纤维镍基板的化学浸渍过程

本文利用真空和静态浸渍相结合的方法,研究了新型纤维镍基板化学浸渍过程若干参数对浸渍增重的影响;对化学浸渍过程,推导出活性物质填充量及镍基板活性物质载量水平与浸渍次数关系的数学表达式,并将实验结果与理论曲线进行了比较分析。     

Study on preparation and properties of CeO2/epoxy resin composite coating on sintered NdFeB magnet

The CeO₂/epoxy resin composite coating was deposited on NdFeB substrate by cathode electrophoresis method for enhancing the anticorrosion and anti-wear performances. The morphologies and structures were characterized by a scanning electron microscope and an X-ray diffractometer. The micro hardness of the composite coating was evaluated by a microhardness tester. The corrosive behaviors of the coatings were studied by potentiodynamic polarization curve, electrochemical impedance spectroscopy and neutral salt spray tests. The concentration of CeO₂ nanoparticles (NPs) in the electrophoresis bath was optimized according to the coating structures and anticorrosion performances. The results show that CeO₂ NPs can enhance the microhardness of the composite coatings. Moreover, the nanoparticles disperse uniformly in the matrix when the concentration is lower than 30 g/L. The microhardness of CeO₂/epoxy resin (30 g/L) composite coating is about 63% higher than that of the blank epoxy resin coating. And the NSS time of the CeO₂/epoxy resin (30 g/L) composite coated sample can reach 1248 h. Meanwhile, the composite coatings possess no deteriorate influence on the magnetic properties of NdFeB substrates. The anticorrosion mechanisms of the composite coatings on the NdFeB substrate are deeply discussed.     

铜钨粉末烧结电极和导电咀

介绍了铜钨粉末烧结材料的性能特点,以及用此材料制成的电极和导电咀在焊按生产中的使用效果。     

烧结式镉镍方形电池的改进

本文介绍了烧结式镉镍方形电池在设计、制造工艺和极带骨架方面的改进,以及改进后的电池性能水平。     

高温合金烧结多孔管在活化器上的应用

叙述了高温合金烧结多孔管用作活化器过渡元件(石化工业用)的情况。使用结果表明,国产高温过滤元件的性能优于原进口的过滤元件。     

Magnetic Properties of Ga Doped Nd-Fe-B Sintered Magnets

The magnetic properties of Nd_(16)Fe_(77)B_7 and Nd_(16)Fe_((61-x))Co_(16)Ga_xB_7(x=0,1,2,4,7)have been measured.Itis found that the remanent magnetization(Br),maximum energy product(BH)_(max)and the Curie temperature(T_c)decrease with the increase of Ga content.The coercive force(He)increases with the increase of Ga contentwhen x is less than 2,but decreases when x>2.At x=2,the coercive force reaches its maximum value.It is alsofound in all the samples investigated that there is a linear relationship between H_c~(1/2)and T~(2/3),which can not beexplained by Gaunt's wall barrier model.The temperature dependence of the calculated values of H_v and(4bf)has been discussed.     

水雾化铁基混合粉末的流动性及其烧结体的尺寸变化率

以水雾化铁基预舍金粉ATOMET4401为原料,研究了添加剂（胶体石墨、电解铜粉和羰基镍粉）对混合粉末流动性及其烧结体尺寸变化率的影响规律。研究表明,添加剂的加入均将延长混合粉体的流失时间,添加剂粉末尺寸越小对混合粉体的流动性影响越大。当碳含量从0.3wt％增加至0.9wt％时,流失时间延长了30％以上。随着铜含量的增加,混合粉体的流失时间呈先缓后快的增加趋势,并且当碳含量为0.9wt％时,增加的趋势更加显著,与未加铜者相比流失时间延长了9.2％。在碳含量为0.9wt％和羰基镍粉含量为4wt％时,混合粉末流失时间延长了25．7％。当碳含量从0．3wt％增加至0．9wt％时,尺寸变化率增加两倍以上。随碳含量增加,尺寸变化率随铜含量的变化趋势显著减小。当碳含量为0．9wt％时,铜含量对尺寸变化率的影响基本稳定。随着镍含量的增加,混合粉末烧结体的尺寸变化率逐渐由正变为负,并且随碳含量增加,这种变化趋势在高镍含量范围内变得更加明显。值得注意的是,在镍含量为-1wt％左右可以获得尺寸变化率接近零的烧结零件。     

板状氧化铝和烧结氧化铝的显微结构

对ＡＬＣＯＡ的ＴａｂｕｌａｒＡｌｕｍｉｎａ（板状氧化铝，１＃）、江苏某厂生产的烧结氧化铝（２＃）和我们用电熔法制备的板状氧化铝（３＃）进行了化学分析、ＸＲＤ、ＳＥＭ和ＥＤＡＸ分析，确定：１＃和３＃试样都是以α－Ａｌ２Ｏ３为主晶相的、具有清晰的板片状结构形貌的氧化铝，而２＃试样具有典型的粒状结构．     

Sintering of Fe–C–BN steel compacts in different atmospheres studied by dilatometry and DTA/TG

Abstract

In the present work, 2%hBN was admixed with Fe–0·8C, and both dilatometric and differential thermal analysis/thermogravimetry investigations were conducted in Ar and N₂ atmospheres, followed by microstructural studies and mechanical testing. The α–γ phase transformation in both atmospheres was found to occur in the temperature range of plain iron and not, as expected, in that common for Fe–C. In the Ar atmosphere, liquid phase formation is recognised by endothermic differential thermal analysis signal and shrinkage in the dilatometer during the heating stage at ～1275°C. In contrast to the activating effect of the inert Ar for the decomposition of hBN, the deactivating effect of the N₂ atmosphere is visible from the dilatometry results: sintering in N₂ even resulted in slight expansion during the isothermal stage. Therefore, the, at first surprising, conclusion can be drawn that the chemically inert Ar is activating the sintering process while the more reactive N₂ passivates it.     

Wear behaviour of stainless steel sintered and alloyed with titanium,cobalt and molybdenum

Abstract

In this study, a powder mixture was prepared by adding 1–3 wt-% of FeMo, FeTi and Co powders to the austenitic stainless steel powders and samples were produced by the powder metallurgy method. Attempts were made to establish correlations between the microstructure, hardness, toughness, and abrasive wear values of these samples. Wear resistance of the materials was measured by a two body pin-on-disk wear tester. SiC abrasive papers of 65 μm and 177 μm sizes were used as the abrasive media. Wear tests were performed at the loads of 10, 20, and 30 N at room temperature. They showed that the softer, base austenitic stainless steel exhibited higher mass loss than the alloyed samples. Furthermore, the abrasive wear resistance of the base austenitic stainless steel composites increased with increasing FeTi, FeMo,Co content. The wear rate with the 177 μm SiC abrasive paper increased more than that with the 65 μm SiC abrasive paper.