2008 Vol. 23 No. 2
2008, 23(2): 1-4.
DOI: 10.19515/j.cnki.1003-1545.2008.02.001
Abstract：
Sinter hardening property of four kinds of low alloy steels with different composition is investigated. Results show that tensile strength and hardness of sintered low alloy steels increase obviously when elements such as Mo, Mn, Cr etc are added. Mechanical property of the low alloy steels manufactured by sinter hardening process are better than that by conventional sintering process. With macrohardness reaching HRC35.4 and strength reaching 540.74 MPa. Metallographic observation indicates that after sinter hardening the microstructure is mainly martensite with a few rudimental austenite ferrite and pearlite.
Sinter hardening property of four kinds of low alloy steels with different composition is investigated. Results show that tensile strength and hardness of sintered low alloy steels increase obviously when elements such as Mo, Mn, Cr etc are added. Mechanical property of the low alloy steels manufactured by sinter hardening process are better than that by conventional sintering process. With macrohardness reaching HRC35.4 and strength reaching 540.74 MPa. Metallographic observation indicates that after sinter hardening the microstructure is mainly martensite with a few rudimental austenite ferrite and pearlite.
Abstract：
Novel HfSiON thin films were prepared on p-type Si substrates by using radio-frequency magnetron sputtering deposition.Composition and structure of the films is determined by means of XPS and XRD respectively.High resolution scanning electron microscope(HRSEM) and atomic force microscope(AFM) have been empoled to observe the cross-section and the surface morphology of the thin films.XRD analyses show that the films are amorphous even after annealed at 900℃.The results of HRSEM and AFM present that the films have very flat surface,indicating a good thermal stability.HfSiON films have excellent dielectric properties with high dielectric constant k of about 18.9 and low leakage current of 2.5×10-7 A/cm2 at Vg of +1.5V. All the characteristics show that HfSiON films will be a promising candidate for SiO2 gate dielectric and it also indicates that radio frequency magnetron sputtering is a good way to deposit HfSiON high-k thin films as dielectric.
Novel HfSiON thin films were prepared on p-type Si substrates by using radio-frequency magnetron sputtering deposition.Composition and structure of the films is determined by means of XPS and XRD respectively.High resolution scanning electron microscope(HRSEM) and atomic force microscope(AFM) have been empoled to observe the cross-section and the surface morphology of the thin films.XRD analyses show that the films are amorphous even after annealed at 900℃.The results of HRSEM and AFM present that the films have very flat surface,indicating a good thermal stability.HfSiON films have excellent dielectric properties with high dielectric constant k of about 18.9 and low leakage current of 2.5×10-7 A/cm2 at Vg of +1.5V. All the characteristics show that HfSiON films will be a promising candidate for SiO2 gate dielectric and it also indicates that radio frequency magnetron sputtering is a good way to deposit HfSiON high-k thin films as dielectric.
Abstract：
The effects of cold-working solution treatment and aging on the phase transformation of near-equi-atomic NiTi shape memory alloy have been investigated systematically by means of DSC. The results show that the microstructure of the cold-worked NiTi wire is fibrous structure and the microstructure of solution treated NiTi alloy is equi axial grains. The defects induced during cold-working restrained the phase transformation of thermoelastic martensite. When aging treatment was taken immediately after cold-working, the transformation process of NiTi alloy was P→M. When aging treatment was taken after solution the transformation process of NiTi alloy was P→R→M. Different types of thermoelastic martensite transformation of the NiTi alloy took place under different treatment conditions. It is recognized that the stress dislocation density and precipitates have big influence on the phase transformation behavior of thermoelastic martensite of NiTi alloy.
The effects of cold-working solution treatment and aging on the phase transformation of near-equi-atomic NiTi shape memory alloy have been investigated systematically by means of DSC. The results show that the microstructure of the cold-worked NiTi wire is fibrous structure and the microstructure of solution treated NiTi alloy is equi axial grains. The defects induced during cold-working restrained the phase transformation of thermoelastic martensite. When aging treatment was taken immediately after cold-working, the transformation process of NiTi alloy was P→M. When aging treatment was taken after solution the transformation process of NiTi alloy was P→R→M. Different types of thermoelastic martensite transformation of the NiTi alloy took place under different treatment conditions. It is recognized that the stress dislocation density and precipitates have big influence on the phase transformation behavior of thermoelastic martensite of NiTi alloy.
2008, 23(2): 14-17.
DOI: 10.19515/j.cnki.1003-1545.2008.02.004
Abstract：
A dry gel was prepared from Al(NO3)3·9H2O,NH3·H2O and 50nm SiC powder via sol-gel technology.Al2O3/SiC nanocomposite ceramic was produced from the dry gel by means of microwave sintering.Compared with conventional sintered Al2O3/SiC nanocomposite ceramic,effects of two sintering methods on the Al2O3/SiC nanocomposite ceramics' mechanical properties were analyzed.The results indicated that the microwave processed Al2O3/SiC nanocomposite ceramic appears with improved density,fracture toughness and bending strength.
A dry gel was prepared from Al(NO3)3·9H2O,NH3·H2O and 50nm SiC powder via sol-gel technology.Al2O3/SiC nanocomposite ceramic was produced from the dry gel by means of microwave sintering.Compared with conventional sintered Al2O3/SiC nanocomposite ceramic,effects of two sintering methods on the Al2O3/SiC nanocomposite ceramics' mechanical properties were analyzed.The results indicated that the microwave processed Al2O3/SiC nanocomposite ceramic appears with improved density,fracture toughness and bending strength.
Abstract：
NFGBS (natural flakes graphite block samples) was prepared via cold pressing without binding.The microstructural characters of the NFGBS after isostatic pressing and the influence of flake graphite orientation on mechanical properties were investigated.It is showed that after isostatic press, the shrink rate of the NFGBS varies in different orientation, with about 10%~11%in Z axis, and 7%~8%in X and Y axis.Compared to that before isostatic pressing, NFGBS became denser, with higher bending strength.The variation of orientation of natural flake graphite are attributed to the changes of radial position.Bending strength of NFGS is related to the grains orientation of shaped NFGBS.A qualitative model is proposed to account for the correlation between bending strength and microstructure of NFGBS.
NFGBS (natural flakes graphite block samples) was prepared via cold pressing without binding.The microstructural characters of the NFGBS after isostatic pressing and the influence of flake graphite orientation on mechanical properties were investigated.It is showed that after isostatic press, the shrink rate of the NFGBS varies in different orientation, with about 10%~11%in Z axis, and 7%~8%in X and Y axis.Compared to that before isostatic pressing, NFGBS became denser, with higher bending strength.The variation of orientation of natural flake graphite are attributed to the changes of radial position.Bending strength of NFGS is related to the grains orientation of shaped NFGBS.A qualitative model is proposed to account for the correlation between bending strength and microstructure of NFGBS.
2008, 23(2): 22-23,26.
DOI: 10.19515/j.cnki.1003-1545.2008.02.006
Abstract：
Fracture mechanism of two-phase alloy is discussed based on the observation of the fracture process of Al-Si hypereutectic alloy by using optical microscopy.It is found that the fracture of Al-Si hypereutectic alloy occurs firstl on the nook of primary silicon and with the increase of outer forces,the crack expands to the internal of primary silicon and the direction changes at the phase boundary and expands along the phase boundary.Analysis suggests that the bonding strength of the phase boundary is the weakest and crack propagation occurs preferably in the weak for Al-Si two-phase alloy.
Fracture mechanism of two-phase alloy is discussed based on the observation of the fracture process of Al-Si hypereutectic alloy by using optical microscopy.It is found that the fracture of Al-Si hypereutectic alloy occurs firstl on the nook of primary silicon and with the increase of outer forces,the crack expands to the internal of primary silicon and the direction changes at the phase boundary and expands along the phase boundary.Analysis suggests that the bonding strength of the phase boundary is the weakest and crack propagation occurs preferably in the weak for Al-Si two-phase alloy.
2008, 23(2): 24-26.
DOI: 10.19515/j.cnki.1003-1545.2008.02.007
Abstract：
Wide temperature stability and high power are always the focus of microwave ferrite research.In this paper,YGdCaSnIG microwave garnet ferrites with saturate magnetization 943 Gs is made which is high power and stable at temperature from-40℃ to 100℃.
Wide temperature stability and high power are always the focus of microwave ferrite research.In this paper,YGdCaSnIG microwave garnet ferrites with saturate magnetization 943 Gs is made which is high power and stable at temperature from-40℃ to 100℃.
2008, 23(2): 27-30,39.
DOI: 10.19515/j.cnki.1003-1545.2008.02.008
Abstract：
RTM(Resin Transfer Moulding) is a closed mould process in which resin is injected into a mould filled with reinforcing materials.Process parameters including injection pressure,injection temperature,assistant vacuum,location of the inlet and ventilation gates,fibre fraction and fibre structure influence the quality of the final composite products significantly.The effect of RTM process parameters on the performance of composites is summarized in this paper.
RTM(Resin Transfer Moulding) is a closed mould process in which resin is injected into a mould filled with reinforcing materials.Process parameters including injection pressure,injection temperature,assistant vacuum,location of the inlet and ventilation gates,fibre fraction and fibre structure influence the quality of the final composite products significantly.The effect of RTM process parameters on the performance of composites is summarized in this paper.
2008, 23(2): 31-34,47.
DOI: 10.19515/j.cnki.1003-1545.2008.02.009
Abstract：
Poly-ε-caprolactone(PCLs)was synthesized by ring-opening polymerization of ε-caprolactone initiated by caprylate stannous and was characterized with GPC,DSC,XRD and FT-IR respectively.PTC composite was prepared from mixing carbon black N990 and PCL and their microstructure,volume expansion and electrical properties were investigated.The results show that the number-average molecular weight(Mn),weight-average molecular weight(Mw)and polydispersity index(Mw/Mn)of PCL are 24175,38666 and 1.60.Its melting point is 62℃ and degree of crystallization is 42.48%.The percolation threshold of the PCL composites is 35%by weight and the PTC intensity are higher than two orders of magnitude.Carbon particles are dispersed uniformly in PCL matrix,mainly in form of aggregates.Curves of the logarithm of resistivity versus volume of N990/PCL composites indicate that volume expansion is only one of important factors of PTC effect.
Poly-ε-caprolactone(PCLs)was synthesized by ring-opening polymerization of ε-caprolactone initiated by caprylate stannous and was characterized with GPC,DSC,XRD and FT-IR respectively.PTC composite was prepared from mixing carbon black N990 and PCL and their microstructure,volume expansion and electrical properties were investigated.The results show that the number-average molecular weight(Mn),weight-average molecular weight(Mw)and polydispersity index(Mw/Mn)of PCL are 24175,38666 and 1.60.Its melting point is 62℃ and degree of crystallization is 42.48%.The percolation threshold of the PCL composites is 35%by weight and the PTC intensity are higher than two orders of magnitude.Carbon particles are dispersed uniformly in PCL matrix,mainly in form of aggregates.Curves of the logarithm of resistivity versus volume of N990/PCL composites indicate that volume expansion is only one of important factors of PTC effect.
Abstract：
The electrochemical behaviors of Mn(II)on metallic titanium electrode was studied with cyclic voltammetry under different conditions.Based on the characterization of electrolytic products by means of X-ray diffraction(XRD)and scanning electron microscope(SEM),the influences of temperature,potential and sulphuric acid concentration on ingredients,appearance and grain size of the products were analyzed.It was found that sulphuric acid concentration had stronger impact on the onset peak potential of oxide current than that of temperature during the electrodepositing of MnO2.The crystal structure,morphology and granular diameter of prepared nano-MnO2 were controllable by changing experiments parameters.
The electrochemical behaviors of Mn(II)on metallic titanium electrode was studied with cyclic voltammetry under different conditions.Based on the characterization of electrolytic products by means of X-ray diffraction(XRD)and scanning electron microscope(SEM),the influences of temperature,potential and sulphuric acid concentration on ingredients,appearance and grain size of the products were analyzed.It was found that sulphuric acid concentration had stronger impact on the onset peak potential of oxide current than that of temperature during the electrodepositing of MnO2.The crystal structure,morphology and granular diameter of prepared nano-MnO2 were controllable by changing experiments parameters.
2008, 23(2): 40-41,60.
DOI: 10.19515/j.cnki.1003-1545.2008.02.011
Abstract：
A nano-copper additive is prepared.A series of test such as four ball machine test,anticorrosion test,antiemulsion test and liquid corrosion test were performed to study the anti-wear,anticorrosion,and antiemulsion properties of this additive in hydraulic fluid HL68 base oil.The results show that the nano-copper additive has good performance against extreme pressure and good anti-wear properties in steel-steel friction,as well as excellent anticorrosion property.
A nano-copper additive is prepared.A series of test such as four ball machine test,anticorrosion test,antiemulsion test and liquid corrosion test were performed to study the anti-wear,anticorrosion,and antiemulsion properties of this additive in hydraulic fluid HL68 base oil.The results show that the nano-copper additive has good performance against extreme pressure and good anti-wear properties in steel-steel friction,as well as excellent anticorrosion property.
2008, 23(2): 42-44.
DOI: 10.19515/j.cnki.1003-1545.2008.02.012
Abstract：
Al2O3 coat is prepared via detonation spraying with NiAl powder as ground floor and 45 steel as base.XRD spectrum of the coat indicates that structure are α-Al2O3 and γ-Al2O3 mainly,indicating the structure changed.The porosity of the coat is 0.019 n/ mm2 by JB/T 7509-94 iron reagent,indicating the coat has denser microstructure and fewer porosity,this suggests that the detonation spraying coat can improve the wear resistance of base steel and is suitable for wear resistance coat.
Al2O3 coat is prepared via detonation spraying with NiAl powder as ground floor and 45 steel as base.XRD spectrum of the coat indicates that structure are α-Al2O3 and γ-Al2O3 mainly,indicating the structure changed.The porosity of the coat is 0.019 n/ mm2 by JB/T 7509-94 iron reagent,indicating the coat has denser microstructure and fewer porosity,this suggests that the detonation spraying coat can improve the wear resistance of base steel and is suitable for wear resistance coat.
2008, 23(2): 45-47.
DOI: 10.19515/j.cnki.1003-1545.2008.02.013
Abstract：
Based on the analysis on requirements for oil-pipe anticorrosion coating,development of stressing anticorrosion epoxy-powder-coating is put forward and the influence of composition of epoxy-powder-coating on its performances is investigated.The coating with high-performance in intensity,salt-resistance,and at extreme temperature is prepared.
Based on the analysis on requirements for oil-pipe anticorrosion coating,development of stressing anticorrosion epoxy-powder-coating is put forward and the influence of composition of epoxy-powder-coating on its performances is investigated.The coating with high-performance in intensity,salt-resistance,and at extreme temperature is prepared.
2008, 23(2): 48-51.
DOI: 10.19515/j.cnki.1003-1545.2008.02.014
Abstract：
NiCoCrAlY coat was deposited via cold spay at a preheating temperature of 600℃,chamber pressure of 2.3 MPa,with helium as powder carrier gas.The microstructure and the micro-hardness of the coat before and after heat treatment were investigated.The results show that the prepared NiCoCrAlY coat is dense and after heat treatment the density of the coat increases,and the micro-hardness is improved.
NiCoCrAlY coat was deposited via cold spay at a preheating temperature of 600℃,chamber pressure of 2.3 MPa,with helium as powder carrier gas.The microstructure and the micro-hardness of the coat before and after heat treatment were investigated.The results show that the prepared NiCoCrAlY coat is dense and after heat treatment the density of the coat increases,and the micro-hardness is improved.
2008, 23(2): 53-56,71.
DOI: 10.19515/j.cnki.1003-1545.2008.02.015
Abstract：
The influences of some factors as chemical composition,aging treatment and pre-deformation on shape memory ability of FeMn-Si based shape memory alloy were reviewed,the mechanism and recent research progress of the alloy were analyzed and the farther research trend was proposed.
The influences of some factors as chemical composition,aging treatment and pre-deformation on shape memory ability of FeMn-Si based shape memory alloy were reviewed,the mechanism and recent research progress of the alloy were analyzed and the farther research trend was proposed.
2008, 23(2): 57-60.
DOI: 10.19515/j.cnki.1003-1545.2008.02.016
Abstract：
The development and industrial application of ferrite-austenite duplex stainless steel at home and abroad is reviewed and research trend of the DSS is discussed.
The development and industrial application of ferrite-austenite duplex stainless steel at home and abroad is reviewed and research trend of the DSS is discussed.
Abstract：
Poly(N-isopropylacrylamide)has been widely used in biomedical for its favorable thermosensitivity.In this paper,the latest advance in the synthesis of poly(N-isopropyl-acrylamide)via ATRP technology was summarized,and the application of the poly(N-isopropylacrylamide) gel in drug release and enzymatic immobilization was introduced briefly.
Poly(N-isopropylacrylamide)has been widely used in biomedical for its favorable thermosensitivity.In this paper,the latest advance in the synthesis of poly(N-isopropyl-acrylamide)via ATRP technology was summarized,and the application of the poly(N-isopropylacrylamide) gel in drug release and enzymatic immobilization was introduced briefly.
2008, 23(2): 67-71.
DOI: 10.19515/j.cnki.1003-1545.2008.02.018
Abstract：
From the material point of view,mechanism of electric field shielding,magnetic field shielding,electric-magnetic fied shielding and the advancement of shielding materials are intruduced.Character of some shielding materials is described.
From the material point of view,mechanism of electric field shielding,magnetic field shielding,electric-magnetic fied shielding and the advancement of shielding materials are intruduced.Character of some shielding materials is described.
2008, 23(2): 72-76.
DOI: 10.19515/j.cnki.1003-1545.2008.02.019
2008, 23(2): 77-82.
DOI: 10.19515/j.cnki.1003-1545.2008.02.020
Abstract：
The rupture theory of ceramics is studied,the mechanisms and method of toughening of ceramic materials are compared including phase transformation toughening,microcracking toughening,fiber/whisker toughening,and nanometer grain toughening.The applications of the toughening technology are described and development prospect is forecast.
The rupture theory of ceramics is studied,the mechanisms and method of toughening of ceramic materials are compared including phase transformation toughening,microcracking toughening,fiber/whisker toughening,and nanometer grain toughening.The applications of the toughening technology are described and development prospect is forecast.
