Effects of the three essential factors of sintering temperature,sintering pressure and heat preser vation time on the preparation of magnetic abrasive grains were investigated. Iron and alumina powder were mixed first by a certain percentage,and then put into pressure sintering furnace for hot pressing sintering. The relationship between magnetic induction intensity and density of the sintered sample was discussed as well as density variation of the sintered sample with different process parameters. The results show that magnetic induction intensity of the sintered magnetic abrasive sample is linearly proportional to its density. with the increase of sintering temperature, sintering pressure and heat preservation time, density of the sample also increases. The optimal conditions are 1 080 ℃ ,46 MPa and 15 rain,and continuing improve ment of the three parameter values cannot significantly change density and magnetic induction intensity of the sample.

In view of some problems including delamination, slag inclusion, electric melting unevenness with residue and fragment when electrolytic nickel is used in electroplating, the quality of electroplating products is affected. The causes are analyzed. Such factors in the electrolytic nickel production process as rising elec- trolyte pH, fierce current intensity movement, unclean surface of electrolytic nickel starting sheet, impure electrolyte and so on, are the main causes of electrolytic nickel quality defects. The corresponding improve ment measures and the proposal for accelerating the development of active electrolytic nickel are put for ward.

Tellurium was enriched as copper telluride from copper anode slime. Tellurium and selenium were separated from chlorination leaching solution of copper telluride by solvent extraction, and tellurium was recovered. The results show that with 20% TOA＋20% octanol＋60% sulfonated kerosene （volume fraction） as the extractant,2 mol/L H2SO4 ＋HCl as the detergent and 200 g/L NH4 Cl solution as the stripping agent, tellurium can be effectively separated from selenium and copper. After stripping solution is reduced by sulfur dioxide or hydrazine hydrate,high purity tellurium powder is obtained.

Coated P507 impregnated resin was prepared with P507 as the extractant, HZ818 macroporous resin as the matrix,polyvinyl alcohol as the coating material and boric acid as the crosslinking agent. The adsorption mechanism of the sample for indium （Ⅲ） in sulfuric acid was investigated by using saturation capacity method and constant molecular series method. Uncoated and coated P507 impregnated resin were characterized by IR spectra before and after indium （Ⅲ ） adsorption. The results show that the process of coated P507 impregnated resin adsorption for indium （ Ⅲ ） in sulfuric acid is contributed to the joint action of cation exchange and coordination reaction.

Direct synthesis method was applied in RhI3 preparation from 12 powder and Rh powder. Analysis is made of the influences of reaction temperature, reaction time and ball to powder ratio on the conversion rate, and the optimal reaction conditions were determined. Activation energy of the reaction was computed by Arrhenius formula. The results show that the effect of reaction temperature is limited. Therefore,the measures of using catalyst,improving I2 concentration and so on should be considered to improve the reactlon rate.

Ta2O5 and Nb2 O5 powders are prepared with tantalum solution and niobium solution as the raw material and by ammonia neutralization precipitation-washing-drying-calcination. Influences of wash water amount and calcining time on fluorine content of the product were studied. The results show that fluorine content in tantalum and niobium oxides increases after they are placed in hydrofluoric acid atmosphere for some time,and therefore their fluorine content can be controlled at 0.07% -0.12 %, meeting the application requirements of foreign fiber field for tantalum and niobium oxides.

Domestic and foreign molten-salt electrolysis device structures for preparing titanium and its alloys are introduced,and their latest development is summarized. The advantages and disadvantages of each electrolytic equipment are comparatively reviewed.

MnO2 and TiO2 were employed as the sintering aids of 8YSZ （8 %Y2 O3-ZRO2 ）. Effects of aid dosage and composition and sintering temperature on the density and mechanical properties of 8YSZ were investigated. The results show that adding MnO2 and TiO2 is beneficial for sintering densification of 8YSZ, and MnO2 is more effective than TiO2 as the sintering aid. MnO2 and TiO2 are successfully doped into the ZrO2 lattice at 1 300 ℃ ,improving the hardness, bending strength, fracture toughness and tetragonal phase content of 8YSZ. The density and mechanical properties of 8YSZ is improved with higher sintering temperature. When TiO2 dosage increases from 0 to 3% and MnO2 dosage decreases from 3% to 0,all the density, Vickers hardness and bending strength of 8YSZ are gradually reduced .

In order to realize W-Cu metallurgical bonding,Ni-containing coating was prepared on pure tungsten surface by infiltration in different melts. The microstructures and composition distribution of coating/ tungsten interface were studied by SEM and EDS. The results show that metallurgical bonding between coating and tungsten forms, including Ni-Fe coating,Ni-Cu coating and Ni coating prepared at 1 500 ℃ in Ni-Fe melt, Ni melt and Ni-Cu melt, respectively. There is tungsten-based high density alloy microstructure composed of smooth W particle phase and a small amount of binder phase on Ni-Fe coating and tungsten interface. A 1-2 μm thick compound layer composed of NiW and NiW2 forms along Ni coating and tungsten interface. Based on experimental results and W-Ni binary phase diagram,Formation mechanism of the microstructure on coating/tungsten interface is analyzed.

The latest development of ultrafine/nano W-Cu composite powders is reviewed recently in China and abroad. Several preparation methods of ultrafine/nano W-Cu composite powders are introduced and analyzed on their technical characteristics, including mechanical alloying, mechanical-thermochemieal meth od,spray drying and sol-gel.