Ni-Mo ore was recovered by acid oxidation leaching and then alkaline leaching of acid residue.The results show that the leaching rates of Ni and Mo are 92% and 60% respectively,when HCl dosage is 0.52 mol per 100 g raw ore,solid oxidant N1 dosage 60% mass of raw ore,liquid-solid ratio 3∶1,leaching temperature 90 ℃ and time 2 h.The Mo leaching rate can be above 90% and its total recovery over 96%,when NaOH dosage is 45% mass of the dry residue from acid oxidation leaching,liquid-solid ratio 3∶1,leaching temperature 40~50 ℃ and time 15 min.The process has the advantages of simple process flowsheet,less energy consumption,and high recovery of Ni and Mo,and it can avoid the smoke pollution problem caused by pyrometallurgical desulphurization.

Evaporation crystallization experiments of（NH4）2WO4 solution were carried out through controlling different APT crystallization ratio,crystallization temperature and initial WO3 concentration in the solution.The rules of P,Mo,S and Fe impurity precipitation from high purity（NH4）2WO4 solution during evaporation crystallization were studied.The results show that reducing APT crystallization ratio and increasing initial WO3 concentration can significantly decrease the impurity content in APT.The least sulfur content in APT can be obtained by raising crystallization temperature,and the reduction level of P,Mo,S and Fe content follows the order of SPMoFe.

In view of the problems existing in the conventional precipitation with MgCl2 for Si and P removal and based on the composition characteristics,Na2MoO4 solution was purified deep by precipitation-coprecipitation.Compared with conventional magnesium or aluminum salt precipitation,precipitation-coprecipitation can bring about better purifying effect and more simple process control,overcoming the shortcomings in the conventional precipitation process,e.g.severe Mo inclusion loss.

The influences of rapid hot pressing and In doping on the microstructure and thermoelectric properties of Ag0.8Pb18SbTe20 were investigated.The n-type Ag0.8Pb18InxSb1-xTe20（x=0.25,0.5,0.75,1） powder alloy is prepared successfully by vacuum sealed melting,and the powder particle size can reach a micron level by high energy ball milling.Rapid hot-pressing sintering was adopted to prepare lumpy thermoelectric material at 693 K and 15 MPa for 30 min.The results show that the substitution of In for Sb enhances the conductivity of the thermoelectric material and thus improves its thermoelectric properties.The max.electrical conductivity at 623 K is up to 239 S/cm when the In dosage x is equal to 1.And the power factor reaches a maximum of 3.1×10-3 W/（m·K2） at the same temperature but with x equal to 0.5.

Al2O3/Mo superfine powder was prepared by sol-gel and secondary deoxidization,its phase composition,morphology and size were analyzed by XRD,SEM and TEM,and the effects of related factors on gelling process were discussed.The results show that the powder of the optimal quality is obtained under the conditions of pH2 and the mass ratio of citric acid to ammonium molybdate equal to 1.5.

The processes of solid solution and aging of Mg-10Y alloy are investigated and the process optimization conditions are confirmed by microstructure observation and hardness measurement.The results show that proper solid solution and aging treatment can improve the microstructure and the hardness.By 540 ℃×6 h solid solution,Mg24Y5 phase is almost entirely dissolved into the matrix.And then by 250 ℃×2 h aging treatment,lots of Mg24Y5 phase precipitates to ensure a maximum hardness of Mg-10Y alloy.

Al2O3 coating was prepared on Ti6Al4V-based alloy by sol-gel process with Al（OC3H7）3（aluminum isopropoxide） as the precursor.The results from SEM and XRD show that the resultant coating has uniform and crack-free surface,and it is mainly composed of amorphous Al2O3.The impact of Al2O3 coating was studied on the isothermal oxidation behavior of Ti6Al4V-based alloy at 600 ℃ and 700 ℃.The results show that 0.8 μm thick Al2O3 coating has the optimum high-temperature oxidation resistance.The parabola oxidation rate constants of the coated sample and the blank sample are 7.60×10-11 and 1.46×10-10 g2/（cm4·s）,respectively for 20 h isothermal oxidation at 700 ℃.The TiO2 content of the oxide skin on the coated sample is obviously less than that on the blank sample.Al2O3 coating can effectively protect the alloy from spalling and cracking.The thickness of the oxide skin on the coated sample is only half of that on the blank sample.

Ti2AlNb alloy was modified by double glow plasma surface carburizing to improve its wear resistance.The microstructure,phase composition and dynamic microhardness of the carburized layer was characterized through SEM,XRD and dynamic microhardness system.And its wear resistance was tested through a HT2500-type friction and wear tester.The results show that about 11 μm carburized layer is obtained on the Ti2AlNb alloy surface,and its carbon content decreases gradually from surface to matrix.The main components of the carburized layer are pure C,TiC and Ti2AlC.The surface dynamic microhardness of the carburized layer is 9.61 GPa.The specific wear rate of the carburized sample is only 1.82% of the matrix alloy.The wear resistance of Ti2AlNb alloy is greatly increased by carburization.

Electrocatalysis synthesis of p-aminophenol（PAP） from nitrobenzene using hydrogen-storage alloy electrode as the catalytic reducer was studied in sulphuric acid system.The effects of technical conditions such as kinds of organic solvent,reaction temperature and sulphuric acid concentration on the yield of PAP and current efficiency were discussed.The PAP content in catholyte was determined directly by spectrophotometry.The results show that hydrogen-storage alloy electrode can electrolyze and reduce nitrobenzene to prepare PAP.And the optimal electrolysis conditions are as follows： Isopropanol is employed as the organic solvent,electrolysis time 4 h,reaction temperature 80 ℃,current density 200 mA/cm2,and sulphuric acid concentration 20%（volume fraction）.Under the optimal conditions the PAP yield is 58.6% and the current efficiency is up to 78.5%.

Impact of sintering temperature and time on the axial density distribution,microstructure,hardness and bending strength of D152 mm YG6 cemented carbide double-faced anvils were studied by drainage method,SEM,EDS and three point bending.The service life of the double-faced anvil was tested by experiment.The results show that the D152 mm double-faced anvil,prepared by vacuum sintering at 1 390 ℃ for 6 h with YG6 alloy,has fine WC grains,low grain adjacency degree between WC and WC,and an average service life of 2 408 times.