Characteristics of Hydrogen Storage Alloy Mg_2Ni Produced by Hydriding Combustion Synthesis

A high activity and large capacity of hydrogen storage alloy Mg2Ni by hydriding combustion synthesis was investigated by means of pressure composition isotherms, X-ray diffraction and scanning electron microscopy. The results showed that the maximum hydrogen absorption capacity of Mg2Ni is 3.25 mass fraction at 523 K, just after synthesis without any activation. The relationships between the equilibrium plateau pressure and the temperature for Mg2Ni were lgp (0.1 MPa)=-3026/T+5.814 (523 K≤T≤623 K) for hydriding and Igp (0.1 MPa)=-3613/T+6.715 (523 K≤T ≤623 K) for dehydriding. The kinetic equation is [-ln(1-a)]3/2 = kt and the apparent activation energy for the nucleation and growth-controlled hydrogen absorption and desorption were determined to be 64.3±2.31kJ/(mol.H2) and 59.9±2.99kJ/(mol.H2)respectively.

Effects of RE and Vanadium on Microalloyed Steel

The effects of RE were studied by TEM, SEM, ICP and thermal simulation methods in vanadium microalloyed steel. The content of RE in the solid solution can reach the order of 10 -5 ～10 -4 in steel. The solid solution of RE was found to reduce the stability of precipitated V(C,N), impede the precipitation of V(C,N) in austenite, and accelerate and refine the precipitation of V(C,N) in ferrite. The combined effect of RE and V is to delay the dynamic recrystallization, refine the grains and second phase particles, and to promote the precipitation of V(C,N) obviously. Thus the microalloying with RE and V leads to raising the strength and toughness of steel.

Corrosion behavior of tantalum and its nitride in alkali solution

The corrosion behavior of tantalum and its nitrides in stirring NaOHsolutions was researched by potentiostatic method, cyclic voltammetry and XPS. The results showedthat the corrosion products were composed of Ta_2O_5 and NaTaO_3. The corrosion reaction formula oftantalum and its nitrides was written according to cyclic volt-ampere curves. The electric chargetransfer coefficient and the electric charge transfer number were calculated

Study on the Anti—oxidation of Al2O3—MgO—C Based Refractory

The anti-oxidation agents containing Al2O3-MgO-C refractories was developed and the properties of them were investigated after being tratd at different temperature.It was found that the anti-oxidation agents could enhance the anti-oxidation property and increase the mechanic property of the refractories,The mineral components of the oxidation film were detected with XRD method.

Preparation of Cd S Microcrystallite Doped Si O_2 Glass Films on Titaniu m-m etal Substrates by Sol- Gel Process

CdS microcrystallite doped SiO 2 glass films on titanium metal substrates were prepared by sol gel process. The effects of solution composition and viscosity, heat treatment parameters and substrate pretreatment method on the film qualities were studied. The transformation process of gel to CdS doped SiO 2 glass film, the structure of these films, the substrate/film interface bonding state and crystalline phase were analyzed by DTA, IRRS, SEM, EDS and XRD. The IRRS results show that Si O Ti linkages are formed between titanium substrate and thin film during heat treatment process. The preferential heat treatment of titanium surface in oxidizing atmosphere will be beneficial to increase the interface bonding strength. The thin films bonded with the substrates chemically and contained very fine CdS crystals with 20～40 nm in size.

Thermal expansion of lattice parameter of (powder) silicon up to 1473 K

The XRPD (X-ray powder diffxactometry) patterns of silicon powder with a unit cell structure of diamond were determined from 298 to 1473 K. Lattice parameters of Si linearly increase with temperature. The thermal shifts of the positions of all reflection peaks are linearly correlated with the temperature. The coefficients of the intrinsic linear thermal expansion and volumetric thermal expansion were determined as 3.87×10-6/K and 1.16×10-5/K respectively. It indicates that Si is still a suitable standard in the XRPD method at high temperatures.

Molten salt phase diagram evaluation by pattern recognition:Part I Divalent rare earth halide and alkali metal halide binary systems

At present CALPHAD (CALculation of PHAse Diagram) technique is notcapable of predicting whether there exists intermediate compound,much less predicting the formulae, the number, and the meltingcongruence of intermedi- ate compounds. To solve this problem, a newapproach called the phase diagram evaluation by pattern recognition(PDEPR) was improved. The micro-parameters. Such as the radius andthe electronegativity of the different features in multi-dimensionalspace.

Computer simulation of order-disorder phase transition in the intercalation compounds M_(1/2)TiS_2 (M=Fe, Co, Ni)

Based on cluster variation method (CVM) and natural iteration method (MM),order-disorder phase transition in the intercalation compounds M_(1/2)TiS_2 is simulated bycomputer. The favorable conditions, under which 3^(1/2)a_0 x a_0 superstructure is formed, aregiven, and the results are in good agreement with the experiments and theoretical calculations. Therelationship between critical temperature and M-ion-vacancy interaction parameter is linear.

Development of MA—C Refractory for Smelting—reduction Iron—Making Process

A kind of carbon-bering refractory (MA-C1) has been developed for smelting-reduction iron-making process and its physical chemistry properties were measured,Smilting-reduction slag (15 wt% FeO) resistance of the developed refractory has been compared with commercially available refractories by curcible test,static slag soaking test and fractal dimension analyses,The results show that slag resistance of the developed refractories(MA-C1) is better than those of alumina-carbon refractory (AM-C1),alumina-magnasia-carbon brick (AM0(J)) ,and Si3N4-SiC brick.