Ni-Fe／Ni-P-W双层合金镀层的制备及性能

采用电沉积法,在45#钢上制备了Ni–Fe/Ni–P–W双层合金镀层。采用原子吸收分光光度法和X射线衍射分别测定了镀层的化学成分及相结构,并测试了其显微硬度和耐腐蚀性能。结果表明,该双层合金镀层具有较强的显微硬度,在5%(质量分数)NaCl溶液中具有比Ni–P–W合金镀层更优异的耐蚀性能。因此,该双层合金镀层可用作防腐耐磨镀层。

高速铰削双层合金材料的硬质合金铰刀

阐述叶片叶轮两种不同性能合金钢装配后的铆钉孔铰削问题 ,论述了加工该铆钉孔用铰刀材料选择及刀具结构和几何角度设计 ,给出加工铆钉孔的工艺参数 。

用云纹干涉法测量和研究双层钴合金的挠度

运用云纹干涉原理对双层钴-合金材料进行三点弯曲试验,测试其常温与高温条件下的挠度值。通过大量试验,且与千分表测试的挠度值进行比较。结果表明,常温条件下的云纹测试挠度值与千分表法可以达到同样的精确度。同时,该实验方法体现了高温云纹干涉法在材料高温力学性能测试方面的优越性。高温云纹法是非接触式测量,在高温环境下有效地解决了量具高温变形的困难,且结合云纹图像可以对试件受力动态变形情况进行实时观测和分析,是一种较为精确测试常温及高温挠度的新方法。

热轧双层复合铁基合金的CD渗碳

研究了 50钢与Fe V合金复合轧制双层材料CD渗碳层的组织与性能。结果表明 ,热轧态复合界面 50钢一侧由于碳的扩散出现厚度约 50 μm的铁素体区。在随后的CD渗碳过程中 ,铁素体区消失。复合界面两侧组织差异不大。在Fe V合金复合层渗透的情况下 ,自Fe V合金表面经界面至 50钢内部 ,硬度梯度平缓。Fe V合金层在 950℃、1 40 %C碳势下渗碳 5h ,表面无Fe3 C析出 ,淬火后可获得高硬度渗层组织。渗层表面为马氏体基体和弥散的碳化物 ,尺寸为 1 0 0nm左右。Fe 1 69%V合金渗层表面硬度高达 82 5HV ,超过淬火、回火后的Cr1

铝合金化学镀Ni-P/Ni-B双层复合镀层及其性能研究

基于雷达波导管内表面电镀银层工作时极易被臭氧(O3)氧化腐蚀,从而影响到使用可靠性。为了解决雷达波导管内表面既具有优良导电性能又耐臭氧腐蚀的技术要求,对铝合金化学镀Ni-P/Ni-B双层复合合金镀层的操作方法、工艺条件及主要性能进行了研究,结果表明,若用Ni-P/Ni-B化学镀层替代电镀银层,导电性能有所降低,而耐臭氧腐蚀性能明显增强。

Zn-Ni合金/Ni-P合金双层镀层性能的研究

在钢铁基体上电镀Zn-Ni合金/Ni-P合金双层镀层,并对其性能进行了研究。结果表明:Zn-Ni合金/Ni-P合金双层镀层兼具Zn-Ni合金的高耐蚀性和Ni-P合金的高耐磨性,与基体的结合力也较好,而且在脆性方面比Zn-Ni合金的好,在耐磨性方面与Ni-P合金的相当。

采用双层辉光等离子表面合金化技术在Q235钢表面制备钽改性层及其耐蚀性

采用双层辉光等离子表面合金化技术在Q235钢表面制备钽改性层,并对钽改性层的组织、成分及耐蚀性能进行了研究。结果表明:改性层中的钽元素含量呈梯度分布,改性层与基材结合良好;钽改性层的耐蚀性明显优于基材的,其保护效率高达99.88%;钽改性层形成的钝化膜完整,能很好地保护基材。

聚合物纳米纤维-多孔镁合金双层支架的构建及对成骨细胞活性的影响

目的 制备一种聚合物纳米纤维-多孔镁合金双层支架,并考察其体外降解性能及对MC3T3-E1Q前成骨细胞生物活性的影响.方法 使用热致相分离法(TIPS)在多孔镁合金支架外层覆盖一层聚合物纳米纤维,将PLA聚合物纳米纤维-多孔镁合金双层支架和PLA聚合物纳米纤维-TCP复合支架进行对比,采用电子天平称重、荧光显微细胞计数、MTT法、钙黄绿素染色分别测定两种支架的失重率、对MC3T3-E1Q前成骨细胞黏附、增殖和分化的影响.结果 PLA聚合物纳米纤维-多孔镁合金双层支架的失重率、黏附的MC3T3-E1Q前成骨细胞数量、MC3T3-E1Q前成骨细胞增殖数量、钙化结节数量及面积较PLA聚合物纳米纤维-TCP复合支架均有显著优势,差异均具有统计学意义(P<0.05).结论 成功制备了一种具有良好生物学功能及快降解速率的PLA聚合物纳米纤维-多孔镁合金双层支架,具有广泛的应用前景.

双层铝合金车体焊接结构设计

依照双层铝合金车体总体设计规范的要求,以车辆动态包络线作为车体断面设计的约束条件,进行车体的三维设计和详细结构设计,按照EN 15085的焊接标准要求优化双层铝合金车体焊接结构,同时对车体母材与焊接材料进行优化匹配。经车体静强度试验验证,优化后的焊接接头型式减少了车体大部件和车体总成的焊接变形,适合车体的模块化制造需求。通过计算车体静强度,证明250 km/h双层铝合金试验车体的强度符合EN 12663要求,产品的安全性、可靠性满足欧洲铁路客车强度规范。

汽车双层铝合金板材焊接工艺优化研究

铝合金是汽车制作业重要材料之一,汽车用双层铝合金板材焊接时存在许多问题,例如焊接表面易氧化、容易产生各种焊接缺陷等等。本文论述了常用焊接方法 TIG焊、MIG焊、电子束焊、激光焊、激光电弧焊、搅拌焊的特点与应用,重点讨论了汽车双层铝合金板材焊接工艺优化研究。

AZ91D镁合金表面Ni-铅基巴氏合金双镀层的摩擦磨损性能

为了改善镁合金的摩擦学性能,采用化学镀镍与热浸镀铅基巴氏合金相结合的方法,在AZ91D镁合金表面获得了Ni-铅基巴氏合金双镀层。用JEOLJSM-7001F型扫描电镜观察了镀层的形貌,以CETRUMT-2型球盘试验机研究了干摩擦条件下AZ91D镁合金基体和Ni-铅基巴氏合金镀层的摩擦学性能及摩擦后的表面磨痕轮廓特征。研究发现,镁合金基体与Ni-铅基巴氏合金镀层载荷为0.5 N时平均摩擦系数分别为0.397和0.145,磨损率分别为3.180×10-3,9.826×10-5mm3/(m·N);载荷为2 N时摩擦系数分别为0.346和0.254,磨损率分别为1.991×10-3,7.763×10-5mm3/(m·N)。结果表明,Ni-铅基巴氏合金双层镀层使镁合金表面的减摩性能得到显著提高,同时也有效地提高了基体的耐磨性能。

Ti-6Al-4V钛合金的等离子W-Mo共渗

采用双层辉光等离子表面合金化技术对Ti-6Al—4V钛合金进行W—Mo共渗，研究了880—1000℃ W-Mo共渗时基体温度对渗层厚度的影响，采用SEM和XRD观察、检测渗层组织结构和相组成。结果显示，Ti-6Al—4V合金的W-Mo渗层组织良好。纳米压痕试验结果表明，合金渗层硬度高于基体。

γ-TiAl表面双辉等离子W-Mo合金化对其氧化行为的影响

目的研究W-Mo表面合金化对γ-TiAl合金抗高温氧化性能的影响。方法采用双层辉光等离子合金化技术在γ-TiAl合金表面进行W-Mo合金化,通过恒温氧化试验评价改性层的抗氧化性能,并通过扫描电子显微镜与X射线衍射仪对氧化膜表面及截面形貌和相组成进行分析。结果使用双层辉光等离子合金化技术可以在γ-TiAl表面制备出W-Mo改性层,改性层厚度为9μm,最外层为厚约6μm的W-Mo沉积层,而在沉积层与基体之间存在厚约3μm的扩散层。W-Mo改性层均匀、致密,基体与改性层之间没有裂纹、孔洞等明显缺陷,扩散层中的元素含量呈梯度分布。在750℃恒温氧化100 h后,γ-TiAl基体的氧化增重为5.306 mg/cm^2,W-Mo改性层的氧化增重为2.578 mg/cm^2,仅为γ-TiAl基体的48.6%。在氧化10、20、50 h后,改性层表面无明显变化,氧化膜层均匀、致密、无缺陷,几乎没有出现剥落现象;氧化100 h后,改性层中Mo与W的原子比由3:1降低到了1:2。结论通过双层辉光等离子合金化技术制备W-Mo改性层,能够改善γ-TiAl合金在750℃下的抗高温氧化性能。W-Mo改性层在经过氧化后所形成的氧化膜连续、致密,可以阻碍氧原子向基体内的扩散。但在氧化100 h后,Mo元素的蒸发会破坏氧化膜的完整性,使抗氧化性能有所降低。

Ti_2AlNb基合金等离子渗碳层的组织结构与摩擦性能

采用双层辉光等离子表面合金化技术在Ti2AlNb基合金表面渗碳以提高其耐磨性,通过扫描电子显微镜、X射线衍射仪、动态显微硬度系统等对渗碳层的微观组织、相组成及动态显微硬度进行表征,并采用HT2500型摩擦磨损试验机对其耐磨性进行测试。结果表明,经等离子渗碳后Ti2AlNb基合金可获得厚度约11μm的表面渗碳层,且该层碳元素含量由表及里呈梯度变化。合金渗碳层主要由纯C、TiC及Ti2AlC相组成,表面动态显微硬度达9.61 GPa。渗碳试样的比磨损率仅为基体合金的1.82%,耐磨性能大大提高。

Corrosion of in-situ grown Mg Al-LDH coating on aluminum alloy

Mg Al-layered double hydroxides（LDH） coatings were fabricated by the in-situ hydrothermal treatment method on the AA5005 aluminum alloy.The characteristics of the coatings were investigated by XRD,FT-IR,SEM and EDS.The effect of the p H value of the solution on the formation of the LDH coatings was studied.The optimum p H value of the solution was 10.0.The corrosion resistance of the LDH coatings was studied using potentiodynamic polarization tests and electrochemical impedance spectrum（EIS）.The results demonstrate that the LDH coatings,characterized by platelets vertically to the substrate surface possess excellent corrosion resistance.The influence of the hydrothermal crystallization time on the corrosion resistance was evaluated.Prolonging the crystallization time can increase the corrosion resistance of the obtained LDH coatings.The anticorrosion mechanism of the LDH coatings was discussed.

Tribological behaviors of Fe-Al-Cr-Nb alloyed layer deposited on 45 steel via double glow plasma surface metallurgy technique

Double glow plasma surface metallurgy technique was used to fabricate a Fe?Al?Cr?Nb alloyed layer onto the surface of the 45 steel. The microstructures and composition of th?eA Fl?eCr?Nb alloyed layer were analyzed by scanning electronic microscopy, X-ray diffraction and energy dispersive spectroscopy. The results indicate thatthe 20 μm alloyed layer is homogeneous and compact. The alloyed elements exhibit a gradient distribution along the cross section. Microhardness and nanoindentation tests imply that the surface hardness of the alloyed layer reaches HV 580, which is almost 2.8 times that of the substrate. Compared with the substrate, the alloyed layer has a much smaller displacement and a larger elastic modulus. According to the friction and wear tests at room temperature, the? FeAl?Cr?Nb alloyed layer has lower friction coefficient and less wear mass, implying that the Fe?Al?Cr?Nb alloyed layer can effectively improve the surface hardness and wear resistance of the substrate.

Fabricating a Micro Electromagnetic Actuator with High Energy Density

This paper introduces a new technology to fabricate a micro electromagnetic actuator with high energy density without an enclosed magnetic circuit. This technology includes fabricating multi-turns planar micro coils and fabricating the thick magnetic （NiFe） core on the silicon wafer. The multi-turns planar micro coils are fabricated by the electroplating method from the surface along the line and by dynamically controlling the current density of the copper electrolytes. In order to fabricate thick NiFe plating,the adhesion properties between the NiFe plating and the silicon substrates are improved by changing the surface roughness of the silicon substrates and increasing the thickness of the seed layer. Furthermore,the micro electromagnetic actuator is tested and the energy density of the actuator is evaluated by force testing. The experiments show that the microactuator is efficient in producing high magnetic energy density and high magnetic force.

Preparation and characterization of MWCNTs/LDHs nanohybrids for removal of Congo red from aqueous solution

The assembly of layered double hydroxides （LDHs） and multi-walled carbon nanotubes （MWCNTs） nanohybrids was prepared as MWCNTs/LDHs by co-precipitation. The synthesized nanoparticles were characterized by using XRD, FT-IR, SEM/EDX, TGA and BET. XRD and SEM studies proved that MWCNTs phases did not enter into the interlayers of LDHs, they dispersed over the LDHs surface homogeneously. BET results showed that MWCNTs/LDHs possessed hierarchically porous nanostructure with large surface area （124.974 m^2/g） and great pore volume （0.604 cm^3/g）. Batch experiments were conducted to study the adsorption efficiency of Congo red （CR）. It was worthy to note that MWCNTs/LDHs exhibited excellent adsorption performance with the maximum CR adsorption capacity of 595.8 mg/g in weak acidic environment. The adsorption kinetics and isotherm parameters can be well described by the pseudo-second-order and the Langmuir isotherm models, respectively. The thermodynamic studies indicated that the adsorption process was spontaneous and endothermic.

纯铜表面等离子渗钽层的摩擦磨损性能和耐腐蚀性能

目的提高纯铜表面等离子渗钽层的耐磨性能和耐腐蚀性能。方法采用双辉等离子表面合金化技术在纯铜表面制备渗钽层。通过扫描电子显微镜、能谱分析仪和X射线衍射仪分析渗钽层的微观形貌、元素分布和物相结构。利用纳米压入和表面划痕试验测量渗钽层的硬度和与基体的结合强度。通过摩擦磨损和电化学试验评价渗钽层的耐磨性能和耐腐蚀性能。结果使用双层辉光等离子表面合金化技术可以在纯铜表面制备出组织致密均匀、内部无孔隙的渗钽层,与基体结合良好,膜层厚度约为12μm且与基体存在3μm厚的互扩散过渡层。渗层物相主要为α-Ta,与基体的结合力为25.8 N,渗Ta处理后,试样表面纳米硬度从1.5 GPa提高到7.0 GPa。与纯铜基体相比,渗钽层的摩擦因数从1.15降低到0.82,比磨损率由基体的46.97×10^(−5) mm^(3)/(N·m)降至渗钽层的22.91×10^(−5) mm^(3)/(N·m),耐磨性得到提高。纯铜基体主要表现出黏着磨损现象,而渗钽层则表现出轻微的磨粒磨损。渗钽试样在3.5%NaCl溶液中的自腐蚀电位和极化电阻均显著提高,自腐蚀电流密度下降,耐腐蚀性能优异,渗钽层对基体起到很好的腐蚀保护作用。结论通过双层辉光等离子表面合金化技术在纯铜表面制备得到致密均匀的渗钽层,可有效地提高纯铜的耐磨性能和耐腐蚀性能。

In-situ layered double hydroxides on Mg−Ca alloy:Role of calcium in magnesium alloy

Mg−Al layered double hydroxides(LDHs),produced on cast Mg−xCa(x=0.5,0.8,2.0,wt.%)alloys by an in-situ growth method,showed good corrosion resistance compared to the bare magnesium substrate.The influence mechanism of the second phase(Mg_(2)Ca)on LDHs production was investigated.Increasing Ca content increased the amount of Mg_(2)Ca,decreasing the grain size and the corrosion rate of the alloys.The increased amount of the second phase particles and the grain refinement promoted the growth of LDHs,and thus led to the decreasing of corrosion rate of the Mg−xCa alloys with LDHs.A higher Mg_(2)Ca amount resulted in forming fluffy LDHs.Due to the dual effects of the second phase(Mg_(2)Ca)for LDHs growth and microgalvanic corrosion,LDHs/Mg−0.8Ca showed the lowest corrosion rate.