Showing papers on "Nickel published in 1969"

Zur Kenntnis der Nickelhydroxidelektrode. II. Über die Oxydationsprodukte von Nickel(II)-hydroxiden

Abstract: Die reinen Phasen oxydierter Nickelhydroxide, die auf der Nickelhydroxidelektrode im alkalischen Akkumulator auftreten konnen, wurden hergestellt, ihre kristallographischen Daten und ihr chemisches Verhalten untersucht und Umwandlungsbedingungen ermittelt. The pure phases of some oxidized nickel hydroxides concerned with the nickel hydroxide electrode of an alkaline accumulator were prepared. The crystallographic data of these phases, their chemical behaviour and conditions of transition were studied.

Structure of Amorphous Ni–Pd–P and Fe–Pd–P Alloys

Abstract: Ternary alloys of nickel‐palladium‐phosphorus and iron‐palladium‐phosphorus containing 15–20 at.% phosphorus were rapidly quenched from the liquid state. The structures of the quenched alloys were investigated by x‐ray diffraction. Broad maxima in the diffraction patterns, indicative of a glass‐like structure, were obtained for 13–73 at.% nickel and 13–44 at.% iron, with palladium and phosphorus adding up to 100%. The interference functions were evaluated from the coherent x‐ray scattering and used to compute the electronic radial distribution functions for these alloys. Average interatomic distances and coordination numbers were obtained from the radial distribution functions. A linear relationship between interatomic distances and composition, similar to Vegard's law in crystalline systems, was shown for these metallic glasses. The structure of the quenched Ni–Pd–P and Fe–Pd–P alloys could be explained in terms of structural units analogous to those existing in the metal‐rich phosphides. A quasi‐crystalline model based on the Pd3P structure, with nickel or iron substituting for palladium, was shown to give a very satisfactory approximation of the amorphous structure of the Ni–Pd–P and Fe–Pd–P alloys. Such a model was also in good agreement with electrical and magnetic properties measured for these metallic glasses.

Diffusion of Iron and Nickel in Magnesium Oxide Single Crystals

Abstract: Diffusion kinetics and mechanisms were studied in the FexO-MgO (vacuum), NiO-MgO (vacuum and air), and Fe203-MgO (air) systems. In the FexO-MgO system, Fe entered MgO by a redox reaction; the diffusivity and activation energy depended on concentration. In the NiO-MgO system in air the diffusivity depended on concentration and the activation energy did not; in vacuum both the diffusivity and activation energy were concentration-independent. In the Fe2O3-MgO system in the MgO phase the activation energy and diffusivity did not depend on concentration. Because of impurities, the diffusion results were for the extrinsic region. Formation of trivalent ions and consequent chemically created vacancies in the FexO-MgO and NiO-MgO (air) systems resulted in the concentration dependence of diffusivity. Concentration dependence of activation energy in the FexO-MgO system is associated with structural changes due to a change with concentration of the Fe3+ octahedraI/Fe3+ tetrahedral ratio. In the Fe2O3-MgO system structural changes do not occur during diffusion because this ratio remains constant.

The thermal properties of some metal complexes of diethyldithiocarbamic acid new volatile metal chelates

Abstract: The cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II), silver(I) and mercury(II) complexes of diethyldithiocarbamic acid were prepared and their thermal properties determined by TG, DTA, and high temperature reflectance spectroscopy. It was found that the copper(II), nickel(II), and zinc(II) chelates were completely volatile and thus represent a new class of volatile metal chelates. Vapor pressure measurements were made on four of the metal complexes; heats of vaporization ranged from 9.3±0.2 kcal/mole for Na[Co(DDC)3] to 24.2±0.6 kcal/mole for Zn(DDC)2.

Protective diffusion layer on nickel and/or cobalt-based alloys

Abstract: Nickel and/or cobalt-based alloys are given a protective coating by diffusing into the surface of the alloy metallic aluminum and one or more metals of the platinum groups.

Superior Analyses of Iron Meteorites

Abstract: New analyses have been made on 100 iron meteorites for the elements nickel, cobalt, phosphorus, carbon, sulfur, and copper. The meteorites were sampled using a new milling technique which provided chipped samples. Replicate analyses of high analytical precision were made on splits from these samples. On the basis of these new analyses graphical methods were used for the evaluation of earlier analyses of iron meteorites. The abundances of phosphorus, carbon and sulfur show variations depending upon the concentrations of non-metallic mineral phases taken in the sampling procedure. Cobalt and nickel show a positive correlation with each other. On the basis of this relationship approximately 35% of analyses done before 1907, as reported by Farrington, may be classified as ‘superior’ and suitable for use in calculations today. More recent analyses show a higher degree of superiority. Within selected gallium-germanium groups direct relationships between cobalt, nickel and phosphorus may also be predicted.

The oxidation of dithiocarbamato complexes of nickel, copper and zinc

Abstract: Oxidation of N,N-di-n-butyldithiocarbamato (bu2dtc) complexes of Cu(I), Ni(II), Zn(II), Cd(II) and Hg(II) is reported. Oxidation of Ni(bu2dtc)2 with Cl2, Br2, or of NiX2 (X = Cl, Br, NO3) with N,N,N′,N′-tetra-n-butylthiuram disulfide (bu4tds) gives complexes of composition [Ni(bu2dtc)3]X. These compounds are diamagnetic and dissolve in nitrobenzene as 1:1 electrolytes, their UV spectra resemble that of the iso-electronic Co(bu2dtc)3. The experimental data are in accord with the assumption that in these compounds Ni(IV) flow spin d6) is surrounded by 6 S atoms in octahedral symmetry. The analogous selenium compound tris (N, N-di-n-butyldiselenocarbamato) nickel(IV) bromide, having the same properties as the thio compounds, can also be prepared. Oxidation of Cu(bu2dtc) with Cl2 or Br2 yields paramagnetic products with the composition CuX3(bu2dtc), in which Cu also has the formal oxidation number + 4, but the structure of these compounds is still obscure. Oxidation of Zn(bu2dtc)2 and the corresponding Cd and Hg compounds yields products, the analysis of which suggests the composition MX2(bu2dtc)2 (M = Zn, Cd or Hg, X = Br or I), but infrared studies indicate that the dithiocarbamato ligands of the starting substances are oxidized to bu4tds, which in the reaction products is coordinated to the metal in its normal oxidation state + 2.

Magnetic properties of polynuclear complexes. Part I. Superexchange in some binuclear nickel(II) complexes

Abstract: The magnetic susceptibilities of a number of binuclear nickel(II) complexes between 80 and 300°K are reported. Most of the compounds exhibit antiferromagnetic exchange, and a curve-fitting procedure is used to obtain values of the exchange parameter J. The compounds studied include Ni2 paa3X4,nH2O (paa = pyridine-2-aldazine; X = I, ClO4, or BF4), Ni2 dppn2X4,nH2O (dppn = 3,6-di(pyrid-2-yl)pyridazine; X = NO3 or ClO4), Ni2 dppl(NO3)2,2H2O [dppIH = 3,5-di(pyrid-2-yl)pyrazole, a new compound], Ni2 dhph2X4,nH2O (dhph = 1,4-dihydrazinophthalazine; X = Cl, Br, or I), and Ni2 en4(C2O4)(NO3)2. The values of J for these and other binuclear nickel(II) complexes are discussed in terms of superexchange mechanisms.

Normal coordinate analysis of dialkyldithiocarbamate and its selenium analogue

Abstract: The infrared spectrum of N,N-dimethyldithiocarbamate complex of nickel(II) has been recorded in the range 2000–250 cm−1. Normal coordinate analyses have been made for nickel dimethyldithiocarbamate and nickel dimethyldiselenocarbamate complexes and their infrared spectra indexed. The frequency shifts observed on alkyl substitution have been discussed. The M—Se stretching frequency occurs about 100 cm−1 lower in the diselenocarbamate complex as compared to M—S frequency of the dithiocarbamate.

Volume and Grain-Boundary Diffusion in 20 Cr/25 Ni/Nb Stainless Steel

Abstract: Standard radiotracer techniques have been used to measure the volume-diffusion rates of chromium and nickel in a 20 Cr/25 Ni/Nb austenitic steel in the temperature range 840–1290° C. Within the limits of experimental uncertainty, the results are described by D Cr = 0·19 exp (−58·8 × 103/RT), D Ni = 4·06 exp (−67·5 × 103/RT). Grain-boundary-diffusion measurements have been made in the range 550–900° C. The diffusion rates of chromium and nickel isotopes are not significantly different from previously reported values for iron. Combining the data for all three elements gives a mean Arrhenius equation δDB = 1·5 × 10−7 exp (−44 × 103/RT).