气密性高Bs合金及其在微波管中的应用

本文简要介绍了新型气密性高饱和磁感应（Ｂｓ）合金的主要特点及其在真空微波管中的应用。     

Optimization of Nd:YAG laser welding onto magnesium alloy via Taguchi analysis

The use of an Nd:YAG laser for thin plate magnesium alloy butt welding was optimized using the Taguchi analytical methodology. The welding parameters governing the laser beam in thin plate butt welding were evaluated by measuring of the ultimate tension stress. The effectiveness of the Taguchi method lies in clarifying the factor that dominates complex interactions in laser welding. The factors can be the shielding gas, laser energy, convey speed of workpiece, point at which the laser is focused, pulse frequency, and pulse shape. Furthermore, 18 combinations of these six essential welding parameters were set and Taguchi's method followed exactly. The optimal result was confirmed with a superior ultimate tension stress of 169 MPa, 2.5 times larger to that from original set for laser welding.     

Ni—Fe合金电沉积层结构的穆斯堡尔谱与X射线衍射研究

用穆斯堡尔谱及X射线衍射技术研究不同Fe含量的Ni-Fe合金电沉积层的结构.当Fe含量小于46 at％时,该合金层为γ相(F. C.C.);Fe含量大于63 at％时为α相(B.C.C.);在46 at％～63 at％之间两相共存.Fe含量为25 at％左右时,存在部分有序的Ni_3Fe结构;Fe含量为35 at％～46 at％时,出现富铁相γ’(F.C.C.).由于富铁相的存在,使Fe含量在约46 at％时出现α相,而在冶炼的Ni-Fe合金中,只有当Fe含量达70 at％时才出现α相.γ相合金的晶格参数一般随Fe含量的增加而增大,Fe含量在～25 at％时,因有序的Ni_3Fe存在使晶格参数略为减小.当α、γ相共存时,γ相合金的晶格参数基本不变.     

退火处理对快淬贮氢合金显微组织及电化学性能的影响

研究了退火处理对快淬贮氢合金电化学性能的影响。分析并讨论了退火处理的影响机制。快淬贮氢合金经退火处理后，P-C-T平台更为平坦，活化性能得到改善，最大放电容量和循环稳定性提高。通过XRD，SEM，DTA分析发现，退火处理后合金单胞体积有所增大，内应力降低，合金成分趋于均匀，从而使合金的电化学性能得到改善。加热过程中，合金在温度高于696℃发生再结晶。     

稀土对铬锰氮不锈钢在稀硫酸介质中腐蚀磨损性能的影响

研究了稀土对铬锰氮不锈钢的腐蚀性能及腐蚀磨损性能的影响，稀土使各锰氮不锈钢的腐蚀电位正移、维钝电流降低、热力学稳定性提高，故其耐蚀性提高，抗磨性改善，铬锰氮不钢的最佳稀土含量为０．０２－０．０６％，为生产提供了必要的工艺参数。     

稀土对锡铅共晶合金定向凝固组织的影响

同稀土含量地锡铅共晶合金定向凝固组织的影响，发现稀土的加入使片间距减小，片支断续、不规稀土量增加使结晶组织向胞晶转变，且凝固过程中由于稀土的“亲Ｓｎ”作用，使锡铅共晶点偏移，促进初生富铅相生成，出现亚共晶生长层；稀土化合物对锡铅的凝固过程几乎没有影响。     

复合载体及其制备方法对非晶态Ni-B合金催化剂性能的影响

采用浸渍法及溶胶-凝胶法制备了TiO2-Al2O3复合载体,采用浸渍还原法制备了负载型非晶态Ni-B合金,以糠醛液相加氢制糠醇为探针反应考察了不同载体及复合载体的不同制备方法对非晶态Ni-B合金催化性能的影响.采用等离子发射光谱(ICP)、差示扫描量热法(DSC)、透射电镜(TEM)、H2化学吸附法、程序升温还原(TPR)和程序升温脱附(TPD)等技术研究了负载型非晶态Ni-B合金的负载量、合金组成、热稳定性、粒子大小和形态、活性表面积、还原性能以及吸附性能等.用N2吸附法测定了催化剂及载体的比表面和孔径.研究结果表明,与单一氧化铝载体相比,复合载体负载的Ni-B合金催化活性和选择性明显提高,浸渍法制备的TiO2-Al2O3复合载体负载Ni-B合金的催化性能优于溶胶-凝胶法.主要的原因为复合载体负载的催化剂中Ni含量更高,Ni-B粒子细化导致活性表面积更大,以及催化剂的还原及吸附性能发生改变.     

原始合金制备方法对RaneyNi催化剂结构及加氢活性的影响

骨架镍催化剂由纳米级镍晶粒、未转变的ＮｉＡｌ３和Ｎｉ２Ａｌ３母相及其界面区组成。Ｘ射线衍射及高分辨电子显微观察发现，脱铝过程中ＮｉＡｌ３晶粒碎裂成纳米级尺寸，而Ｎｉ２Ａｌ３相则不出现碎裂现象。     

Examination and analysis of Indian silver punch‐marked coins employing WD‐XRF and other noninvasive techniques

The archaeometallurgical analysis of ancient silver coins provides useful information regarding fabrication methodology, provenance, and trade route and explains large diversification in elementary composition, weight, and physical features. The present investigation deals with the chemical analysis and examination of the processing history of Indian punch‐marked silver coins dating to 400–200 bc . The chemical analysis was carried out by wavelength dispersive X‐ray fluorescence and X‐ray Diffraction (XRD). The microstructural examination was performed using field emission scanning electron microscope (FE‐SEM) and different phases were identified by Scanning Electron Microscopy coupled with Energy Dispersive X‐ray (SEM‐EDX) Spectroscopy. It was observed that all eight coins were manufactured with silver‐copper alloy. The ore used for obtaining silver was argentiferous galena, and cupellation was carried with perfection. The absence of slag inclusions as revealed by SEM examination indicated that coins (numbers 2, 4, 5, and 7) were cast from a molten state. The presence of Cu₂O, CuO, and Ag₂O on the surfaces of the coins was confirmed by XRD. The formed oxide layers provided protection and saved the coins from bulky corrosion products. The data reveal great divergence of coin surface from the composition of the core with the far better metallurgical process for refining of silver for this hoard.     

The interface electrochemical and chemical mechanism of a low alloy steel in a 3.5% NaCl solution containing Ce3+‐based inhibitor

The interface electrochemical and chemical mechanism of the low alloy steel in a 3.5% NaCl solution containing the Ce³⁺‐based inhibitor was investigated by the electrochemical techniques in conjunction with the surface analysis technologies. It was shown that the Ce^3+‐based inhibitor was an anodic inhibitor with more than 90.0% inhibitory efficiency. The net‐shaped inhibiting film with 200 to 500‐nm greyish balls was observed on the specimen surface. During the corrosion reaction occurred on the surface of the low alloy steel, the hydrolysis reaction of P₃O₁₀⁵⁻ and the disproportionation reaction of Ce³⁺ ions simultaneously occurred, too, resulting in the formation of the net‐shaped inhibiting film with nano‐scale greyish ball‐type products, which contained Ce element and had an obvious effect on the electrochemical process of the low alloy steel in a 3.5% NaCl solution containing the Ce³⁺‐based inhibitor. Therefore, the EIS spectra of the low alloy steel in a 3.5% NaCl solution containing the Ce³⁺‐based inhibitor were composed of a capacitive loop at a high‐frequency region and an inductive impedance loop at a low‐frequency region. The charge‐transfer resistance (R_t) increased with the immersion elapsed time, indicating that the inhibition efficiency of the Ce³⁺‐based inhibitor increased with immersion elapsed time. The calculated data based on the fitted electrochemical parameters showed the partial coverage of the inhibitor. This was further revealed by the analysis of electrochemical kinetics that the inductive impedance (L) loop at a low frequency region resulted from the localized absorption of the Ce³⁺‐based inhibitor on the surface of the low alloy steel in a 3.5% NaCl solution. It was also verified by micro‐morphologies.