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。     

Zr和Mg对快速凝固Cr—Cr合金时效析出过程的影响

快速凝固Ｃｕ－Ｃｒ和Ｃｕ－Ｃｒ－Ｚｒ－Ｍｇ合金经时效处理后显微硬度显著升高,在５００℃时效后,Ｃｕ－Ｃｒ合金的硬度峰值为２０６ＨＶ,Ｃｕ－Ｃｒ－Ｚｒ－Ｍｇ合金的硬度峰值为２５０ＨＶ。用透射电镜对两台合金时效过程中析出的相的变化及共对同工的影响进行了分析,Ｃｕ－Ｃｒ合金达到峰值硬度时析出相为与母相共格的面心立方Ｃｒ随后逐渐与母相失去共格关系并转变成体心立方的Ｃｒ,Ｃｕ－Ｃｒ－Ｚｒ－Ｍｇ合金对应峰值状     

3Cr2W8V钢粉末钛铬共渗的研究

研究了３Ｃｒ２Ｗ８Ｖ钢粉末钛铬共渗的渗剂、工艺参数及其对共渗层的影响，结果表明，共渗温度等工艺参数对共渗层的影响遵循扩散的一般规律，１０００℃保温４ｈ条件下，能得到较佳的共渗层，３Ｃｒ２Ｗ８Ｖ钢钛铬共渗层的相结构为（Ｃｒ，Ｆｅ）７Ｃ３和Ｃｒ７Ｃ３，其表面硬度可达１６８２－１９５０ＨＶ０．１，耐磨、抗氧化、耐腐蚀性能均有显著提高，共渗试样可进行热处理，以提高基体性能。     

Zr和 Mg对快速凝固Cu-Cr合金时效析出过程的影响

快速凝固ＣｕＣｒ和ＣｕＣｒＺｒＭｇ合金经时效处理后显微硬度显著升高,在５００℃时效后,ＣｕＣｒ合金的硬度峰值为２０６ＨＶ,ＣｕＣｒＺｒＭｇ合金的硬度峰值为２５０ＨＶ。用透射电镜对两种合金时效过程中析出相的变化及其对显微硬度的影响进行了分析。ＣｕＣｒ合金达到峰值硬度时析出相为与母相共格的面心立方Ｃｒ,随后逐渐与母相失去共格关系并转变成体心立方的Ｃｒ。ＣｕＣｒＺｒＭｇ合金对应峰值状态的析出相为Ｈｅｕｓｌｅｒ相ＣｒＣｕ２（ＺｒＭｇ）,过时效状态下转变成面心立方的Ｃｕ５Ｚｒ和体心立方的Ｃｒ     

等离子体源氮离子注入层的组织与性能

采用等离子体源离子注入技术，对Ｃｒ１２ＭｏＶ钢进行了氮离子注入，用俄歇谱仪和透射电镜对注入层的成分和组织进行了分析了，分析结果表明，注入层的氮浓度分布具有类高斯分布特征；注放入层中的马氏体组织被细化并有非晶态组织形成。显微硬度和摩擦性能测试结果表明，注入层的显微硬度和摩擦性能得到了明显的提高和改善。     

H13钢的离子束处理研究和应用

利用从金属蒸汽真空弧离子源（简称ＭＥＶＶＡ源）引出的钛离子对Ｈ１３钢（０．３５Ｃ６Ｃｒ１．５ＭｏＶ）进行了不同剂量的离子注入，结果表明，钛离子注入Ｈ１３钢能显著地改善其表面磨损性能，并能避免预热过程中氮化钢表面腐蚀。     

铸造铬锰氮下锈钢耐蚀性的研究

添加了Ｍｏ和Ｃｕ的铬锰氮不锈钢，合金钝化膜更加完整，且稳定性高钝化膜主要由Ｆｅ，Ｃｒ和Ｍｏ的含水氧化物组成，添加Ｍｏ和Ｃｕ的合金钝化膜有Ｃｒ，Ｍｏ和Ｃｕ的富集，且Ｃｒ／Ｆｅ的比值高，膜薄却密，耐蚀性能好。它具有优于１８－８和１Ｃｒ１８Ｎｉ１２Ｍｏ２Ｔｉ钢的耐均匀腐蚀、耐点蚀和耐晶间腐蚀性能。     

中间过渡金属V＋Cu对钛合金与不锈钢扩散焊接头性能的影响

采用Ｖ＋Ｃｕ复合夹层，对钛合金ＴＣ４与不锈钢１Ｃｒ１８Ｎｉ９Ｔｉ扩散焊接头的性能进行了试验研究，结果表明：Ｖ＋Ｃｕ复合夹层可以有效地防止Ｔｉ与不锈钢中Ｆｅ，Ｃｒ，Ｎｉ，Ｃ的相互扩散和迁移，消除了Ｔｉ－不锈钢接头中的脆性金属间化合物和碳化物。接头的性能与软质中间层Ｃｉ的相对厚度有关。     

Nb+C离子注入磁过滤真空电弧镀TiAlN薄膜研究

利用MeVVA离子源技术对阴极磁过滤真空弧沉积的TiAlN薄膜进行了不同注入剂量的Nb及Nb+C离子注入。采用EDS、TEM、GIXRD、显微硬度等测试方法研究了离子注入剂量对于薄膜微观结构和性能的影响。结果表明,注入剂量为Nb 5×1017ions/cm2+C 5×1017ions/cm2时,Nb在TiAlN薄膜内的注入投影射程为130 nm;在薄膜表层形成厚度约50 nm的非晶与纳米晶的复合结构;在次表层,晶粒发生局部扭曲变形。随着离子注入剂量的增加,薄膜与基底的复合硬度由HV 1 900增加到HV 3 000,在高剂量离子注入条件下,薄膜的硬度提升更为显著。     

复合运用Cr—Mo—V—Cu合金元素离心铸造大功率柴油机HT300汽缸套

分析了复合运用Ｃｒ、Ｍｏ、Ｖ、Ｃｕ合金元素对离心铸造大功率柴油机汽缸套组织和性能的影响，总结了离心铸造ＨＴ３００汽缸套的一些经验与技术     

Yb/Dy掺杂改性Fe-Cr合金热生长氧化膜的电化学阻抗谱研究

研究了掺杂0.2 mass%Yb和Dy对Fe-20Cr合金在900℃空气中的氧化性能的影响,应用电化学阻抗技术研究在中性硫酸钠溶液中合金表面氧化膜的电导率,对高温氧化膜的性能进行描述并建立适当的等效模型。结果表明,加入元素Yb和Dy有助于促进合金表面富Cr氧化膜的形成,提高氧化膜的粘附性,从而改善合金的抗氧化性能,其中元素Dy的作用效果比Yb更好。Fe-20Cr 和Fe-20Cr-0.2Yb合金表面氧化膜在溶液中的电化学阻抗谱不能看到明显的双容抗弧特性,而Fe-20Cr-0.2Dy的双容抗弧特性明显,表明氧化膜是双层结构,且其表面氧化膜的电导率最小,显示更好的抗氧化性能,这与氧化动力学测量结果一致。通过与其它高温氧化分析方法进行比较,发现对于研究氧化膜的结构特点、孔隙率、缺陷性等电化学阻抗谱有其独特的优势。     

Formation of oxides on copper in alkaline solution and their photoelectrochemical properties

The anodic formation of Cu(I) and Cu(II) oxides on polycrystalline copper in a deaerated alkaline solution is studied using the technique of the synchronous recording of transients of the photocurrent and polarization current. The oxide formation in a currentless mode is analyzed via the synchronous recording of photopotential and corrosion potential. It is found that copper is susceptible to corrosion oxidation due to traces of dissolved oxygen with the formation of a Cu(I) oxide. The preliminary formation of the underlayer of anodic Cu(I) oxide on copper hinders its further corrosion oxidation. It is confirmed that copper oxides Cu₂O and CuO, which appear on copper in both anodic and corrosion modes of formation, are p-type semiconductors. The initial stage of anodic oxidation of copper is characterized by the formation of an intermediate compound of Cu(I), possibly CuOH, which exhibits n-type conductivity. A film of Cu(I) oxide is thin and has a band gap of 2.2 eV for indirect optical transitions. Anodic polarization in the range of potentials of CuO formation leads to the formation of a thicker oxide film, which is a mixture of Cu(I) and Cu(II) oxides.     

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.     

离子注入对铜失泽行为的影响

本文用表面光反射,电化学库仑还原、扫描和透射电子显微镜研究了经Cr、Ta和惰性气体离子注入后的高纯铜,暴露在含H_2S大气中的失泽行为。暴露试验是在H_2S浓度为0.006—6VPM,25℃和100％RH条件下进行的。结果表明,Cr、Ta离子注入显著地提高了铜的抗失泽能力,Xe离子注入效果较小,而Ar离子注入无改进效果。阴极还原曲线显示经Cr、Ta离子注入的试样上形成的失泽膜,比未经离子注入铜上形成的膜薄,其结构组成亦不同。电子衍射结构分析和扫描电镜(附WDAX)分析进一步证明,Cr离子注入抑制了铜表面膜中金属硫化物的形成。     

The high-temperature oxidation of some oxidation-resistant copper-based alloys

The oxidation behavior of Cu-2Be, Cu-5Al, Cu-8Al, Cu-3Si, Cu-2Al-2Si, Cu-2.5Al-2.5Si, Cu-4.5Al-2Si, Cu-7.5 Al-2Si, Cu-6.5Al-4Si, and Cu-4.5Al-5Si, in the temperature range 100–800°C, in air, has been investigated by gravimetric measurements and by electron microscopical examination of stripped oxide films. Most of the alloys showed considerable resistance to oxidation. This was given mainly by a thermally grown film of -alumina on the Cu-Al and Cu-Al-Si alloys and by a beryllia film on the Cu-Be alloy. Other oxide phases, principally copper oxides, were also found to grow on the alloys and these are described. Silicon additions to Cu-Al alloys are found to improve their oxidation resistance, although no crystalline oxides containing silicon were observed in the oxide films stripped from the Cu-Al-Si alloys.     

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     

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     

Some aspects in designing passive alloys with an enhanced corrosion resistance

The technical and biomedical use of alloys containing reactive metals in aggressive environments is possible due to the spontaneous formation of thin oxide layers which slow down corrosion reactions by several orders of magnitude. Oxide films of important technical metals like Cr and Cu are cation semiconductors, and therefore they are electrochemically unstable and susceptible to anodic decomposition in the contact with electrolyte solutions. Alloying with elements that easily undergo oxidation and formation of highly charged cations, which interact electrostatically with the mobile cation vacancies, results in an enhanced electronic conductivity of their oxide films.This is an effective way how to design an alloy with significantly greater corrosion resistance in aggressive environments in comparison with its constitutive elements. The present paper describes several selected systems investigated under conditions of their real application.     

石墨含量对镍基高温合金在900 ℃氧化行为的影响

采用粉末冶金方法制各不同石墨含量(0%、3%、6%)的镍基高温合金,研究合金材料在900℃和100 h下的恒温氧化行为,用扫描电镜和X射线衍射对其氧化表面形貌和成分进行观察和分析.结果表明:石墨含量较低(0%,3%)时,镍基合金氧化动力学符合抛物线规律,表面氧化膜无剥落;石墨含量为0%的合金氧化膜由Cr2O3和NiCr2O4组成,石墨含量为3%的合金氧化膜由Cr2O3组成,当石墨含量增加到6%时,大量石墨的氧化分解导致合金初始氧化严重,石墨分解后的孔洞加速氧化反应过程.根据氧化膜的组成分析了合金的氧化机制.     

Microstructure and oxidation resistance of reactive plasma clad Cr7C3 /γ-Fe ceramic composite coating

A new type oxidation resistance in situ Cr7C3/γ-Fe ceramic composite coating was fabricated on hardened and tempered grade C steel by reactive plasma clad with Fe-Cr-C alloy powders. The oxidation resistance of the ceramic composite coating was investigated under the test condition of 900℃ and 50 hours. The results indicate that the coating has a rapidly solidified microstructure consisting of blocky primary Cr7C3 and the inter-blocky Cr7C3/γ-Fe eutectics and is metallurgically bonded to the hardened and tempered grade C steel substrate. The high temperature oxidation resistance of the coating is up to 1.9 times higher than that of grade C steel. The oxidation kinetics curve of the coating is conforming to the parabolic-rate law equation. The excellent oxidation resistance of the coating is mainly attributed to the continuous oxide films which consist of Cr2O3 and Fe2O3. The continuous oxide films can prevent the inner part of the coating from being further oxidized.