Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy.However,the long-term protective property of single silicide coating remains a long-time endeavor ...Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy.However,the long-term protective property of single silicide coating remains a long-time endeavor due to the deficiency of oxygen-consuming phases,as well as the self-healing ability of the protective layer.Herein,a silicide-based composite coating is constructed on niobium alloy by incor-poration of nano-SiC particles for enhancing the high-temperature oxidation resistance.Isothermal oxi-dation results at 1250℃ for 50 h indicate that NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multilayer coated sample with a low mass gain of 2.49 mg/cm^(2) shows an improved oxidation resistance compared with NbSi_(2) coating(6.49 mg/cm^(2)).The enhanced high-temperature antioxidant performance of NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multi-layer coating is mainly attributed to the formation of the protective SiO_(2) self-healing film and the high-temperature diffusion behavior of NbSi_(2)/substrate.展开更多
A Cr/CoNiCrAlTaY bilayer coating was prepared on the Ti-45Al-8.5Nb alloy by plasma surface metallurgy technique.The as-prepared coating with a grain size of~2μm exhibited a dense microstructure and strong adhesion du...A Cr/CoNiCrAlTaY bilayer coating was prepared on the Ti-45Al-8.5Nb alloy by plasma surface metallurgy technique.The as-prepared coating with a grain size of~2μm exhibited a dense microstructure and strong adhesion due to metallurgical bonding,consisting of outermost Cr layer and CoNiCrAlTaY transition layer.The typical power-law relationship between mass gain and time was obtained for the coated specimens with a rate exponent of 3.18 following oxidation at 1173 K.The top Cr_(2)O_(3)film and spinel oxides(i.e.,NiCr_(2)O_(4)and CoCr_(2)O_(4))exhibited a protective effect with a low oxidation reaction rate.Interfacial analysis identified Ta precipitates(Cr_(2)Ta and TaAl_(3))and Ta oxides(Ta_(2)O_(5)and Ta_(2)O_(3)),which played an essential role in retarding rapid diffusion and enhancing adhesion and oxidation resistance.展开更多
Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,a...Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,as well as the wear resistance of the coatings.Besides,the effect of changing the laser melting process on the coatings was also investigated.The oxidation mass gain at 800–1200℃and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied.Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation.After oxidizing at 1000℃for 1 h,the thickness of the oxide layer of the uncoated sample was 241.0μm,whereas that of the sample with Co-based coating is only 11.8–35.5μm.The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate,indicating that the hardness and wear resistance of the Zr substrate are greatly improved.The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt%NaCl solution.展开更多
To improve the oxidation resistance of HfB_(2)-SiC coatings on carbon/carbon composites at 1700°C in air,CeO_(2) was introduced to improve oxygen blocking and its mechanism was investigated.During the rapid oxida...To improve the oxidation resistance of HfB_(2)-SiC coatings on carbon/carbon composites at 1700°C in air,CeO_(2) was introduced to improve oxygen blocking and its mechanism was investigated.During the rapid oxidation stage,CeO_(2) accelerated the formation of a multiphase glass layer on the coating surface.The maximum oxidation rates of CeO_(2)-HfB2-SiC coatings with 1%,3%,and 5%CeO_(2) were 24.1%,20.3%,and 53.2%higher than that of the unmodified HfB2-SiC coating,respectively.In the stable oxidation stage,the maximum oxidation rates of coatings with 1%and 3%CeO_(2) decreased by 31.4%and 21.9%,respectively,demonstrating adequate inert protection.CeO_(2) is a“coagulant”and“stabilizer”in the composite glass layer.However,increasing the CeO_(2) content accelerates the reaction between the SiO_(2) glass phase and SiC,leading to a higher SiO_(2) consumption and reduced self-healing ability of the glass layer.The 1%CeO_(2)-60%HfB2-39%SiC coating showed improved glass layer viscosity and stability,moderate SiO_(2) consumption,and better self-healing ability,significantly boosting the oxidation protection of the coating.展开更多
To improve the high-temperature service properties of coppery tuyere,Co06 coating with a Ni60A interlayer was prepared on copper by plasma cladding.Ni60A interlayer acted as a bridge to promote the element diffusion,t...To improve the high-temperature service properties of coppery tuyere,Co06 coating with a Ni60A interlayer was prepared on copper by plasma cladding.Ni60A interlayer acted as a bridge to promote the element diffusion,thus achieving metallurgical bonding.Due to the strengthening effect ofγ-Co,Cr_(23)C_(6)and Cr_(7)C_(3)phases,the wear resistance of Co06–Ni60A coating was much higher than that of copper substrate.As the temperature increased,the wear resistance of coating decreased first and then increased.The coating exhibited better wear resistance at 600℃ due to the oxidation wear mechanism.Compared with copper substrate and Ni60A,the oxidation resistance of Co06 was increased by 6.0 and 1.9 times,respectively.For melting loss resistance,Co06–Ni60A coating was superior to Ni60A single-layer coating,but the molten iron can still form a micro-metallurgical bonding with the coating surface.展开更多
Laser shock peening(LSP)was used to enhance the high-temperature oxidation resistance of laser melting deposited Ti45Al8Nb alloy.The microstructure and high-temperature oxidation behavior of the as-deposited Ti45Al8Nb...Laser shock peening(LSP)was used to enhance the high-temperature oxidation resistance of laser melting deposited Ti45Al8Nb alloy.The microstructure and high-temperature oxidation behavior of the as-deposited Ti45Al8Nb alloy before and after LSP were investigated by scanning electron microscopy,X-ray diffraction,and electron backscatter diffraction.The results indicated that the rate of mass gain in the as-deposited sample after LSP exhibited a decrease when exposed to an oxidation temperature of 900℃,implying that LSP-treated samples exhibited superior oxidation resistance at high temperatures.A gradient structure with a fine-grain layer,a deformed-grain layer,and a coarse-grain layer was formed in the LSP-treated sample,which facilitated the diffusion of the Al atom during oxidation,leading to the formation of a dense Al_(2)O_(3)layer on the surface.The mechanism of improvement in the oxidation resistance of the as-deposited Ti45Al8Nb alloy via LSP was discussed.展开更多
The high-temperature oxidation resistance of AISI 321 stainless steel used in solar thermal power heat exchangers determines its service life.In this study,aluminizing and subsequent laser shock peening(LSP)treatments...The high-temperature oxidation resistance of AISI 321 stainless steel used in solar thermal power heat exchangers determines its service life.In this study,aluminizing and subsequent laser shock peening(LSP)treatments were employed to improve the high-temperature oxidation resistance of AISI 321 stainless steel at 620°C.These two treatments decreased the oxidation rate of AISI 321 steel.Specifically,the optimal oxidation resistance was observed in aluminized steel before oxidation for 144 h owing to the increased entropy of the LSP-treated specimen.After 144 h,LSP-treated steel achieved the best oxidation resistance because of the formation of a protectiveα-Al2O3film.Moreover,the large amount of subgrain boundaries formed on the aluminized layer of the LSP-treated samples could act as short-circuit paths for the outward diffusion of Al,facilitating the rapid nucleation ofα-Al2O3.Meanwhile,the aluminized layer could isolate the contact between the oxidation environment and matrix,thereby decreasing the oxidation rate.Furthermore,the minimum oxidation parabolic constant was calculated for LSP-treated steel(6.45787×10^(-14)),which was 69.18%and 36.36%that of aluminized and 321 steel,respectively,during the entire oxidation process.Therefore,the combination of aluminizing and LSP treatments can improve the high-temperature oxidation resistance of 321 stainless steel,providing a new idea for its surface treatment to achieve a long service life at high temperatures.展开更多
The effects of niobium on the high-temperature oxidation resistance of austenitic stainless steel were systematically investigated.Two austenitic stainless steels with different Nb contents were prepared and exposed t...The effects of niobium on the high-temperature oxidation resistance of austenitic stainless steel were systematically investigated.Two austenitic stainless steels with different Nb contents were prepared and exposed to air at 850℃for 200 h.Results show that Nb positively affects the high-temperature oxidation resistance of austenitic stainless steels.The matrix organization of austenitic stainless steels with added niobium does not change,while the austenitic grain size is significantly refined,and it also promoted the release of internal stresses in the oxide film,which in turn improved the integrity of the oxide film and adhesion to the substrate.In addition,with the addition of Nb element,a large number of Nb(C,N)particles are diffusely distributed in the matrix.Nb(C,N)phase distributed in the matrix and the niobium-rich layer formed by the diffusion of niobium into the interface between the metal matrix and the oxide film during the high-temperature oxidation process effectively prevents the diffusion of iron into the outer layer and enhances the oxidation resistance at high temperatures.展开更多
Rare-earth elements(REEs)received special attention and widespread application because of their extremely active chemical property.Many researches demonstrated that doping of REEs(Y,La and Ce)in superalloys can signif...Rare-earth elements(REEs)received special attention and widespread application because of their extremely active chemical property.Many researches demonstrated that doping of REEs(Y,La and Ce)in superalloys can significantly improve the high temperature oxidation resistance,corrosion resistance and mechanical properties,which are recognized as a promising route to broaden the manufacturing process window and enhance the overall performance of next-generation superalloys.The first part of this review described the special behavior of REEs during the metallurgical solidification process,including the REEs loss in the melt and the macro-segregation phenomenon.The second part summarized a broad spectrum of works reporting the dual role of REEs addition on the mechanical properties of superalloys.The third part overviewed the effect of REEs on the anti-oxidation resistance of the fourth and fifth nickel-based superalloys.Finally,the prospect of development of REEs-containing superalloys was discussed.展开更多
This work investigated the effect of Cr and Si on the mechanical properties and oxidation resistance of press hardened steel.Results indicated that the microstructure of the Cr-Si micro-alloyed press hardened steel co...This work investigated the effect of Cr and Si on the mechanical properties and oxidation resistance of press hardened steel.Results indicated that the microstructure of the Cr-Si micro-alloyed press hardened steel consisted of lath martensite,M_(23)C_(6)carbides,and retained austenite.The retained austenite and carbides are responsible for the increase in elongation of the micro-alloyed steel.In addition,after oxidation at 930℃for 5 min,the thickness of the oxide scales on the Cr-Si micro-alloyed press hardened steel is less than 5μm,much thinner than 45.50μm-thick oxide scales on 22MnB5.The oxide scales of the Cr-Si micro-alloyed steel are composed of Fe_(2)O_(3),Fe_(3)O_(4),mixed spinel oxide(FeCr_(2)O_(4)and Fe_(2)SiO_(4)),and amorphous SiO_(2).Adding Cr and Si significantly reduces the thickness of the oxide scales and prevents the generation of the FeO phase.Due to the increase of spinel FeCr_(2)O_(4)and Fe_(2)SiO_(4)phase in the inner oxide scale and the amorphous SiO_(2)close to the substrate,the oxidation resistance of the Cr-Si micro-alloyed press hardened steel is improved.展开更多
Carbon materials(graphite or C/C composites)are widely used in aerospace applications due to their unique performance advantages,including low density,high specific strength and low coefficients of thermal expansion.H...Carbon materials(graphite or C/C composites)are widely used in aerospace applications due to their unique performance advantages,including low density,high specific strength and low coefficients of thermal expansion.However,carbon materials are highly susceptible to destructive oxidation in high-temperature oxygen-containing environments,limiting their application scope and service life.Coating technology is an effective approach for solving the above problem,and ceramic coatings are the most widely used protective system.In this review,the latest research progress regarding different types of silicon carbide-based antioxidation and anti-ablation ceramic coatings on the surfaces of carbon materials is described,and the protective properties and mechanism analysis of the SiC and modified SiC coatings by ultrahigh-temperature ceramic borides,carbides,silicides and other reinforcements are elucidated.In addition,the current main challenges of ceramic coatings are carefully analysed,and the perspectives for the future development of ceramic protection coatings are also discussed.展开更多
The high-temperature oxidation resistance of the nickel superalloy prepared by the laser powder bed fusion(LPBF)has been significantly increased as a result of in-situ formation of a thermal barrier layer(α-Al_(2)O_(...The high-temperature oxidation resistance of the nickel superalloy prepared by the laser powder bed fusion(LPBF)has been significantly increased as a result of in-situ formation of a thermal barrier layer(α-Al_(2)O_(3)+CaMoO4)during oxidative annealing of surface layers modified by electric spark treatment(EST).The reactive EST of the LPBF-built items based on nickel EP741NP alloy was carried out with low-melting Al−12%Si,Al−6%Ca−0.6%Si and Al−7%Ca−1%Mn electrodes.It was found that under EST done by Al−7%Ca−1%Mn electrode an intermetallic(β-NiAl+γ'-Ni3Al)15μm-thick layer reinforced by spherical oxide(CaMe)O nanoparticles was formed.Formation of that structure increases the wear resistance of LPBF nickel superalloy by 4.5 times.Further oxidative annealing at 1000°C leads to a formation of continuous two-layered coating with an inner layer ofα-Al_(2)O_(3) and an outer layer of CaMoO4,which together act as an effective barrier preventing the diffusion of oxygen into the bulk of the superalloy.展开更多
Oxidation resistance enhancement of pure Ti often comes at the cost of reduced ductility,which is frequently the problem through alloying with sole Al,Si,W,Mo and B.To overcome the short coming of single element alloy...Oxidation resistance enhancement of pure Ti often comes at the cost of reduced ductility,which is frequently the problem through alloying with sole Al,Si,W,Mo and B.To overcome the short coming of single element alloying,this paper proposes a multi-element low-alloying strategy to take advantage of synergistic effects and resolve the conflict between oxidation resistance and ductility.It demonstrates that the addition of a small quantity of Ta(0.51wt%)can boost both oxidation resistance and ductility in comparison to pure Ti.Furthermore,the combined addition of a small amount(0.54 wt%)of Ta,Nb and Si not only preserves good ductility of pure Ti,but also reduces mass gains to 14%-67%of pure Ti during 100 h oxidation at 650-850℃in air.This indicates even better oxidation resistance than that obtained through the use of Ta,Nb,or Nb+Ta additions.The Ta+Nb+Si alloying creates an oxide layer that is less porous and more resistant to stratification and spalling.Consequently,a 3-μm N-rich layer can form in the Ti substrate beneath the oxide scale,in which phase transformation generates coherent Ti_(2)N with(0001)_(Ti)as the habit plane,with N atoms prefers to diffuse along■than along[0001]_(Ti).The completely transformed Ti_(2)N region or partially transformed Ti+Ti_(2)N region can effectively impede oxygen invasion.Therefore,the multielement low-alloying strategy is promising for enhancing both oxidation resistance and mechanical properties of metallic materials in the future.展开更多
In this paper,the isothermal oxidation experiments were used to study the effect of Ag on the high-temperature oxidation behavior of Mg-6.5Gd-5.6Y-0.1Nd-0.01Ce-0.4Zr(wt%)alloy oxidized at 350℃,400℃ and 450℃ for 120...In this paper,the isothermal oxidation experiments were used to study the effect of Ag on the high-temperature oxidation behavior of Mg-6.5Gd-5.6Y-0.1Nd-0.01Ce-0.4Zr(wt%)alloy oxidized at 350℃,400℃ and 450℃ for 120 h.The results show that the oxidation weight gain of the alloy mainly occurs in the early oxidation stage(0-20 h).This reason attributes to the lack of protective oxide film and the rapid inward diffusion of oxygen through the macroscopic defects of the incomplete oxide film.When dense oxide films such as Y_(2)O_(3),Gd_(2)O_(3),and ZrO2 form,they hinder the inward transport of oxygen ions and improve the high-temperature oxidation resistance of the alloy.In addition,the role of the Ag element at three temperatures is different.The addition of Ag mainly promotes the formation of eutectic phases such as Mg3Gd,Mg24Y5,and Ag2Gd,which reduces the content of Gd and Y elements in the alloy matrix,resulting in a decrease in the diffusion rate of Gd and Y elements during the oxidation process at 350℃ and 400℃,and weakens the oxidation resistance of Ag-containing alloys.However,in the oxidation experiment at 450℃,a large amount of eutectic phase is solid dissolved into the matrix,reducing the difference in element content.At this time,it is detected that the Ag element promoted the outward diffusion of Gd and Y elements,accelerating the formation of the oxide film.The oxidation resistance of Ag-containing alloys is improved.展开更多
To solve the problem of poor high-temperature service performance caused by low carbonization of MgO-C refractories,low-carbon MgO–C refractories with excellent thermal shock,oxidation and corrosion resistances were ...To solve the problem of poor high-temperature service performance caused by low carbonization of MgO-C refractories,low-carbon MgO–C refractories with excellent thermal shock,oxidation and corrosion resistances were successfully designed by using SiC whiskers as reinforcing phases and introducing micro-Al_(2)O_(3) powders as additives.The results indicated that the addition of micro-Al_(2)O_(3) powders optimized the internal structure of the material,like the columnar β-Si_(3)N_(4) with a stepped distribution and the mosaic structure formed between granular and flaky Mg_(2)SiO_(4),which synergistically strengthened and toughened the material and gave the material excellent mechanical properties and thermal shock resistance.Specifically,the cold modulus of rupture and cold crushing strength after thermal shock were increased by 4.1 and 20.3 MPa,respectively.Moreover,the addition of micro-Al_(2)O_(3) powders promoted the formation of fine particles of Mg_(2)SiO_(4),MgAl_(2)O_(4) and MgO,as well as a dense protective layer of Mg_(2)SiO_(4) in the material under high-temperature environment.Furthermore,spinel and high-temperature solid solution were formed in the corrosion environment.The oxidation and corrosion resistances were greatly improved by 41%and 15%,respectively.展开更多
ZrB_(2)-based ceramic composites were prepared by spark plasma sintering using ZrB_(2) powder prepared by molten salt method as raw material and SiC and nano-graphite as additives.The effects of nano-graphite addition...ZrB_(2)-based ceramic composites were prepared by spark plasma sintering using ZrB_(2) powder prepared by molten salt method as raw material and SiC and nano-graphite as additives.The effects of nano-graphite addition on the physical properties and oxidation resistance of ZrB_(2)-based ceramic samples were investigated.The results show that the addition of an appropriate amount of nano-graphite can effectively improve the density of ZrB_(2)-based ceramic composites and improve the physical properties of the materials.The flexural strength of the ceramic sample with 8 vol.%nano-graphite reached 418.54 MPa,which was 53.14% higher than that of ZrB_(2)-SiC ceramic material(273.31 MPa),and its oxidation resistance was also significantly improved.It demonstrats that the addition of an appropriate amount of nano-graphite can effectively improve the physical properties and oxidation resistance of ZrB_(2)-SiC ceramic composites.Via prolonging its service life in application and promoting the development of ZrB_(2)-based ceramic composites,it is of great significance for clean steel smelting.展开更多
In this work,possible short-term thermal exposure oxidation in hot processing including semi-solid processing is focused.We aim to investigate the short-term oxidation behavior of a novel powder metallurgy Al_(0.8)Co_...In this work,possible short-term thermal exposure oxidation in hot processing including semi-solid processing is focused.We aim to investigate the short-term oxidation behavior of a novel powder metallurgy Al_(0.8)Co_(0.5)Cr_(1.5)CuFeNi high entropy alloy(HEA)in high-temperature solid(1000-1100℃)and semi-solid(1125-1225℃)intervals.From 1000 to 1225℃,mass gain increases from 0.31 to 0.45 mg cm^(-2)after 60 min oxidation,presenting superior oxidation resistance in the semi-solid state compared with other semi-solid alloys.Equiaxedα-Al_(2)O_(3)grains are the predominant component of oxide scales and no obvious internal oxidation layer occurs in both solid and semi-solid intervals.Al_(2)O_(3)scale growth is predominantly determined by outward Al^(3+)diffusion.For solid oxidation,different scale formation kinetics occur on various phases and the BCC(B2)phase has faster scale formation kinetics.This is attributed to outward Al^(3+)diffusion rate differences in various component systems.During semi-solid oxidation,the increased degree of chaos and number of vacancies in the liquid phase provide a diffusion channel,leading to rapid Al_(2)O_(3)formation.Oxidation resistance in the semi-solid state is attributed to dense Al_(2)O_(3)scales formed through selective oxidation of Al.展开更多
To protect carbon materials from oxidation, mullite/SiC coatings were prepared on graphite by chemical vapor reaction (CVR) and slurry sintering. The XRD analyses show that the phase of the outer-layer coating is comp...To protect carbon materials from oxidation, mullite/SiC coatings were prepared on graphite by chemical vapor reaction (CVR) and slurry sintering. The XRD analyses show that the phase of the outer-layer coating is composed of SiO2 and mullite, and the inner-layer coating is mainly composed of β-SiC. The anti-oxidation behavior of the coating and the Rockwell hardness (HRB) of the coating after oxidation were investigated. The oxidation test shows that the as-prepared multi-layer coating exhibits excellent antioxidation and thermal shock resistance at high temperature. After oxidation at 1150 ℃ for 109 h and thermal shock cycling between 1150 ℃ and room temperature for 12 times, the mass gain of the coated sample is 0.085%. Meanwhile, the indentation tests also demonstrate that the as-prepared coating has good bonding ability between the layers.展开更多
To improve the oxidation resistance of carbon/carbon （C/C） composites in air at high temperatures, a SiC- MoSi2/ZrO2-MoSi2 coating was prepared on the surface of C/C composites by pack cementation and slurry method....To improve the oxidation resistance of carbon/carbon （C/C） composites in air at high temperatures, a SiC- MoSi2/ZrO2-MoSi2 coating was prepared on the surface of C/C composites by pack cementation and slurry method. The microstructures and phase compositions of the coated C/C composites were analyzed by scanning electron microscopy and X-ray diffraction, respectively. The result shows that the SiC-MoSi2/ZrO2-MoSi2 coating is dense and crack-free with a thickness of 250-300 μm. The preparation and the high temperature oxidation property of the coated composites were investigated. The as-received coating has excellent oxidation protection ability and can protect C/C composites from oxidation for 260 h at 1773 K in air. The excellent anti-oxidation performance of the coating is considered to come from the formation of ZrSiO4, which improves the stability of the coating at high temperatures.展开更多
In order to protect C/C composites from oxidation, SiC-MoSi2 composite coating was synthesized by chemical vapor infiltration /reaction （CVI/CVR） technology. A porous Mo layer was prefabricated on SiC coated C/C com...In order to protect C/C composites from oxidation, SiC-MoSi2 composite coating was synthesized by chemical vapor infiltration /reaction （CVI/CVR） technology. A porous Mo layer was prefabricated on SiC coated C/C composites, and then MoSi2 and SiC were subsequently prepared in a CVI /CVR process using methyltrichlorosilane （MTS） as precursor. The deposition and reaction mechanism of the MoSi2-SiC composite coating was investigated by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The oxidation behavior of SiC-MoSi2 coated specimens was tested. The results show that the porous Mo layer can be densified with SiC phase decomposed from MTS, and transformed into SiC-MoSi2 by reacting with MTS as well. A dense composite coating was prepared with optimized deposition parameters. The coated specimen exhibits a good oxidation resistance with a little mass loss of 1.25% after oxidation at 1500 °C for 80 h.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U21B2053,52071114,52001100,and 523B2010)Outstanding Youth Project of Natural Science Foundation of Heilongjiang Province(No.YQ2023E008)+1 种基金Young Elite Scientists Sponsorship Program by CAST(NO.2021QNRC001)Heilongjiang Touyan Team Program.
文摘Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy.However,the long-term protective property of single silicide coating remains a long-time endeavor due to the deficiency of oxygen-consuming phases,as well as the self-healing ability of the protective layer.Herein,a silicide-based composite coating is constructed on niobium alloy by incor-poration of nano-SiC particles for enhancing the high-temperature oxidation resistance.Isothermal oxi-dation results at 1250℃ for 50 h indicate that NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multilayer coated sample with a low mass gain of 2.49 mg/cm^(2) shows an improved oxidation resistance compared with NbSi_(2) coating(6.49 mg/cm^(2)).The enhanced high-temperature antioxidant performance of NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multi-layer coating is mainly attributed to the formation of the protective SiO_(2) self-healing film and the high-temperature diffusion behavior of NbSi_(2)/substrate.
基金financial supports from Shanxi Provincial Natural Science Foundation,China(No.20210302123162)Shanxi Scholarship Council of China(No.2024-057)+2 种基金State Key Laboratory of Advanced Metal Materials,China(No.2019-ZD02)Science and Technology Achievement Transformation and Cultivation Project of Shanxi,China(No.2020CG011)Shanxi“1331 Project”Quality Improvement and Efficiency Project,China。
文摘A Cr/CoNiCrAlTaY bilayer coating was prepared on the Ti-45Al-8.5Nb alloy by plasma surface metallurgy technique.The as-prepared coating with a grain size of~2μm exhibited a dense microstructure and strong adhesion due to metallurgical bonding,consisting of outermost Cr layer and CoNiCrAlTaY transition layer.The typical power-law relationship between mass gain and time was obtained for the coated specimens with a rate exponent of 3.18 following oxidation at 1173 K.The top Cr_(2)O_(3)film and spinel oxides(i.e.,NiCr_(2)O_(4)and CoCr_(2)O_(4))exhibited a protective effect with a low oxidation reaction rate.Interfacial analysis identified Ta precipitates(Cr_(2)Ta and TaAl_(3))and Ta oxides(Ta_(2)O_(5)and Ta_(2)O_(3)),which played an essential role in retarding rapid diffusion and enhancing adhesion and oxidation resistance.
基金National Natural Science Foundation of China(52071126)Natural Science Foundation of Tianjin City,China(22JCQNJC01240)+2 种基金Central Guidance on Local Science and Technology Development Fund of Hebei Province(226Z1009G)Special Funds for Science and Technology Innovation in Hebei(2022X19)Anhui Provincial Natural Science Foundation(2308085ME135)。
文摘Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,as well as the wear resistance of the coatings.Besides,the effect of changing the laser melting process on the coatings was also investigated.The oxidation mass gain at 800–1200℃and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied.Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation.After oxidizing at 1000℃for 1 h,the thickness of the oxide layer of the uncoated sample was 241.0μm,whereas that of the sample with Co-based coating is only 11.8–35.5μm.The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate,indicating that the hardness and wear resistance of the Zr substrate are greatly improved.The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt%NaCl solution.
文摘To improve the oxidation resistance of HfB_(2)-SiC coatings on carbon/carbon composites at 1700°C in air,CeO_(2) was introduced to improve oxygen blocking and its mechanism was investigated.During the rapid oxidation stage,CeO_(2) accelerated the formation of a multiphase glass layer on the coating surface.The maximum oxidation rates of CeO_(2)-HfB2-SiC coatings with 1%,3%,and 5%CeO_(2) were 24.1%,20.3%,and 53.2%higher than that of the unmodified HfB2-SiC coating,respectively.In the stable oxidation stage,the maximum oxidation rates of coatings with 1%and 3%CeO_(2) decreased by 31.4%and 21.9%,respectively,demonstrating adequate inert protection.CeO_(2) is a“coagulant”and“stabilizer”in the composite glass layer.However,increasing the CeO_(2) content accelerates the reaction between the SiO_(2) glass phase and SiC,leading to a higher SiO_(2) consumption and reduced self-healing ability of the glass layer.The 1%CeO_(2)-60%HfB2-39%SiC coating showed improved glass layer viscosity and stability,moderate SiO_(2) consumption,and better self-healing ability,significantly boosting the oxidation protection of the coating.
基金supported by the University Synergy Innovation Program of Anhui Province(Grant Nos.GXXT-2023-025 and GXXT-2023-026)Natural Science Foundation of Anhui Province(Grant Nos.2008085ME149,2308085QE132 and 2308065ME171)Anhui University Scientific Research Project(Grant Nos.2022AH040247,2023AH051660,2023AH051670 and 2023AH051671).
文摘To improve the high-temperature service properties of coppery tuyere,Co06 coating with a Ni60A interlayer was prepared on copper by plasma cladding.Ni60A interlayer acted as a bridge to promote the element diffusion,thus achieving metallurgical bonding.Due to the strengthening effect ofγ-Co,Cr_(23)C_(6)and Cr_(7)C_(3)phases,the wear resistance of Co06–Ni60A coating was much higher than that of copper substrate.As the temperature increased,the wear resistance of coating decreased first and then increased.The coating exhibited better wear resistance at 600℃ due to the oxidation wear mechanism.Compared with copper substrate and Ni60A,the oxidation resistance of Co06 was increased by 6.0 and 1.9 times,respectively.For melting loss resistance,Co06–Ni60A coating was superior to Ni60A single-layer coating,but the molten iron can still form a micro-metallurgical bonding with the coating surface.
基金supported by the Class Ⅲ Peak Discipline of Shanghai,China-Materials Science and Engineering(High-Energy Beam Intelligent Processing and Green Manufacturing).
文摘Laser shock peening(LSP)was used to enhance the high-temperature oxidation resistance of laser melting deposited Ti45Al8Nb alloy.The microstructure and high-temperature oxidation behavior of the as-deposited Ti45Al8Nb alloy before and after LSP were investigated by scanning electron microscopy,X-ray diffraction,and electron backscatter diffraction.The results indicated that the rate of mass gain in the as-deposited sample after LSP exhibited a decrease when exposed to an oxidation temperature of 900℃,implying that LSP-treated samples exhibited superior oxidation resistance at high temperatures.A gradient structure with a fine-grain layer,a deformed-grain layer,and a coarse-grain layer was formed in the LSP-treated sample,which facilitated the diffusion of the Al atom during oxidation,leading to the formation of a dense Al_(2)O_(3)layer on the surface.The mechanism of improvement in the oxidation resistance of the as-deposited Ti45Al8Nb alloy via LSP was discussed.
基金Supported by National Natural Science Foundation of China(Grant Nos.52075048,51675058,12232004)Hunan Provincial Excellent Youth Project of the Education Department(Grant No.21B0304)+2 种基金Natural Science Foundation of Hunan Province(Grant No.2023JJ30025)Science and Technology Innovation Program of Hunan Province(Grant No.2023RC1058)Scientific Research Innovation Project for Graduate Student of Changsha University of Science and Technology(Grant No.CLSJCX22096)。
文摘The high-temperature oxidation resistance of AISI 321 stainless steel used in solar thermal power heat exchangers determines its service life.In this study,aluminizing and subsequent laser shock peening(LSP)treatments were employed to improve the high-temperature oxidation resistance of AISI 321 stainless steel at 620°C.These two treatments decreased the oxidation rate of AISI 321 steel.Specifically,the optimal oxidation resistance was observed in aluminized steel before oxidation for 144 h owing to the increased entropy of the LSP-treated specimen.After 144 h,LSP-treated steel achieved the best oxidation resistance because of the formation of a protectiveα-Al2O3film.Moreover,the large amount of subgrain boundaries formed on the aluminized layer of the LSP-treated samples could act as short-circuit paths for the outward diffusion of Al,facilitating the rapid nucleation ofα-Al2O3.Meanwhile,the aluminized layer could isolate the contact between the oxidation environment and matrix,thereby decreasing the oxidation rate.Furthermore,the minimum oxidation parabolic constant was calculated for LSP-treated steel(6.45787×10^(-14)),which was 69.18%and 36.36%that of aluminized and 321 steel,respectively,during the entire oxidation process.Therefore,the combination of aluminizing and LSP treatments can improve the high-temperature oxidation resistance of 321 stainless steel,providing a new idea for its surface treatment to achieve a long service life at high temperatures.
基金support of this work by the Major Program of Science and Technology in Shanxi Province(202202050201019)the National Natural Science Foundation of China(52271067)Shaanxi Outstanding Youth Fund Project(2021JC-45).
文摘The effects of niobium on the high-temperature oxidation resistance of austenitic stainless steel were systematically investigated.Two austenitic stainless steels with different Nb contents were prepared and exposed to air at 850℃for 200 h.Results show that Nb positively affects the high-temperature oxidation resistance of austenitic stainless steels.The matrix organization of austenitic stainless steels with added niobium does not change,while the austenitic grain size is significantly refined,and it also promoted the release of internal stresses in the oxide film,which in turn improved the integrity of the oxide film and adhesion to the substrate.In addition,with the addition of Nb element,a large number of Nb(C,N)particles are diffusely distributed in the matrix.Nb(C,N)phase distributed in the matrix and the niobium-rich layer formed by the diffusion of niobium into the interface between the metal matrix and the oxide film during the high-temperature oxidation process effectively prevents the diffusion of iron into the outer layer and enhances the oxidation resistance at high temperatures.
基金supported by the National Science and Technology Major Project(Nos.J2019-VI-0023-0139 and J2019-VII-0004-0144)the National Key R&D Program of China(No.2020YFA0714904).
文摘Rare-earth elements(REEs)received special attention and widespread application because of their extremely active chemical property.Many researches demonstrated that doping of REEs(Y,La and Ce)in superalloys can significantly improve the high temperature oxidation resistance,corrosion resistance and mechanical properties,which are recognized as a promising route to broaden the manufacturing process window and enhance the overall performance of next-generation superalloys.The first part of this review described the special behavior of REEs during the metallurgical solidification process,including the REEs loss in the melt and the macro-segregation phenomenon.The second part summarized a broad spectrum of works reporting the dual role of REEs addition on the mechanical properties of superalloys.The third part overviewed the effect of REEs on the anti-oxidation resistance of the fourth and fifth nickel-based superalloys.Finally,the prospect of development of REEs-containing superalloys was discussed.
基金The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China(Nos.52274372 and 52201101)the National Key R&D Program of China(No.2021YFB3702404)the Fundamental Research Funds for the Central Universities(No.FRF-TP-22-013A1).
文摘This work investigated the effect of Cr and Si on the mechanical properties and oxidation resistance of press hardened steel.Results indicated that the microstructure of the Cr-Si micro-alloyed press hardened steel consisted of lath martensite,M_(23)C_(6)carbides,and retained austenite.The retained austenite and carbides are responsible for the increase in elongation of the micro-alloyed steel.In addition,after oxidation at 930℃for 5 min,the thickness of the oxide scales on the Cr-Si micro-alloyed press hardened steel is less than 5μm,much thinner than 45.50μm-thick oxide scales on 22MnB5.The oxide scales of the Cr-Si micro-alloyed steel are composed of Fe_(2)O_(3),Fe_(3)O_(4),mixed spinel oxide(FeCr_(2)O_(4)and Fe_(2)SiO_(4)),and amorphous SiO_(2).Adding Cr and Si significantly reduces the thickness of the oxide scales and prevents the generation of the FeO phase.Due to the increase of spinel FeCr_(2)O_(4)and Fe_(2)SiO_(4)phase in the inner oxide scale and the amorphous SiO_(2)close to the substrate,the oxidation resistance of the Cr-Si micro-alloyed press hardened steel is improved.
基金supported by the“Jie Bang Gua Shuai”of Science and technology Projects of Liaoning Province in 2021,grant number 2021JH1/10400091Liao Ning Revitalization Talents Program,grant number XLYC2005002+3 种基金Liaoning BaiQianWan Talents Program,grant number[2020]78Scientific Research Funding Project of the Educational Department of Liaoning Province in 2020,grant number LZ2020002Shenyang Science and Technology Program-Major Key Core Technology Project,grant number 20-202-1-15Provincial Doctoral Research Initiation Fund Program,grant number 2021-BS-187.
文摘Carbon materials(graphite or C/C composites)are widely used in aerospace applications due to their unique performance advantages,including low density,high specific strength and low coefficients of thermal expansion.However,carbon materials are highly susceptible to destructive oxidation in high-temperature oxygen-containing environments,limiting their application scope and service life.Coating technology is an effective approach for solving the above problem,and ceramic coatings are the most widely used protective system.In this review,the latest research progress regarding different types of silicon carbide-based antioxidation and anti-ablation ceramic coatings on the surfaces of carbon materials is described,and the protective properties and mechanism analysis of the SiC and modified SiC coatings by ultrahigh-temperature ceramic borides,carbides,silicides and other reinforcements are elucidated.In addition,the current main challenges of ceramic coatings are carefully analysed,and the perspectives for the future development of ceramic protection coatings are also discussed.
基金supported by the Ministry of Science and Higher Education of the Russian Federation under State Research Assignment(No.0718-2020-0034)Development Program of MISIS(No.K7-2023-009)within the Framework Strategic Academic Leadership Program"Priority-2030".
文摘The high-temperature oxidation resistance of the nickel superalloy prepared by the laser powder bed fusion(LPBF)has been significantly increased as a result of in-situ formation of a thermal barrier layer(α-Al_(2)O_(3)+CaMoO4)during oxidative annealing of surface layers modified by electric spark treatment(EST).The reactive EST of the LPBF-built items based on nickel EP741NP alloy was carried out with low-melting Al−12%Si,Al−6%Ca−0.6%Si and Al−7%Ca−1%Mn electrodes.It was found that under EST done by Al−7%Ca−1%Mn electrode an intermetallic(β-NiAl+γ'-Ni3Al)15μm-thick layer reinforced by spherical oxide(CaMe)O nanoparticles was formed.Formation of that structure increases the wear resistance of LPBF nickel superalloy by 4.5 times.Further oxidative annealing at 1000°C leads to a formation of continuous two-layered coating with an inner layer ofα-Al_(2)O_(3) and an outer layer of CaMoO4,which together act as an effective barrier preventing the diffusion of oxygen into the bulk of the superalloy.
基金financially supported by the National Natural Science Foundation of China(No.52271088)Beijing Nova Program(2022 Beijing Nova Program Cross Cooperation Program No.20220484178)the National Key R&D Program of China(No.2016YFB0301200)。
文摘Oxidation resistance enhancement of pure Ti often comes at the cost of reduced ductility,which is frequently the problem through alloying with sole Al,Si,W,Mo and B.To overcome the short coming of single element alloying,this paper proposes a multi-element low-alloying strategy to take advantage of synergistic effects and resolve the conflict between oxidation resistance and ductility.It demonstrates that the addition of a small quantity of Ta(0.51wt%)can boost both oxidation resistance and ductility in comparison to pure Ti.Furthermore,the combined addition of a small amount(0.54 wt%)of Ta,Nb and Si not only preserves good ductility of pure Ti,but also reduces mass gains to 14%-67%of pure Ti during 100 h oxidation at 650-850℃in air.This indicates even better oxidation resistance than that obtained through the use of Ta,Nb,or Nb+Ta additions.The Ta+Nb+Si alloying creates an oxide layer that is less porous and more resistant to stratification and spalling.Consequently,a 3-μm N-rich layer can form in the Ti substrate beneath the oxide scale,in which phase transformation generates coherent Ti_(2)N with(0001)_(Ti)as the habit plane,with N atoms prefers to diffuse along■than along[0001]_(Ti).The completely transformed Ti_(2)N region or partially transformed Ti+Ti_(2)N region can effectively impede oxygen invasion.Therefore,the multielement low-alloying strategy is promising for enhancing both oxidation resistance and mechanical properties of metallic materials in the future.
基金supported by the National Key Research and Development Program of China(No.2021YFB3701100)the National Key Research and Development Program of China(No.2016YFB0301105)+2 种基金the Applied Basic Research Program Project of Liaoning Province of China(No.2023020253-JH2/1016)the Key Research and Development Plan of Shanxi Province(No.202102050201005)the Dongguan Innovative Research Team Program(No.2020607134012).
文摘In this paper,the isothermal oxidation experiments were used to study the effect of Ag on the high-temperature oxidation behavior of Mg-6.5Gd-5.6Y-0.1Nd-0.01Ce-0.4Zr(wt%)alloy oxidized at 350℃,400℃ and 450℃ for 120 h.The results show that the oxidation weight gain of the alloy mainly occurs in the early oxidation stage(0-20 h).This reason attributes to the lack of protective oxide film and the rapid inward diffusion of oxygen through the macroscopic defects of the incomplete oxide film.When dense oxide films such as Y_(2)O_(3),Gd_(2)O_(3),and ZrO2 form,they hinder the inward transport of oxygen ions and improve the high-temperature oxidation resistance of the alloy.In addition,the role of the Ag element at three temperatures is different.The addition of Ag mainly promotes the formation of eutectic phases such as Mg3Gd,Mg24Y5,and Ag2Gd,which reduces the content of Gd and Y elements in the alloy matrix,resulting in a decrease in the diffusion rate of Gd and Y elements during the oxidation process at 350℃ and 400℃,and weakens the oxidation resistance of Ag-containing alloys.However,in the oxidation experiment at 450℃,a large amount of eutectic phase is solid dissolved into the matrix,reducing the difference in element content.At this time,it is detected that the Ag element promoted the outward diffusion of Gd and Y elements,accelerating the formation of the oxide film.The oxidation resistance of Ag-containing alloys is improved.
基金the Scientific Research Fund of Hunan Provincial Education Department(22B0856)the Hengyang"Xiaohe"Science and Technology Talent Special Project([2023]45)+3 种基金the Guidance Plan Project of Hengyang City([2023]40)the National Natural Science Foundation of China(U20A20239)the College Students'Innovation and Entrepreneurship Training Project(S202311528055)the Characteristic Application Discipline of Material Science Engineering in Hunan Province([2022]351).
文摘To solve the problem of poor high-temperature service performance caused by low carbonization of MgO-C refractories,low-carbon MgO–C refractories with excellent thermal shock,oxidation and corrosion resistances were successfully designed by using SiC whiskers as reinforcing phases and introducing micro-Al_(2)O_(3) powders as additives.The results indicated that the addition of micro-Al_(2)O_(3) powders optimized the internal structure of the material,like the columnar β-Si_(3)N_(4) with a stepped distribution and the mosaic structure formed between granular and flaky Mg_(2)SiO_(4),which synergistically strengthened and toughened the material and gave the material excellent mechanical properties and thermal shock resistance.Specifically,the cold modulus of rupture and cold crushing strength after thermal shock were increased by 4.1 and 20.3 MPa,respectively.Moreover,the addition of micro-Al_(2)O_(3) powders promoted the formation of fine particles of Mg_(2)SiO_(4),MgAl_(2)O_(4) and MgO,as well as a dense protective layer of Mg_(2)SiO_(4) in the material under high-temperature environment.Furthermore,spinel and high-temperature solid solution were formed in the corrosion environment.The oxidation and corrosion resistances were greatly improved by 41%and 15%,respectively.
基金the project supported by the Natural Science Foundation of Hubei Province(Grant No.2023BAB106)the National Natural Science Foundation of China(Grant No.U20A20239)the Scientific Research Project of Education Department of Hubei Province(D20211104).
文摘ZrB_(2)-based ceramic composites were prepared by spark plasma sintering using ZrB_(2) powder prepared by molten salt method as raw material and SiC and nano-graphite as additives.The effects of nano-graphite addition on the physical properties and oxidation resistance of ZrB_(2)-based ceramic samples were investigated.The results show that the addition of an appropriate amount of nano-graphite can effectively improve the density of ZrB_(2)-based ceramic composites and improve the physical properties of the materials.The flexural strength of the ceramic sample with 8 vol.%nano-graphite reached 418.54 MPa,which was 53.14% higher than that of ZrB_(2)-SiC ceramic material(273.31 MPa),and its oxidation resistance was also significantly improved.It demonstrats that the addition of an appropriate amount of nano-graphite can effectively improve the physical properties and oxidation resistance of ZrB_(2)-SiC ceramic composites.Via prolonging its service life in application and promoting the development of ZrB_(2)-based ceramic composites,it is of great significance for clean steel smelting.
基金supported by the National Natural Science Foun-dation of China(NSFC)under Grant No.52071113.
文摘In this work,possible short-term thermal exposure oxidation in hot processing including semi-solid processing is focused.We aim to investigate the short-term oxidation behavior of a novel powder metallurgy Al_(0.8)Co_(0.5)Cr_(1.5)CuFeNi high entropy alloy(HEA)in high-temperature solid(1000-1100℃)and semi-solid(1125-1225℃)intervals.From 1000 to 1225℃,mass gain increases from 0.31 to 0.45 mg cm^(-2)after 60 min oxidation,presenting superior oxidation resistance in the semi-solid state compared with other semi-solid alloys.Equiaxedα-Al_(2)O_(3)grains are the predominant component of oxide scales and no obvious internal oxidation layer occurs in both solid and semi-solid intervals.Al_(2)O_(3)scale growth is predominantly determined by outward Al^(3+)diffusion.For solid oxidation,different scale formation kinetics occur on various phases and the BCC(B2)phase has faster scale formation kinetics.This is attributed to outward Al^(3+)diffusion rate differences in various component systems.During semi-solid oxidation,the increased degree of chaos and number of vacancies in the liquid phase provide a diffusion channel,leading to rapid Al_(2)O_(3)formation.Oxidation resistance in the semi-solid state is attributed to dense Al_(2)O_(3)scales formed through selective oxidation of Al.
基金Project (2012M511752) supported by China Postdoctoral Science FoundationProject (2011CB605801) supported by the National Basical Research Program of China+3 种基金Project (2012QNZT004) supported by the Fundamental Research Funds of the Central Universities, ChinaProject supported by the Freedom Explore Program of Central South University, ChinaProject (CSUZC2012026) supported by the Open-End Fund for the Valuable and Precision Instruments of Central South University, ChinaProject supported by the Postdoctoral Science Foundation of Central South University, China
文摘To protect carbon materials from oxidation, mullite/SiC coatings were prepared on graphite by chemical vapor reaction (CVR) and slurry sintering. The XRD analyses show that the phase of the outer-layer coating is composed of SiO2 and mullite, and the inner-layer coating is mainly composed of β-SiC. The anti-oxidation behavior of the coating and the Rockwell hardness (HRB) of the coating after oxidation were investigated. The oxidation test shows that the as-prepared multi-layer coating exhibits excellent antioxidation and thermal shock resistance at high temperature. After oxidation at 1150 ℃ for 109 h and thermal shock cycling between 1150 ℃ and room temperature for 12 times, the mass gain of the coated sample is 0.085%. Meanwhile, the indentation tests also demonstrate that the as-prepared coating has good bonding ability between the layers.
基金Projects(51221001,51222207)supported by the National Natural Science Foundation of ChinaProject(090677)supported by the Program for New Century Excellent Talents in University of ChinaProject(B08040)supported by Program of Introducing Talents of Discipline to Universities,China
文摘To improve the oxidation resistance of carbon/carbon （C/C） composites in air at high temperatures, a SiC- MoSi2/ZrO2-MoSi2 coating was prepared on the surface of C/C composites by pack cementation and slurry method. The microstructures and phase compositions of the coated C/C composites were analyzed by scanning electron microscopy and X-ray diffraction, respectively. The result shows that the SiC-MoSi2/ZrO2-MoSi2 coating is dense and crack-free with a thickness of 250-300 μm. The preparation and the high temperature oxidation property of the coated composites were investigated. The as-received coating has excellent oxidation protection ability and can protect C/C composites from oxidation for 260 h at 1773 K in air. The excellent anti-oxidation performance of the coating is considered to come from the formation of ZrSiO4, which improves the stability of the coating at high temperatures.
基金Projects(51221001,51272213,51072166)supported by the National Natural Science Foundation of ChinaProject(GBKY1021)supported by the Fundamental Research Foundation of Northwestern Polytechnical University,ChinaProject(B08040)supported by Program of Introducing Talents of Discipline to Universities,China
文摘In order to protect C/C composites from oxidation, SiC-MoSi2 composite coating was synthesized by chemical vapor infiltration /reaction （CVI/CVR） technology. A porous Mo layer was prefabricated on SiC coated C/C composites, and then MoSi2 and SiC were subsequently prepared in a CVI /CVR process using methyltrichlorosilane （MTS） as precursor. The deposition and reaction mechanism of the MoSi2-SiC composite coating was investigated by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The oxidation behavior of SiC-MoSi2 coated specimens was tested. The results show that the porous Mo layer can be densified with SiC phase decomposed from MTS, and transformed into SiC-MoSi2 by reacting with MTS as well. A dense composite coating was prepared with optimized deposition parameters. The coated specimen exhibits a good oxidation resistance with a little mass loss of 1.25% after oxidation at 1500 °C for 80 h.
