金属相20Ni-80Cu表面包覆NiFe2O4尖晶石对15（20Ni-80Cu）/85（NiFe2O4-10NiO）金属陶瓷腐蚀性能的研究

金属陶瓷金属相优先腐蚀是目前惰性阳极工业化难点之一,在金属相表面包覆NiFe2O4尖晶石来提高其耐高温熔盐腐蚀性能。包覆实验结果显示,包覆后的颗粒尺寸为2～5μm,且有团聚现象,金属相20Ni-80Cu表面除形成NiFe2O4尖晶石外,可能还含有NiFe2O4-x、Cu2O、NiO、CuxNi1-x、NiyFe1-yFe2O4-a和NizFe1-zO。腐蚀实验表明,金属表面包覆10%、20%、30%、40%和50%NiFe2O4尖晶石后制备的金属陶瓷惰性阳极样品其金属腐蚀层厚度都在20～50μm,其年腐蚀率分别为1.89、1.73、1.65、1.58和2.03cm/a,未包覆金属陶瓷惰性阳极金属腐蚀层厚度为200μm和年腐蚀率为4.15cm/a,说明金属表面包覆NiFe2O4尖晶石能提高惰性阳极的抗熔盐腐蚀性能。     

低压等离子喷涂MoB/CoCr涂层的组织及耐磨性

采用低压等离子喷涂技术(LPPS)制备MoB/CoCr涂层,对涂层进行磨粒磨损试验研究。采用SEM观察涂层的表面和截面形貌,显微硬度计测试涂层的力学性能,湿式橡胶轮磨粒磨损试验机测试涂层的磨粒磨损性能。结果表明,涂层组织致密,呈层状结构;涂层具有良好的力学性能,显微硬度达到930HV0.3,结合强度在71MPa以上,具有较高的耐磨性能。     

NAK80模具钢表面2种激光器熔覆Ni基碳化钨合金层组织结构及耐磨性比较

为了研究激光器对Ni基碳化钨合金熔覆层组织结构和性能的影响,分别采用Nd:YAG与CO2激光熔覆技术在NAK80模具钢表面制备了Ni基碳化钨合金层,利用X射线衍射仪(XRD)、扫描电镜(SEM)、能谱仪、显微硬度计以及摩擦磨损试验机测试分析了2种熔覆层的组织结构、显微硬度及耐磨性能。结果表明:2种熔覆层与基体之间均呈现良好的化学冶金结合;熔覆层组织主要为粗大的未熔碳化钨颗粒和均匀分布的树枝晶,Nd:YAG激光熔覆层的组织比CO2激光熔覆层的细小;2种熔覆层相结构主要包括WC,W2C,Cr23C6,NiCr,CrB2以及γ-Ni等;2种激光器熔覆处理后,NAK80模具钢表面硬度和耐磨性都得到显著改善,CO2激光熔覆层的硬度和耐磨性高于Nd:YAG激光熔覆层,2种激光熔覆试样的磨损机制均为磨粒磨损。     

Q235钢表面金属陶瓷涂层熔覆技术的研究进展

综述了近年来Q235钢表面金属陶瓷涂层制备技术的研究进展,重点介绍了常见的金属陶瓷涂层制备方法如氩弧熔覆、感应熔覆、等离子熔覆、激光熔覆等及其存在的问题,展望了今后的发展方向。     

Effect of WC content on the microstructure and mechanical properties of Ti(C0.5N0.5)–WC–Mo–Ni cermets

Ti(C_0.5N_0.5)–xWC–Mo–Ni system cermets were studied to investigate the effect of WC content on the microstructure and mechanical properties. The results showed that the lattice constant of Ti(C,N) hard phase in the Ti(C_0.5N_0.5)–WC–Mo–Ni system increases with the increase of WC content, but it is smaller than that in Ti(C_0.7N_0.3)–WC–Ni system. The microstructures of the cermets exhibit three kinds of grains: one has black core-grey rim structure, the second has white core-grey rim structure and the third has black core-white rim structure. The thickness of inner rim increases with the increasing of WC content. Additionally, the particle size of black core decreases with the increase of WC content in the range of 0–10 wt.%, and then increases slightly with further increase of WC. The TRS increases with the increase of WC content, but hardness decreases with the increase of WC content.     

横向磁场对镍基高温合金定向凝固组织的影响

研究了横向磁场对镍基高温合金DZ417G定向凝固显微组织的影响. 在较低生长速率条件下, 磁场显著影响合金的枝晶生长和宏观偏析. 施加磁场后一次枝晶间距减小并在沿磁场方向试样的左侧出现了“斑状”偏析. 随着生长速率的增加, 磁场的影响减弱. 从磁场在合金熔体中诱发热电磁对流, 并影响枝晶生长的角度对实验结果进行了分析.     

镍基合金圆柱形热模拟试样热变形后鼓形的有限元研究

通过abaqus有限元分析软件,对镍基合金圆柱形热模拟试样在加热和保温后的单向压缩变形过程进行了模拟。研究结果表明,由于镍基合金材料导热系数较小,在快速变形条件下,试样在单向压缩过程中产生的变形热不能充分扩散,从而导致变形后试样内部局部温度升高。通过与热模拟试样变形后鼓形的实测值进行比较,结果均表明,变形后试样的鼓形随着应变速率的提高而增大。     

活塞环耐磨涂层及其摩擦磨损机理研究进展

活塞环面临着极为严重的磨损问题,目前工业界广泛采用涂层技术来提高其耐磨性。对近年来活塞环表面耐磨涂层制备技术及相关材料进行了综述,分析了活塞环表面摩擦磨损机理的研究成果及存在的问题,总结了相关磨损实验装置的研究进展。     

Ni-Based Metallic Glass Composites Containing Cu-Rich Crystalline Nanospheres

In this work, a quaternary Ni–Cu–Nb–Ta system has been designed to obtain composite microstructure with spherical crystalline Cu-rich particles embedded in amorphous Ni-rich matrix. The alloy samples were prepared by using singleroller melting-spinning method. The microstructure and thermal properties of the as-quenched alloy samples were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and differential scanning calorimetry. It shows that the spherical crystalline Cu-rich particles are embedded in the amorphous Ni-rich matrix. The average size of the Cu-rich particles is strongly dependent upon the Cu content. The effect of the alloy composition on the behavior of liquid–liquid phase separation and microstructure evolution was discussed. The phase formation in the Ni-based metallic glass matrix composite was analyzed.     

激光熔覆纳米La2O3添加镍基合金涂层的耐磨与显微组织研究

本研究以激光工艺制备了添加纳米La2O3初料的镍基涂层。激光熔覆之前,高能球磨机充分混合的Ni60A和La2O3粉床预置于基体30CrMnSiNi2A表面。La偏聚于枝晶间从而限制了二次枝晶的成长和熟化。显微组织得到了细化。由于更高的La富集,涂层上表面显微组织细化更为显著,这一现象的上述解释得到EPMA结果佐证。同时EPMA结果说明Fe稀释会造成涂层硬度降低。熔覆涂层经过RE显微组织细化和净化,硬度、耐磨性均相对基体金属显著提升,而涂层中裂纹和孔隙均未出现。Ni60A-La涂层的摩擦系数曲线COF明显低于基体和Ni60A涂层,Ni60A-La磨擦体积损失率分别少于基体和Ni60A涂层数值的1/10和1/5,显微硬度值是基体4倍。