The effect of some anions,such as SO 2- 4,CI - and OH -,on the W exchange capacity is studied in this paper.The experiment results show that with the increasing of these anions,the W exchange capacity decreases.Meanwhile,with the existence of these three kinds of anions,the orthogonal experiment results show that the order of the degree effect on W exchange capacity is CI ->SO 2- 4>OH -,and that in the solution before exchange,[WO 3]=20g/l,[SO 2- 4]<0.03125mol/L,[CI -]<0.00846mol/L and [OH -]<0.4706 mol/L is feasible.With the existence of these anions,the W exchange capacity can be increased through series columns.

Based on pH situ determination data,together with the results of variation in precipitation volume and precipitation partical size,the properties of lanthanum carbonate precipitated with sodium bicarbonate were investigated.The results show that crystalliazation active zone of lanthanum carbonate is in low molar ratio zone,where the moalr ratio is between 0.541～2.828.However,the crystallization of lanthanum carbonate in high molar ratio zone is inactive.At the same tine,the influence of stirring on the crystallization of lanthanum carbonate was examined ,the crystallization mechanism was discussed and the corresponding reaction equations were proposed.

The bulk density of Nb 2O 5 can be improved from 0.4～0.5g/c.c to 1.1g/c.c,and the content of Nb 2O 5 to 98%,LOI be reduced down to less 1% by changing the precipitating condition,controlling of washing time and adjusting of calcination temperature,addition of a proper quantity of additive if necessary,for precipitation of Nb solution with ammonium.

Study is made of production of high purity Dy metals by magnesium reduction.The results showed that high purity (up to 99.99%)Dy can be obtained by the following process:preparation of unhydrous DyCl 3 by chloridization of high purity(4N)Dy 2O 3 with high purity chloridizing agent;then magnesium reduction of unhydrous DyCl 3 to obtain Mg Dy alloy followed by distillation to obtain Dy metal.

The mixture of Mo and Si powders was milled by mechanical ball milling.The effect of ball milling technology on mechanical alloying of MoSi 2 was systematically investigated.The results showed that MoSi 2(t) Was more easily formed by hard alloy ball milling than stainless steel ball when the ball to powder mass ratio was 5∶1,10∶1 and 30∶1.The time of the formation of MoSi 2 Was the same with two different ball milling medium when the ball to powder mass ratiowas 20∶1

PIM(powder injection molding) is an advanced forming technology and is drawing more and more attention.Powder injection molding of cemented carbides is a complicated process due to the materials'characteristics.There are still several big problems to be solved to improve the technology.In this Paper,defect control,carbon control,dimension precision control and its mechanical property improvement are discussed and some measures are proposed to solve the problems.

The applied techniquies on forging,heat treatment and machining of GT 35 steel bonded carbide ingots are studied in this paper,the process parameters are provided.The rsults are important reference data for the further development and application of the said material.

Based on TZC material for PIM Mo ejector,study and on the site tests were made in respect of the high temperature strength and hardness and microscopic structures of the TZC alloy with the addition of single RE cerium and also Ce Yt RE element.The results showed that the addition of Ce in the alloy can greatly improve the alloy hardness while addition of Yt can greatly improve the alloy high temperature strength.The addition of both Ce amd Yt at the same time will result in compound intensifying effect with much larger high temperature strength and hardness,allowing for～25%more ST billet through capacity

The effects of cobalt on the drawing and proccessing hardening of molybdenum wire were studied.The microstructure and mechanical properties of annealed molybdenum wire with or without cobalt addition were observed and analyzed.The results show that cobalt addition increases processing hardness and decreases recrystallization temperature by about 100℃.Furthermore,the doping of cobalt greatly benefits the ductility of molybdenum.Mo Co wire is really an attractive alloy.

Study is made of recovery of organic reagents during the preparation of ultrafine powder by metal alcoxides hydrolysis.The Phase diagrams of isopropanol benzene system and isopropanol benzene water system have been plotted,based on which,isopropanol and benzene can be recovered and recirculated by distillation rectification process.The recovery and reused rate of alcohol and benzene are above 75%.So both the environmental pollution and cost of ultrfine powder are reduced.