Binary TiMn₂ alloys with various compositions were arc melted in an Ar atmosphere. These alloys consist of TiMn₂ and a small amount of TiMn depending on alloy composition. Annealed Ti-59.4%Mn exhibits the greatest capacity for hydrogen absorption and the smallest degradation of capacity during repeated hydrogen absorption and desorption. No apparent macro- and microstructural changes are observed in Ti-59.4%Mn by repeated hydrogenation of 30 cycles. At Mn content higher than 59.4%Mn, the formation of nano-sized Ti-hydride and the lattice expansion due to retained interstitial hydrogen were confirmed in repeatedly hydrogenated alloys. Pulverized powders were refined in all the alloys with in creasing the number of repeated hydrogenation cycles. Many onion-like cracks are introduced in annealed pure Ta with 100μm equi-axed grains by holding at 1473K followed by furnace cooling to room temperature in a hydrogen atmosphere, but no crack is observed after holding at 1473K in a hydrogen atmosphere followed by furnace cooling in an Ar atmosphere. It is concluded that the surface activation is attained in a hydrogen atmosphere at 1473K and multiple cracking occurs by absorbing a large amount of hydrogen at lower temperature. Volume expansion and dislocations generated b y hydrogenation and hydride formation are responsible for multiple cracking. Hydrogen-induced multiple cracking in Ta occurs in the following sequence: hydrogen absorption, lattice expansion, hydride formation, and crack nucleation and propagation. Powder fabrication of Ta by hydrogenation is discussed in comparison with the hydrogen pulverization of intermetallic alloys.

TiPdNi thin films were prepared by magnetron sputtering onto unheated glass and silicon substrate. Atomic force microscope, energy-dispersive X-ray microanalyzer, X-ray diffractometer, differential scanning calorimeter and optical microscope were used to characterize the films. It is found that the surface morphology of the films change during the sputtering process and a shift of about 3%Ti(mole fraction) content from the center to the edge of the substrate occurs. The freestanding asdeposited films undergo crystallization followed by three kin d s of cooling conditions. For all these heat-treated films, B2→B19→B19′ two-stage phase transformation takes place. Many Ti₂Ni and Ti₂Pd type of precipitates are detected in the films. The constraint films on silicon substrate are crystallized at high temperature. After crystallization, the films show a two-way shape memory effect.

With an attempt to investigate the effect of gold impurity and tungsten oxide on the recombination and separation of electron-hole pairs, and disclose the effect of surface state on the photo-catalytic activity of TiO₂, an innovative photo-catalyst 3%WO₃/0.5%Au³⁺/TiO₂ was prepared by means of sol-gel method. The photo-oxidation efficiency of photo-catalyst was evaluated by conducting a set of experiments to photo-degrade methylene blue (MB) in aqueous solution. The surface state properties were examined by means of surface photo-voltage spectra (SPS) and electron-field-induced SPS (EFISPS). The experiments demonstrate that the strongest peak is attributed to electron excited from valence band to conduction band and the second strongest peak is attributed to electron excited from valence band to oxygen molecular for all samples. Electron is trapped by O₂ absorbed on the surface of TiO₂. And the surface state of O^-₂ forms. For(1%, 3%)Au³⁺/TiO₂ sample, two new peaks that significantly present at 414nm and 400nm respectively should be attributable to gold impurity energy level. And for tungsten oxides doping samples, 4 peaks that significantly present in the region of 500～800nm should be attributable to tungsten impurity energy level. The intensity of EFISPS decreases with increasing the content of gold ion or tungsten oxide when its content is no more than their optimal dosage. However, when the content of gold ion or tungsten oxide is more than their optimal dosage, impurity energy level becomes recombination center from separation center and the intensity of all peaks increases for them. 

The martensite structure in Cu-25Al-3Mn alloy and its thermal cycling a nd aging behavior are studied. It is convinced that the M2H martensite can be obtained by water-quenched, and the atoms distribution on the basal plane of the martensite is: (corner)—Al; (center of the plane)—Cu; (middle o f b-side)—22/25Cu+3/25Mn. The lattice parameters are determined to be a=0.4459nm, b=0.5279nm, c=0.4241nm, β=88.64°. The triangle and other complicated configurations consisting of the variant group in the martensite are discovered. It is showed that the tested alloy has a high thermal stability when aging at average temperature in the parent phase, and the thermoelastic martensite amount is up to 90% after aging for 96h at 400℃. The thermal cycling has a little influence on the transformation temperature (M_s). When the number of thermal cycles is up to 1000, the increasing of M_s is only 8℃.

The effects of thermal cycling on marten site transformation in Cu-11.9Al-2.5Mn(mass fraction, %) shape memory alloy(SMA) with high M_s temperature were studied by means of electrical tension vs temperature (U—T) measurement, optical microscopy observation and X-ray diffractometry. It shows that with increasing thermal cycles, the transformation temperatures decreased, which are accompanied by changes of martensite structure such as the decline of NNN ordering degree and monoclinic angle β→90°. Compared with traditional Cu-base SMA, the alloy has rather high thermostability and can work at 2 00～300℃. Its excellent thermostability comes from two factors: 1) its β₁ parent structure is stable and difficult to decompose at work temperature; 2) its martensite structure is close to N18R(β=89.6°), which restrains the process of M18R→N18R and the tendency of martensite stabilization and decomposition.

The crystallization behavior of melt-spun Nd_8.5Fe₇₈Co₅Cu₁Nb₁B_6.5 ribbons was investigated using dynamic differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). It was found that the as-spun ribbons crystallize in two steps: at first the Nd₃Fe₆₂B₁₄+α-Fe phases are formed and subsequently Nd₃Fe₆₂B₁₄ transformed to Nd₂Fe₁₄B and α-Fe upon heating above 680℃. The effective activation energy of two crystallization peaks are 332.0kJ/mol and 470.5kJ/mol, respectively. As the wheel speed increases, the magnetic properties of the magnet change obviously. When the wheel speed is 18m/s, the best magnetic properties of the magnet was obtained after the sample was annealed at 690℃ for 8min: B_r=0.74T, _iH_c=421.7kA/m, (BH)_max=64.5kJ/m³.

Nd_8.5Fe₇₅Co₅Cu₁Zr₃Nb₁B_6.5 bonded magnet was prepared by melt-spinning (v_s=18m/s) and subsequent heat treatment (670℃, 4min). Excellent magnetic properties of the bonded magnet were achieved: B_r=0.68T, _iH_c=620.3kA/m, (BH)_max=74kJ/m³. The addition of Cu and Zr elements shows to be advantageous in improving an intrinsic coercivity and squareness of hysteresis loop, as well as energy product. It has a remarkable remanence enhancement and the isotropic saturation remanence ratio M_r/M_s is 0.83.