Nickel various temperatures

The metal looks like iron it exists in four allotropic modifications, stable over various temperature ranges. Although not easily attacked by air. it is slowly attacked by water and dissolves readily in dilute acids to give manganese(II) salts. The stable form of the metal at ordinary temperatures is hard and brittle—hence man ganese is only of value in alloys, for example in steels (ferroalloys) and with aluminium, copper and nickel. 

Fig. 2.7 Anodic polarisation of nickel at various temperatures, in 0-05 n H2SO4 + 0-05 N K2SO4, pH 1-3 (after Cowan and Staehle )...

Hardness The hardness of electroless deposits is higher after heating to intermediate temperatures, the final value depending upon temperature and time of heating. Values of maximum hardness of nickel-phosphorus after heating to various temperatures are plotted in Fig. 13.11 the variation of... 

The spherical fine nickel powders have been prepared fiom aqueous NiCU and hydrazine hydrate at various temperatures wife ethanol-water solvent by the conventional and ultrasonic hydrothermal reduction method. The induction time decreased wife inrareasing fee reaction temperature in both fee method, but was relatively shorter in fee ultrasonic mefeod. Compared to the conventional one, the surface morphology and particle size of fee sample obtained by the ultrasonic method was much smooth and regular in spherical shape and was much small, respectively. Therefore, the tap density of the sample obtained by fee ultrasonic mefeod was relatively higher than feat obtained by fee conventional one. 

Fig. 4. Sorption isobars of hydrogen ( —196°C. to temperature of presintering, up and down) at 0.1 mm. Hg pressure on evaporated nickel films presintered at various temperatures.

Fig. 6.1.8 Pore size distribution of uniform spherical nickel phosphate particles treated at various temperatures (a) in vacuo and (b) in air.

The magnetic method has been applied in studying the growth of the nickel particles due to the reduction process for the co-precipitated sample 5421. Reduction treatments have been performed at various temperatures in the range 400-600° C. (for which the reduction is assumed to be complete) and during various periods of time (% to 16 hrs.). Particle sizes of the products were characterized by the magnetic parameter a. 

An in depth study of the deposition mechanism was carried out by Sun et al. who studied the 1 1 [EMIMJCl/ZnCf system at various temperatures on glassy carbon (GC), nickel and platinum electrodes [106], The GC electrode required the largest overpotential for deposition. The stripping process showed a single peak on GC, whereas on Ni two oxidation processes were observed, separated by ca. 0.6V. Itwas proposed that the more positive oxidation process corresponded to the dissolution of an intermetallic compound formed during electrodeposition. 

The steam reforming of methane cycle suffers from the problem of coke deposition on the catalyst bed. The primary objective of this project was to study the stability of a commercial nickel oxide catalyst for the steam reforming of methane. The theoretical minimum ratios of steam to methane that are required to avoid deposition of coke on the catalyst at various temperatures were calculated, based on equilibrium considerations. Coking experiments were conducted in a tubular reactor at atmospheric pressure in the range of 740-915°C. 

The solubility of nickel sulphate in water at various temperatures... 

Amount of carbon deposited on nickel specimens which have been reacted at various temperatures in 1 atm ethane for 1 h... 

Figure 5. Stress-strain curves of a 718 nickel base superalloy deformed in compression (e = 10-2 s 1) and various temperatures in the hot working range (Dj = 50 pm)...

Carbon Deposited on Nickel via 02 Exposure TPSR with 1-atm H2 Carbon deposited on alumina-supported nickel (17 wt%) following ethylene exposure at various temperatures has a wide range of activity for reaction with H2 (Figure 2). Different states of carbon are identified by maxima in the rate of CH production. The temperature of the rate maximum (T ) for a particular carbon state was generally found to he independent of both the amount of carbon in that state and the temperature of deposition. Thus T will be taken as characteristic of the reactive state of... 

The effect of nickel content and catalyst preparation on demethyla-tion activity was pursued further. A catalyst of 10.5 wt % nickel, Preparation C, was tested in the fixed bed reactor, after activation in place at 540°F for 2 hours, with the feed at 0.8 LHSV, 150 psig, and a H2-to-methylcyclohexane mole ratio of 6. The temperature was raised over a period of 17 hours to 580°F, other factors held constant, and the effluent analyzed for cyclohexane at various temperatures. The conversion to cyclohexane was low, and only 1.5 wt % cyclohexane was found in the liquid effluent at 580°F. Under somewhat similar conditions, a conversion of over 50% of the methylcyclohexane was obtained with the 26 wt % nickel catalyst. These results suggest that interaction of nickel with the support occurs, and the resulting nickel-aluminate is not active for the demethylation reaction. 

Fio. 1. Butylamine titer vs acid strength for nickel sulfate heat-treated at various temperatures. 

Fig. 4. Variation of water (moles) in nickel sulfates treated at various temperatures.

Figure 3. Arrhenius plot of rate of synthesis (Nch ) over different nickel catalysts in various temperature regimes. Ni(100)—present work. = 96 Torr, Fco = 4 Torr (geometrical area = 0.85 cm, Ea = 103 kj/mol). (a) Poly crystalline nickel ribbon (geometrical area = 10 cm, Ea = 66 kJ/mol (3)) Torr,...

Fig. 8 Corrosion of nickel in different solvents with 0.05 wt% H2SO4 at various temperatures [5].

Bra] Bradley, A.J., Cox, W.F., Goldschmidt, H.J., An X-Ray Study of the Iron-Copper-Nickel Equilibrium Diagram at Various Temperatures , J. Inst. Met., 67, 189-201 (1941) (Crys. Stracture, Experimental, Phase Diagram, Phase Relations, 14)... 

This reaction also occurs during irradiation with a CO2 laser [6]. Thermodynamic data were calculated to be AH298=-7.80 and AG298=-3.10 kcal/mol. Calculated conversion factors of NF3 for 0favorable equilibrium situation at moderate temperatures for the products [11]. °Co y-irradiation of a heterogeneous mixture of NF3 and NO at 77 K produces FNO, F2NNO, and N2F4 [7]. Only traces of FNO were formed when NO2 or N2O were passed with NF3 through a nickel tube at temperatures up to 770°C [8]. The product distributions (N2, O2, F) in combustion of NF3-NO and NF3-N2O mixtures at 1500 K [9] as well as the attainable F-atom concentrations at various temperatures (>1400 K) and ratios of reactants [4] have been calculated. 

Figure 3 shows the impedance spectra obtained with Nickel pattern anodes at various temperatures. For this work only the total electrode conductivity is used i.e. the intercept with the... 

Figure I. A2 shows the weight loss against time curve for nickel in various solvents containing 0 05 wt.7oH2S04 at various temperatures, and illustrates the unpredictable nature of corrosion in organic solvents. Thus the corrosion rates in ethanol are far greater than those in the aqueous acid whereas in acetone the rate is practically zero even more surprising is the fact that in acetic acid the addition of 0 05% HjSO actually decreases the cono-sion rate.

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