The process technology was studied of mirror white molybdenum wire preparation by electrolytic polishing.Electrolytic method,electrolytic parameter,electrolytic medium,electrode material,and high temperature annealing were experimentally studied.The results show that mirror white molybdenum wire with surface roughness（Ra）of 0.2 can be produced by direct current electrolysis with direct contact between molybdenum wire and anode and using sulfuric acid electrolyte as the medium.Surface passivation and polishing of white molybdenum wire by high temperature annealing can not only improve surface oxidation resistance of white molybdenum wire,but also adjust its physical performance indexes.

The single alloy composition was designed by adding rare earth Ho to replace rare earth Dy,and the technology research scheme of melting,hydrogen decrepitation,jet mill grinding,seal press forming and low temperature sintering was employed.Finally,48 M（NdFeB380/107）sintered NdFeB permanent magnetic material with high magnetic energy product was producted at a low cost.The jet mill grinding is low pressure grinding to reduce the loss of Nd-rich phase and the particle size of the magnetic powder.

The corrosion of irregular sintered NdFeB magnets was researched with weight loss method in such solutions as distilled water,river water,sulfuric acid,potassium hydroxide solution and potassium chloride solution of different temperature and concentration.The specific surface area of the samples was estimated according to their shape,to calculate their corrosion rate under different conditions.The results show that the corrosion rate of the sample in the acid medium is relatively fast,and the corrosion rate increases with the increase of the acid solution concentration.However,alkali and salt solutions of low temperature and high concentration have relatively weak corrosivity to the samples.Distilled water has higher corrosivity to the samples than tap water.

Sintered（PrNd）29.8Tb1Dy0.2Cu0.5Al0.2Co1.5B0.99TixFe（x=00.8）magnets with different Ti content were prepared by intergranular alloying,and their microstructure,magnetic properties and mechanical properties were studied.The results show that the magnet grain can be effectively refined by adding Ti.The proper addition of Ti can improve intrinsic coercivity force and squareness of the magnets,but decrease the remanence and maximum magnetic energy product.Furthermore,Ti addition can decrease the bending strength of the magnets without no obvious effect on their hardness.

Using the premixed H2/Air as explosion source,TiO2 nanoparticles were prepared by gaseous detonation in a self-made explosion reaction tube.The variation law was discussed of the detonation pressure in the tube under different initial conditions（initial temperature of 25200℃and H2/Air mixing ratio of 0.20.8）.Particle size,composition of crystal phase and morphologies of TiO2 nanoparticles synthesized by detonation at different initial temperature and calcinated at high temperature were characterized by means of XRD and TEM.The results show that the end of the explosion reaction tube has the largest detonation pressure when the premixed H2/Air with the chemical equivalent ratio is employed as explosion source.The detonation pressure at the tube end is increased eventually increased by 39.03% with the increase of H2/Air mixing ratio,and the increasing rate firstly increases and then decreases.However,the detonation pressure at the tube end is reduced eventually by 36.86% with the initial environmental temperature increasing.The prepared TiO2 nanoparticles are mixed crystals of anatase and rutile,their grain size increases at first and then decreases with the increase of initial temperature,and the anatase phase is gradually reduced.The phase-transition temperature from anatase to rutile is 700900 ℃ during high temperature calcination of detonation products,and the grain size is gradually increased with the rise of calcination temperature.

The effects were investigated of different aging temperatures and holding time on the microstructure and mechanical properties of near beta type titanium alloy TLM.The results show that the characteristics of alloy microstructure after beta single phase solid solution and aging treatment are as follows：αphase precipitates out on both sides of the grain boundary along a certain crystal orientation in colony form,and there is also a large amount of precipitatedαphase inside the crystal grains.With the increase of aging temperature,the size of precipitatedαphase is gradually increasing and tends to be uniform,alloy strength is decreasing and ductility is increasing.When aging temperature rises from 480 ℃ to 510 ℃,the strengthening effect is the most obvious,and the increment of tensile strength reaches the maximum value of 184 MPa.When the temperature rises from 510 ℃ to 540 ℃,the increment of tensile strength reaches the minimum value equal to 63 MPa.With the increase of aging time,the size is obviously enlarged of precipitatedαphase along the grain boundary in colony form,there is also someαphase appearing in the precipitation-free zone,and its distribution gradually tends to be uniform.Aged at 480℃,alloy strength increases and ductility decreases with the increase of holding time.Aged at 510 ℃,alloy strength and ductility have no obvious change with the increase of holding time.Aged at 540 ℃,alloy strength is decreasing and ductility is increasing with the increase of holding time.

Using Ti3SiC2 as the external strengthening phase and Al-Mg alloy as the matrix,Ti3SiC2/Al-Mg composites were prepared by spark plasma sintering（SPS）.The effect of subsequent heat treatment on interfacial reaction was researched.The results show that Ti3SiC2/Al-Mg composites can be prepared successfully by SPS,and insulation temperature is a key factor affecting interfacial reaction during heat treatment.When the temperature is lower than 550℃,no interfacial reaction occurs.When the temperature reaches 600 ℃,a slight interfacial reaction occurs,and the main products are Al4 C3 and Mg2 Si.Interfacial reaction leads to an increase of material hardness,but a decrease of the density and conductivity.In addition,with the increase of Mg content in the matrix,the grain size of Ti3SiC2/Al-Mg composites gradually decreases and the hardness gradually increases.

TiAlSiN coating and TiAlN coating were deposited on Zr-4 alloy surface by multi-arc ion plating,respectively.Surface micromorphology of the coatings were observed by scanning electron microscope.Statistics and analysis of the large particle distribution of the coatings were carried out by ImageJ.The phase composition of the coatings was analyzed by X-ray diffractometer.The mechanical properties of the coatings were tested by an automatic scratch tester.And the samples were subjected to 800℃ high temperature oxidation resistance test in a high temperature heat treatment furnace.The results show that the amount of large particles on the surface of TiAlSiN coating is less than that of TiAlN coating.Both TiAlSiN coating and TiAlN coating have Ti2N phase and Ti3AlN phase.In addition,TiAlSiN coating also has AlN phase and Si3N4 amorphous phase.Because the addition of Si elements leads to residual stress,TiAlSiN coating has lower coating/substrate adhesion strength than TiAlN coating.Oxidation weight gain of TiAlSiN coating sample is far lower than that of TiAlN coating sample.

Cr metal layer of about 12μm thickness was prepared on zirconium alloy surface by multi-arc ion plating technology.Oxidation behavior and film adhesion strength to substrate of Cr-coated sample were investigated at 1 200℃ high temperature.The results from SEM analysis show that multi-arc ion plating layer has uniform thickness,smooth surface and clear film/substrate interface,and there are a large number of micro-holes and large particles on its surface.High temperature oxidation experimental results show that Cr-coated sample has obviously better high temperature oxidation resistance than the original zirconium alloy.There is a lot of Cr2O3 forming on the surface of the Cr-coated sample after oxidation at 1 200℃for 2 400 s,and its weight gain per unit area is only 12% of that of the original zirconium alloy.Scratch experimental results show that the critical load of Cr-coated sample is 18 N,and the bonding performance between the film and the substrate is excellent.

Zirconium alloy Zr-4 was melted by vacuum induction in BaZrO3 crucible.The interfacial reaction between the crucible and zirconium alloy melt was analyzed by SEM,EDS and XRD,and then reaction mechanism was investigated.The results show that the BaZrO3 crucible still has complete structure after alloy melting.There is a certain degree of wetting between alloy melt and BaZrO3 refractory material,but no significant interfacial reaction layer is observed between the crucible and the alloy,only about 20μm thick permeable layer existing.