WANG Xu-dong, FAN Zi-shuan, SUN Dong-bai, MENG Hui-min, YU Hong-ying. Glass Binder Effects on the Properties of Ni Electrodes in Ceramic Capacitors[J]. Journal of Materials Engineering, 2005, 0(11): 3-5.
An experimental investigation was undertaken to study the glass composition and content effects on the adhesion,square resistance and weldability of Ni electrodes in ceramic capacitors.The mechanisms by which the above actions were also analyzed using SEM and EDS.The results show that ZnO and PbO can enhance the wetting properties of the glass on the ceramic substrate,and therefore produce higher adhesion of Ni electrodes.An increase in glass content is able to enhance the adhesion of Ni electrodes,but the excess glass phase precipitating out on the grain boundaries and inside the Ni grains causes the degradation of electrical properties and weldabilities.An acceptable mass ratio of glass to Ni in the Nickel conductive paste is 0.08.
SUN Jing, HUANG Chuan-zhen, LIU Han-lian, ZOU Bin. Study of Properties and Microstructure of TiN/3Y-TZP[J]. Journal of Materials Engineering, 2005, 0(11): 6-8,45.
TiN/3Y-TZP ceramic composites are fabricated by doping TiN particles,whose average grain sizes are 2.7μm,into 3Y-TZP.The effects of TiN on mechanical properties,microstructure and low-temperature degradation of 3Y-TZP are investigated.The results show that there is a good physical and chemical compatibility between TiN and 3Y-TZP,and that 3Y-TZP is toughened and strengthened by doping TiN particles.The highest fracture toughness and flexural strength are 13.3MPa·m1/2 and 1410MPa,respectively.The resistance of low-temperature degradation of 3Y-TZP at 220℃ in air is also evidently improved by dispersing TiN particles.
QIAO Yu-lin, LIANG Zhi-jie, SUN Xiao-feng, XU Bin-shi, AZUSHIMA Akira. High Temperature Tribological Behaviors of Hot Rolling Steel-steel Pairs at Dry Lubrication[J]. Journal of Materials Engineering, 2005, 0(11): 9-12,31.
The antiwear and friction-reducing properties of steel/steel pairs under dry lubrication were determined by the SRV multifunctional test system at 500℃.The high temperature lubricating mechanism was discussed.The results showed that the friction coefficient of the steel/steel pairs shows the declining trend with increasing test loads and growing trend with increasing test time at high temperature.The friction coefficient of steel/steel pairs at line contact conditions is lower than that of at point contact conditions obviously.The friction coefficient of SPHC/GCr15 pair is higher than that of GCr15/GCr15 pair obviously.The wear volume of the steel/steel pair at the point contact condition takes on the line-increasing trend with increasing test loads,but the contrary thing was found at line contact conditions.The worn volume of SPHC/GCr15 pair is bigger than that of GCr15/GCr15 pair appreciably.The high temperature worn mechanism of steel/steel pairs is dominating grain wear at higher speed like as 0.32m/s and is adhesive worn and grain worn at lower speed like as 0.10m/s.
YAO Yi-jun, QIU Tai, SHEN Chun-ying, YANG Jian. Study on Rheological Behavior of Alumina Black Porcelain Slurry[J]. Journal of Materials Engineering, 2005, 0(11): 13-15,18.
Preheating is used to increase the dimension of ceramics powder,lower the specific surface energy and improve the phenomenon of aggregation.The alumina black porcelain slurries containing 55% solid volume were obtained by using the preheating technique.The effects of the amount of dispersant,solid volume fraction and the R ratio on the rheological behaviors of the slurries were studied.The results indicate that rheological behavior of alumina black porcelain slurries appear shearing thinning and the optimum amount of dispersant increases with the increase of solid loading.The viscosity of slurries decreases sharply with the increase of the R ratio,the rheological behaviors of alumina black porcelain slurries were improved obviously.
SUN De-ming, LU Xiao-yang, LI Cheng-mei, XUE Zhong-shun, CHEN Huai-ming, YUE Xue-tao, SUN Sheng. Effect of Cr3C2 and(W,Ti)C on the Vickers Hardness of Al2O3/Cr3C2/(W,Ti)C Ceramic Composites[J]. Journal of Materials Engineering, 2005, 0(11): 16-18.
Ceramic composite materials Al2O3/(W,Ti)C/Cr3C2 with different contents of Cr3C2 and(W,Ti)C particles were fabricated with hot-pressing technique,at 1700℃ under 28MPa pressure for 30min in N2 atmosphere.The effects of Cr3C2,(W,Ti)C on the Vickers hardness and the microstructure of ACW composites were investigated.The results indicate that Cr3C2 and(W,Ti)C can retard the migration of grain boundary,and can suppress the grain growth,but each suitable content of Cr3C2 and(W,Ti)C is 10%-20%(volume fraction),and the total suitable content is about 30%.The solid solution of elements Cr,W,Ti into Al2O3 grain strengthens the matrix.
GAO Qiang, CAO Chao, DUAN Hao, ZHU Xin-sheng. Structure and Properties of Corrosion Resistant and Fire Retardant Stratified Composite Slabs[J]. Journal of Materials Engineering, 2005, 0(11): 19-23,27.
The corrosion resistant and fire retardant stratified composite slabs were made in in-situ workshop,which included organic covering layer and silicate substrate layer.Organic covering layer was composed of phenol-and epoxy-modified vinyl based thermoset resins,curing agents,polyester fiber reinforced materials,flame retardants and inorganic fillers.The corrosion test,impact test and reaction-to-fire test results show that the stratified composite slabs have excellent corrosion resistant,toughness and fire retardancy.SEM micrographs indicate that there existed perfect interfacial adhesion between the surface layer and the substrate one.
ZHANG Guang-ye, ZHANG Hua, GUO Jian-ting. Investigation of Microstructure and BDTT for Multiphase NiAl-Cr Alloy[J]. Journal of Materials Engineering, 2005, 0(11): 24-27.
The microstructure and brittle-ductile-transient(BDT) for multiphase NiAl-25Cr alloy have been investigated.The microstructure of the tested alloy as-cast includes β-Ni(Al,Cr),γ'-Ni3(Al,Cr)and α-Cr phase.After hot-extruded,the microstructure consists of equiaxed primary β-NiAl with mean grain size of 3~5μm and elongated eutectic colonies along the extrusion direction.The results reveal the BDT behavior of the tested alloy is typically dependent on the parameter of strain rate and temperature.At the temperatures below BDTT,the fracture surfaces are characterized by complete debonding along the β/γ' interface;above BDTT,the fracture surfaces become ductile witha large amount of cracks.It is proposed that the debonding of the ductile phase β/γ' is arising from the poor strength of the phase boundary.
DENG Chen-hong, CHEN Guang-zhi, GE Qi-lu. Effect of Different Pairing Materials on Friction and Wear Properties of Particles Reinforced Bronze-based Composite[J]. Journal of Materials Engineering, 2005, 0(11): 28-31.
Friction and wear properties and abrasion mechanism of particles reinforced bronze-based composite and pairing the four kinds of different materials such as 12CrNi3A,38CrMoAlA,GCr15,Cr12MoV were studied.It was found that the different pairing materials affected greatly on friction and wear properties of particles reinforced bronze-based materials.The result showed that the better pairing material for particles reinforced bronze-based materials was 12CrNi3A under the conditions.
JIA Wen-jun, BAI Shu-xin, ZHANG Hong, CHEN Ke, YE Fei, WANG Jing. Aging Behavior of Premixed Powder for Bonded NdFeB Magnets[J]. Journal of Materials Engineering, 2005, 0(11): 32-34.
Aging behavior of premixed powder is a main factor affecting the properties of bonded NdFeB magnets.After preparing premix material with a kind of resin binder,the effects of premixed powder aging on mechanic and magnetic properties of bonded magnets were analyzed.It shows that the binder will be partly crosslinking during aging,which affects largely on magnetic but little on mechanic properties.It is suggested that the valid storage period of premixed powder should be determined by the reduced degree of magnetic properties.
ZHANG Na, TANG Zhi-Yuan, LU Xing-He. Research on Performance of Spinel LiMn1.98RE0.02O4(RE=Ce,Nd)[J]. Journal of Materials Engineering, 2005, 0(11): 35-37,63.
Some rare earth doping spinel LiMn1.98RE0.02O4(RE=Nd,Ce)cathode materials for lithium ion batteries were synthesized with the solid-state reaction method.The structure and characteristics of these produced samples were investigated by XRD,particle size distribution analysis and constant current charge-discharge testing.According to the microstructure,charge-discharge and cycle performance,the effect of doping rare earth on stabilizing the properties of the spinel material was analyzed.The results show that the doped materials have perfect spinel structure and the cycle performances of the materials are greatly improved both at normal temperature and high temperature.The discharge capacity of the sample LiMn1.98Ce0.02O4 and LiMn1.98Nd0.02O4 remained 114.2 mAh·g-1 and 117.5mAh·g-1 after 50 cycles at normal temperature.
WANG Ge, LI Xiao-dong, LI Gong-yi, TANG Yun, ZHANG Ling-han. Study on the Compatibility Characterization of Polymeric Materials with Liquid Oxygen[J]. Journal of Materials Engineering, 2005, 0(11): 38-42,49.
Four types of epoxy resins with different chemical structures were co-cured with cyanate ester.The compatibility of the co-cured compounds with liquid oxygen was ranked according to the liquid oxygen sensitivity impact test results.Then some thermal oxidation and combustion properties such as oxidation mass gains,oxidation decomposition mass loss and flash points of the cured compounds were obtained by thermal analysis.The results showed the thermal oxidation and combustion properties of polymers were in good consistence with their compatibility with liquid oxygen.Based on the discussion of the mechanism of liquid oxygen impact test,it was confirmed that the chemical mechanism of polymers' compatibility with liquid oxygen lies in polymers' oxidation and combustion.As a result,thermal analysis can be applied to indicating polymers' compatibility with liquid oxygen along with the liquid oxygen impact test.
ZHANG Yu-xian, WANG Hong. Laboratorial Research on Yield Strength of Materials[J]. Journal of Materials Engineering, 2005, 0(11): 43-45.
Based on the relation between the incipient yield pressure and the limit of yielding in cylinder according to the elastic disabled rule,a laboratorial method of determining limit of yielding of material is designed and a set of experimental data were gained by the method.The incipient yield pressure of the cylinder is gained by analyzing the experimental data,and then the limit of yielding is gained.The laboratorial method has a good reliability as the experimental value has a little error to the theory value.It has a definite engineering signification and theoretical value to research the mechanical property of material and the disabled rule of high pressure vessel.
LU Ming-hui, YANG Yi, CHEN Yi-fang, FU De-yong. Determination of Elastic Constants in Composite Insulator from Ultrasonic Method[J]. Journal of Materials Engineering, 2005, 0(11): 46-49.
A test method of velocity measurement for elastic constants of composite material is proposed.Based on the relationship between elastic constants and sound velocities in composite material and measuring very few velocities of different propagation direction,the elastic constant matrix can be calculated out.Taking the composite insulator as a measurement sample,knowing the waveform conversion condition on the boundary,only a conventional longitudinal testing probe is needed to measurement transverse wave produced by grazing incidence longitudinal wave.
LÜ Xiao-jun, ZHANG Qi, MA Zhao-qing, XU Jun-hua, XIAO Wen-ping. Study of Hydrothermal Aging Effect on Mechanical Properties of Carbon Fiber/Epoxy Resin Composites[J]. Journal of Materials Engineering, 2005, 0(11): 50-53,57.
In order to study the influence of solution immersion on mechanism properties of carbon fiber reinforced epoxy resin composites,3.5%(mass fraction) NaCl and pure water solution were used to immersion solution,and the immersion temperature were 30℃ and 80℃ respectively.The results showed that the mechanical properties of carbon fiber reinforced epoxy resin composites decreased after the composites were immersed by the 3.5% NaCl and pure water solution,and the decrease of mechanical properties was more obvious in 80℃ temperature immersion solutions.The effect of solution contents on mechanical properties was not obvious at 30℃,however at 80℃ the decreasing of mechanical properties of carbon fiber/epoxy composites in pure water was more notable.
WANG Zhi-bin, GAO Feng. Analysis on Failures of Slipping Shoe in Hydraulic Pump and Its Improvement Design[J]. Journal of Materials Engineering, 2005, 0(11): 54-57.
Failure analysis of slipping shoe in life extension of aeronautical hydraulic pumps was addressed.The work was carried out based on the comparison of analysis computation with experiments.The slippery shoe static pressure supporting mechanism was studied,and flow field stream form of shoe's bottom was then computed based on Navier-Stocks equation.It was done by using two kinds of design algorithms.The resulting conclusions were compared.The shortcomings of original design of the product was also pointed out,and improved optimal design was performed using the methods such as hydromechanics.Practical tests proved that the improved redesign measures makes the life span of product to exceed 750 hours,and thus greatly benefit for the development of this type of hydraulic pumps.
KE Qing-qing, CHENG Lai-fei, TONG Qiao-ying, ZHANG Qing. Joining Methods for Continuous Fiber Reinforced Ceramic Matrix Composites[J]. Journal of Materials Engineering, 2005, 0(11): 58-63.
Continuous fiber reinforced ceramic matrix composites(CMCs) will be widely applied to the high temperature field.Because of the limitation of the CMCs' fabrication,it is hard to produce sophisticated and complex components.Moreover,due to the wide applications of CMCs,the problem of compatibility between CMCs and metals material must be solved.Joining is one of the critical subjects needing to be solved for CMCs' application.The present status of CMCs joining are reviewed.Several effective joining methods are emphasized:brazing,partial transient liquid phase bonding(PTLPB),solid-state reaction bonding without pressure,joining with pre-ceramic polymer,ARCJoinT,on-line liquid infiltration joining process etc.
