High-temperature oxidation-resistant coatings on niobium and its alloys

Змий, В. И.; Ruden’kii, S. G.; Bredikhin, M. Yu.; Kunchenko, V. V.

doi:10.1007/s11106-008-9012-8

Cited by 4 publications

(3 citation statements)

References 3 publications

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“…It should be noted the best results to date for the protection of niobium alloys -developed a method of vacuum activated diffusion saturation [12]. The method provides for the application of a complex coating on niobium when Mo, Ti, Cr, Ni, Al, Si, B are present in the reaction zone.…”

Section: Problem Statusmentioning

confidence: 99%

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Heat protective coatings on niobium alloys

Babak

Lyashenko

Щепетов

et al. 2020

Mechanics and Advanced Technologies

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The article shows that during plasma-diffusion deposition, a multilayer coating was formed on the surface of the niobium alloy. A highly porous plasma-sprayed layer of molybdenum silicide has a significant spread in thickness (h=100...350 μm, Hμ20=6880 MPa). When studying the microstructure of samples with a plasma-diffusion coating after testing, it was found that cracks in the coating originate in the process of creep, mostly at the interface between the plasma and diffusion layers of the coating. The source of their origin is individual discontinuities in the diffusion layer as delivered. Crack propagation occurs both into the plasma and diffusion layers of the coating. Crack growth in the plasma layer is inhibited due to the rounded nature of the pores and the increased plasticity of this layer. The growth of cracks deep into the sample is, as a rule, inhibited by a boride sublayer. The advantage of plasma-diffusion technology provided an increased plasticity of the coating, the presence of thin barrier sublayers, a discontinuous coating structure, the presence of low-melting compounds that contribute to the healing of defects in the coating, an increase in its corrosion resistance and resistance to thermal fatigue destruction. The combination of these properties made it possible to provide an increase in durability compared to silicide and borosilicide coatings under conditions of isothermal creep in air (1400 °C, 50 MPa) 1.9...3.7 times and under conditions of thermal cyclic creep (1400-250 °C, 50 MPa) in 6.8...8.5 times. It has been determined that the use of a discrete structure will increase the thickness of the coating layer and ensure an increase in their working properties.

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Section: Problem Statusmentioning

confidence: 99%

“…Insufficient heat resistance and heat fatigue of coatings on Nb-alloys are noted [9,12]. The change of the main mechanical characteristics of the coated niobium alloy depending on the number of heating cycles up to 1315 °C at a pressure of 3...5 mm Hg is shown.…”

Section: Problem Statusmentioning

confidence: 99%

Heat protective coatings on niobium alloys

Babak

Lyashenko

Щепетов

et al. 2020

Mechanics and Advanced Technologies

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“…Few literatures have been published about coatings preventing tantalumalloys from high-temperature oxidation.Zmiiet al [5] reported that complex silicide systems including Si-Ti are always used to protect tantalum and Ta-based alloys.Shah et al [6]argued thatonly Ti 5 Si 3 is known to have reasonable oxidation resistance among M 5 Si 3 silicides.Besides, Si-Ti coatings have been successfully applied in niobium high-temperature protection.In our previous work, development of Si-Ti coatings on T-222 alloy by fused slurry method at different temperature from 1425°C to 1500°C has been attempted.The pure titanium and silicon powders were used in the slurry for coating, and polyethylene glycol was used as the caking agent as well. The morphology, microstructure and phase composition of Si-Ti coatingswere characterized by scanning electron microscopy (SEM),X-ray diffraction(XRD),energy disperse spectroscopy(EDS).The mass change of coatings during static oxidation at 1500°C in pure oxygen is measured by thermogravimetricequipment.…”

Section: Introductionmentioning

confidence: 99%

Research on the Si-Ti High Temperature Oxidation-Resistant Coatings for Tantalum Alloys

Song

et al. 2013

AMR

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Si-Ti coatings were prepared on the surface of T-222 alloy by fused slurry method at different temperatures (1425-1500°C). Microstructure and composition of the coatings were characterized and analysed through scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), energy dispersive X-ray spectrometry (EDS) respectively. The coating fabricated at 1450°C exhibited excellent structure compatible with high temperature oxidation resistance. Its surface is relatively smooth with few holes and cracks and the main phase on the surface is (Ti, Ta)Si that possesses outstanding corrosion resistance. Moreover, the cross-sectional structure of the coating is smooth and compact which can effectively prevent O2 from permeation. The isothermal oxidation behaviors in pure O2 atmosphere at 1500°C for 2h finally demonstrate that the optimum coating temperature is 1450°C.

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