% O2 + 0.08% SO2 + 0.15% HCl at 800 °C for 250, 500, 750 and 1000 h. Tests results of coatings made of Ni-Cr-B-Si alloys subjected to the influence of a corrosive environment showed the formation of a layer of scale on the surface, composed mainly of Cr2O3 oxide, which was a passive layer, reducing the rate of corrosion. Coatings sprayed with Ni-B-Si alloys showed significantly lower corrosion resistance. It was found that the developed technology of subsonic flame spraying with powders of the Ni-Cr-B-Si type allows the production of coatings compliant with the requirements of the energy industry, which allows their use as anti-corrosion protection on boiler elements intended for waste disposal and biomass combustion.

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Section: Resultsmentioning

confidence: 99%

High-Temperature Corrosion of Flame-Sprayed Power Boiler Components with Nickel Alloy Powders

et al. 2023

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Phase transformation and microstructural features of NiAl/Ni3Al two-phase alloys containing ternary elements

et al. 2004

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Various ternary elements were added to observe the effects on the microstructural features of β+γ' two-phase alloys. The microstructural features of β+γ' two-phase (Ni66Al34)100-χXχ(X=Ti, Si, Nb) depended on the As (austenite start) temperature of β'-martensite with alloying elements. For As>250 o C, a lamellar microstructure was found to form by the following phase transformation: Martensite→Ni5Al3→β+γ'. For As<250 o C, twotype microstructures, mesh and Widmanstätten, were formed depending on the ternary element. When Ti or Nb was added as a ternary element, the β→Ni5Al3 transformation occurred very quickly. Conversely, this transformation proceeded very slowly in the case of Si addition, and the resultant microstructure assumed somewhat different features. Consequently, it could be suggested that the microstructures of NiAl/Ni3Al twophase alloys are determined by not only the As temperature but also by the β→Ni5Al3 transformation.

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RETRACTED ARTICLE: Microstructure of Co precipitation strengthened B2-ordered NiAl

Han

Chun

et al. 2010

Met. Mater. Int.

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A transmission electron microscopy investigation on the phase decomposition of B2-ordered (Ni,Co)Al supersaturated with Ni and Co has revealed the precipitation of (Ni,Co) 2 Al which has not been expected from the reported equilibrium phase diagram. The (Ni,Co) 2 Al phase has a hexagonal structure and takes a rodlike shape with the long axis of the rod parallel to the <111> directions of the B2 matrix. By aging at temperatures below 873 K, a long period superlattice structure appears in the hexagonal (Ni,Co) 2 Al phase. The orientation relationship between the (Ni,Co) 2 Al precipitates and the B2-(Ni,Co)Al matrix is found to be (0001) p / /(111) B2 and [1210] p //[110] B2 , where the suffix p and B2 denote the (Ni,Co) 2 Al precipitate and the B2-(Ni,Co)Al matrix, respectively. (Ni,Co)Al hardens appreciably by the fine precipitation of the (Ni,Co) 2 Al phase.

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The effect of fe on high temperature oxidation of NiAl

Cited by 7 publications

References 34 publications

High-Temperature Corrosion of Flame-Sprayed Power Boiler Components with Nickel Alloy Powders

High-Temperature Corrosion of Flame-Sprayed Power Boiler Components with Nickel Alloy Powders

Phase transformation and microstructural features of NiAl/Ni3Al two-phase alloys containing ternary elements

RETRACTED ARTICLE: Microstructure of Co precipitation strengthened B2-ordered NiAl

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