Growth kinetics and isothermal oxidation behavior of a Si pack cementation-coated Mo-Si-B alloy

Choi, Kwang-Soo; Yang, Wonchul; Baik, Kyeong Ho; Kim, Youngmoo; Lee, Seong; Lee, Sangyeob; Park, Joon Sik

doi:10.1016/j.apsusc.2019.06.020

Cited by 28 publications

(14 citation statements)

References 35 publications

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“…The sealed alumina crucibles were dried at room temperature for 24 h, then placed in a furnace and annealed at 1100 • C for 24 h under an Ar atmosphere. A more detailed description of the specimen preparation procedure is given elsewhere [16]. The temperature of the furnace was raised at a rate of 5 • C/min and then held for the desired time.…”

Section: Methodsmentioning

confidence: 99%

“…While they have high melting points and excellent strength at high temperatures [2,12,13,16], the alloys are known to show serious defects upon exposure to high temperatures under ambient atmosphere [4,16,17]. For Mo-based alloys, the Mo component is known to have poor oxidation resistance as a result of the formation of volatile oxides MoO 3 (g) at temperatures above about 500 • C [16][17][18][19]. When Mo-based alloys were exposed to high temperatures in air, they usually disintegrated.…”

Section: Introductionmentioning

confidence: 99%

“…In order to enhance the oxidation behavior, many studies have been reported, such as pack cementation, spray coatings, plasma coatings, etc. [16,23,24]. Among the examined coating routes, pack cementation processing appears to be an effective manner to produce oxidation resistant coatings.…”

Section: Introductionmentioning

confidence: 99%

“…The pack cementation process can provide mass production and ensure high bond strength between the coating materials and substrates. Further, complex-shaped component parts can be uniformly coated, since the coating method adopts gas diffusion to substrates [16].…”

Section: Introductionmentioning

confidence: 99%

“…A number of studies have been conducted to improve oxidation resistance by forming SiO 2 or Al 2 O 3 oxide on the surface in a high temperature oxidation environment with pack cementation coatings [16,17,20,21,25]. K. Choi et al discussed the growth and oxidation behavior of coating layers after Si pack cementation coatings on Mo-3Si-1B (wt.%) alloys [16]. K. Choi et al also investigated the oxidation behavior under the condition of 1350 • C after forming a MoSi 2 -silicide layer on the surface of TZM alloys.…”

Section: Introductionmentioning

confidence: 99%

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Microstructures and Oxidation Behavior According to Nb:Mo Ratio in a Nb–Mo–Si System with Si Pack Cementation Coatings

et al. 2019

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Research is being conducted on Mo- and Nb-based alloys that are used in the aerospace sector, including those used for advanced gas turbines and aircraft engines. There is a limit to using Mo, which has a high density among refractory metals, and a few studies exist describing the addition of Nb to Mo–silicide alloys. There is a lack of guidance research on the basic Nb:Mo ratio of alloys, and it is necessary to study how to improve oxidation resistance. Therefore, this study aims to improve oxidation resistance by controlling the ratio of Nb and Mo in (Nbx, Moy)Si2 coating layers with Si pack cementation coatings on Nb–Mo alloys. Static oxidation tests were carried out at 1200 °C for 6 h to confirm the oxidation characteristics. As a result, a SiO2 or SiO2 + Nb2O5 ceramic protective layer was formed on the surface. After the oxidation tests, alloys with a Nb content of less than 35 at.% were found to protect the surface. The ratios of Nb and Mo in the Nb–Mo alloy and silicide coating layer were compared, and the improvement of oxidation resistance is discussed in terms of microstructural evolution.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Microstructures and Oxidation Behavior According to Nb:Mo Ratio in a Nb–Mo–Si System with Si Pack Cementation Coatings

et al. 2019

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Oxidation‐Resistant Environmental Barrier Coatings for Mo‐Based Alloys: A Review

et al. 2020

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Molybdenum‐based materials offer high melting temperatures and promising mechanical properties; therefore, they are potential candidates for high‐temperature components, such as turbine blades. However, at temperatures above 700 °C, molybdenum suffers from severe pesting phenomenon, leading to decomposition of the component. Therefore, oxidation‐resistant environmental barrier coatings are crucial to prevent the material from degradation and to maintain its excellent mechanical properties at high temperatures. This review provides a detailed overview on the different coating concepts for Mo and Mo‐based alloys.

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Relationship among Thermodynamic, Growth Kinetics, and Microstructure Characterization of the Simple and Silicon‐Modified Aluminide Coating on Ni‐based Superalloy

Dai,

Zou,

Ning

et al. 2024

ChemistrySelect

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This research investigates the effects of pack cementation parameters on the thermodynamics, growth kinetics, and microstructure of the simple and silicon‐modified aluminide coatings on the IN718 superalloy. The growth kinetic modelling of the aluminide coating, activated by NH4Cl, is established as . further optimizing the kinetics modelling that includes both CaCl2 activator or the mixture of CaCl2 and NH4Cl. The results showed that NH4Cl as an activator generated a higher equilibrium partial pressure of halides, which enhanced the deposition efficiency of active Al atoms and facilitated the significant precipitation of Cr‐rich carbides. Additionally, part of the CaCl2 substitute NH4Cl could maintain a high coating growth rate and reduce the hazards. Adding Si element preferentially combines with Cr formed the Cr9.1Si0.9 phase along grain boundaries, which blocked the inner‐diffusion channels of Al atoms and reduced the thickness of the silicon‐modified aluminide coating compared to simple aluminide coating. These researches revealed the relationship among the thermodynamics, growth kinetics, and microstructure of simple and silicon‐modified aluminide coatings. The thickness and microstructure of coatings can be effectively regulated by adjusting the powder composition, content, and process parameters to achieve precise control.

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Growth kinetics and isothermal oxidation behavior of a Si pack cementation-coated Mo-Si-B alloy

Cited by 28 publications

References 35 publications

Microstructures and Oxidation Behavior According to Nb:Mo Ratio in a Nb–Mo–Si System with Si Pack Cementation Coatings

Microstructures and Oxidation Behavior According to Nb:Mo Ratio in a Nb–Mo–Si System with Si Pack Cementation Coatings

Oxidation‐Resistant Environmental Barrier Coatings for Mo‐Based Alloys: A Review

Relationship among Thermodynamic, Growth Kinetics, and Microstructure Characterization of the Simple and Silicon‐Modified Aluminide Coating on Ni‐based Superalloy

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