水性镍系内墙电磁屏蔽涂料

用导电镍粉与丙烯酸乳液为主要原料,制备了水性镍系内墙电磁屏蔽涂料.采用扫描电镜(SEM)对导电镍粉以及涂层的微观形貌进行了表征,研究了无机改性膨润土对涂料沉降率的影响,并对其机理进行了探讨;对涂料中挥发性有机化合物(VOC)以及游离甲醛的含量进行了测定,在30~1000 MHz频段范围内,对涂料涂层在远场区(平面波)与近场区(电场)的屏蔽性能进行了测试,并对不同区域屏蔽性能的差异进行了分析.     

Machinability of a nickel aluminide intermetallic alloy

This article reports the results of an experimental study on the machinability of a nickel aluminide intermetallic alloy. Machining was conducted at various speeds, and results indicate low material removal rates. Chips collected for each test run were measured for thickness for shear angle calculation and were subsequently observed microscopically. Chip segmentation was observed microscopically, and a fluctuation in the shear angle was evidenced. A parameter characterizing the severity of the machining process, the chip reduction coefficient (K), was calculated from chip thickness measurements. The calculated values ofK were found to be low, indicating a low severity of the metalcutting process. This, however, is in contract with the observed low rates of metal removal and low tool life. Thus, conventional metalcutting characterization parameters require re- examination in terms of machining high-strength materials.     

次亚磷酸钠体系化学镀镍的电化学研究

运用阳极扫描法他次亚磷酸钠体系化学镀镍在镍电极上的电化学行为。结果表明,化学镀镍的两个部分反应之间存在的强烈的相互作用; 亚磷酸钠的直接氧化产物不是Ｈ３ＰＯ３,其氧化行为受自身浓度、溶液温度、ｐＨ、扫描速度以及Ｎｉ＾２＋浓度的影响。     

Manufacture of Raney Ni catalyst with metastable Ni2Al3 by high-energy milling

１　ＩＮＴＲＯＤＵＣＴＩＯＮＲａｎｅｙＮｉｃａｔａｌｙｓｔ,ｗｈｏｓｅｃｏｍｐｏｎｅｎｔｉｓＮｉＡｌａｌｌｏｙ,ｉｓａｆｉｎｅｐｏｗｄｅｒｋｎｏｗｎａｓｈｙｄｒｏｇｅｎａｔｉｏｎｃａｔａｌｙｓｔ．Ａｃｃｏｒｄｉｎｇｔｏｔｈｅｃｈｅｍｉｃａｌｒｅａｃｔｉｏｎ,ｓｏｍｅｔｉｍｅｓＲａｎｅｙＮｉｃａｔａｌｙｓｔｍｕｓｔｂｅｆｉｌｌｅｄｗｉｔｈｓｏｍｅｍｉｒｃｒｏｅｌｅｍｅｎｔｓｏｆｃａｔａｌｙｓｔａｃｃｅｌｅｒａｔｏｒｓｕｃｈａｓＣｒ,Ｃｕ,Ｃｏ,Ｍｎ,Ｆｅ,ｅｔｃ．Ｔｈｅｓｋｅｌｅｔｏｎｎｉ…     

Fe,Co,Ni纳米粉化学还原制备机理的光谱研究

通过Ｆｅ（Ⅱ）,Ｃｏ（Ⅱ）和Ｎｉ（Ⅱ）的Ｈ２Ｏ,ＮＨ３,ＯＨ＾－,Ｃ２Ｈ５ＯＨ及Ｎ２Ｈ４配合物的紫外,－可见光谱研究,表明了在金属离子被Ｎ２Ｈ４还原过程中,可以通过和金属离子配位而活化,通过表面吸附或高压诱导作用消除动力学障碍,实现金属纳米粉的合成。并首次在水－乙醇体系中高效快速合成了纯度高,性能良好的纳米金属粉以及一些金属的复合粒子。     

铸造镍基高温合金中的初生μ相

研究了铸造镍基高温合金中初生μ相的形成条件及μ相的特征,结果表明：在碳量低于０．０７％的铸造镍基高温合金中,当难熔元素Ｃｒ,Ｍｏ,Ｗ,Ｎｂ,Ｈｆ总量超过１１％超过８％,Ｍｏ／（Ｗ＋Ｍｏ）（原子分数）超过０．１７时会形成初生μ相,该相在高温下是不稳定的,它会转变成Ｍ６Ｃ碳化物。Ｍｏ,Ｗ,ＣｒＨｆ,Ｎｂ,Ｃｏ是μ相形成元素,Ｍｏ在形成μ相方面作用更强,Ｗ,Ｃｒ,Ｈｆ,Ｎｂ的作用差别不明显,Ｃｏ的作用小     

Ni-25Al-15Cr多相金属间化合物的显微组织

研究了Ｎｉ２５Ａｌ１５Ｃｒ（ 摩尔分数, ％ ） 多相金属间化合物合金的显微组织及热处理对其组织的影响。结果表明：１２００ ℃２４ ｈ 均匀化后的冷却速度不仅影响β相中αＣｒ 析出物的尺寸, 且影响β相的成分及体积分数; 空冷后时效, β相分解成γ′相和有序度更高的β相, 炉冷后时效, β相保持稳定; 并对时效过程中β相稳定性与时效前冷却速度之间的关系进行了讨论     

Qualitative analysis of files of four different rotary systems,before and after being used for the twelfth time

The aim of this study was to make a comparative evaluation of the surface topography of the cervical third and tip of four different rotary systems, before and after being used 12 times, in resin blocks with simulated root canals with standardized 45° curvatures, and analyzed by scanning electronic microscopy (SEM). A total of 1,440 resin blocks with simulated root canals and standardized curvatures were used. The blocks were divided into four groups and prepared by the crown down technique according to the manufacturers' recommendations: Group 1 (G1)—K3®, Group 2 (G2)—Protaper Universal®, Group 3 (G3)—Twisted Files®, and Group 4 (G4)—Biorace®. After each preparation, the instruments were washed and autoclaved. A total of 24 instruments were selected, being three new instruments and three after having been used for the 12th time, from each group. These instruments were analyzed by SEM. To perform the evaluation, 24 micrographs were observed by 12 evaluators who attributed a score to the images according to a template. In the qualitative analysis of the cervical region and tip of new instruments, it was observe that the files of Groups G4 and G2 were the least rough and those of G1, the roughest. In the same manner, the cervical region of the instruments was qualitatively analyzed after the 12th time of using them, and there was no statistically significant difference at a level of 1% (ANOVA P < 0.01) between G2 and G4 as well as between G1 and G3. As regards the tip, it was observed that there was no statistically significant difference, at a level of 1%, between the groups: G1 and G3, G1 and G4, and between G3 and G4, and there was statistically significant difference at a level of 1%, between group G2 and the other groups, with G3 having the greatest roughness (ANOVA P < 0.01). Microsc. Res. Tech., 2013. © 2012 Wiley Periodicals, Inc.     

泡沫镍裂纹形成机理及防止方法的研究

研究了泡沫镍生产中镀层硫含量对泡沫镍性能的影响以及电镀工艺参数对镀层硫含量的影响。实验结果表明:镀层中硫的存在是导致镀层变脆产生裂纹的根本原因;电镀液中糖精的质量浓度≤0.1 g/L是防止泡沫镍产生裂纹的安全糖精浓度范围;改变烟囱的抽力也是防止裂纹的辅助手段。     

喹喔啉类衍生物与甲基噻吩共聚物的合成及性质

在二价镍配合物催化下,2,5-二溴-3-甲基噻吩格氏试剂与5,8-二溴-萘基喹喔啉和5,8-二溴-菲基喹喔啉共聚,得到相应的喹喔啉类共轭共聚物,收率分别为65%和68%。通过FT IR、1H-NM R对聚合物及中间体的结构进行了表征。聚合物的循环伏安图中,分别在0.66 V(Epa)/0.37 V(Epc)(Copo ly-m er I),0.78 V(Epa)/-0.06V(Epc)和1.26(Epa)/0.46(Epc)(Copo lym erⅡ)处观察到氧化还原峰,表明该类聚合物有电化学活性。在紫外-可见光谱中,分别在263 nm,323 nm处(Copo lym erⅠ)和299 nm,402 nm处(Copo lym erⅡ)出现吸收峰。所得聚合物分别在504 nm和513 nm处出现荧光最大发射峰。