DEVELOPMENT OF MoS_2-CONTAINING Ni-Cr BASED ALLOYS AND THEIR HIGH-TEMPERATURE TRIBOLOGICAL PROPERTIES

ＤＥＶＥＬＯＰＭＥＮＴＯＦＭｏＳ２ＣＯＮＴＡＩＮＩＮＧＮｉＣｒＢＡＳＥＤＡＬＬＯＹＳＡＮＤＴＨＥＩＲＨＩＧＨＴＥＭＰＥＲＡＴＵＲＥＴＲＩＢＯＬＯＧＩＣＡＬＰＲＯＰＥＲＴＩＥＳ①ＸｉｏｎｇＤａｎｇｓｈｅｎｇＣｏｌｅｇｅｏｆＭｅｃｈａｎｉｃａｌＥｌ...     

IMPROVEMENT OF HOT CORROSION RESISTANCE OF Ti_3Al INTERMETALLIC COMPOUND BY

ＩＭＰＲＯＶＥＭＥＮＴＯＦＨＯＴＣＯＲＲＯＳＩＯＮＲＥＳＩＳＴＡＮＣＥＯＦＴｉ_３ＡｌＩＮＴＥＲＭＥＴＡＬＬＩＣＣＯＭＰＯＵＮＤＢＹＳＰＵＴＴＥＲＥＤＮｉＣｒＡｌＹＣＯＡＴＩＮＧＺｅｎｇ；ＣｈａｏｌｉｕＺｈａｎｇ；ＪｉａｎｑｉｎｇＷｕ，；Ｗｅｉｔａｏ?..     

DIFFUSION PHENOMENA AND MICROSTRUCTURE STABILITY OF Ni－Cr－Al－Y－Si COATING ON THENi_3Al BASED ALLOY SUBSTRATE

ＤＩＦＦＵＳＩＯＮＰＨＥＮＯＭＥＮＡＡＮＤＭＩＣＲＯＳＴＲＵＣＴＵＲＥＳＴＡＢＩＬＩＴＹＯＦＮｉ－Ｃｒ－Ａｌ－Ｙ－ＳｉＣＯＡＴＩＮＧＯＮＴＨＥＮｉ_３ＡｌＢＡＳＥＤＡＬＬＯＹＳＵＢＳＴＲＡＴＥＺ．Ｐ．Ｘｉｎｇ;Ｙ．Ｆ．Ｈａｎ;Ｙ．Ｌ．ＪｉａｎｄＭ．Ｇ?..     

MICROSTRUCTURE OF ELECTRODEPOSITED Ni-W-P-SiC COMPOSITE COATINGS

ＭＩＣＲＯＳＴＲＵＣＴＵＲＥＯＦＥＬＥＣＴＲＯＤＥＰＯＳＩＴＥＤＮｉＷＰＳｉＣＣＯＭＰＯＳＩＴＥＣＯＡＴＩＮＧＳ①ＧｕｏＺｈｏｎｇｃｈｅｎｇ，ＹａｎｇＸｉａｎｗａｎ，ＬｉｕＨｏｎｇｋａｎｇＤｅｐａｒｔｍｅｎｔｏｆＭｅｔａｌｕｒｇｙ，Ｋｕｎｍｉｎ...     

1Cr18Ni9Ti的TIG焊接头的电弧表面改性

开展了微束等离子弧对焊接接头的表面改性改性研究。采用４Ａ微束等离子弧对１Ｃｒ１８Ｎｉ９ＴｉＲＴ Ａ ＱＱＮＧＳＥ ＲＮＧＧＸＲＣ ＯＪＦ ＯＪＦ ＲＵＶ ＲＵＶ ＵＤＩ ＦＪＴＦＧＥ ＤＭ ＲＶ ＲＡＬ ＴＧＪ ＯＰＷＫ,ＣＭＰＷＷＶＳＲＢ ＹＡＡ ＳＵ ＪＯ ＴＭＧ ＸＥＸＫ,     

COMBINATION STRENTHENING PROCESS OF Ni-W-Ti-SiC COMPOSITE COATING AND NITROCARBURIZATION

ＣＯＭＢＩＮＡＴＩＯＮＳＴＲＥＮＴＨＥＮＩＮＧＰＲＯＣＥＳＳＯＦＮｉＷＴｉＳｉＣＣＯＭＰＯＳＩＴＥＣＯＡＴＩＮＧＡＮＤＮＩＴＲＯＣＡＲＢＵＲＩＺＡＴＩＯＮ①ＭａＫｅｙｉ，ＧｕｏＺｈｏｎｇｃｈｅｎｇ，ＷｅｎＭｉｎｇｆｅｎ，ＹａｎｇＸｉａｎｗａｎＤ...     

EFFECT OF TRACE ELEMENTS P AND Mn ON THE MICROSTRUCTURE AND HYDROGEN EMBRITTLEMENT OF AN Fe－Ni－Co BASED SUPERALLOY

ＥＦＦＥＣＴＯＦＴＲＡＣＥＥＬＥＭＥＮＴＳＰＡＮＤＭｎＯＮＴＨＥＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＨＹＤＲＯＧＥＮＥＭＢＲＩＴＴＬＥＭＥＮＴＯＦＡＮＦｅ－Ｎｉ－ＣｏＢＡＳＥＤＳＵＰＥＲＡＬＬＯＹＷＡＮＧＡｎｃｈｕａｎ;ＹＡＮＧＫｅ;ＦＡＮＣｕｎｇａｎ...     

Zr-Cr-Ni BASED MULTICOMPONENT METAL HYDRIDE ELECTRODES

ＺｒＣｒＮｉＢＡＳＥＤＭＵＬＴＩＣＯＭＰＯＮＥＮＴＭＥＴＡＬＨＹＤＲＩＤＥＥＬＥＣＴＲＯＤＥＳ①ＹａｎｇＸｉａｏｇｕａｎｇ，ＬｅｉＹｏｎｇｑｕａｎ，ＣｈｅｎＹａｎｇｌｉｎ，ＷａｎｇＱｉｄｏｎｇＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃ...     

PHASE TRANSITION OF W－Co OXIDE MIXTURE DURING DIRECT REDUCTION／CARBURIZATION BY H_2／CH_4

ＰＨＡＳＥＴＲＡＮＳＩＴＩＯＮＯＦＷ－ＣｏＯＸＩＤＥＭＩＸＴＵＲＥＤＵＲＩＮＧＤＩＲＥＣＴＲＥＤＵＣＴＩＯＮ／ＣＡＲＢＵＲＩＺＡＴＩＯＮＢＹＨ_２／ＣＨ_４￥Ｑｉａｎ，Ｃｈｏｎｇｌｉａｎｇ；Ｗｕ，Ｅｎｘｉ（ＰｏｗｄｅｒＭｅｔａｌｌｕｒｇｙＲｅｓｅａｒｃ...     

Influence of RE oxide additions on hot corrosion bdhaviors of NiAl coatings

ＩＮＦＬＵＥＮＣＥＯＦＲＥＯＸＩＤＥＡＤＤＩＴＩＯＮＳＯＮＨＯＴＣＯＲＲＯＳＩＯＮＢＥＨＡＶＩＯＲＳＯＦＮｉＡｌＣＯＡＴＩＮＧＳ￣①Ｍａ，Ｘｉｎｇｑｉｎｇ；Ｌｉ，Ｔｉｅｆａｎ（ＣｏｒｒｏｓｉｏｎＳｃｉｅｎｃｅＬａｂｏｒａｔｏｒｙ，ＡｃａｄｅｍｉａＳｉ...     

NiCoCrAlY/NiCoCrAlYN涂层的腐蚀磨损行为

目的在中碳钢表面制备金属+氮化物涂层以研究其在腐蚀、磨损耦合环境下的服役行为。方法利用电弧离子镀技术在42CrMo钢基体表面制备NiCoCrAlY/NiCoCrAlYN双层涂层,通过改变氮气流量来调控涂层中氮元素含量。采用显微硬度计以及特制的腐蚀磨损试验机,同时结合XRD、XPS、SEM等各类表征技术研究涂层力学及腐蚀磨损行为。结果NiCoCrAlYN涂层物相主要为γ-Ni、γ'-Ni₃Al、fcc-CrN和fcc-AlN。随着N₂流量的逐步引入,涂层中CrN/AlN陶瓷相含量增加,显微硬度从575HV_0.05逐渐提升至730HV_0.05,而结合力等级从HF 2下降至HF 3。NiCoCrAlY/NiCoCrAlYN双层涂层比NiCoCrAlY单层涂层具有更佳的腐蚀磨损性能,且随着N含量的增加而显著提升。当N2流量为400 mL/min时,涂层显示出最佳的腐蚀磨损性能。此外,涂层的失效形式也由磨损失效逐渐转变为腐蚀失效。结论由于氮化物表层的高硬度特性增强了涂层耐磨性,NiCoCrAlY-NiCoCrAlYN界面的阻挡作用提高了涂层耐蚀性,加之底部NiCoCrAlY层具有良好的韧性和延展性,三者的综合作用导致NiCoCrAlY/NiCoCrAlYN双层涂层的腐蚀磨损性能优于NiCoCrAlY单层涂层。     

Oxidation protection of NiCoCrAlY coatings on γ-TiAl

The effect of NiCoCrAlY overlay coatings on the oxidation resistance of γ-TiAl was studied at 900 ℃ in static air. To hinder the interdiffusion of the elements, the Al/Al2O3 layer was added between the coating and the alloy. The results show that the TiAl alloy exhibits poor oxidation resistance. NiCoCrAlY coating can not effectively protect the γ-TiAl substrate from high temperature oxidation because of the serious interdiffusion between the coating and the substrates. With Al/Al2O3 diffusion barrier, the NiCoCrAlY coating exhibits excellent oxidation protection on γ-TiAl alloy.     

High temperature damping behavior of plasma sprayed NiCoCrAlY coatings

There is a trend to design the turbine coating and the substrate as in integral, layered, engineering assembly. Under the harsh environment of the turbine engine, a failure in one component can quickly lead to failure in other components. Materials that are used in structural applications are prone to mechanical vibration, which, when not attenuated, will lead to fatigue of components and shortening of life cycle. Therefore, it is necessary to examine the thermal stability and dynamic mechanical properties of coatings under dynamic conditions. In addition to these noise reduction and vibration amplitude control motivated objectives, however, mechanical energy dissipation processes also find intrinsic applications in cases for which a thorough understanding of the mechanisms responsible for the damping response of the material is required. This article describes the damping behavior and mechanisms that exist in plasma sprayed NiCoCrAlY coatings.     

热处理态NiCoCrAlY涂层的抗中性盐雾腐蚀性能

通过500 h中性盐雾试验研究了在低膨胀高温合金GH907上低压等离子喷涂(LPPS)的NiCoCrAlY涂层在热处理后的抗腐蚀性能,并与热处理态的LPPS制备的NiCr涂层的抗腐蚀性能进行了对比.结果表明,盐雾腐蚀500 h后,NiCoCrAlY涂层在扫描电镜下可以看到几个无破坏性作用的腐蚀坑,涂层表面仍保持较好的完整性和光洁性,对腐蚀产物的EDS面扫描表明腐蚀产物主要为Al的氧化物,涂层的腐蚀保护等级仅下降到9级;而NiCr涂层的表面出现了较多的腐蚀斑点,涂层的完整性和均匀性均已经被破坏,涂层表面产生了腐蚀裂纹,其腐蚀等级下降到4级.EDS分析表明腐蚀产物主要为Ni、Fe、Co等的氧化物.对比结果表明,NiCoCrAlY涂层表现出比NiCr涂层更强的抗中性盐雾腐蚀性能.     

炮钢表面电弧离子镀NiCoCrAlY涂层的性能研究

用电弧离子镀技术在炮钢表面沉积NiCoCrAlY涂层,研究了涂层的硬度与摩擦磨损性能、高温抗氧化性及耐腐蚀性.结果表明:涂层的硬度较炮钢提高了近36％,炮钢的磨损机制主要为严重的磨料磨损和塑性流动,NiCoCrAlY涂层磨损机制主要是粘着磨损,NiCoCrAlY涂层的摩擦系数(0.57～0.65)小于炮钢的摩擦系数(0.78～0.86);NiCoCrAlY涂层在850℃空气中氧化100 h后的动力学结果表明,涂层大大提高了炮钢的高温抗氧化性能,其原因是表面形成了θ-Al2O3和α-Al2O3氧化膜阻止了炮钢基体被氧化,同时NiCoCrAlY涂层由β-(Ni,Co)Al、α-Cr与γ-Ni相转变为γ-Ni、γ’-Ni3Al和FeNi相;NiCoCrAlY涂层在3.5％NaCl溶液中较炮钢自腐蚀电位提高了近200 mV,能够显著提高炮钢的抗腐蚀能力.     

Microstructural observations of as-prepared and thermal cycled NiCoCrAlY bond coats

Microstructures of as-prepared and 1100 °C/100 h isothermally annealed NiCoCrAlY bond coat specimens as well as a bond coat obtained from an end of life turbine blade were characterized with TEM. In all specimens the γ grains were observed to consist of fine γ′ precipitates, which form during cooling and are unstable at the higher operating temperatures. The β grains present in the as-prepared specimens were observed to transform to L1₀ martensite in the 1100 °C/100 h isothermally annealed specimen. As a result of substrate-bond coat interdiffusion the M_s temperature increases during thermal cycling due to an increase in Ni and decrease in the Cr concentrations of the β-phase. The turbine blade bond coat was also found to contain Cr and Co-rich σ-phase precipitates.     

纳米颗粒增强NiCoCrAlY熔覆涂层的高温摩擦磨损行为

采用激光熔覆技术,在镍基高温合金表面制备相同含量的3种不同纳米颗粒增强的NiCoCrAlY涂层,考察它们在500℃空气氛围下的干摩擦磨损行为,并与未加纳米颗粒的涂层进行比较。结果表明：纳米颗粒增强涂层的高温摩擦磨损机制与未加纳米颗粒的涂层一致,均为强烈塑性变形引起的剥层磨损和氧化磨损;加入纳米颗粒后,涂层的摩擦因数增大且随滑行距离的增加呈减小趋势,涂层的磨损率仅为未加纳米颗粒涂层的34.0%～64.5%。在3种纳米颗粒中,纳米SiC颗粒对涂层高温耐磨性的改善最为显著。     

The Effect of Grain Size on the Cyclic Oxidation of NiCoCrAlY

NiCoCrAlY samples were fabricated via spark-plasma sintering with and without prior cryomilling of the as-received powder. Thermal cycling oxidation tests were conducted at 1000°C in air for up to 200 1-h cycles. The mass gain data indicate a notably lower mass gain for the cryomilled NiCoCrAlY sample. In both the conventional and cryomilled samples, scanning electron microscopy and x-ray diffraction data indicate a single-layer oxide scale of α-alumina has formed, having undergone a transition from θ-alumina during oxidation testing. Spallation in the conventional sample allowed a significant amount of internal spinel oxide formation, and this was not found in the cryomilled sample. The difference in behavior is attributed to increased pathways for aluminum diffusion to the surface and nucleation sites for the α-alumina transition, as well as improved scale adhesion through nanostructuring and stress relief through the accelerated θ–α transition.     

Oxidation and Hot Corrosion Performance of NiCoCrAlY Coatings Fabricated Via Electrolytic Codeposition

Oxidation of Metals - The oxidation and hot corrosion performance of NiCoCrAlY coatings fabricated via electrolytic codeposition was investigated. The cyclic oxidation behavior of NiCoCrAlY...