Boronizing of the silicide coating on a multicomponent Nb Ti Si based alloy as protection against corrosion at high temperatures

Qiao, Yanqiang; Kong, Jianping; Zhou, Rongyi; Guo, Xiping

doi:10.1016/j.vacuum.2018.12.054

Cited by 19 publications

(2 citation statements)

References 44 publications

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“…In addition, a large number of dense and solid oxide films will be formed on the surface of the alloy at high temperature, which will make the structure of the alloy (BCC1 + BCC2 + Laves phase) preserved, and this structure will hinder the diffusion of oxygen in the alloy. Therefore, compared with Nb alloy [109][110][111], Nb-Si-Al-Ti alloy [112][113][114], and Nb-Si-Mo alloy [115,116], NbCrMo 0.5 Ta 0.5 TiZr high-entropy alloy has better mechanical properties and high-temperature oxidation resistance.…”

Section: Oxidation Resistancementioning

confidence: 99%

Development and Property Tuning of Refractory High-Entropy Alloys: A Review

Hua

Xing

et al. 2022

Acta Metall. Sin. (Engl. Lett.)

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In the past decade, multi-principal element high-entropy alloys (referred to as high-entropy alloys, HEAs) are an emerging alloy material, which has been developed rapidly and has become a research hotspot in the field of metal materials. It breaks the alloy design concept of one or two principal elements in traditional alloys. It is composed of five or more principal elements, and the atomic percentage (at.%) of each element is greater than 5% but not more than 35%. The high-entropy effect caused by the increase of alloy principal elements makes the crystals easy form body-centered cubic or face-centered cubic structures, and may be accompanied by intergranular compounds and nanocrystals, to achieve solid solution strengthening, precipitation strengthening, and dispersion strengthening. The optimized design of alloy composition can make HEAs exhibit much better than traditional alloys such as high-strength steel, stainless steel, copper-nickel alloy, and nickel-based superalloy in terms of high strength, high hardness, high-temperature oxidation resistance, and corrosion resistance. At present, refractory high-entropy alloys (RHEAs) containing high-melting refractory metal elements have excellent room temperature and high-temperature properties, and their potential high-temperature application value has attracted widespread attention in the high-temperature field. This article reviews the research status and preparation methods of RHEAs and analyzes the microstructure in each system and then summarizes the various properties of RHEAs, including high strength, wear resistance, high-temperature oxidation resistance, corrosion resistance, etc., and the common property tuning methods of RHEAs are explained, and the existing main strengthening and toughening mechanisms of RHEAs are revealed. This knowledge will help the on-demand design of RHEAs, which is a crucial trend in future development. Finally, the development and application prospects of RHEAs are prospected to guide future research.

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Section: Oxidation Resistancementioning

confidence: 99%

Development and Property Tuning of Refractory High-Entropy Alloys: A Review

Hua

Xing

et al. 2022

Acta Metall. Sin. (Engl. Lett.)

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“…[5], M-CrAlY (M=Ni, Co or NiCo) coatings [6,7], ceramic coatings [8,9], silicide coatings [10][11][12] and composite coatings doped with noble metals [13]. Among the these coating systems, silicide coatings exhibit excellent thermal stability and can form a flowable and self-healing SiO2 protective scale at high temperatures, making them suitable for load-bearing applications in TiAl alloys [14]. At present, there has been several studies on the high temperature oxidation resistance of the silicide coatings applied to TiAl alloys, while limited studies has focused on their hot corrosion behavior.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Hot Corrosion Property of a Si–Co–Y Diffusion Coating Deposited on TiAl–Nb Alloy

Li,

Lv,

Xie

et al. 2023

High Temperature Corrosion of mater.

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Si-Co-Y diffusion coatings were deposited on TiAl-Nb alloy using pack cementation process. The influence of activators and deposition temperatures on the coating structures was investigated, alongside the coating formation process and hot corrosion performance of the optimized coating in molten salt of 25%NaCl+75%K2SO4 at 850 ℃. The results show that a dense and compact Si-Co-Y diffusion coating can be prepared on TiAl-Nb alloy, with a multi-layered structure including an outmost layer of (Ti,X)Si2 (X represents Co, Al, Nb, Y), an outer layer composed of TiSi2+Ti5Si4+Ti5Si3 mixtures, a middle layer of Ti5Si3, and an inner layer of TiAl2. The coating prepared with AlCl3•6H2O and NH4Cl had many pores. Increase in deposition temperature led to a higher coating growth rate within the range of 1050-1100 o C, but temperature exceeding 1100 ℃ caused the formation of intensive holes in the coating. Hot corrosion tests at high temperatures proved that the Si-Co-Y diffusion coating prepared on TiAl-Nb alloy exhibited excellent hot corrosion resistance in 25%NaCl-75%K2SO4 molten at 850 o C. A protective hot corrosion product scale composed of a TiO2+Na2SiO3+Na2TiO3 outer layer and an Al2O3 middle layer, formed on coating after hot corrosion for 50 h. The scale can effectively inhibit the inward diffusion of corrosion medial of O, Cl and S elements.

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