超细Ni,Co—石墨层间化合物的制备及其电极催化性能

采用二步法先合成钾的石墨层间化合物,然后再通过它合成Ｃｏ,Ｎｉ系石墨层间化合物。化学分析、Ｘ射线衍射、Ｘ射线光电子能谱及透射电镜的分析结果表明,这些化合物中金属主要以正２价形态存在,化合物的粒度为纳米级。用微电极测试了它们在ＫＯＨ溶液中对氧还原的催化活性,发现Ｃ４８Ｃｏ及Ｃ４８Ｎｉ为好,尤以Ｃ４８Ｃｏ为优;加入Ｃ４８Ｃｏ的气体扩散电极的电流密度,比未加的高６８倍。用旋转圆盘电极研究了对氧的还原过程,发现该过程同时受扩散与化学反应两种作用的混合控制,反应电子数为２。     

ELECTROCHEMICAL STUDIES ON ANODIC DISSOLUTION OF SYNTHETIC NICKEL SULFIDES

The anodic behavior of synthetic nickel sulfides in sulfuric acid solutions was studied.Whenthe anodes of Ni_3S_2 ,Ni_7S_6 and NiS are actively dissolved respectively,a solid layer forms onthe electrode surface with its nature and composition depending on the potentials applied.Based on the electrochemical phenomena,phase and elemental compositions of the solid layerformed on the electrode surface were determined.The apparent number of electrons transfer-red during dissolution of Ni~(2+)was also measured.It can be considered that there are threeparallel reactions ocurred on the electrode:the reaction with formation of HSO_4~- or SO_4~(2-),the reaction with formation of sulfides as intermediates and the reaction of Jorming elementalsulfur.With NiS_2 as an anode,formation of SO_4~(2-)or HSO_4~- can be considered as the only re-action occurred on the electrode.     

中温碱性化学镀镍磷实用新工艺研究

用正交试验设计法和中心组合规则研究了以硫酸镍、次亚磷酸钠为主盐的化学镀液优 化配方,通过SAS8．2进行模拟得到二次多项式回归方程数学模型。研究了镀液中微量光亮 剂对镀速的影响。结果表明:在施镀温度为62．7℃,pH值为8．0,装载量为1 dm2／L,NiSO4· 6H20 36．03 g／L,NH4Ac 36．96 g／L,NaF 6．3 g／L,Na3C6H5O7·2H2O 23．52 g／L,NaH2PO2 42．4 g／L条件下,施镀1h,所得到的平均镀速为14．65μm／h,且镀层光亮,镀层含磷量为 7．8％～8．2％,镀层硬度为HV457,镀液可循环利用7个周期,能满足生产的实际需要。     

Oxidation and intergranular disintegration of the aluminides NiAl and NbAl3 and phases in the system Nb-Ni-Al

The oxidation behavior is very different for an aluminide with a wide homogeneity range such as -NiAl than for a line compound such as NbAl ₃.Oxidation of -NiAl at temperatures 1273 K leads to a slow-growing -alumina layer. The metal phase beneath the scale remains as -NiAl; however, cavity formation is observed. The cavity formation may be favored by sulphur surface segregation. Oxidation of NbAl ₃ at temperatures 1273 K initially leads to -Al ₂O₃,but the Al depletion causes the formation of Nb ₂ Al beneath the oxide layer. Cracking of the Al ₂O₃ layer opens Nb ₂ Al to the atmosphere, which oxidizes rapidly to Nb ₂O₅ and NbAlO₄.After consumption of the Nb ₂ Al, a layer of Al ₂O₃ formed again on the NbAl ₃ phase, but failure of the alumina and the fast growth of the other oxides occur as a repeated process. Thus, NbAl ₃ exhibited rapid linear oxidation kinetics. Multiphase alloys in the system Nb-Ni-Al generally behave better than NbAl ₃,and the low oxidation rates of -NiAl can be approached. In the temperature range below 1273 K, with a maximum at 1000 K, both NiAl and NbAl ₃ show the pest phenomenon, an intergranular disintegration. Preceding the disintegration, oxygen diffuses into the grain boundaries of the material and Al ₂O₃ is formed at the grain boundaries, beginning from the surface region. NiAl is susceptible only in a very limited range of oxygen pressures and temperatures, whereas NbAl ₃ is much more susceptible.     

CO2体积分数对碱激发镍渣水泥砂浆抗碳化性能的影响

利用机械化学方法制备了单组分碱激发镍渣水泥,分析了CO₂体积分数对不同碱激发剂制备的单组分碱激发镍渣水泥砂浆抗碳化性能的影响规律,结合孔结构分析、X射线衍射（XRD）分析等研究了其作用机理.结果表明：水泥砂浆的碳化产物与碱激发剂种类无关,与CO₂体积分数有关.在CO₂体积分数为3%条件下进行试验,水泥砂浆的碳化产物为碳酸盐产物,且碳化速率远低于CO₂体积分数为10%与20%的试验组;而在CO₂体积分数为10%与20%条件下进行试验,水泥砂浆的碳化产物为碳酸盐与碳酸氢盐.碳酸盐对孔隙填充效果优于碳酸氢盐,因此CO₂体积分数为3%时砂浆碳化后的孔结构、抗压强度均优于其体积分数为10%与20%时.     

软包动力电池过充电热失控特征研究

研究了正极和负极分别为8系高镍三元NCM811（Li（Ni0.8Mn0.1O0.1）O2）和硅碳（SiOx/graphite）的25 Ah软包动力电池过充电触发热失控特征。结合电池材料热特性和热失控产气成分分析,揭示了绝热与非绝热环境下,电池热失控期间内部微观变化和动态产热特性。过充电触发热失控的路径为：过充电超过安全边界电压后电池内部发生副反应和内部极片微短路,引起气体和热量累积,最终电池过热达到热失控临界点。与非绝热环境相比,绝热环境下热失控触发瞬间温度高出37.5 ℃,且触发时长有不同程度的缩短（约为90～500 s）。最后对电池的安全和失效边界做出了界定。     

氧化铝模板的制备

本文采用二次阳极氧化方法,以草酸溶液为电解液制备了孔径为60nm的有序的氧化铝模板,采用扫描电镜观察其表面和截面形态,并对阳极氧化过程硬有序孔洞的形成机理进行了分析。采用电化学沉积的方法制备了Ni纳米丝阵列,并采用扫描电镜、透射电镜、X射线衍射仪对其结构进行表征。     

镍渣矿渣免烧砖的试验研究

研究了镍渣矿渣比和水泥掺量对镍渣矿渣复合胶凝材料体系的影响,并在此基础上,辅以化学激发剂NS、CA,采用正交试验方法,研制开发新型镍渣矿渣基复合胶凝材料,最佳配比为:镍渣和矿渣的质量比5∶5,水泥、激发剂NS和CA分别占镍渣和矿渣总质量的20％、0.5％和2％,胶砂比1∶3,水胶比0.5,可制得符合MU25等级的免烧砖.     

电沉积法制备纳米晶材料

电沉积法是制备完全致密的纳米晶体材料最有前途的方法之一。本文综述了电沉积法制备纳米晶镍及其合金的研究现状及制备方法对纳米晶材料性质的影响。     

Ordered intermetallic alloys: an assessment

The paper summarizes our present understanding, as established at a recent workshop, of two classes of intermetallic alloys: nickel and iron aluminides, which are currently used by industries; and advanced intermetallic alloys including silicides and Laves-phase alloys, which have a great potential to be developed as new high-temperature structural materials for future industrial use. The workshop emphasized close interaction and co-operation between basic research, applied research, and industrial development, and stressed discussion of critical scientific and technological issues. The current status of these intermetallic alloys was assessed, and the directions for future research and development, as well as emerging opportunities, were identified. The information presented in the text is summarized from the presentations at the workshop, and so no references are given to the published literature. However, an extensive bibliography is appended, in which further details may be found.