Ni-16Cr-xAl合金在600℃Na2SO4-NaCl混合盐中的热腐蚀行为（英文）

研究Ni-16Cr-xAl(x=4.5%,6.8%,9.0%)合金在600°CNa2SO4-NaCl混合盐中的热腐蚀行为,分析预氧化及铝含量对合金抗热腐蚀行为的影响。结果表明,随着铝含量由4.5%增加到9.0%(质量分数),Ni-16Cr-xAl(x=4.5%,6.8%,9.0%)合金在Na2SO4-NaCl混合盐中的抗热腐蚀性能提高。因为β-NiAl相的存在能修复热腐蚀中被破坏的Al2O3膜,所以Ni-16Cr-9.0Al合金表现出最优异的抗热腐蚀性能。在预氧化后的样品表面形成了一层具有保护性的氧化膜,其抗热腐蚀性能优于原始态样品的。     

不同锰含量的Fe-Cr-Mn三元合金耐锌蚀能力

研制了4种Mn含量不同的Fe-Cr-Mn三元合金,并系统研究和分析了其在450℃熔融锌液中的腐蚀行为及组织变化规律。结果表明,4种不同锰含量的Fe-Cr-Mn三元合金腐蚀层的形貌基本相似,但与纯铁在液锌中的腐蚀形貌差别很大,其主要是由致密的δ相层和分布于η相中稀疏的ζ相颗粒组成,且δ相层厚度随锰含量的提高先增加后减少,其中属含Mn量为9.55%的Fe-Cr-Mn三元合金腐蚀层中致密的δ相层厚度最厚,表现出较好的耐锌蚀能力,同时,此三元合金基体与腐蚀层界面处存在Cr的富集区,此区约含27.48%的Cr,厚度在1μm左右。连续完整的富Cr抑制层的形成,能够减缓铁锌反应的速度,减慢对基体的腐蚀速度,提高了耐锌蚀能力。     

Nb−Si基超高温合金在900℃下的氧化和热腐蚀行为

对Nb?Si基超高温合金在900℃下的氧化和热腐蚀行为进行研究。结果表明:合金的氧化和热腐蚀动力学均由初始的抛物线增长阶段和随后的线性快速增长阶段组成。在氧化的初始阶段(1~50 h),合金表面形成较薄且连续的氧化膜,而在随后的线性阶段,合金表面发生严重的“粉化”现象。合金经热腐蚀后,其线性增长阶段发生得更早,同时在热腐蚀20~100 h后发生灾难性的氧化膜剥落现象,表明熔盐(Na2SO4和NaCl)能显著加快合金的氧化过程。STEM结果显示,热腐蚀后的氧化膜主要由TiO2、Nb2O5、TiNb2O7、非晶硅酸盐和NaNbO3组成。     

Ni-xCr-6.8Al基合金热腐蚀行为

研究铸态和预氧化态Ni-xCr-6.8Al基合金在Na2SO4＋25%NaCl混合盐中873K时的热腐蚀行为。结果表明：NixCr6.8Al基合金的质量损失随着Cr元素含量的增加而减少,预氧化可以明显改善材料的抗热腐蚀性能,并且与Cr含量无关。Ni12Cr6.8Al基和Ni16Cr6.8Al基合金的热腐蚀动力学遵循抛物线规律,Ni-20Cr-6.8Al基合金遵循指数规律,所有的预氧化试样的热腐蚀动力学都符合对数规律。铸态合金热腐蚀的机理可以用酸碱熔融模型解释,而预氧化合金的热腐蚀机理在很大程度上由预氧化过程中形成的氧化层的性质决定。     

新型Te-Ni-Cr合金在Na2SO4-25％NaCl熔盐中的腐蚀行为

利用粉末冶金技术制备了新型Te-Ni-Cr合金材料.通过静态质量损失试验,X射线物相分析,扫描电镜形貌观察及微区成分分析等手段,研究了合金在750℃Na2SO4-25wt％NaCl熔盐中的热腐蚀行为及热腐蚀动力学规律.研究表明:稀有元素碲的加入,使合金的腐蚀速率较Ni-Cr合金有比较明显的下降;随时间的延长,合金表面的腐蚀程度不断增加;腐蚀产物主要为铁的氧化物、镍及铬的硫化物和氧化物;热腐蚀层主要由铁的氧化物和CrO3组成.     

Influence of Cr Content on the Corrosion of Fe–Cr Alloys: The Synergistic Effect of NaCl and Water Vapor

The corrosion behavior of pure Fe and Fe–Cr alloys with different Cr content in the presence of a solid NaCl deposit and water vapor at 600°C was studied. Results indicated that the corrosion of pure Fe was severe even in air at 600°C and the scale formed on the surface was compact and uniform. However, with a solid NaCl deposit on its surface, the corrosion of pure iron in air was suppressed to some extent, but the presence of water vapor in the atmosphere causes accelerated corrosion. Under the synergistic effect of NaCl and water vapor, the corrosion of pure iron is accelerated more significantly. In contrast with the known effect of Cr content on the oxidation of Fe–Cr alloys, an increasing Cr content in Fe–Cr alloys increases the corrosion rate of the alloys under the synergistic effect of solid NaCl and water vapor. A mechanism to explain the effect of water vapor and NaCl on the corrosion of pure iron and Fe–Cr alloy is proposed.     

Effects of Chlorate on the Hot Corrosion Behaviors of Cr0.82Al0.18N Coating Deposited on a Ti3Al Based Alloy

为了研究氯化物熔盐对Cr-Al-N涂层热腐蚀性能的影响,采用反应磁控溅射的方法在Ti3Al合金表面制备了Cr0.82Al0.18N涂层,研究了涂层在Na2SO4+25%K2SO4和Na2SO4+25%Na Cl(质量分数)2种熔盐中的热腐蚀行为,采用XRD和SEM分析了涂层热腐蚀产物的相组成和形貌。结果表明:涂层在含有氯化物盐的熔盐中腐蚀时表现为失重而在硫酸盐中腐蚀时表现为增重;Cr0.82Al0.18N涂层在2种熔盐中的腐蚀都主要由Cr2O3和θ-Al2O3组成。氯化物熔盐和腐蚀产物的挥发导致了在含有氯化物熔盐中腐蚀时的失重现象。当含有氯化物盐时会增加熔盐中氧离子的活度,从而加速Cr2O3在熔盐中的溶解。此外,热腐蚀过程中产生的氯气也会参与腐蚀反应,从而加速涂层的消耗。     

Hot Corrosion Behavior of a Ni3Al-Based IC21 Alloy in a Molten Salt Environment

Ni₃Al-based alloys have become important candidates for hot components in turbine engines, owing to their low densities and outstanding mechanical properties in service environments. The hot corrosion behavior of a Ni₃Al-based IC21 alloy in a molten salt environment of 75 wt% Na₂SO₄ and 25 wt% NaCl at 900 °C was studied, via oxidation kinetics analyses, scanning electron microscope observations and energy dispersive as well as diffraction analyses by X-ray. A multilayer corrosion oxide scale and dendritic morphology internal corrosion zone formed after hot corrosion, and inter-phase selective corrosion phenomena were also observed. Salt fluxing and oxidation-sulfidation processes were inferred to be the essential hot corrosion mechanisms of the alloy. Moreover, additions of Cr and Y proved to be beneficial to the hot corrosion resistance of the IC21 alloy, while the Mo content should be strictly controlled.     

Relationship between phase composition and corrosion resistanceof Ni-Ti-Nb based shape memory alloys

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不同状态FeCr8P13B5和FeCr8P13C7合金的耐蚀性能

本文以电化学方法(动电位极化曲线测量)和全浸法考察了不同状态(无定形态、无定形合金退火态以及晶态)FeCr8P13B5和FeCr8P13C7合金在氯离子介质中的耐蚀性能,结果表明(1)无定形FeCr8 P13 B5和FeCr8P13C7合金都具有优异的耐蚀性能。它们的动电位极化曲线十分相似,当极代电压为+1.5伏(SCE)以下时。试样不出现破裂电位Eb,钝态电流维持在10微安/厘米~2以下;这两种无定形耐蚀合金在30℃的0.5N-2.5NHCl、40和60℃的10％,FeCl_3、6H_2O、60℃的3.5％NaCl以及30℃的1MH_2SO_4+0.5MNaCl中全浸168小时其腐蚀速率为10~(-3)-10~(-4)毫米/年。(2)无定形FeCr8P1385和FeCr8P13C7合金经500℃1小时真空退火(晶化)处理后,后者的耐蚀性能急剧恶化,而前者仍保持无定形状态的优异耐腐蚀性能。电化学测量与全浸试验所得的结果是一致的。     

Fe-14Cr-Mn合金在不同温度熔融共晶NaCl-MgCl2中腐蚀行为及机理研究

熔融共晶NaCl-MgCl₂作为太阳能中高温相变储热介质,运行状态下其温度常在熔点附近波动。但不同温度下该熔融盐对金属容器材料腐蚀行为不清楚。以Fe-14Cr-Mn合金为例,采用浸盐法研究了718K、768K和818K熔融共晶NaCl-MgCl₂对该合金的腐蚀行为,探讨了腐蚀机理。结果表明：腐蚀速率随温度增加略微增加,三种温度下试样腐蚀动力学曲线服从线性规律(斜率约k=-4.806E-4)。腐蚀初期,试样表面形成泡状腐蚀产物,腐蚀80h后形成腐蚀坑洞,主要是Fe、Fe-Cr和MgO,也检测到含微量Fe和Ni的Mg-Fe-Ni的氧化物。腐蚀机理主要是MgCl₂吸潮后以H₂O形式引入的氧原子和溶解在熔融盐中的微量氧作为阴极去极化剂,合金元素Cr和Mn与Cl_-反应生成的氯化物,氯化物吸附水分子,形成具有低熔点的含水氯化物(如CrCl₃.6 (H₂O) 和MnCl₂.n (H₂O))逃逸腐蚀体系。另外,在熔岩表面形成了由MgCl₂. (H₂O) ₆, NaCl 和 MgO组成的盐壳,而在熔融盐内部,NaCl与NaMgCl₃共存。本研究为研发耐熔融NaCl-MgCl₂腐蚀的新合金奠定了基础。     

Corrosion behavior of Fe-20Cr and Ni-20Cr alloys in Ar-H2O-HBr gas mixtures at 1000 K

Discontinuous mass-change measurements and corrosion-product analyses were made for Fe-20Cr and Ni-20Cr alloys after exposing them to Ar-H ₂ O-HBr gas mixtures at 1000 K for 24 hours. Predominantly chromia scales formed on both alloys. Upon cooling, the scales remained adherent to the Fe-20Cr alloy but spalled extensively from Ni-20Cr samples. After tests in HBr-rich gas mixtures, bromine-rich corrosion products were found underneath chromia scales on both alloys while nickel evaporation was observed from Ni-20Cr samples. Preoxidation of the Ni-20Cr alloy prior to exposure to Ar-H ₂ O-HBr gas mixtures increased chromia scale adherence but did not prevent nickel loss from the alloy. Chromia scales formed on the Fe-20Cr alloy were more protective due to the absence of iron oxides in the scale. Large NiO crystals formed over the Ni-20Cr alloy decreased chromia-scale adherence and increased nickel loss from the alloy due to the low stability of NiO in HBr-containing gas mixtures.     

Ni-Cr-Mo合金在真空熔盐中的腐蚀动力学行为

采用失重法对真空状态下几种Ni-Cr-Mo合金在熔盐中的腐蚀动力学行为进行了研究。结果表明,合金在真空熔盐中的腐蚀深度随时间延长而加大,腐蚀速率随时间的延长而减小;腐蚀过程主要是Cr和Mo合金元素在熔盐中的脱溶过程,腐蚀造成了合金表面组织的疏松和孔洞,这些孔洞为熔盐的进一步腐蚀提供了通道。     

The High-Temperature Corrosion of Austenitic Stainless Steel with a NaCl Deposit at 850°C

Three austenitic Fe–Cr–Ni alloys (253MA, 310SS and 353MA) coated with 2 mg/cm² NaCl were oxidized at 850°C in a slow airflow. The results indicate that the initial NaCl coating accelerated oxidation of alloys by oxychloridation and chloridation/oxygen-substitution cyclic reactions, resulting in the formation of a thick scale and an interconnecting void network in the substrate. Voids were tunnels in shape. Some were filled with corrosion products, and some corrosion products formed on the walls of the voids. The thickness of metal loss was related to the consumption of both chromium and iron in the alloy substrate. In this study, 310SS had better corrosion resistance after 36 hr exposure, followed by 353MA, and the worst was 253MA.     

铝合金表面BTSE硅烷化处理研究

通过极化曲线与电化学阻抗谱(EIS)等技术对LY12铝合金表面形成的BTSE硅烷膜在NaCl溶液中的性能进行了研究．结果表明，硅烷膜的存在，一方面很大程度上增大了铝合金的耐蚀性，另一方面并不影响合金电极在腐蚀介质中的电极动力学．这意味着BTSE膜对侵蚀粒子仅起到阻挡层的作用．提出了硅烷化试样在测试溶液中的合理等效电路，并对EIS数据进行了拟合．采用正交设计方法对硅烷化工艺参数进行了优化，其中采用电极体系的极化电阻(由EIS拟合得出)来量化硅烷膜的耐蚀性．文中还对各因素对膜性能的影响规律进行了初步探讨。     

Effect of enamel coating on long-term oxidation and hot corrosion behavior of Ti-24Al-17Nb-0.5Mo alloys

The effect of enamel coating on long-term isothermal oxidation at 700 ℃ and cyclic oxidation at 800 ℃ in air and hot corrosion resistance of Ti-24Al-17Nb-0. 5Mo in 75% (Na2SO4 K2SO4 ) 25% NaCl (mass fraction) molten mixed salts at 700 ℃ was investigated. The results indicate that Ti-24Al-17Nb-0.5Mo alloy exhibits relatively poor long-term oxidation resistance due to the formation of Al2O3 TiO2 Nb2O5 mixed scales and poor hot corrosion resistance due to the spallation of scales formed in molten (Ns, K)2 SO4 NaCl. Enamel coating can effectively protect Ti-24Al-17Nb-0.5Mo alloy from long-term oxidation at high temperature in air and remarkably improve the hot corrosion resistance of Ti-24Al-17Nb-0. 5Mo alloy, and can act as the barrier to suppress the migration of oxygen and corrosive ions into the substrate.     

碳钢和铁-铬-镍基合金在相变储能材料用熔融共晶氯化钠和氯化镁中的腐蚀行为

研究了3种铁-铬-镍基合金(Fe-Cr-Ni)和一种碳钢试样在520℃熔融共晶NaCl-MgCl2盐中的腐蚀行为。结果表明,碳钢试样晶界处Fe原子优先变为亚铁离子(Fe2+)和铁离子(Fe3+),发生了严重的沿晶腐蚀,但表面形成了厚而致密的MgO壳,对试样起到了一定的保护作用。3种Fe-Cr-Ni基试样表面也形成了MgO壳,但因铬元素优先被腐蚀,试样表面形成了疏松的富Ni骨架状微观组织结构,MgO壳或颗粒极易剥落,未能起到有效的保护作用;Cr含量越高,腐蚀越严重。对于太阳能储能技术,在廉价的铁基合金中添加镍元素作为熔融氯化盐相变储热介质的容器或者管道材料,具有良好发展前景。     

Evaluation of the Corrosion Resistance of Fe–Al–Cr Alloys in Simulated Low NO x Environments

Due to their excellent corrosion resistance, iron aluminum alloys are currently being considered for use as weld claddings in fossil fuel fired power plants. The susceptibility to hydrogen cracking of these alloys at higher aluminum concentrations has led researchers to examine the effect of chromium additions on the corrosion resistance of lower aluminum alloys. In this work, three iron aluminum alloys were exposed to simulated coal combustion environments at 500 and 700 °C for short (100 h) and long (5000 h) isothermal durations. Scanning electron microscopy was used to analyze the corrosion products. All alloys exhibited excellent corrosion resistance during short term exposures. For longer test times, increasing the aluminum concentration improved alloy corrosion resistance. The addition of chromium to the binary iron aluminum alloy prevented the formation iron sulfide and resulted in slower corrosion kinetics. A general classification of the scales developed on these alloys is presented.     

Y、Ta、Cr元素对Ni-10%Cu-10%Fe-10%Al合金在850℃冰晶石熔盐气氛中热腐蚀行为的影响

通过真空铸造得到Ni-10%Fe-10%Al-10%Cu(质量分数)及分别添加0.8%Y、5.3%Ta和13.6%Cr(质量分数)的Ni-Fe-Al-Cu-X(X:Y或Ta或Cr)4种合金,采用熔盐腐蚀实验及SEM,XRD及EDX测试研究各合金在850℃静态冰晶石熔盐气氛中的腐蚀行为。结果表明:在850℃冰晶石熔盐气氛中,Ni-10%Fe-10%Al-10%Cu合金表面形成的氧化物保护膜;由于氧的聚集、扩散,并在熔盐/氧化膜界面处发生O2+2e=2O2还原反应,而生成的O2与MeO反应生成MeO22,致使NiO和Al2O3等氧化物层疏松、多孔、易剥落;另外,氧化物保护膜也被熔盐挥发的氟化物通过物理化学作用而溶解,形成坑洞,腐蚀层呈现层叠状;添加0.8%Y和5.3%Ta可净化合金晶界,使腐蚀层中氧化产物更致密,提高合金抗冰晶石熔盐气氛腐蚀性能;添加13.6%Cr的Ni-10%Fe-10%Al-10%Cu合金,其腐蚀层形成Cr2O3及NiCr2O4冰晶石结构的化合物,降低其他氧化物的活度,提高氧化膜的保护作用,该合金抗冰晶石熔盐气氛腐蚀性能最好。     

EFFECTS OF TRACE ELEMENTS ON THE OXIDATION OF LOW SEGREGATION Ni－Cr－Al BASED SUPERALLOYS

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