非晶态Fe—W镀层铬酸盐钝化膜耐蚀机理探讨

Ｆｅ－Ｗ非晶镀层经铬酸盐钝化处理，可获得有装饰的含Ｃｒ钝化膜，经测定，孔蚀电位较钝化前正移１．６８Ｖ，明显改善了抗Ｃｌ＾－腐蚀的能力，ＡＥＳ与ＸＰＳ的分析结果表明，钝化膜由内外两层构成，外层为Ｆｅ（ＣｒＯ４）３．Ｃｒ２（ＣｒＯ４）３／Ｃｒ２（Ｃｒ２Ｏ７）３．Ｆｅ（ＯＨ）３／ＦｅＯＯＨ．ＷＯ３．ｎＨ２Ｏ等化合物，内层由Ｃｒ２Ｏ３，ＣｒＯ３，ＣｒＯＯＨ，ＦｅＯ，Ｆｅ２Ｏ３及ＷＯ３组成。钝化膜厚度约为６     

非晶态Fe－W镀层铬酸盐钝化膜耐蚀机理探讨

Ｆｅ－Ｗ非晶镀层经铬酸盐钝化处理，可获得具有装饰效果的含Ｃｒ钝化膜。经测定，孔蚀电位较钝化前正移１．６８Ｖ，明显改善了抗ＣＩ－腐蚀的能力。ＡＥＳ与ＸＰＳ的分析结果表明：钝化膜由内外两层构成，外层为Ｆｅ（ＣｒＯ４）３·Ｃｒ２（ＣｒＯ４）３／Ｃｒ２（Ｃｒ２Ｏ７）３·Ｆｅ（ＯＨ）３／ＦｅＯＯＨ·ＷＯ３·ｎＨ２Ｏ等化合物，内层由Ｃｒ２Ｏ３，ＣｒＯ３，ＣｒＯＯＨ，ＦｅＯ，Ｆｅ２Ｏ３及ＷＯ３组成。钝化膜厚度约为６０ｎｍ。该双层饨化膜有效地阻止了Ｃｌ－对基体金属的腐蚀。     

环境扫描电镜原位研究纯Fe表面氧化过程

应用动态环境扫描电镜法原位观察纯Ｆｅ在５００－７５０℃。氧分压１０＾－４－４５Ｐａ下生成不同形貌。结构及组分的铁氧化物晶粒／晶须所组成的氧化层的演化历程。结果表明,在不同的反应条件下生成的氧化锈皮中,不但氧化物组成（ＦｅＯ,Ｆｅ３Ｏ４,Ｆｅ２Ｏ３等）不同,而且氧化物晶粒／晶须有着不同形貌与微观结构。根据６０００１７０氧化时的实验结果,提出了一个纯Ｆｅ表面拟立方全Ｆｅ２Ｏ３晶粒生长模型和晶粒在亚纳米     

改善锆合金耐腐蚀性能的概述

发展高性能核燃料组件是提高核电经济性的必由之路，改善核燃料元件包壳锆合金的性能是其中关键问题之一。本文概述了我们近几年研究改善锆合金耐腐蚀性能的结果：控制Ｚｒ４合金成材时的热加工制度，可以明显改善它的耐腐蚀性能，尤其是耐疖状腐蚀性能。其主要原因是αＺｒ中Ｆｅ＋Ｃｒ的固溶含量变化，而不是析出相微粒的大小。由于Ｚｒ４合金中析出相Ｚｒ（Ｆｅ，Ｃｒ）２微粒的氧化比αＺｒ基体慢，并与成分中的Ｆｅ／Ｃｒ比有关，当嵌镶在氧化膜中的Ｚｒ（Ｆｅ，Ｃｒ）２微粒继续氧化形成单斜结构ＺｒＯ２和立方结构（Ｆｅ，Ｃｒ）３Ｏ４后，由于体积膨胀会造成氧化膜中的局部张应力。从这一角度出发，热处理对析出相细化、均匀分布以及Ｆｅ／Ｃｒ比的变化等也是应考虑的问题。发展ＺｒＳｎＮｂ（Ｆｅ＋Ｃｒ）新合金，对改善锆合金的耐腐蚀性能有更大的潜力，成分（％，质量分数，下同）的选择应为Ｓｎ１～１２，Ｎｂ～１，Ｆｅ＋Ｃｒ可保持或略高于Ｚｒ４的水平。     

Fe—23Cr—5Al合金1000^0C氧化形成的Al2O3膜生长应力研究

采用一种测定氧化膜生长应力的双面氧化弯曲方法,测量了Ｆｅ－２３Ｃｒ－５Ａｌ（Ｆｅ－２２．６Ｃｒ－．４２Ａｌ－０．２１Ｔｉ,ｗｔ％）合金在１０００＾０Ｃ空气中氧化形成的Ａｌ２Ｏ３膜的平均生长应力,研究了氧化膜应力释放机制,Ａｌ２Ｏ３膜的平均生长应力随膜厚增大而减小,其大小从－１ＧＰａ数量级变化到－１００ＭＰａ数量级。基体全金和Ａｌ２Ｏ３膜在１０００＾０Ｃ时均发生蠕变,合金氧化一定时间后于真空保温退火     

氧化物薄膜促使镍铬合金高温选择氧化的研究

表面沉积Ｙ２Ｏ３薄膜可以促使Ｎｉ－１５％Ｃｒ合金在１０００℃中生成Ｃｒ２Ｏ３选择性氧化膜，氧化量下降约２０倍，而沉积Ａｌ２Ｏ３薄膜仅在较短的时间内使合金的局部表面生成Ｃｒ２Ｏ３选择性氧化膜。从沉积氧化物薄膜对Ｃｒ２Ｏ３氧化膜的生核及生长过程的作用，对氧扩散的阻挡作用，以及氧化物薄膜与Ｃｒ２Ｏ３氧化膜掺杂后引起氧化膜中传质过程和应力状态的变化，分析了氧化物薄膜促使镍铬合金在较低铬含量下发生高温选择氧     

铝基复合材料－不锈钢摩擦焊接过渡区的显微结构特征

研究了铝基复合材料与奥氏体不锈钢间异种金属摩擦焊焊接过渡区在不同焊接条件下的显微组织变化规律．扫描电镜（ＳＥＭ）观察到强度较高的奥氏体不锈钢在焊接过程中发生明显的塑性变形，焊接界面附近不同部位变形机制和特征不同，变形方式主要是形成形变孪晶、滑移带和位错亚结构；透射电镜（ＴＥＭ）观察到过渡区是由微晶氧化物Ｆｅ（Ａｌ，Ｃｒ）_２Ｏ_４或ＦｅＯ·（Ａｌ，Ｃｒ）_２Ｏ_３氧化物层和ＦｅＡｌ_３金属间化合物层组成     

表面施加含稀土氧化物薄膜对Fe25Cr高温氧化的“活性元素效应"

研究了表面施加含有不同量Ｙ２Ｏ２的Ｃｒ２Ｏ３和Ａｌ２Ｏ３薄膜对Ｃｒ２Ｏ３形成合金Ｆｅ２５Ｃｒ在１０００℃、１０４ＰａＯ２环境中高温氧化的作用。结果发现含Ｙ氧化物薄膜明显降低了Ｃｒ２Ｏ３层的生长速度,而且含Ｙ复合氧化物薄膜的作用大于 Ｙ２Ｏ３薄膜,此时,Ｃｒ２Ｏ３层表面形貌发生了较大的变化,间接证据表明Ｃｒ２Ｏ３的生长机制的由阳离子向外扩散为主转变阴离子向内扩散为 主,通过表面施加含Ｙ的氧化物薄膜产生     

304不锈钢氧离子溅射的同步辐射光电子能谱原位研究：Ⅰ …

利用同步辐射光电子能谱（ＳＲ－ＸＰＳ）原位研究了经３ｋｅＶＯ２＾＋溅射的ＳＵＳ３０４不锈钢中Ｆｅ、Ｎｉ、Ｃｒ合金元素与氧离子的化学反应活性差异及三种金属元素间的相互作用规律,经低能氧离子溅射后,不锈钢表面形成了一薄层氧化物膜,元素Ｃｒ和Ｎ分别以Ｃｒ２Ｏ３和ＮｉＯ形式存在;铁元素的氧化产物随氧离子溅射量的增加分别以ＦｅＯ、ＦｅＯ和Ｆｅ２Ｏ３共存、全部生成Ｆｅ２Ｏ３的形式存在,在ＳＵＳ３０４不锈钢钢中     

THE OXIDATION OF A TWO-PHASE Cu-50Cr ALLOY IN AIR AT 70O ─900℃

Ｃｕ－５０Ｃｒ合金在７００－９００℃空气中的氧化结果表明,合金的氧化动力学在７０和８００℃遵循抛物线速度规律,在９００℃其瞬时抛物线速度常数随时间而降低。合金氧化外层膜是ＣｕＯ和Ｃｕ２Ｏ,内层膜由氧化铜和尖晶石型氧化物为基并嵌有Ｃｒ颗粒组成,Ｃｒ表面有Ｃｒ２Ｏ３和Ｃｕ２Ｃｒ２Ｏ４膜。９００℃的氧化膜与基体金属界面粘可观察到连续的Ｃｒ２Ｏ３层。合金未形成Ｃｒ的选择性外氧化。     

Prediction of Oxide Phases Formed upon Internal Oxidation of Advanced High-Strength Steels

The effect of Cr on the oxidation of Fe–Mn-based steels during isothermal annealing at different dew points was investigated. The Fe–Mn–Cr–(Si) phase diagrams for oxidizing environments were computed to predict the oxide phases. Various Fe–Mn steels with different concentrations of Cr and Si were annealed at 950 °C in a gas mixture of Ar or N₂ with 5 vol% H₂ and dew points ranging from ? 45 to 10 °C. The identified oxide species after annealing match with those predicted based on the phase diagrams. (Mn,Fe)O is the only oxide phase formed during annealing of Fe–Mn binary steel alloys. Adding Cr leads to the formation of (Mn,Cr,Fe)₃O₄ spinel. The dissociation oxygen partial pressure of (Mn,Cr,Fe)₃O₄ in the Fe–Mn–Cr steels is lower than that of (Mn,Fe)O. The Si in the steels results in the formation (Mn,Fe)₂SiO₄, and increasing the Si concentration suppresses the formation of (Mn,Cr,Fe)₃O₄ and (Mn,Fe)O during annealing.     

Fe—Ni—Cr封接合金的高温氧化及氧化膜,氧化物晶须的结构

试验表明,Fe-Ni-Cr封接合金在高温湿氢气氛中氧化膜的生长受扩散控制,其主要组成为刚玉型的Cr_2O_3与尖晶石型的(Fe,Mn)O·Cr_2O_3。电子衍射及能谱分析证实,氧化过程中生长的晶须为(Fe,Mn)O·Cr_2O_3。     

HIGH TEMPERATURE OXIDATION AND STRUCTURE OF SCALE AND WHISKERS FOR Fe-Ni-Cr SEALING ALLOYS

The oxidation rate,the growth,morphology and structure of oxide scale and whiskers forFe-Ni-Cr sealing alloys in H_2-H_2O atmosphere at high temperatures have been studied.The growth rate of scale is controlled by diffusion.The scale is composed of Cr_2O_3 andspinel(Fe,Mn)O·Cr_2O_3 and the oxide whisker,are spinel(Fe,Mn)O·Cr_2O_3.     

NiAl-28Cr-6Mo共晶合金的高温氧化行为

本文采用恒温氧化实验方法,在900~1150℃下测试了NiAl-28Cr-6Mo共晶合金的氧化性能,分析了合金的氧化动力学,SEM观测了合金表面以及横截面的形貌。研究表明,NiAl-28Cr-6Mo共晶合金在900~1100℃下合金表面生成了连续的Al_2O_3氧化膜,具有较好的抗氧化性能;900~1000℃氧化膜主要由θ-Al_2O_3和Cr_2O_3组成,随着恒温氧化温度的升高,θ-Al_2O_3和Cr_2O_3减少,α-Al_2O_3增多,1100℃下的氧化膜表面则主要由细小、致密的α-Al_2O_3组成;氧化过程中,表面氧化膜存在着θ-Al_2O_3→α-Al_2O_3的相变过程;θ-Al_2O_3较α-Al_2O_3的保护性差导致1000℃合金氧化增重大于1050℃和1100℃;1150℃下共晶合金氧化膜发生剥落,没有形成完整的Al_2O_3氧化膜导致合金的抗氧化性能恶化,氧化增重迅速增加。     

Fe-Cr-Mn合金在湿润环境中的氧化行为研究

研究比较了Fe-13Cr-xMn(x=0.5,1,2) 系列合金在干燥和湿润空气中800 ℃下的氧化行为。结果表明,在干燥气氛中合金表现出良好的抗氧化性能,当Mn含量低于1%时有助于合金表面生成阻碍Cr挥发的 (Mn,Cr)₃O₄尖晶石相;而当Mn含量达到2%,合金表面则会产生Mn₂O₃,从而影响合金的抗高温氧化性能。在含水蒸气气氛中,合金发生了失稳态氧化,表面生成了大量氧化物,合金的氧化速率随Mn含量的增大而减小,主要原因是Mn含量增加导致膜层中形成 (Mn,Cr)₃O₄尖晶石相,从而有效阻碍了水气环境中Cr的挥发,尤其Fe-13Cr-2Mn合金在氧化初期12 h内并没有发生加速腐蚀,Fe-Cr-Mn合金的加速氧化是由表面氧化铬膜与水蒸气发生反应所致。通过SEM,XRD等分析手段深入探讨了合金加速氧化机制以及Mn效应。     

Ni-Cr-W合金在1100 ℃的氧化膜演变

对新型Ni-Cr-W合金在1100 ℃下不同保温时间下的恒温氧化行为进行了研究。采用扫描电镜（SEM）以及能谱（EDS）对合金热暴露后的表面氧化膜形貌、元素含量以及合金基体的恶化情况进行了分析,表面氧化膜的相组成通过XRD进行确定。结果表明：在氧化初期（<3 h）,合金表面生成的单层氧化膜主要由Cr2O3组成,随着氧化时间的延长（>7 h）,在Cr2O3外逐渐形成了一层具有尖晶石结构的NiCr2O4。一旦外表面被均匀致密的尖晶石膜所覆盖,双层氧化膜NiCr2O4·Cr2O3便能有效的减慢合金基体被进一步氧化。合金亚表层的恶化形式包括晶界的内氧化、空洞以及无碳化物区的形成。合金中高的W含量并没有明显恶化合金的抗氧化性能。     

Oxidation of Fe-8Cr-14Ni-Al-Si-Mn from 700 to 1000°C

This paper reports an investigation into reducing the Cr concentration in commercial-grade stainless steels while maintaining oxidation protection at elevated temperatures. Aluminum and Si were added as partial substitute alloy elements to enhance the reduced operation protection resulting from Cr concentration reduced by approximately 50 pct of that found in stainless steels. The goal of this study was to determine the oxidation mechanism of such an Fe, Al-Si alloy: Fe-8Cr-14Ni-1Al-3.5Si-1Mn. During the initial oxidation period the protection resulted from a thin film of Al₂O₃ over an Fe and Cr spinel. Long-term oxidation protection resulted from the gradual formation of a Cr sesquioxide (Cr₂O₂) inner oxide layer. Eventually an outer oxide layer formed that was a mixed composition spinel of Cr and Mn (MnO · Cr₂O₃). The Al₂O₃, which was part of the original protective layer flaked off early in the oxide testing, and the aluminum oxide that formed later appeared as an internal oxide precipitate.     

Roles of Manganese in the High-temperature Oxidation Resistance of Alumina-forming Austenitic Steels at above 800?°C

A new family of alumina-forming austenitic (AFA) stainless steels is under development for uses in aggressive oxidizing conditions. This paper investigates the effect of manganese additions on the oxidation kinetics and alumina scale formation in two series of AFA steels, i.e., Fe–20Ni–14Cr–2.5Al and Fe–18Cr–25Ni–3Al base. At 800?°C in dry air, the oxidation resistance was moderately degraded with additions of larger than 1 wt% Mn in the AFA steels based on Fe–14Cr–20Ni–2.5Al. At 900?°C in air with 10?% water vapor, however, additions of Mn in these AFA steels based on Fe–18Cr–25Ni–3Al would significantly destabilize the alumina scale formation and degrade the oxidation resistance. Our analysis revealed that additions of Mn stimulated formation of the coarse spinel CrMn_1.5O₄ and Cr₂O₃ oxide and destroyed the continuity of the protective alumina scales, thus worsening the oxidation performance. In addition, it was found that there exists an upper limit for the Mn additions which is decreased with the increase of the service temperatures and presence of aggressive oxidizing agents.     

表面施加含稀土氧化物薄膜对Fe25Cr高温氧化的"活性元素效应"

研究了表面施加含有不同量Y     

Oxidation Behaviors of Different Grades of Ferritic Heat Resistant Steels in High-Temperature Steam and Flue Gas Environments

For steam tubes used in thermal power plant, the inner and outer walls were operated in high-temperature steam and flue gas environments respectively. In this study, structure, microstructure and chemical composition of oxide films on inner and outer walls of ex-service low Cr ferritic steel G102 tube and ex-service high Cr ferritic steel T91 tube were analyzed. The oxide film was composed of outer oxide layer, inner oxide layer and internal oxidation zone. The outer oxide layer on the original surface of tube had a porous structure containing Fe oxides formed by diffusion and oxidation of Fe. More specially, the outer oxide layer formed in flue gas environment would mix with coal combustion products during the growth process. The inner oxide layer below the original surface of tube was made of Fe-Cr spinel. The internal oxidation zone was believed to be the precursor stage of inner oxide layer. The formation of internal oxidation zone was due to O diffusing along grain boundaries to form oxide. There were Fe-Cr-Si oxides discontinuously distributed along grain boundaries in the internal oxidation zone of G102, while there were Fe-Cr oxides continuously distributed along grain boundaries in that of T91.