中间层材料对Ti/Al异种金属搅拌摩擦焊组织性能影响

以3mm厚2A14铝合金和TC4钛合金为试验材料,分别添加0.05mmZn和Ni箔片,研究了不同工艺参数下Zn和Ni对接头微观组织、力学性能的影响。试验结果表明：当添加中间层Zn时,在旋转速度为375r/min、焊接速度为75mm/min时,接头抗拉强度达到最大值237.3MPa,为铝合金母材拉伸强度的56.7%。同样参数下,添加中间层Ni后,能显著减少接头中脆性相TiAl₃,接头抗拉强度最大值提高到285.3MPa,达到铝合金母材抗拉强度的68％,接头断裂方式呈脆性+韧性混合型断裂。     

钛基亚氧化钛电极强化电解失效行为研究

亚氧化钛具电化学窗口宽、耐蚀性好等诸多优点,是非常有应用潜力的污水处理用阳极材料。但目前关于其在污水处理方面的研究主要集中在其电化学性能,还未对其用于污水处理的强化电解性能进行过评价。本研究采用强化电解方法测试钛基亚氧化钛电极的寿命和失效前后的形貌和结构变化,分析其电化学性能和表面反应的机理。结果表明,亚氧化钛电极的强化电解寿命是320 h左右,每12 h反置电流可延长电解池整体寿命至840 h(电极寿命420 h),失效前后的亚氧化钛组成变化不大,涂层出现裂纹和脱落,导致基体钝化,使得槽压迅速升高而发生失效。     

不同前驱体制备的锡锑中间层对Ti／SnO2＋Sb2O3／PbO2电极性能的影响

研究了以乙二醇与柠檬酸反应制得的乙二醇柠檬酸酯溶液、乙二醇、乙醇、正丁醇为前驱体溶剂制备的锡锑中间层对Ti/SnO2 Sb2O3/PbO2电极性能的影响,用XRD、ESEM对不同前驱体制备的锡锑中间层和对应的二氧化铅活性层进行了表征,并用极化曲线法和阳极寿命快速检测法比较了不同前驱体对Ti/SnO2 Sb2O3/PbO2电极的阳极寿命和在1．0mol/L硫酸溶液中的电催化活性的影响。结果表明,不同前驱体溶剂对锡锑中间层的结构和形貌有着显著的影响;以乙二醇与柠檬酸反应制得的聚合前驱体为溶剂制备的锡锑中间层表面致密,锡锑含量相对较高,该中间层的均匀度和平整度明显好于其它3种前驱体。由聚合前驱体中间层制得的Ti/SnO2 Sb2O3/PbO2电极的使用寿命明显提高,但不同中间层前驱体对电极的电催化活性影响不大。     

耐酸非贵金属Ti／MO2阳极SnO2＋Sb2O4中间层研究

采用热分解法制备了非贵金属Sn02＋Sb204中间层Ti基MO2活性层电极，利用SEM，XRD和XPS方法对中间层进行了表征。测定了Ti／SnO2＋Sb2Od／MnO2和Ti／SnO2＋Sb2O4／PbO2电极在硫酸溶液中的析氧极化曲线，二者起始析氧过电位均比贵金属小；考察了在高电流密度（4A／cm^2）下的加速寿命，二者依次分别达到18h和86h。实验表明，SnO2＋Sb2O4是一种具有良好导电性和结合力的耐酸Ti基MO2电极中间层材料。     

工艺参数对Ti/Zn/Al异种金属搅拌摩擦焊接头力学性能的影响

以3 mm厚2A14铝合金和TC4钛合金为对接材料,0.05 mm厚Zn薄片为中间层材料进行搅拌摩擦焊对接。研究了不同焊接参数对钛/铝异种金属搅拌摩擦焊对接接头宏观形貌、微观组织、力学性能的影响。结果表明:当焊接速度为75 mm/min,旋转速度为375~950 r/min,偏移量2.5 mm时,均可获得表面成形良好的焊接接头。但随着旋转速度的增加,焊缝表面粗糙度先减小后增大,而对接接头抗拉强度逐渐降低;当旋转速度为600 r/min,焊接速度从60mm/min增大到95 mm/min时,焊缝的飞边逐渐减少。当旋转速度为375 r/min,焊接速度为75 mm/min,偏移量2.5 mm时,抗拉强度达到最大值237.3 MPa,达铝合金母材抗拉强度的56.7%。     

Effect of AlN intermediate layer on growing GaN film by hydride vapor phase epitaxy

Thick GaN layer deposited by hydride vapor phase epitaxy (HVPE) on a metalorganic chemical vapor deposition (MOCVD) GaN template with a thin low temperature (LT) AlN intermediate layer was investigated.High resolution X-ray resolution diffraction (HRXRD) shows that the crystalline quality of thick GaN layer was improved compared with the template.As confirmed by atomic force microscopy (AFM) observations, the surface morphology of AlN intermediate layer helps to improve the nucleation of GaN epilayer.Photoluminescence (PL) spectra measurement shows its high optical quality and low compressive stress, and micro Raman measurement confirms the latter result.Thus, the deposition of the LT-AlN interlayer has promoted the growth of an HVPE-GaN layer with an excellent crystalline quality.     

基于Ti中间层的SiCp/6061-T6Al MMCs低功率激光-TIG复合焊组织与性能

以0.1mm厚的Ti箔做中间夹层,使用低功率激光-TIG复合焊的方式对SiCp/6061-T6Al MMCs 进行焊接,并对接头的宏观形貌、显微组织、物相、电阻率、抗拉强度及断口形貌进行分析。结果表明：激光功率对焊缝的成形有着较大影响;Ti箔的加入基本抑制了焊缝中针状Al₄C₃生成,并生成TiC增强相以及条状TiAl₃;焊缝区为等轴晶组织,熔合区为柱状晶组织,热影响区组织变化不明显;随着激光功率的增加接头的电阻率呈现出增加的趋势,并明显高于母材;在554W时接头的抗拉强度可达196.98MPa,是母材强度的54.71%。接头断口中几乎没有气孔,韧窝中的第二相粒子以TiC为主,接头呈现出以脆性断裂为主的脆-韧性混合断裂特征。     

Ti4+掺杂对SnO2基压敏陶瓷电学性能的影响

研究了TiO2掺杂浓度对SnO2-Bi2O3-Nb2O5-Sb2O3-MnO基压敏陶瓷非线性特性的影响.利用X射线衍射(XRD)与扫描电镜对相组成和微结构的分析表明:TiO2的添加没有新的相生成.随着TiO2含量的增加,密度与晶粒尺寸均明显减小,压敏电压(EB)以及非线性系数(α)随TiO2掺杂量的增加而增加.当掺杂浓度为3%,烧结温度为1250℃时样品具有最高的压敏电压(EB=1169 V/mm)和非线性系数(α=56).     

十二烷基硫酸钠对IrO2-Ta2O5/SnO2- Sb-Mn/Ti电极电催化性能影响

采用涂刷-热分解法制备不同浓度阴离子表面活性剂十二烷基硫酸钠（SDS）的IrO2-Ta2O5/SnO2- Sb-MnO2/Ti电极,通过扫描电子显微镜（SEM）和X射线衍射仪（XRD）对其微观形貌及物相组成进行分析;应用循环伏安、极化等测试手段,表征制备电极的电催化活性.结果表明,适量添加十二烷基硫酸钠能够改善IrO2-Ta2O5/SnO2-Sb-Mn/Ti电极的微观形貌,提高电催化活性.在本实验条件下,SDS最佳添加量是1.6 g/L,结晶化度高达99.83%.利用苯酚电催化降解实验和强化寿命测试进一步考察所制电极的电催化活性与稳定性,结果显示,在电流密度15 mA/cm2条件下电解180 min,SDS的加入使苯酚去除率由原来的68.5%提高到79.2%.COD去除率由60.1%提高到 67.5%,电催化性能得到提升,电极强化寿命由52 h延长至68 h.     

无汞扣式碱锰电池的安全性能

探讨电池配方和工艺参数对无汞扣式碱锰电池安全性能的影响,采用短路测试和过放电测试的方法研究各种工艺配方下电池的安全性能,通过实验研究了影响电池安全性能的各种因素,并确定最佳的工艺参数分别如下：负极与正极容量配比为0.9：1,KOH电解液浓度为43%（质量分数）,电解液中氧化锌的含量为7%,锌膏中的氧化锌用量为0.8%～1.0%,锌膏中电解液用量为锌粉量的40%～42%,锌膏中增稠剂用量为锌粉量的1%且其中聚丙烯酸钠与聚丙烯酸的质量比为6：4,锌膏中缓蚀剂用量为锌粉量的0.01%。在此工艺条件下制得的无汞扣式碱锰电池短路测试后不爆炸、过放电测试后尺寸变形不超过规定最大尺寸的0.12 mm。     

Preparation and Characterization of Titanium Based PbO2 Electrodes Doped with Some Common Elements

采用电沉积法制备了4种钛基体PbO2电极,其中3种分别采用Fe、Ni和Ag进行掺杂。利用SEM、XRD、强化寿命测试及线性伏安扫描对所制备4种电极性质进行表征,结果表明:4种电极表面均为四方体形PbO2颗粒;非掺杂电极及Ni掺杂电极的平均颗粒直径非常接近,且要小于Fe掺杂及Ag掺杂电极;Fe掺杂电极的强化测试寿命最长(116h),这可能是由其致密的表面所导致;Ni掺杂电极的析氧电位为4种电极中最高,并在苯酚降解实验中拥有最高的COD去除效率及平均电流效率,以及最低的能耗值。     

电镀镍中间层对钛基二氧化铅阳极性能的影响

通过阴极电镀在钛基表面制备出镍中间层,随后在其上再进行阳极电沉积β-PbO_2涂层来制备Ti/Ni/PbO_2电极,并与无镍中间层的Ti/PbO_2电极进行对比。通过微结构分析、1 mol/LH_2SO_4溶液中的加速寿命试验、电化学性能测试和电氧化苯酚模拟废水行为研究,考察了电镀镍中间层对二氧化铅涂层电极的结构和性能的影响。结果表明,电镀镍中间层的引入不仅使活性β-PbO_2涂层的晶粒细化,增强了电极的催化活性,而且有效地改善了电极表面的导电性,降低了槽压,使得电极表面电势均匀分布,从而明显地延长了电极寿命,降低了电催化氧化降解苯酚模拟废水的能耗。     

SnO_2-Sb_2O_3-RuO_2/Ti电极制备及其性能研究

采用热分解法制备了SnO_2-Sb_2O_3-RuO_2/Ti电极,并将其用于苋菜红模拟染料废水处理。实验表明电极制备的最佳条件为:烧结温度为500℃,涂层数为6层,n(Sn):n(Sb):n(Ru)=10:1:1。通过XRD、SEM和CV对电极表面形貌、表面微观结构和电化学性能进行测试,结果表明:SnO_2-Sb_2O_3-RuO_2/Ti电极表面晶体为四方金红石结构且晶型单一;表面晶粒细小平整,晶粒间结合紧密;具有较好的电催化活性和较长的强化试验寿命。     

La掺杂的SnO2-Sb中间层对钛基IrO2+Ta2O5电极性能的影响

目的改善Ti/IrO_2+Ta_2O_5涂层电极的析氧电催化性能。方法用热分解法在钛基材上制备了La掺杂的SnO_2-Sb中间层,并以此作为基体涂覆IrO_2+Ta_2O_5活性层,制备了Ti/SnO_2-Sb-La/IrO_2+Ta_2O_5涂层电极。采用扫描电子显微镜(SEM)、能量散射能谱(EDS)及X-射线衍射光谱(XRD)技术分别分析了中间层和活性层的表面形貌、元素组成及晶相结构。采用线性扫描伏安曲线(LSV)和强化寿命测试方法在硫酸溶液中分别研究了Ti/SnO_2-Sb-La/IrO_2+Ta_2O_5涂层电极的析氧电催化活性和使用稳定性。同时,考察了La的掺杂比例对Ti/SnO_2-Sb-La/IrO_2+Ta_2O_5电极强化寿命的影响。结果相对未掺杂La的中间层,掺杂La后的中间层表面裂纹减少,有更高的析氧过电位和更低的析氧电流密度。La掺杂对活性层的表面形貌和晶相结构基本没有影响,但电极的析氧电流密度有所提高。通过测试不同La掺杂比例涂层电极的强化寿命,发现La最佳掺杂比例为nLa:nSn=0.5:100。和未掺杂La涂层相比,La最佳掺杂比例涂层电极的强化寿命提高了22.8%。结论相对于未掺杂的Ti/SnO_2-Sb/IrO_2+Ta_2O_5电极,La掺杂后的Ti/SnO_2-Sb-La/IrO_2+Ta_2O_5涂层电极析氧电催化活性和强化寿命都得到改善。     

制备温度和电流密度对不锈钢基PbO2 电极电化学性能的影响

在不同温度和电流密度的条件下,制备不锈钢基PbO2电极,分析了电极的析氧曲线及析氧动力学参数,进而考察了温度和电流密度对PbO2电极节能性和电催化活性的影响。结果表明:温度为80℃,电流密度为30mA/cm2时,制备的电极成分稳定,重现性好,可有效降低槽电压,电催化活性良好;在小电流密度下的主要产物为β-PbO2,大电流密度下生成部分α-PbO2;与传统的铅基阳极材料相比,该PbO2电极节能性和催化活性均有较大程度的提高。     

Effect of the intermediate layer on the properties of a coating of 50KhFA steel produced by electrical resistance welding

The results of investigations of deposition of a coating of 50KhFA steel (0.46–0.54% C, 0.80–1.10% Cr, and 0.15% V) on shafts of steel 45 through an intermediate layer produced from a powder material and an amorphous strip brazing alloy are presented. It is shown that at the optimum combination of the parameters of electric resistance surfacing the bonding strength of the coating with the component is identical with that of the parent metal, the microhardness of the coating equals 6900–8100 MPa, the length of the zone of the thermomechanical effect does not exceed 0.35–0.6 mm, and the impact toughness and fatigue strength decrease by no more than 10% in comparison with steel 45 in the initial condition.     

热压工艺对SiCf/Ti复合材料界面反应层生长影响的数值模拟

提出一个热-力-扩散-反应强耦合相场模型来研究热压烧结制备工艺对连续碳化硅纤维增强钛基复合材料中金属间化合物生长规律的影响。模拟结果表明,在两种不同温度下各个界面反应层(Ti₃SiC₂/Ti₅Si₃C_x/Ti₅Si₃C_x+TiC/TiC)的厚度生长与试验值吻合较好。增大外加压力能促进界面层厚度的生长,但对其中抗拉强度最低的Ti₅Si₃层的生长起显著的抑制作用,同时使各界面反应层由周向拉应力状态逐渐转变为压应力。温度的升高使断裂韧度最大的Ti₃SiC₂层厚度增大,但也使总界面层和Ti₅Si₃层的厚度增加。因此,在制备工艺上适当增加压力并选择合适的温度,得到厚度适宜的界面反应层的同时,尽可能使Ti₅Si₃层变薄和Ti₃Si...     

Effect of porous silicon layer on the performance of Si/oxide photovoltaic and photoelectrochemical cells

Photovoltaic and photoelectrochemical systems were prepared by the formation of a thin porous film on silicon. The porous silicon layer was formed on the top of a clean oxide free silicon wafer surface by anodic etching in HF/H₂O/C₂H₅OH mixture (2:1:1). The silicon was then covered by an oxide film (tin oxide, ITO or titanium oxide). The oxide films were prepared by the spray/pyrolysis technique which enables doping of the oxide film by different atoms like In, Ru or Sb during the spray process. Doping of SnO₂ or TiO₂ films with Ru atoms improves the surface characteristics of the oxide film which improves the solar conversion efficiency.The prepared solar cells are stable against environmental attack due to the presence of the stable oxide film. It gives relatively high short circuit currents (I_sc), due to the presence of the porous silicon layer, which leads to the recorded high conversion efficiency. Although the open-circuit potential (V_oc) and fill factor (FF) were not affected by the thickness of the porous silicon film, the short circuit current was found to be sensitive to this thickness. An optimum thickness of the porous film and also the oxide layer is required to optimize the solar cell efficiency. The results represent a promising system for the application of porous silicon layers in solar energy converters. The use of porous silicon instead of silicon single crystals in solar cell fabrication and the optimization of the solar conversion efficiency will lead to the reduction of the cost as an important factor and also the increase of the solar cell efficiency making use of the large area of the porous structures.     

Effect of ambient oxygen pressure on structural, optical and electrical properties of SnO2 thin films

PolycrystaUine SnO2 thin films were deposited on sapphire substrates at 450℃ under different ambient oxygen pressures by pulsed laser deposition technique. The effect of ambient oxygen pressure on the structural, optical and electrical properties of SnO2 thin films was studied. X-my diffraction and Hall measurements show that increasing the ambient oxygen pressure can improve crystallization of the films and decrease resistivity of the films. A violet emission peak centered at 409 nm was observed from photoluminescence measurements for SnO2 films under deposition ambient oxygen pressure above 5 Pa, which is related to the improvement of crystalline of the films.     

Dehydroxylation action on surface of TiO2 films restrained by nitrogen carrier gas during atomic layer deposition process

A strong influence of nitrogen gas on the content of surface hydroxyl groups of TiO2 films by atomic layer deposition（ALD） was investigated by X-ray photoelectron spectroscopy（XPS）, contact angle measuring system, and UV–Vis spectrophotometer. XPS spectra of O 1s indicate that the content of surface hydroxyl groups is varied when using N2 as carrier gas. The results of water contact angles and optical reflection spectra show that the content variation of surface hydroxyl groups influences the wetting properties and optical reflectivity of TiO2 films. A surface reaction model is suggested to explain the ALD reaction process using N2 as carrier gas.