轻质化MA/ODS镍基高温合金高温氧化行为

采用机械合金化(MA)和真空烧结工艺制备了Y2O3质量分数为2%～20%的氧化物弥散强化(ODS)镍基高温合金,在1 000℃空气中对合金试样进行100h的静态氧化实验,研究了Y2O3含量对合金高温氧化性能的影响与作用机制.结果表明:适量稀土氧化物Y2O3的加入(质量分数≤5%)可促进完整Cr2O3氧化膜的形成,提高氧化膜与合金基体的附着力,改善氧化膜的抗剥落性,减缓合金在1 000℃的氧化速度,从而有效提高合金的抗高温氧化性能.但过量添加则会使其抗氧化性能迅速下降.     

镍基高温合金表面Co-Al渗层的抗氧化性研究

对涂层镍基高温合金进行一系列实验研究来评估涂层抗氧化能力,采用静态增重法绘制了氧化动力学曲线,结合X射线仪对处理后的涂层镍基高温合金表面组成成分进行分析,通过扫描电子显微镜实验观察了处理后的氧化膜状态和截面形貌,氧化膜均匀致密,氧化动力学曲线也近似呈抛物线规律,提高了合金抗氧化性能。     

铸造镍基高温合金K35的氧化动力学

用静态增重法研究了K35镍基铸造高温合金的800℃氧化动力学·结果表明,K35合金的氧化动力学遵循抛物线规律,属于完全抗氧化级·利用X射线衍射、扫描电镜和能谱分析确定K35合金氧化膜组成以Cr2O3为主,含有NiCr2O4及TiO·TiO2·由于钛氧化物的存在,在高温氧化期间,K35合金发生了内氧化·     

钴基高温合金GH5605的恒温氧化行为研究

通过采用现代分析手段OM、XRD及SEM/EDX,研究了钴基高温合金GH5605的高温静态空气氧化行为。得到了该合金的氧化动力学曲线、氧化膜形貌及其相组成,评价了合金的抗氧化性能并分析了合金氧化机理。结果表明:钴基高温合金GH5605在750~950℃时氧化动力学遵循抛物线规律,生成的氧化膜以Cr203为主,无氧化膜剥落;合金氧化过程中无内氧化现象发生;该合金可满足1 100℃以下高温使用要求。     

DD3单晶镍基超合金高温力学性能

采用扫描电镜（ＳＥＭ）研究了单晶镍基高温合金ＤＤ３的高温蠕变性能和低应变速率下的拉伸行为。结果表明，ＤＤ３合金表现出良好的蠕变强度和较高的蠕变寿命；拉伸过程中合金的屈服强度在室温１１０３３Ｋ之间保持不变，当温度大于１０３３Ｋ后，屈服强度显著降低。断口分析表明，这类材料具有独特的断裂方式，断口为混合型，即包括韧性断裂和局部区域的解理断裂特征。     

堆垛层错能与反应力蠕变理论在第二相强化高温合金中的应用

在第二相强化的多元高温合金稳态蠕交速率方程的基础上,考虑了堆垛层错能与反应力蠕变理论,进而提出了一个新的稳态蠕变速率普遍式: 根据对Ni—Co二元合金,γ′相强化和氧化物弥散强化的镍基高温合金、以及γ′相含量不高不同含Co量的镍基高温合金(Waspaloy)和高γ′相含量的不同含Co量的镍基高温合金(Udimet 700)的蠕变进行验证,说明作者提出的稳态蠕变速率方程是可行的。     

表面粗糙度对Ni-20Cr合金高温氧化行为的影响

表面粗糙度作为重要的参数,对合金高温氧化膜剥落有重要影响.为此,研究表面粗糙度对Ni-20Cr合金氧化20 h内的氧化动力学及氧化膜剥落行为的影响.通过热重法绘制动力学曲线,可以看出2.5 μm砂纸磨痕的合金氧化速率明显低于90 μm砂纸磨痕的氧化速率.利用扫描电镜观察氧化膜表面形貌,显示粒状的氧化物在2.5 μm砂纸磨痕合金表面生成,而刻面状的氧化物在90 μm砂纸磨痕合金表面形成.XRD分析表面,在2.5 μm砂纸磨痕合金表面生成的氧化物为Cr2O3,在90 μm砂纸磨痕表面形成的氧化物为NiO.结果表明：平滑的Ni-20Cr合金表面有利于生成保护性的Cr2O3而不发生脱落,具有优良的抗氧化性能.     

镍基高温合金单晶的生长和氧化行为

采用改进型坩埚下降法生长了镍基高温合金单晶,使用氧化铝坩埚和〈001〉方向的籽晶,生长得到直径为30～40 mm、长度260 mm的晶棒。采用异型氧化铝坩埚,生长出特殊形状且中空的高温合金单晶涡轮机叶片构件。腐蚀显示所生长的晶体具有典型的镍基高温合金单晶形貌,在枝晶区域有少量的γ′/γ共晶,枝晶的平均间距是367μm,γ′相是立方结构且分布均匀。研究了晶体在900和1 000℃氧化200 h的氧化行为,氧化120 h后其增重达到一个恒定值。     

涡轮叶片用GH4033高温低周疲劳特性实验研究

采用总应变控制方法,在INSTRON8032上对镍基高温合金GH4033在400、500、600、700 ℃温度下的疲劳行为进行了研究,用扫描电镜观察了疲劳断口.采用Manson-Coffin方程对实验结果进行了分析,得到了该材料的高温低周疲劳特性参数.从断口的扫描电镜照片中看出:高温疲劳失效断口的萌生区断裂机制为沿晶断裂,扩展区为沿晶和穿晶断裂的混合断裂,失稳断裂区为穿晶断裂.     

新型定向凝固高温合金750℃抗热腐蚀性能

研究了涂有75%Na2SO4+25%NaCl盐膜的新型定向凝固镍基高温合金在750℃的热腐蚀行为,采用X射线衍射仪和带能谱的扫描电镜分析腐蚀产物相组成以及微观结构.结果表明:该合金在开始阶段腐蚀速率较大,随着腐蚀时间的延长以及合金腐蚀层厚度的增加,腐蚀速率降低.腐蚀层可分为3个区域:外层是以TiO2和Cr2O3为主相对疏松的氧化层,中间层具有保护性的是富Cr层,内层是以Al,Ti为主的氧化物以及点状分布的硫化物.合金的热腐蚀主要由氧化-硫化共存伴随着表面腐蚀物挥发形成,在此过程中腐蚀持续向合金基体推进,使得腐蚀层不断增厚.     

304不锈钢在模拟压水堆一回路水中高温电化学腐蚀行为

通过模拟压水堆一回路水环境,研究了氯离子浓度和溶解氧对304不锈钢高温电化学腐蚀行为的影响.动电位极化曲线结果表明,氯离子浓度主要影响高电位下的二次钝化效应,低电位下影响效果不明显,结合X射线光电子能谱对氧化膜元素成分的分析发现二次钝化效应与氧化膜中Fe/Cr元素含量比密切相关.电化学阻抗谱和扫描电镜结果表明,随着氯离子浓度增加,氧化膜阻抗逐渐降低,表面外层氧化物颗粒和间隙逐渐增大,耐腐蚀性能降低.随着溶解氧含量的升高,304自腐蚀电位逐渐升高,钝化电流密度降低,钝化区间缩小,表面氧化膜阻抗逐渐增加.     

Rare earth effect of yttrium on formation and property of Cr_2O_3 oxide film formed on Co-Cr binary alloy

The isothermal oxidizing kinetics of Co-40Cr alloy and its yttrium ion-implanted samples were studied at 1000 ℃ in air by thermal-gravity analysis (TGA). Scanning electronic microscopy (SEM) was used to examine the Cr2O3 oxide film's morphology after oxidation. Secondary ion mass spectrum (SIMS) method was used to examine the binding energy change of chromium caused by Y-doping and its influence on formation of Cr2O3 film. Acoustic emission (AE) method was used in situ to monitor the cracking and spalling of oxide films formed on both samples during oxidizing and subsequent air-cooling stages. Theoretical model simulating the film fracture process was proposed to analyze the acoustic emission spectrum both on time domain and on AE-event number domain. It is found that yttrium ion-implantation can remarkably reduce the isothermal oxidizing rate of Co-40Cr and improve the anti-cracking and anti-spalling properties of Cr2O3 oxide film. Reasons for the improvement are mainly that the implanted yttrium can reduce the grain size of Cr2O3 oxide, increase the high temperature plasticity of oxide film, and remarkably reduce the number and size of Cr2O3/Co-40Cr interfacial defects.     

Influence of metallurgical processing parameters on defects in cold-rolled steel sheet caused by inclusions

The cleanliness and defects for cold-rolled steel sheet caused by inclusions are greatly influenced by parameters in the metallurgical processing. Good control of parameters during the processing can lead to a better product. In this paper, data mining was used to explore the influence of parameters on defects in steel sheets. A decision tree model was established and it was found that the oxygen content before deoxidation, the end-point temperature of the converter, and the temperature before deoxidation had a great impact on the defects in the cold-rolled sheet that were caused by inclusions. This finding was confirmed by experiments with infrared absorption, scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS), and automatic inclusion analysis methods. After optimization according to results from the model and experiments, the defect rate caused by the inclusions was reduced from 0.92% to 0.38%.     

利用电化学法制备Pt纳米线

利用阳极氧化铝（AAO）作为模板,制备出高定向的Pt纳米线。Pt纳米线的形貌由环境扫描电镜证实,并通过x-射线能谱（EDX）、X-射线粉末衍射谱（XRD）测试手段进行了表征。     

Evolution of insoluble eutectic Si particles in anodic oxidation films during adipic-sulfuric acid anodizing processes of ZL114A aluminum alloys

The effects of insoluble eutectic Si particles on the growth of anodic oxide films on ZL114A aluminum alloy substrates were investigated by optical microscopy (OM) and scanning electron microscopy (SEM). The anodic oxidation was performed at 25℃ and a constant voltage of 15 V in a solution containing 50 g/L sulfuric acid and 10 g/L adipic acid. The thickness of the formed anodic oxidation film was approximately 7.13 μm. The interpore distance and the diameters of the major pores in the porous layer of the film were within the approximate ranges of 10-20 nm and 5-10 nm, respectively. Insoluble eutectic Si particles strongly influenced the morphology of the anodic oxidation films. The anodic oxidation films exhibited minimal defects and a uniform thickness on the ZL114A substrates; in contrast, when the front of the oxide oxidation films encountered eutectic Si particles, defects such as pits and non-uniform thickness were observed, and pits were observed in the films.     

CuInSe<Subscript>2</Subscript> thin films obtained by pulse-plating electrodeposition technique with novel pulse wave

CuInSe₂ films were electrodeposited onto indium tin oxide (ITO) substrate in constant current mode using bell-like wave modulated square wave in aqueous solution. The films obtained at different pulse frequencies were characterized by scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). UV-Vis-NIR absorption spectro- scopy was used to study the optical properties of these films. The results showed that the chalcopyrite phase CuInSe₂ films with a smooth surface and stoichiometric composition could be obtained at appropriate pulse frequency. The crystallinity of CuInSe₂ films could be further improved after annealing treatment. Despite this, we also found that the films obtained using the pulse-plating electrodeposition technique had a faster deposition rate and better film adhesion ability than that using the traditional CIS elec-trodeposition technique, which is significant to the low-cost CIS thin film solar cell production.     

CO气氛下CaO对铁晶须生长影响的原位观察和机理研究

利用光学体视显微镜和高温热台对CO气体还原Fe2O3过程进行原位观察,并结合扫描电镜、能谱和红外光谱分析,研究掺入CaO对还原过程中铁晶须生成和生长机理的影响.实验结果表明:铁晶须是在实现FeO→Fe转变时形成和不断生长的;CaO对氧化铁的还原有抑制作用,当掺入CaO质量分数≥8%时,没有铁晶须生成和生长.因此,可以通过控制CaO掺入量的方式抑制铁晶须的生成和生长,进而减少矿粉颗粒团聚的发生.     

氧化膜对14Cr12Ni2WMoVNb钢QPQ渗层的室温摩擦磨损和腐蚀性能的影响

为了研究14Cr12Ni2WMoVNb钢QPQ(淬火-抛光-淬火)处理后的氧化膜对渗层室温摩擦磨损和腐蚀性能的影响,利用金相、X射线衍射分析、扫描电镜、能谱分析、划痕仪、摩擦磨损试验机和电化学工作站对试样进行了表征.结果表明:氧化膜对渗层室温摩擦学性能的影响与载荷大小有关.在摩擦时间均为4min情况下,载荷较小(50N)时,氧化膜可以降低摩擦系数和体积磨损率;载荷较大(100N)时,氧化膜被破坏无法降低体积磨损率.氧化膜可明显提高渗层的耐腐蚀性能.含氧化膜试样的极化曲线有明显的钝化区,点蚀电位为-13mV,去除氧化膜试样在盐雾腐蚀12h后表面有大范围的腐蚀区域,而含氧化膜试样盐雾腐蚀48h后才有大区域腐蚀发生.     

8-羟基喹啉插层双氢氧化膜与溶胶–凝胶涂层对镁合金的腐蚀防护性能研究

采用8-羟基喹啉（8-HQ）插层双氢氧化物（LDH）膜为底层和溶胶–凝胶层相结合的方法,对AM60B镁合金进行了腐蚀防护性能的研究。采用扫描电子显微镜（SEM）、场发射扫描电子显微镜（FESEM）、能量色散X射线能谱（EDS）、X射线衍射（XRD）、原子力显微镜（AFM）和电化学阻抗谱（EIS）等方法对LDH、LDH/溶胶–凝胶和LDH@HQ/溶胶–凝胶涂层进行分析。SEM图像显示,垂直生长的纳米片组成的LDH膜完全覆盖在表面。LDH/溶胶–凝胶和LDH@HQ/溶胶–凝胶涂层的形貌相同。此外,除了LDH@HQ/溶胶–凝胶涂层具有相对较高的表面粗糙度外,两种复合涂层的形貌几乎相同。虽然在3.5wt% NaCl溶液中,LDH膜具有与合金样品相同的阻抗行为,但其耐蚀性要高得多,这可能是由于其阻隔性以及对氯离子的捕获。与LDH薄膜相似,随着暴露时间的延长,LDH/溶胶–凝胶复合材料的耐蚀性降低。但其值远高于LDH膜,这主要与溶液路径的封闭有关。LDH@HQ/溶胶–凝胶复合材料的抗腐蚀性能优于LDH/溶胶–凝胶涂层,原因是8-HQ通过络合作用吸附在损伤部位。     

Influence of silane coupling agent on the conversion film forming of galvanized steel treated with cerium salt

The influence of silane coupling agent on the film forming of galvanized steel treated with cerium salt was studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), and the corrosion resistance of conversion films was analyzed by electro interstitial scanning (EIS). The results show that silane coupling agent KH-570 has significant influence on the compactness and homogeneity of cerium conversion films, and the process of film forming is promoted by increasing the content of tervalent and tetravalent cerium oxide. The impedance value of the cerium conversion film, especially modified with KH-570, is greater than that of the base metal, which reveals that it is necessary to add silane coupling agent to the film-forming solution in order to improve the corrosion resistance of the conversion film.