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Tribological properties of nanostructured Al_2O_3-40%TiO_2 multiphase ceramic particles reinforced Ni-based alloy composite coatings 被引量:9
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作者 何龙 谭业发 +2 位作者 谭华 周春华 高立 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第9期2618-2627,共10页
The Ni-based alloy composite coatings reinforced by nanostructured Al2O3-40%TiO2 multiphase ceramic particles were prepared on the surface of 7005 aluminum alloy by plasma spray technology. The microstructure and trib... The Ni-based alloy composite coatings reinforced by nanostructured Al2O3-40%TiO2 multiphase ceramic particles were prepared on the surface of 7005 aluminum alloy by plasma spray technology. The microstructure and tribological properties of the composite coatings were researched. The results show that the composite coatings mainly consist of γ-Ni, α-Al2O3, γ-Al2O3 and rutile-TiO2 etc, and exhibit lower friction coefficients and wear losses than the Ni-based alloy coatings at different loads and speeds. The composite coating bears low contact stress at 3 N and its wear mechanism is micro-cutting wear. As loads increase to 6-12 N, the contact stress is higher than the elastic limit stress of worn surface, and the wear mechanisms change into multi-plastic deformation wear, micro-brittle fracture wear and abrasive wear. With the increase of speeds, the contact temperature of worn surface increases. The composite coating experiences multi-plastic deformation wear, fatigue wear and adhesive wear. 展开更多
关键词 nanostructured A1203-TiO2 multiphase ceramic particles Ni-based alloy composite coating plasma spray friction wear
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Effects of current density on microstructure and properties of plasma electrolytic oxidation ceramic coatings formed on 6063 aluminum alloy 被引量:10
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作者 项南 宋仁国 +3 位作者 庄俊杰 宋若希 陆筱雅 苏旭平 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第3期806-813,共8页
Plasma electrolytic oxidation (PEO) ceramic coatings were fabricated in a silicate-based electrolyte with the addition of potassium fluorozirconate (K2ZrF6) on 6063 aluminum alloy, and the effects of current density o... Plasma electrolytic oxidation (PEO) ceramic coatings were fabricated in a silicate-based electrolyte with the addition of potassium fluorozirconate (K2ZrF6) on 6063 aluminum alloy, and the effects of current density on microstructure and properties of the PEO coatings were studied. It was found that pore density of the coatings decreased with increasing the current density. The tribological and hardness tests suggested that the ceramic coating produced under the current density of 15 A/dm2showed the best mechanical property, which matched well with the phase analysis. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves proved that the coating obtained under 15 A/dm2 displayed the best anti-corrosion property, which was directly connected with morphologies of coatings. 展开更多
关键词 6063 aluminum alloy ceramic coating plasma electrolytic oxidation(PEO) current density MICROSTRUCTURE mechanical property
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Thermodynamic analysis of interactions between Ti-Al alloys and oxide ceramics 被引量:2
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作者 崔仁杰 唐晓霞 +2 位作者 高明 张虎 宫声凯 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第4期887-894,共8页
The thermodynamics of interactions between various oxides(CaO,MgO,Al2O3 and Y2O3) and molten Ti and Ti alloys was investigated.The dissolution mechanism of oxides in molten Ti alloys was provided and the stability o... The thermodynamics of interactions between various oxides(CaO,MgO,Al2O3 and Y2O3) and molten Ti and Ti alloys was investigated.The dissolution mechanism of oxides in molten Ti alloys was provided and the stability of oxides in molten Ti alloys was investigated and predicted by thermodynamic analysis.Interactions between oxides and Ti-Al melts were studied by oxide crucible melting experiments.By quantitative analysis,it is indicated that impurity contents in alloys are proportionally decreased with increasing the Al content in alloys and decreasing the melt temperature,which is in agreement with the results of the predicting thermodynamic stability. 展开更多
关键词 Ti alloys THERMODYNAMICS oxide ceramics INTERACTION
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Preparation and structure of microarc oxidation ceramic coatings containing ZrO2 grown on LY12 Al alloy 被引量:6
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作者 WU Zhendong YAO Zhongping JIANG Zhaohua 《Rare Metals》 SCIE EI CAS CSCD 2008年第1期55-58,共4页
Ceramic coatings containing ZrO2 were prepared in situ on LY12 aluminum alloy by microarc oxidation(MAO) in the mixed solution of zirconate and phosphate solution.The phase composition and morphology of the coatings... Ceramic coatings containing ZrO2 were prepared in situ on LY12 aluminum alloy by microarc oxidation(MAO) in the mixed solution of zirconate and phosphate solution.The phase composition and morphology of the coatings were studied by XRD and SEM,respectively.The growing mechanism of ceramic coatings was discussed in a preliminary manner.The results show that with an increase in MAO time,the compactness of the coating improved and the thickness increased.From the inner layer to the coating surface,the content of Zr increased,while the content of Al decreased.In addition,the coating was composed of m-ZrO2,t-ZrO2,and a little amount of γ-Al2O3.With an increase in reaction time,the relative content of t-ZrO2 within the coating sharply decreased while the relative content of m-ZrO2 sharply increased,and then both generally kept at a constant level after 60 min. 展开更多
关键词 microarc oxidation aluminium alloy ceramic coating zirconium dioxide
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Evolution of Residual Stresses in Micro-arc Oxidation Ceramic Coatings on 6061 Al Alloy 被引量:4
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作者 SHEN Dejiu CAI Jingrui +1 位作者 GUO Changhong LIU Peiyu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第6期1149-1153,共5页
Most researches on micro-arc oxidation mainly focus on the application rather than discovering the evolution of residual stresses. However, residual stresses in the surface coatings of structural components have adver... Most researches on micro-arc oxidation mainly focus on the application rather than discovering the evolution of residual stresses. However, residual stresses in the surface coatings of structural components have adverse effects on their properties, such as fatigue life, dimensional stability and corrosion resistance, etc. The micro-arc oxidation ceramic coatings are produced on the surfaces of 6061 aluminum alloy by a homemade asymmetric AC type of micro-arc oxidation equipment of 20 kW. A constant current density of 4.4___0.1 A/dm2 and a self-regulated composite electrolyte are used. The micro-arc oxidation treatment period ranges from 10 min to 40 min, and the thickness of the ceramic coatings is more than 20 Bin. Residual stresses attributed to 7-A1203 constituent in the coatings at different micro-arc oxidation periods are analyzed by an X-ray diffractometer using the sin2~u method. The analysis results show that the residual stress in the ceramic coatings is compressive in nature, and it increases first and then decreases with micro-arc oxidation time increase. The maximum stress value is 1 667_+20 MPa for period of 20 min. Through analyzing the coating thickness, surface morphology and phase composition, it is found that the residual stress in the ceramic coatings is linked closely with the coating growth, the phase composition and the micro cracks formed. It is also found that both the heat treatment and the ultrasonic action release remarkably the residual compressive stress. The heat treatment makes the residual compressive stress value decrease 1 378 MPa. The ultrasonic action even alters the nature of the residual stress, making the residual compressive stress change into a residual tensile stress. 展开更多
关键词 residual stress ceramic coating micro-arc oxidation 6061 aluminum alloy
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Improvement in collapsibility of ZrO2 ceramic mould for investment casting of TiAl alloys 被引量:8
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作者 Chen Yanfei Xiao Shulong +3 位作者 Tian Jing Xu Lijuan Kong Fantao Chen Yuyong 《China Foundry》 SCIE CAS 2011年第1期9-13,共5页
Investment casting has been widely recognized as the best option in producing TiAl components with key benefits of accuracy,versatility and integrity.The collapsibility of ceramic moulds for investment casting is crit... Investment casting has been widely recognized as the best option in producing TiAl components with key benefits of accuracy,versatility and integrity.The collapsibility of ceramic moulds for investment casting is critical in the manufacturing process of TiAl components due to TiAl's intrinsic brittleness at room temperature.The aim of the present research is to provide a method for production of TiAl components by investment casting in ZrO2 ceramic moulds with improved collapsibility.Slurries prepared with high polymer additions were utilized during the preparation of ceramic moulds.The stress/strain curves obtained from green and baked ceramic moulds demonstrate that the green strength was increased with the application of high polymer,while baked strength decreased,thus the collapsibility of ceramic moulds was improved.It is suggested that this result is related to the burn-out of high polymer which left a lot of cavities.The experimental findings were also verified by the investment casting of "I"-shaped TiAl components. 展开更多
关键词 COLLAPSIBILITY IMPROVEMENT ZrO2 ceramic mould TiAl alloys investment casting
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Properties of a reaction-bonded β-SiAlON ceramic doped with an FeMo alloy for application to molten aluminum environments 被引量:3
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作者 Yan-jun Li Hai-liang Yu +3 位作者 Hai-yun Jin Zhong-qi Shi Guan-jun Qiao Zhi-hao Jin 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2015年第5期530-536,共7页
An FeMo-alloy-doped β-SiA1ON (FeMo/β-SiA1ON) composite was fabricated via a reaction-bonding method using raw materials of Si, Al2O3, A1N, FeMo, and Sm2O3. The effects of FeMo on the microstructure and mechanical ... An FeMo-alloy-doped β-SiA1ON (FeMo/β-SiA1ON) composite was fabricated via a reaction-bonding method using raw materials of Si, Al2O3, A1N, FeMo, and Sm2O3. The effects of FeMo on the microstructure and mechanical properties of the composite were investi- gated. Some properties of the composite, including its bending strength at 700℃ and after oxidization at 700℃ for 24 h in air, thermal shock resistance and corrosion resistance to molten aluminum, were also evaluated. The results show that the density, toughness, bending strength, and thermal shock resistance of the composite are obviously improved with the addition of an FeMo alloy. In addition, other properties of the composite such as its high-temperature strength and oxidized strength are also improved by the addition of FeMo alloy, and its corrosion re- sistance to molten aluminum is maintained. These findings indicate that the developed FeMo/β-SiA1ON composite exhibits strong potential for application to molten aluminum environments. 展开更多
关键词 composite materials SiAION ceramics iron molybdenum alloys reaction bonding mechanical properties molten aluminum
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Salt spray corrosion test of micro-plasma oxidation ceramic coatings on Ti alloy 被引量:3
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作者 HAO Guodong YAO Zhongping JIANG Zhaohua 《Rare Metals》 SCIE EI CAS CSCD 2007年第6期560-564,共5页
Ceramic coatings were prepared on Ti-6Al-4V alloy in NaAlO2 solution by micro-plasma oxidation (MPO). The salt spray tests of the coated samples and the substrates were carded out in a salt spray test machine. The p... Ceramic coatings were prepared on Ti-6Al-4V alloy in NaAlO2 solution by micro-plasma oxidation (MPO). The salt spray tests of the coated samples and the substrates were carded out in a salt spray test machine. The phase composition and surface morphology of the coatings were investigated by XRD and SEAM. Severe corrosion occurred on the substrate surface, while there were no obvious corrosion phenomena on the coated samples. The coatings were composed of Al2TiO5 and a little α-Al2O3 and mille TiO2, and the salt spray test did not change the composition of the coatings. The weight loss rate of the coatings decreased with increasing MPO time because of the increase in density and thickness of the coatings. The surface morphology of the coatings was influenced by salt spray corrosion test. Among the coated samples, the coating prepared for 2 h has the best corrosion resistance under salt spray test. 展开更多
关键词 micro-plasma oxidation ceramic coating salt spray corrosion test Ti alloy
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Fabrication of ceramic layer on an Al-Si alloy by MAO process 被引量:2
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作者 SONG Xigui, BIAN Xiufang, QI Xiaogang, and ZHANG JunyanKey Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University (Southern Campus), Jinan 250061, China (Received 2002-04-11) 《Rare Metals》 SCIE EI CAS CSCD 2003年第2期103-106,共4页
The MAO (Micro-Arc Oxidation) process is applied to a eutectic Al-Si alloy(Al-12.0 percent Si-l.0 percent Cu-0.9 percent Mg (mass fraction)). The oxide ceramic layer wasfabricated with about 220 mum thickness and 3000... The MAO (Micro-Arc Oxidation) process is applied to a eutectic Al-Si alloy(Al-12.0 percent Si-l.0 percent Cu-0.9 percent Mg (mass fraction)). The oxide ceramic layer wasfabricated with about 220 mum thickness and 3000 Hv micro-hardness. By XRD (X-ray diffractometry)and DSC (differential scanning calorimetry) analyses, the oxide layer consists of amorphous Al_2O_3,which is distinct from the results reported by the other researchers. The SEM photographs of suchlayer show that the layer is fixed tightly on the substrate alloy. So this alloy can he used in thehigh temperature and friction environment alter it is treated with such process. 展开更多
关键词 metal material ceramic layer MAO process Al-Si alloy
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Effects of Yttrium Ion on Formation Mechanism of ZrO_2-Y_2O_3 Ceramic Coatings Formed by Plasma Electrolytic Oxidation on Al-12Si Alloy 被引量:3
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作者 王萍 LI Jianping +2 位作者 GUO Yongchun YANG Zhong WANG Jianli 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第5期1044-1048,共5页
ZrO2-Y2O3 ceramic coating was produced by plasma electrolytic oxidation (PEO) on ZAlSil2Cu3Ni2 alloy. The microstructure and phase composition of the coating were investigated by SEM and XRD.: The results show that... ZrO2-Y2O3 ceramic coating was produced by plasma electrolytic oxidation (PEO) on ZAlSil2Cu3Ni2 alloy. The microstructure and phase composition of the coating were investigated by SEM and XRD.: The results show that adding an appropriate amount of yttrium ion can improve the growing rate of ceramic coating at different oxidation stages and decrease arc voltage. The thickness of ZrO2-Y2O3 coating is 16 μn thicker than that of ZrO2 coating and the maximum oxidation rate improves by 0.6 μm/min. In addition, the arc voltage decreases from 227 to 172 V. It can be seen that the rate of oxidation firstly increases to some extent and then decreases with the content of yttrium ion increasing. The growth rate reaches the maximum while the content of yttrium ion is 0.05 g-L-1The maximum thickness is 90 μm.Compared to ZrO2 coating, the micropores of ZrO2-Y2O3 coating are less and the ceramic layer is repeatedly deposited by ZrO2 and Y2O3 ceramic particles. Meanwhile, the binding force between coating and substrate is better and the coating is uniform and compact. The ceramic layer is mainly composed of c-Y0.15Zr0.85O1.93□0.07, m-ZrO2, α-Al2O3, ,γ-Al2O3 and Y2O3. It is indicated that ZrO2 has beert fully stabilized by yttrium ion through the formation of solid solution. 展开更多
关键词 Al-12Si alloys yttrium ion plasma electrolytic oxidation ZrO2-Y2O3 ceramic coating
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TLP bonding of alumina ceramic and 5A05 aluminum alloy using Ag-Cu-Ti interlayer 被引量:2
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作者 王颖 曹健 +2 位作者 冯吉才 张丽霞 徐富家 《China Welding》 EI CAS 2009年第4期39-42,共4页
In order to join alumina ceramic to 5A05 aluminum alloy and obtain the excellent airtightness of joints whose maximum service temperature is 623 K, transient liquid phase (TLP) bonding technique was ,investigated us... In order to join alumina ceramic to 5A05 aluminum alloy and obtain the excellent airtightness of joints whose maximum service temperature is 623 K, transient liquid phase (TLP) bonding technique was ,investigated using Ag-Cu-Ti alloy as interlayer. The wetting experimental results confirm that Ti can react with alumina ceramic at 833 K by adding 2 wt.% Ti in Sn. But during bonding alumina ceramic and 5A05 aluminum alloy with Ag-Cu-Ti interlayer at 833 K, Ti preferentially reacts with Al and there is no reaction layer on alumina ceramic/Ag-Cu-Ti interface, which finally results in a poorly airtight joint. 展开更多
关键词 transient liquid phase bonding alumina ceramic 5A05 aluminum alloy Ag-Cu-Ti interlayer
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Vacuum brazing of Si/SiC ceramic composite and Invar alloy using TiSOCu-W filler metals 被引量:2
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作者 张华 黄继华 +2 位作者 张志远 赵兴科 陈树海 《China Welding》 EI CAS 2012年第1期76-80,共5页
Si/SiC ceramic composite and lnvar alloy were successfidly joined by vacuum brazing using Ti5OCu-W filler metals into which W was added to release the thermal stress of the brazed joint. Microstructures of the brazed ... Si/SiC ceramic composite and lnvar alloy were successfidly joined by vacuum brazing using Ti5OCu-W filler metals into which W was added to release the thermal stress of the brazed joint. Microstructures of the brazed joints were irwestigated by scanning electron micrascope (SEM) and energy dispersive spectrometer (EDS). The mechanical properties of the brazed joints were measured by shearing tests. The results showed that the brazed joints were composed of Ti-Cu phase, W phase and Ti-Si phase. W had no effect on the wettability and mobility of the .filler metals. The growth of Ti2 Cu phase was restrained, and the reaction between ceramic composite and filler metals was weakened. The specimen, brazed at 970°C for 5 rain, had the maximum shear strength of 108 MPa at room temperature. 展开更多
关键词 Si/SiC ceramic composite lnvar alloy BRAZING Ti50Cu-W filler metals
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Fabrication of in-situ synthesized ceramic reinforced Ni-based alloy composite coatings by reactive braze coating processing 被引量:3
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作者 Pei Xinjun Liu Wenbin +3 位作者 Cheng ge Pan Xinyu Li Aina Li haishen 《China Welding》 EI CAS 2019年第4期56-62,共7页
In-situ synthesized ceramic such as TiC,Cr7C3 and Cr5B3 reinforced Ni-based alloy composite coating was fabricated on the surface of mild steel substrate by reactive braze coating processing with colloidal graphite,Cr... In-situ synthesized ceramic such as TiC,Cr7C3 and Cr5B3 reinforced Ni-based alloy composite coating was fabricated on the surface of mild steel substrate by reactive braze coating processing with colloidal graphite,Cr,Ni,ferro-boron,Si and titanium powders as the raw materials at low temperature of 1000℃,and a new kind of coating materials was developed.By means of SEM,EDS,XRD and surface hardness tester,the microstructures,phases,hardness and wear-resistance of the coating were analyzed,respectively.The results revealed that the coating was mainly composed of the ceramic in-situ synthesized reinforcement phases of TiC,Cr7C3 and Cr5B3 and the binder phases in-situ synthesized of Ni31Si12 and(Ni,Fe)solid solution;The ceramic reinforcement phases of TiC,Cr7C3 and Cr5B3 were randomly distributed in the binder phases of Ni31Si12 and(Ni,Fe)solid solution;The coating had about 15vol%pores and can possibly be applied as a self-lubrication coating;The coating and the substrate were integrated together by metallurgical bonding;The coating had a hardness up to 91-94HR15N. 展开更多
关键词 reactive braze coating processing composite coating Ni-based alloy ceramic self-lubrication coating
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Identification and evolution of interfacial structure of SiO2 glass ceramic/Ti-6AI-4V alloy joint bonded with AgCu/Ni interlayer 被引量:1
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作者 刘多 王美荣 +2 位作者 唐冬雁 马蔷 冯吉才 《China Welding》 EI CAS 2014年第3期37-41,共5页
AgCu/Ni composite interlayer was utilized to join SiO2 glass ceramic (74. 52% SiO2-23. 40% Al2 03 -2. 08 % K2 O, wt. % ) and Ti-6Al-4V alloy by eutectic reaction. Interface structures of the joints were identified b... AgCu/Ni composite interlayer was utilized to join SiO2 glass ceramic (74. 52% SiO2-23. 40% Al2 03 -2. 08 % K2 O, wt. % ) and Ti-6Al-4V alloy by eutectic reaction. Interface structures of the joints were identified by means of TEM analysis. This joining method contains three characteristic processes, which are the melting of AgCu eutectic alloy, eutectic reaction between interlayer and Ti-6Al-4V base material and active reaction of element Ti to SiO2 glass ceramic. It is different from traditional active brazing because active element Ti totally dissolves from Ti-6Al-4 V and reacts with SiO2 glass ceramic. SiO2 glass ceramic can be joined suecessfuUy to Ti-6Al-4 V alloy by this novel bonding method and the joint exhibits high shear strength, up to 110 MPa. 展开更多
关键词 ceramic Ti-6Al-4V alloy reaction joining microstructure interface
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Interfacial reaction between zirconium alloy and graphite mold/yttrium oxide ceramic mold 被引量:2
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作者 Xie Huasheng Liu Hongyu +2 位作者 Zhao Jun Liu Shibing Shi Kun 《China Foundry》 SCIE CAS 2014年第2期85-90,共6页
Zirconium alloys are active in the molten state and tend to react with the mold during casting. The casting technology of zirconium is not yet well established; especially in selecting the mold materials, which are di... Zirconium alloys are active in the molten state and tend to react with the mold during casting. The casting technology of zirconium is not yet well established; especially in selecting the mold materials, which are difficult to determine. In the present work, the interfacial reactions between zirconium casting and casting mold were studied. The zirconium alloy was melted in a vacuum arc skull furnace and then cast into the graphite mold and ceramic mold, respectively. The zirconium casting samples were characterized using SEM, EDS and XRD with an emphasis on the chemical diffusion of elements. A reaction layer was observed at the casting surface. Chemical analysis shows that chemical elements C, O and Y from the mold are diffused into the molten zirconium, and new phases, such as ZrC, Zr30, YO1.335 and Y6ZrO11, are formed at the surface. In addition, an end product of zirconium valve cast in a yttria mold has a compact structure and good surface quality. 展开更多
关键词 graphite mold yttrium oxide ceramic mold zirconium alloy reaction layer
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Interaction between AE44 magnesium alloy and SiC-Al_2O_3-SiO_2 ceramic foam 被引量:1
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作者 Matej STEINACHER Primoz MRVAR Franc ZUPANI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第3期1011-1019,共9页
The interaction between a molten magnesium alloy AE44 and a SiC?Al2O3?SiO2 ceramics and the resulting reaction products were studied. The samples were investigated using optical and electron microscopy, energy dispers... The interaction between a molten magnesium alloy AE44 and a SiC?Al2O3?SiO2 ceramics and the resulting reaction products were studied. The samples were investigated using optical and electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. SiO2was predominantly reduced by Mg during the contact of the magnesium-rich melt with the ceramics. The main reaction product was MgO, whilst Si dissolved in the melt. Two novel tetragonal phases formed at the interface: AlSiRE and AlMgSiRE, having a specific mutual crystallographic orientation relationship. The interactions resulted in strongly connected interfaces between the metal and ceramics after short interaction time; however, interactions lead to disintegration of the ceramics after longer contact time. 展开更多
关键词 metal matrix composites AE44 Mg alloy ceramicS interfacial reaction
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Microstructure and fracture behavior of SiO_2 glass ceramic and TC4 alloy joint brazed with TiZrNiCu alloy 被引量:1
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作者 刘多 张丽霞 +2 位作者 冯吉才 刘洪斌 何鹏 《Journal of Central South University》 SCIE EI CAS 2009年第5期713-718,共6页
Vacuum brazing of SiO2 glass ceramic and TC4 alloy using a commercially available TiZrNiCu foil was investigated. The interfacial microstructure and the fractures were examined with an optical microscope (OM) and an... Vacuum brazing of SiO2 glass ceramic and TC4 alloy using a commercially available TiZrNiCu foil was investigated. The interfacial microstructure and the fractures were examined with an optical microscope (OM) and an S-4700 scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS) and an electron probe X-ray microanalyzer (EPMA). The structure of joint interface was identified by XRD (JDX-3530M). Meanwhile, the fracture paths of the joints were comprehensively studied. The results show that processing parameters, especially the brazing temperature, have a significant effect on the microstructure and mechanical properties of joints. The typical interface structure is SiO2/Ti2O+Zr3Si2+Ti5Si3/(Ti,Zr)+Ti2O+ TiZrNiCu/Ti(s.s)/TiZrNiCu+Ti(s.s)+Ti2(Cu,Ni)/TC4 from SiO2 glass ceramic to TC4 alloy side. Based on the mechanical property tests, the joints brazed at 880 ℃ for 5 rain has the maximum shear strength of 23 MPa. 展开更多
关键词 SiO2 glass ceramic TC4 alloy BRAZING joints interface MICROSTRUCTURE mechanical properties
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Wettability of TiAl alloy melt on ceramic moulds in electromagnetic field 被引量:3
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作者 李邦盛 刘爱辉 +3 位作者 南海 毕维生 郭景杰 傅恒志 《中国有色金属学会会刊:英文版》 EI CSCD 2008年第3期518-522,共5页
In the electromagnetic field, the wettability between Ti50Al alloy melt and oxide ceramic moulds was studied by the self-designed measuring apparatus. The thermodynamic and kinetic laws and mechanism on wetting were s... In the electromagnetic field, the wettability between Ti50Al alloy melt and oxide ceramic moulds was studied by the self-designed measuring apparatus. The thermodynamic and kinetic laws and mechanism on wetting were studied systematically. The results show that in the electromagnetic field, the order of contact angles for the molten Ti50Al alloy for the eight oxide materials is θ(Y2O3)>θ(ZrO2(Y2O3))>θ(ZrO2(CaO))>θ(CaO)>θ(ZrO2(MgO))>θ(Al2O3)>θ(Zircon)>θ(MgO). The wetting process of Ti50Al alloy and ceramic moulds includes the nonreactive wetting at the first stage, and the reactive wetting at the final stage. And the higher the ceramic chemical stability, the longer the nonreactive wetting time. 展开更多
关键词 钛铝合金 陶器制品 电磁领域 润湿性 界面反作用
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Metal-ceramic Bond Mechanism of the Co-Cr Alloy Denture with Original Rough Surface Produced by Selective Laser Melting 被引量:7
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作者 ZHANG Sheng LI Yong +3 位作者 HAO Liang XU Tian WEI Qingsong SHI Yusheng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第1期69-78,共10页
The porcelain fracture caused by low metal-ceramic bond strength is a critical issue in porcelain fused to metal(PFM) restorations. Surface roughening methods, such as sand blasting, acid etching and alkaline degrea... The porcelain fracture caused by low metal-ceramic bond strength is a critical issue in porcelain fused to metal(PFM) restorations. Surface roughening methods, such as sand blasting, acid etching and alkaline degreasing for the metal matrix are used to increase bond strength. However, the metal matrix of PFM processed by selective laser melting(SLM) has natural rough surface. To explore the effect of the original roughness on metal-ceramic bond strength, two groups of specimen are fabricated by SLM. One group of specimen surface is polished smooth while another group remains the original rough surface. The dental porcelain is fused to the specimens' surfaces according to the ISO 9693:1999 standard. To gain the bond strength, a three-point bending test is carried out and X ray energy spectrum analysis(EDS), scanning electron microscope(SEM) are used to show fracture mode. The results show that the mean bond strength is 116.5 16 MPa of the group with rough surface(Ra= 17.2), and the fracture mode is cohesive. However, when the surface is smooth (Ra =3.8), the mean bond strength is 74.5 MPa _+ 5 MPa and the fracture mode is mixed. The original surface with prominent structures formed by the partly melted powder particles, not only increases surface roughness but also significantly improves the bond strength by forming strong mechanical lock effect. Statistical analysis (Student's t-test) demonstrates a significant difference (p〈0.05) of the mean value of bond strength between the two groups. The experiments indicate the natural rough surface can enhance the metal-ceramic bond strength to over four times the minimum value (25 MPa) of the ISO 9693:1999 standard. It is found that the natural rough surface of SLM-made PFM can eliminate the porcelain collapse defect produced by traditional casting method in PFM restorations. 展开更多
关键词 selective laser melting(SLM) Co-Cr alloy metal-ceramic bond strength
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Wear resistance of ceramic coating on AZ91 magnesium alloy by micro-arc oxidation 被引量:2
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作者 赵晖 刘正 +2 位作者 陈立佳 陈吉 韩忠 《中国有色金属学会会刊:英文版》 CSCD 2006年第A03期1814-1818,共5页
The ceramic coating formed on AZ91 magnesium alloy by micro-arc oxidation (MAO) was characterized. The results show that the ceramic coating(3.4-23μm in thickness)on the surface of AZ91 alloy was attained under diffe... The ceramic coating formed on AZ91 magnesium alloy by micro-arc oxidation (MAO) was characterized. The results show that the ceramic coating(3.4-23μm in thickness)on the surface of AZ91 alloy was attained under different micro-arc oxidation treatment conditions, which consist mainly of MgO, Mg2SiO4 and MgSiO3 phases. Nano-hardness in a cross-sectional specimen was determined by nano-indentation experiment. The MAO coatings exhibit higher hardness than the substrate. Dry sliding wear tests for the MAO coatings and AZ91 alloy were also carried out using an oscillating friction and wear tester in a ball-on-disc contact configuration. The wear resistance of the MAO coatings is improved respectively under different treatment time as a result of different structures of ceramic coatings formed on AZ91 alloy. 展开更多
关键词 陶瓷涂层 镁合金 氧化行为 金属加工 磨损行为
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