The phase composition of the molybdenum ammonia leaching residue was analyzed by XRD.The results indicate that there are calcium molybdate and a small amount of low-valence molybdenum compounds in the residue.Thermodynamic research of calcium molybdate leaching with sodium carbonate shows that the leaching reaction spontaneously occurs at the temperature higher than 86℃.The higher the temperature,the easier the leaching reaction.The optimum process parameters of residue leaching with sodium carbonate at high temperature are established as follows：sodium carbonate concentration 70g/L,reaction temperature 190℃,pretreating time 1.5h,liquid-solid ratio 3∶1.Under the optimal leaching conditions,the molybdenum leaching ratio can reach 91.44%,the molybdenum content in the residue decreases to 1.91%,and calcium molybdate is completely leached.Kinetic study of the leaching process shows that the apparent activation energy is 10.38kJ/mol in the leaching reaction of molybdenum ammonia leaching residue with sodium carbonate,and the leaching process is mainly controlled by solid-membrane diffusion.

The Δ_fGθ of CoPO_4,Co_3（PO_4）_2 and MeCoPO_4（Me=Li,Na,K,Mg_（0.5））was estimated by congeneric linearity rule.Theφ-pH diagram of the Me-Co-P-H_2O system at 298.15 K was drawn according to the thermodynamic calculation.Thermodynamic analysis was made of lithium extraction using lithium ion battery electrode material LiCoPO_4,and the differences were discussed of adsorption behaviors between Na＋,K＋ or Mg2＋ and Li＋ in salt lake by CoPO_4.The results show that CoPO_4/LiCoPO_4 electrode is stable in aqueous solution（pH=4~11）.Controlling the redox potential of the system at 0.066~0.201V（vs SHE）,CoPO_4 material can absorb Li＋ selectively from the natural brine containing a large number of Na＋,K＋ and Mg2＋,and then Li＋can be desorbed reversibly from lithium-inserted CoPO_4 ion sieve material by controlling the redox potential over 0.201V（vs SHE）.

The process was investigated of capping reduction-high temperature carbonization to prepare ultra-coarse grained WC powder.WO_3 is put into a special boat for hydrogen reduction at 930～980 ℃ at first and then carbonization at 2 300℃.Compared with the two processes of traditional medium temperature reduction-high temperature carbonization and doping reduction-high temperature carbonization,the process of capping reduction-high temperature carbonization can produce ultra-coarse grained WC powder with fuller particles,coarser grain size,more uniform particle size distribution and more complete crystal.WC powder prepared by this process has abrasive grain size of 7.4μm,reaching the requirement of ultra-coarse grained WC for grain size.

High-temperature oxidation-resistant protective coating was prepared by slurry fusion sintering on the surface of Nb-W alloy Nb521-1 used in aerospace engine.The bottom layer and surface layer were successively prepared by twice slurry fusion sintering processes to obtain silicide composite coating.Morphology and element content of the coating were analyzed by SEM and EDS.High temperature oxidation resistance at 1 700 ℃ and thermal cycling performance from room temperature to 1 600 ℃ of the coating were tested.And the failure mechanism of the coating was preliminarily discussed.The results show that there is a diffusion layer between the composite coating and the substrate attributed to their mutual diffusion,and the interface is of metallurgical bond.The coating can be continuously used at 1 700 ℃ for 22 h,and its limit frequency of thermal cycling tests from room temperature to 1 600℃ is 1 124 times.The composite coating can effectively prevent the external oxygen from further diffusion to the substrate,and therefore the substrate is well protected in high temperature environment.

Vacuum electron beam butt welding was carried out on 3mm thick TaW12 alloy sheets,and then the welded sheet was successively thinned to 2mm and 1.5mm by cold rolling,exhibiting good cold workability of the electron beam weld of TaW12 alloy.Tensile test results show that the tensile strength of the alloy can only reach 699.65～721MPa by simple electron beam welding with 9.38%～13.15%elongation.However,the tensile strength of the machined weld of 1.5 mm thick sheets can be up to 934 MPa,about 93.8%～94.7%tensile strength of 1.5mm thick cold-rolled substrate,and its elongation reaches 8.0%～9.0%.And all the weld tensile samples fracture along the weld center.The cold-rolled electron beam weld has higher strength and plasticity,attributed to weld microstructure refinement and pore decrease caused by cold rolling.

Research on the mechanical properties of Ti-Mo alloy was carried out during hydrogen absorption,and test data of mechanical properties of alloy microstructure were obtained,reflecting its characteristics of elastic and plastic deformation in microscopic field.The results show that the average value of Vickers microhardness HV_（0.5） of Ti-Mo alloy is 332 before hydrogen absorption and 419 after hydrogen absorption with the test force of 4.903 N.The compressive strength of the alloy is higher than 1 730 MPa either before or after hydrogen absorption,and the maximum load force in the test is 50 kN.The change of mechanical properties of Ti-Mo alloy during hydrogen absorption is caused by its phase transformation.

Ti（C_（0.7）N_（0.3））-WC-Mo_2C-TaC-Fe/Co/Ni series cermets were fabricated by low pressure sintering.The effects were investigated of Fe content on microstructure,phase composition and mechanical properties of the Ti（C,N）-based cermets.The results show that with the increase of Fe content,the volume fraction increases of the hard phase with white core-grey rim structure.In addition,a lot of M_（12）C-typeηphase transforms to M_（6）N-type brittle phase during solid-state sintering,and therefore higher Fe content can promote formation of the brittle phase in the cermets.The results of mechanical tests show that appropriate Fe substitution for Ni can obviously improve the fracture toughness and hardness of Ti（C,N）-based cermets,firstly increasing and then decreasing with the increase of Fe content.When Fe content is 2%,the cermet has the maximum hardness of 1 642 MPa and fracture toughness of 10.63 MPa·m1/2,higher than the cermet without Fe by 96 MPa and 11.3%,respectively.However,adding excessive Fe will greatly worsen the mechanical properties of the cermets,mainly due to the increase of M_6N-type brittle phase content in the cermet with high Fe content.

The effects were investigated of melt-spinning velocity on microstructure and hydrogen storage properties of 40Ti-40V-10Cr-10 Mn.The phase analysis shows that the original sample consists of V-based solid solution with body centered structure（BCC phase）.The melt-spun samples at 10 m/s and 30 m/s consist of BCC phase and C14-Laves phase.The melt-spun sample at 20m/s consists of BCC phase and C15-Laves phase.Kinetic mechanism research shows that hydrogen absorption kinetic process can be described by chemical reaction mechanism for the original sample and melt-spun samples at 10m/s and 30m/s and described by 3-D diffusion mechanism for the melt-spun sample at 20m/s.Moreover,with the increase of melt-spinning velocity,hydrogen absorption capacity of the sample at room temperature decreases at first and then increases,getting the minimum at 20 m/s.All the melt-spun samples have higher hydrogen desorption capacity at room temperature than the original sample,and the melt-spun sample at 10 m/s has the maximum with improved hydrogen absorption and desorption hysteresis.With melt-spinning velocity increasing,hydrogen desorption capacity of the sample at 373 Kfirstly decreases and then increases,getting the minimum at 20m/s,and the melt-spun sample at 10m/s and the original sample have the close value.

TiAlN coatings were deposited on the surface of TiCN ceramic tools by ion enhanced magnetron sputtering and evaporating deposition combination source equipments.In order to improve the adhesion of the TiAlN coatings to the substrate,a layer of CrN/Cr film was deposited firstly on TiCN ceramic tools by evaporating deposition.The effects were systematically investigated of CrN/Cr interlayer on microstructure,microhardness,film-substrate adhesion and wear resistance of the coatings by the equipments of X-ray diffractometer,Vickers microhardness tester,Rockwell hardness tester,friction and wear tester and so on.The results show that the CrN/Cr interlayer can effectively improve the adhesion and wear resistance of the coatings.

TbDyFe alloy or DyFe alloy plus terbium metal were used as the raw materials to prepare high performance sintered NdFeB with the similar smelting equipment and process.Comparison was made of thickness distribution,chemical composition,microstructure and magnet properties between the two strip casting products prepared with the same ingredient proportion but in different addition ways.And magnetic properties were investigated of sintered NdFeB magnets with lower terbium content.NdFeB alloy composition was designed according to RE（Pr,Nd,Tb,Dy）_（32.6）M（Fe,Co,Al,Ga,Cu,Nb,Zr）_（bal）B_（1.0）（mass fraction）.The results show that different material addition ways have no obvious effects on the appearance,thickness distribution and microstructure of strip casting products.However,effective terbium components increase by 10.71% in the strip casting product with TbDyFe alloy as the raw material,its magnet coercivity increases by 14.04%,and the remanence slightly decreases.Using TbDyFe alloy with 10% lower terbium dosage of DyFe alloy plus terbium metal,the prepared sintered NdFeB can reach the magnetic property level of the latter,greatly saving the rare earth resources.