Os–Ir–Al alloy was fabricated by powder metallurgy technique.IrAl and OsIr interalloys were synthesized to reduce the Al evaporation and ensure the composition of the ternary alloy.Analysis on microstructures shows ...Os–Ir–Al alloy was fabricated by powder metallurgy technique.IrAl and OsIr interalloys were synthesized to reduce the Al evaporation and ensure the composition of the ternary alloy.Analysis on microstructures shows that each component is distributed homogeneously,and the green density reaches 94.9%.Ba–W cathodes with Os–Ir–Al alloy magnetic sputtered on the tips are prepared and directly current density tests are carried out on these cathodes.It is found that at 1,050℃,the average zero field emission density of the cathode reaches up to 20 Aácm-2.The improvements of cathodic current density and stability may indicate the prosperous application of Os–Ir–Al alloy on cathode.展开更多
The effects of cryogenic treatment(CT)and tempering-cryogenic treatment(TCT)on the microstructure and properties of coarse-grained WC-10Co cemented carbides with different carbon contents were researched.The binder ph...The effects of cryogenic treatment(CT)and tempering-cryogenic treatment(TCT)on the microstructure and properties of coarse-grained WC-10Co cemented carbides with different carbon contents were researched.The binder phase,WC mean grain sizes,W solubility in the binder,relative magnetic s aturation,densities,hardness,wear resistance and second phase precipitation of cemented carbides with different heat treatments were discussed.The results show that there are significant changes of microstructure and properties in the samples with CT and TCT,especially due to the precipitation of metastable nanoparticles W_(x)Co_(y)C_(z) in the binder during the heat treatments of CT and TCT.With the simultaneous combination of microstructure and nanoparticle-reinforced binder,a dramatically improved combination of hardness and wear resistance of the samples after TCT has been achieved.展开更多
The W-4.9 Ni-2.1 Fe-xDy2 O3 heavy alloy was fabricated by high-energy ball milling and spark plasma sintering(SPS)technique,and the microstructure,mechanical and friction behavior and anti-corrosion ability were inves...The W-4.9 Ni-2.1 Fe-xDy2 O3 heavy alloy was fabricated by high-energy ball milling and spark plasma sintering(SPS)technique,and the microstructure,mechanical and friction behavior and anti-corrosion ability were investigated by scanning electron microscope(SEM),Rockwell hardness tester,X-ray diffraction(XRD),reciprocating friction and wear tester,electrochemical station,etc.The results show that the trace Dy2 O3 particles,which mainly distributes in the W-M(tungsten-matrix)interface and the tungsten matrix phase,can dramatically decrease the tungsten grain size and the amount of O and P impurities aggregating in the interface,promote the γ-(Ni,Fe)bonding phase and tungsten particles uniform distribution,and increase the relative density,hardness,and wear and corrosion resistance properties.But the excessive Dy2 O3 addition can make the inhibition effect weaken,resulting in the decrease in the comprehensive performances of the alloy.So,the amount of Dy2 O3 should be appropriate.When the adding amount of Dy2 O3 particles is 0.7 wt%,the comprehensive performances of the heavy alloy are the best.展开更多
Impurities and their distributions in osmium targets for M-type cathodes affect the coating quality on porous tungsten and cathode emission performance.Glow discharge mass spectrometry(GDMS)and X-ray photoelectron spe...Impurities and their distributions in osmium targets for M-type cathodes affect the coating quality on porous tungsten and cathode emission performance.Glow discharge mass spectrometry(GDMS)and X-ray photoelectron spectroscopy(XPS)were used to analyze the impurity contents and distributions in the osmium target.The chemical states of impurity elements were analyzed and characterized.The total amount of metallic impurity in the target was lower than 0.01 wt%.展开更多
基金supported by the Special Fund Project for Technology Research and Development of Scientific Research Institute (No. 2012EG115001)
文摘Os–Ir–Al alloy was fabricated by powder metallurgy technique.IrAl and OsIr interalloys were synthesized to reduce the Al evaporation and ensure the composition of the ternary alloy.Analysis on microstructures shows that each component is distributed homogeneously,and the green density reaches 94.9%.Ba–W cathodes with Os–Ir–Al alloy magnetic sputtered on the tips are prepared and directly current density tests are carried out on these cathodes.It is found that at 1,050℃,the average zero field emission density of the cathode reaches up to 20 Aácm-2.The improvements of cathodic current density and stability may indicate the prosperous application of Os–Ir–Al alloy on cathode.
基金financially supported by the General Research Institute for Nonferrous Metals Youth Science Foundation(No.52147)。
文摘The effects of cryogenic treatment(CT)and tempering-cryogenic treatment(TCT)on the microstructure and properties of coarse-grained WC-10Co cemented carbides with different carbon contents were researched.The binder phase,WC mean grain sizes,W solubility in the binder,relative magnetic s aturation,densities,hardness,wear resistance and second phase precipitation of cemented carbides with different heat treatments were discussed.The results show that there are significant changes of microstructure and properties in the samples with CT and TCT,especially due to the precipitation of metastable nanoparticles W_(x)Co_(y)C_(z) in the binder during the heat treatments of CT and TCT.With the simultaneous combination of microstructure and nanoparticle-reinforced binder,a dramatically improved combination of hardness and wear resistance of the samples after TCT has been achieved.
基金financially supported by the National Natural Science Foundation of China(Nos.518711145 and51804138)the Natural Science Foundation of Jiangxi Province(Nos.20161BAB206136,20161BAB216121 and GJJ150638)
文摘The W-4.9 Ni-2.1 Fe-xDy2 O3 heavy alloy was fabricated by high-energy ball milling and spark plasma sintering(SPS)technique,and the microstructure,mechanical and friction behavior and anti-corrosion ability were investigated by scanning electron microscope(SEM),Rockwell hardness tester,X-ray diffraction(XRD),reciprocating friction and wear tester,electrochemical station,etc.The results show that the trace Dy2 O3 particles,which mainly distributes in the W-M(tungsten-matrix)interface and the tungsten matrix phase,can dramatically decrease the tungsten grain size and the amount of O and P impurities aggregating in the interface,promote the γ-(Ni,Fe)bonding phase and tungsten particles uniform distribution,and increase the relative density,hardness,and wear and corrosion resistance properties.But the excessive Dy2 O3 addition can make the inhibition effect weaken,resulting in the decrease in the comprehensive performances of the alloy.So,the amount of Dy2 O3 should be appropriate.When the adding amount of Dy2 O3 particles is 0.7 wt%,the comprehensive performances of the heavy alloy are the best.
基金financially supported by the Key R&D Program of Ministry of Science and Technology(No.2017YFB0305400)。
文摘Impurities and their distributions in osmium targets for M-type cathodes affect the coating quality on porous tungsten and cathode emission performance.Glow discharge mass spectrometry(GDMS)and X-ray photoelectron spectroscopy(XPS)were used to analyze the impurity contents and distributions in the osmium target.The chemical states of impurity elements were analyzed and characterized.The total amount of metallic impurity in the target was lower than 0.01 wt%.
