TC18 titanium alloy bars were heat treated at different temperatures,and then cooled in the fur-nace.The effects of heat treatment temperature on the microstructure,phase composition,impact perfor-mance and impact fracture micromorphology of the alloy were analyzed by optical microscope,scanning e-lectron microscope,X-ray diffractometer and impact tester.The results show that the size,distribution and morphology ofαphase in TC18 titanium alloy have different degrees of change after heat treatment at dif-ferent temperatures.In the process of increasing the heat treatment temperature,the large blockαphase gradually disappears,the long stripαphase becomes finer,and more fine needleαphase precipitates.The microstructure of the alloy after heat treatment at different temperatures and furnace cooling formsαphase andβphase,and with the increase of heat treatment temperature,the diffraction peak intensity of someαphase andβphase increases.The equiaxed and strip-shapedαphase can make the crack propagation path smoother,while the needleαphase andβphase can disperse the stress of the alloy when it is impacted and avoid brittle fracture caused by stress concentration.The impact performance of the alloy gradually decrea-ses with the increase of heat treatment temperature.When the heat treatment temperature is 835℃,the al-loy has the best impact performance with an impact absorption energy of 46 J and an impact toughness of 57 J/cm².When the heat treatment temperature is low(835℃and 855℃),the impact fracture micromor-phology of the alloy is mainly characterized by large dimples,which contain a large number of small dim-ples.When the heat treatment temperature is high(875℃and 895℃),the fracture dimple size becomes smaller,tearing edges appear,and the void size increases.

Plasma nitriding were carried out on TiCN-based cermet by varying N₂/Ar flow ratio,and TiAlN coating was deposited on the surface of the nitrided sample.GIXRD,EDS,SEM,HR-TEM,scratch test,nano indentation test and optical image tester were applied to study the influence of N₂/Ar flow ratio du-ring nitriding process on the microstructure,status of coating-substrate interface,mechanical properties of the coating and cutting performance of the coated cermet blades.The results show that with the increase of the N₂/Ar flow ratio,TiAlN coating grains gradually refine,the thickness of the coating decreases,and part of binder phase remains on the surface of the substrate,which affects the growth and properties of the coa-ting.When the N₂/Ar flow ratio is 1,there are two kinds of coating growth areas at the coating-substrate interface:hard phase growth area and binder-rich phase growth area.The coating grows coherently on the surface of the hard phase.There is a transition zone with disordered atomic arrangement in the binder-rich phase area,and the coating grows semi-coherently.Besides,the coating is dominated by crystal plane(200)orientation with a texture coefficient of 1.91,and the H/E ratio reaches the highest of 0.094.When the N₂/Ar flow ratio is 2,the hardness and elastic modulus of the TiAlN coating are the highest,which are 34.15 GPa and 416.64 GPa,respectively.During cutting,abrasive wear and adhesive wear mainly occur in the cutting contact area.The coated TiCN-based cermet blades exhibit the best cutting performance when the N₂/Ar flow ratio is 1.

TiC-strengthened AlCoCrFeNi-based high-entropy alloy composite coatings were fabricated on the surface of 2255 DSS by laser cladding.The phase composition and micromorphology of AlCoCrFeNi+TiC cladding layers were characterized by X-ray diffractometer and field emission scanning electron micro-scope.The microhardness of the cladding layer was measured by Vickers hardness tester,the wear resis-tance was tested by linear reciprocating friction and wear tester,and the corrosion resistance was tested in an electrochemical workstation.The results show that TiC-strengthened AlCoCrFeNi-based cladding layers mainly consist of BCC phase and TiC phase.As the TiC addition increases,the relative content of TiC phase gradually increases and that of BCC phase gradually decreases.The microstructure of the cladding layer is composed of equiaxed crystal matrix and the second phase,and the matrix grains are gradually refined with the increase of TiC content.With the rising content of TiC,the microhardness of the cladding layer gradu-ally grows due to the dispersion strengthening effect,while the wear resistance first increases and then de-clines.Excessive TiC results in the agglomeration of the second phase and the formation of microstructure defects,which leads to the decrease of the compactness and wear resistance of the cladding layer.The wear mechanism of cladding layers is mainly abrasive wear.As the TiC content rises,the corrosion resistance first increases and then gradually decreases.This is because Ti produced by the dissolution of a small amount of TiC can improve the passivation film formation ability of the cladding layer,while excessive TiC can enhance the galvanic couple corrosion effect.

TiC-reinforced Ni-based single coatings and gradient coatings were generated in situ on the sur-face of H13 steel by laser cladding technology.The micromorphology,composition distribution,phase com-position,microhardness and frictional wear resistance of the coatings were analyzed and compared by scan-ning electron microscope,energy spectrometer,X-ray diffractometer,microhardness tester and universal friction and wear testing machine.The results show that the single coating is prone to macroscopic pores,cracks,poor bonding with the matrix and other defects,while the gradient coating can realize the gradient change of composition,microstructure and properties,and form a good metallurgical bonding with the ma-trix.Fe-Cr,TiC and other reinforcing phases generate in the gradient coating,which significantly improves the surface hardness and wear resistance of the steel.The average hardness of the gradient coating is about 1.44 times that of the single coating and about 2.58 times that of the matrix.The average wear loss of the gradient coating is 45.6%of that of single coating and 32.4%of that of the matrix.The wear mechanism of the gradient coating is mainly abrasive wear and adhesive wear.

The Co composite powder doped with Y₂O₃ was prepared by planetary grinding,the WC-Co mixed powder containing Y₂O₃ was prepared by adding WC powder,and then WC-Co-Y₂O₃ cemented car-bide was prepared by SPS.Scanning electron microscope,energy spectrum analyzer,X-ray diffractometer,Vickers hardness tester and friction and wear testing machine were used to investigate the effects of ball milling time on the microstructure and phase composition of Co-1%Y₂O₃ composite powder,and ball mil-ling time and Y₂O₃ content on the microstructure,phase composition,density,Vickers hardness,fracture toughness and wear resistance of WC-Co-Y₂O₃ cemented carbide.The results show that the Co diffraction peak shifts towards a larger angle after adding Y₂O₃ and ball milling.As the ball milling time increases,the Co grains are disrupted and their size becomes smaller,leading to a decrease in the intensity of Co diffraction peak.The density,Vickers hardness and fracture toughness of the cemented carbide increase with the extension of ball milling time.When the ball milling time exceeds 36 h,the hardness of the cemented car-bide tends to stabilize,while the fracture toughness decreases.The density,Vickers hardness,fracture toughness and wear resistance of the cemented carbide first increase and then decrease with the increase of Y₂O₃ content.The best overall performance of the cemented carbide is obtained when the Y₂O₃ content is 1%.The addition of rare earth oxide Y₂O₃ by stepwise ball milling can strengthen the Co binder,inhibit the growth of WC grains,and enhance the mechanical properties of the cemented carbide.

To address the environmental pollution caused by waste lithium iron phosphate batteries and the shortage of lithium resources,an innovative bipolar membrane method was proposed using recycled waste lithium iron phosphate batteries as the raw materials.LiOH was prepared from acid leached Li₂SO₄ by bi-polar membrane electrodialysis,then refined Li₂CO₃ was obtained,and battery grade LiFePO₄ cathode ma-terial was ultimately prepared.The main processes include crushing and sorting of lithium iron phosphate battery,black powder leaching,impurity removal of material liquid,and synthesis of iron phosphate and lithium iron phosphate,thereby obtaining the main products of Li₂CO₃ and FePO₄ and by-products such as aluminum particles and copper particles.Through synthesis regeneration technology,LiFePO₄ cathode ma-terials that meet the gradeⅠstandard in GB/T 30835-2014 are obtained.The prepared LiFePO₄ products have a first coulombic efficiency of over 96%and a rate performance of over 94.5%.This process achieves the goal of saving production costs of LiFePO₄ and realizing the recycling of renewable resources.

The ingredients,performance indicators and recycling value of cathode materials of waste lithium iron phosphate batteries are analyzed.The latest research progress on the current recycling technology of cathode materials of waste lithium iron phosphate batteries,including physical methods(magnetic separa-tion,flotation,and gravity separation)and chemical methods(dry methods and wet methods),is reviewed in detail.Finally,the development direction and challenges of the recycling technology of cathode materials of waste lithium iron phosphate batteries are pointed out,aiming at promoting the recycling and sustainable utilization of cathode materials of waste lithium iron phosphate batteries.

The adsorption and separation of molybdenum from crude ammonium tungstate solution using ZGA351 macroporous strong base anion exchange resin were studied.The effects of resin type,sulfur content,aging time and temperature and pH of the feed solution,adsorption flow rate and adsorption temperature on the adsorption and separation of molybdenum by the resin were studied.The results show that using 100 mL ZGA351 resin in dynamic adsorption tests,the tungsten loss rate in the feed solution is only 0.54%when the tests are conducted under the optimal conditions of sulfur content of 1.1 times the theoretical amount,aging time at 40℃of 48 h,solution pH of 10.0,adsorption flow rate of 15 mL/h,and adsorption temperature of 40℃.The molybdenum penetration capacity of the resin is 107.77 g/L_(wet resin),which is 3.15 times higher than that of the HBDM-1 resin currently used in industrial production.In addition,the repeated experiments showcase good stability,and the average molybdenum-to-tungsten ratio of pure ammonium tungstate solution obtained after adsorption by ZGA351 resin is 0.88×10^-4,which meets the requirement of molybdenum-to-tungsten ratio of pure ammonium tungstate solution to be less than 2×10^-4for industrial production of APT products.In summary,the separation of molybdenum from crude ammonium tungstate solution by strong base anion exchange resin has the advantages of high molybdenum penetration capacity,low tungsten loss rate,high separation efficiency of tungsten from molybdenum,providing an effective technical reference for industrial applications.

The desorption solution of thiomolybdate-saturated resin(molybdenum desorption solution)was treated by hydrogen peroxide oxidation and sulfuric acid regulation.The effects of the type,dosage and adding method of oxidants,and the temperature and time of reaction on S^2-removal from molybdenum desorption solution were studied.The results show that under the conditions of reaction temperature of 35℃,constant stirring speed of 200 r/min,hydrogen peroxide dosage of 1.0 time the theoretical amount added at once,and reaction time of 20 min,the concentration of S^2-in the molybdenum desorption solution could be reduced to below 0.01 g/L,and no hydrogen sulfide gas or molybdenum trisulfide slag are detected in the acid regulation process.This method provides a reference for the green and efficient treatment of molybdenum desorption solution in ion exchange section.

By analyzing the composition of lepidolite ore and the current status of lithium extraction techno-logy,a innovative technology applying sulfuric acid-sulfate mixed roasting to extract lithium from lepidolite is put forward in this paper.A systematic analysis of a designed process using the innovative technology to extract lithium from lepidolite is conducted from the perspectives of process flow,main equipment,technical index,and pollution control in production process.The technology enables the effective extraction of Li,Rb,and Cs from lepidolite,with their recovery rates of 80.3%,54%,and 61%,respectively.