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Powder injection molding of pure titanium 被引量:9
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作者 GUO Shibo DUAN Bohua +1 位作者 HE Xinb QU Xuanhui 《Rare Metals》 SCIE EI CAS CSCD 2009年第3期261-265,共5页
An improved wax-based binder was developed for powder injection molding of pure titanium. A critical powder loading of 69 vol.% and a pseudo-plastic flow behavior were obtained by the feedstock based on the binder. Th... An improved wax-based binder was developed for powder injection molding of pure titanium. A critical powder loading of 69 vol.% and a pseudo-plastic flow behavior were obtained by the feedstock based on the binder. The injection molding, debinding, and sintering process were studied. An ideal control of carbon and oxygen contents was achieved by thermal debinding in vacuum atmosphere (10^-3 Pa). The mechanical properties of as-sintered specimens were less than those of titanium made by the conventional press-sintering process. Good shape retention and ±0.04 mm dimension deviation were achieved. 展开更多
关键词 powder injection molding TITANIUM DEBINDING SINTERING mechanical properties
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NUMERICAL SIMULATION OF FEEDSTOCK MELT FILLING IN A CYLINDRICAL CAVITY WITH SOLIDIFICATION IN POWDER INJECTION MOLDING 被引量:9
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作者 Qu Xuanhui, Li Yimin, Yue Hongsheng, Mao Jinying, Zhu Lei and Huang Baiyun State Key Laboratory for Powder Metallurgy, Central South University of Technology, Changsha 410083, P. R. China 《中国有色金属学会会刊:英文版》 CSCD 1998年第4期13-18,共6页
INTRODUCTIONPowderinjectionmolding(PIM)isaprocesingrouteforfabricatingmetalorceramiccomponentswithcomplexsh... INTRODUCTIONPowderinjectionmolding(PIM)isaprocesingrouteforfabricatingmetalorceramiccomponentswithcomplexshapeandhighperfor?.. 展开更多
关键词 powder injection molding NUMERICAL SIMULATION SOLIDIFICATION
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Preparation of high nitrogen and nickel-free austenitic stainless steel by powder injection molding 被引量:1
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作者 Dawei Cui Junsheng Jiang +2 位作者 Guangming Cao Enzhong Xiao Xuanhui Qu 《Journal of University of Science and Technology Beijing》 CSCD 2008年第2期150-154,共5页
High nitrogen and nickel-free austenitic stainless steel has received much recognition worldwide because it can solve the problem of "nickel-allergy" and has outstanding mechanical and physical properties. In this a... High nitrogen and nickel-free austenitic stainless steel has received much recognition worldwide because it can solve the problem of "nickel-allergy" and has outstanding mechanical and physical properties. In this article, 0Cr17Mn11Mo3N was prepared by powder injection molding (PIM) technique accompanied with solid-nitriding. The results show that the critical solid loading can achieve up to 64vol% by use of gas-atomized powders with the average size of 17.4 μm. The optimized sintefing conditions are determined to be 1300℃,2 h in flowing nitrogen atmosphere, at which the relative density reaches to 99% and the N content is as high as 0.78wt%. After solution annealing at 1150℃for 90 rain and water quench, the 0.2% yield strength, ultimate tensile strength (UTS), elongation, reduction in area, and hardness can reach as high as 580 MPa, 885 MPa, 26.0%, 29.1%, and Hv 222, respectively. 展开更多
关键词 high nitrogen steel powder injection molding (pim stainless steel mechanical properties
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Powder injection molding of Fe-Ni soft magnetic alloys 被引量:2
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作者 DUAN Bohua QU Xuanhui +1 位作者 QIN Mingli GUO Shibo 《Rare Metals》 SCIE EI CAS CSCD 2006年第z1期440-444,共5页
With miniaturization and complication of the shape of electronic devices in recent years,powder injection molding(PIM)seems to be a suitable process for fabricating the higher performance soft magnetic components.In t... With miniaturization and complication of the shape of electronic devices in recent years,powder injection molding(PIM)seems to be a suitable process for fabricating the higher performance soft magnetic components.In this paper,high quality Fe-50Ni soft magnetic alloy was fabricated by PIM with carbonyl iron and nickel,and the effect of sintering process on its microstructure and magnetic properties were investigated.The mechanical and magnetic properties can be obviously improved by increasing the sintering temperature or using the hydrogen atmosphere instead of high vacuum,which causes by the increase of grain size and the densification.At the optimum sintering conditions,the PIM Fe-50Ni soft magnetic alloy with high properties are obtained,whose relative density,tensile strength,B_(m),H_(c),μ_(m)are 97%,465 MPa,1.52 T,16.62 A·m^(-1),42.5 mH·m^(-1),respectively. 展开更多
关键词 powder injection molding soft magnetic alloy SINTERING
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Injection molding of nano structured 90W-7Ni-3Fe alloy powder prepared by high energy ball milling 被引量:1
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作者 范景莲 曲选辉 黄伯云 《中国有色金属学会会刊:英文版》 CSCD 2000年第6期794-797,共4页
Blended elemental 90W 7Ni 3Fe (mass fraction, %) powder was mechanically alloyed in a planetary ball mill. Nano crystalline grains were obtained after 10 h milling. The nano structured powder was processed to full den... Blended elemental 90W 7Ni 3Fe (mass fraction, %) powder was mechanically alloyed in a planetary ball mill. Nano crystalline grains were obtained after 10 h milling. The nano structured powder was processed to full density by metal injection molding approach. Compacts from the optimal powder binder mixture were studied for molding and sintering behaviors. Milling significantly increases the maximum powder loading and homogeneity of the feedstock, and enhances the sintering densification process. When solid state sintered at 1 350~1 450 ℃, the alloy shows very fine grains (~3 μm), high tensile strength (>1 130 MPa) and almost no distortion. [ 展开更多
关键词 TUNGSTEN HEAVY alloy NANO STRUCTURED powder injection molding
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Phase Behaviors in Bi-phase Simulation of Powder Segregation in Metal Injection Molding 被引量:1
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作者 柳葆生 范小欣 成志强 《Journal of Southwest Jiaotong University(English Edition)》 2006年第4期363-371,共9页
Powder segregation induced by mold filling is an important phenomenon that affects the final quality of metal injection molding (MIM). The prediction of segregation in MIM requires a bi-phase flow model to describe ... Powder segregation induced by mold filling is an important phenomenon that affects the final quality of metal injection molding (MIM). The prediction of segregation in MIM requires a bi-phase flow model to describe distinctly the flows of metallic powder and polymer binder. Viscous behaviors for the flows of each phase should hence be determined. The coefficient of interaction between the flows of two phases should also be evaluated. However, only viscosity of the mixed feedstock is measurable by capillary tests. Wall sticking is supposed in the traditional model for capillary tests, while the wall slip is important to be taken into account in MIM injection. Objective of the present paper is to introduce the slip effect in bi-phase simulation, and search the suitable way to determine the viscous behaviors for each phase with the consideration of wall slip in capillary tests. Analytical and numerical methods were proposed to realize such a specific purpose. The proposed method is based on the mass conservation between the capillary flows in mono-phase model for the mixed feedstock and in bi-phase model for the flows of two phases. Examples of the bi-phase simulation in MIM were realized with the software developed by research team. The results show evident segregation, which is valuable for improving the mould designs. 展开更多
关键词 Viscous behaviors Bi-phases simulation powder segregation Metal injection molding Wall slip
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A novel binder and binder extraction method for powder injection molding of tungsten cemented carbide 被引量:1
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作者 祝宝军 曲选辉 陶颖 《中国有色金属学会会刊:英文版》 CSCD 2003年第2期262-266,共5页
An improved wax based multi component binder and a new debinding method termed high pressure condensed solvent extraction were developed for powder injection molding of tungsten cemented carbide. The results indicate ... An improved wax based multi component binder and a new debinding method termed high pressure condensed solvent extraction were developed for powder injection molding of tungsten cemented carbide. The results indicate that a critical powder loading of 65% (volume fraction) and an ideal rheological properties were obtained by the feedstock based on the binder. High debinding rate and specimens with high strength were obtained by the debinding method. Moreover, by making high temperature holding time adjustable, it makes the subsequent thermal degradation process more flexible to debinding atmosphere and carbon content of the as debinded specimens controllable. The transverse rupture strength, hardness and density of the as sintered specimens made by an optimized PIM process are 2.48 GPa, HRA90 and 14.72 g/cm 3, respectively. Good shape retention and about 0.02% dimension deviation were achieved. 展开更多
关键词 粘结剂 萃取 粉末注射成型 硬质合金 碳化钨
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Comparison of rheological analytic model with numerical simulation in powder injection molding filling process
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作者 刘跃军 李祥刚 +2 位作者 黄宇刚 魏珊珊 曾广胜 《Journal of Central South University》 SCIE EI CAS 2008年第S1期51-56,共6页
Mathematical model of filling disk-shaped mold cavity in steady state was studied.And the mathematical model under vibration field was developed from the model in steady state.According to the model of filling disk-sh... Mathematical model of filling disk-shaped mold cavity in steady state was studied.And the mathematical model under vibration field was developed from the model in steady state.According to the model of filling disk-shaped mold cavity in steady state,the filling time,the distribution of velocity field and the pressure field were obtained.The analysis results from rheological analytic model were compared with the numerical simulation results using Moldflow software in the powder injection molding filling process.Through the comparison,it is found that it is unreasonable to neglect the influence of temperature when calculated the pressure changing with the time at the cavity gate,while it can be neglected in other situations such as calculating the distribution of the velocity fields.This provides a theoretical reference for the establishment of correct model both in steady state and under vibration force field in the future. 展开更多
关键词 MATHEMATICAL model moldFLOW software vibration force field powder injection molding FILLING process
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Microstructure and properties of nano-TiN modified Ti(C,N)-based cermets fabricated by powder injection molding and die pressing
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作者 Shan-jie Yi Hai-qing Yin +3 位作者 Ke Chen Dil-Faraz Khan Qing-jun Zheng Xuan-hui Qu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2013年第11期1115-1121,共7页
Powder injection molding (PIM) and die pressing were employed to fabricate nano-TiN modified Ti(C,N)- based cermets. The shrinkage behavior, microstructure, porosity, and mechanical properties of the samples with ... Powder injection molding (PIM) and die pressing were employed to fabricate nano-TiN modified Ti(C,N)- based cermets. The shrinkage behavior, microstructure, porosity, and mechanical properties of the samples with and without nano-TiN addition fabricated by PIM and die pressing were analyzed. It is demonstrated that for either PIM or die pressing, the porosities are obviously reduced, the mechanical properties are significantly improved after adding nano-TiN, and the hard particles are refined; the rim phase thickness obviously becomes thinner, and the number of dimples in fracture also increases. Compared the samples fabricated by die pressing, it is difficult for PIM to obtain dense Ti(C,N)-based cermets. Due to the too much existence of pores and isolated carbon, the mechanical properties of the sintered samples by PIM are inferior to those of the sintered ones by die pressing. 展开更多
关键词 cermets powder injection molding die pressing titanium nitride NANOPARTICLES mechanical properties
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Numerical Simulation of Powder Injection Molding Filling Process Based on ANSYS
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作者 Zhoushun ZHENG Xuanhui QU Yunping LI Jianfeng GUO 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2003年第z1期144-146,共3页
A mathematical model of two-dimensional flows of PIM derived from the momentum, continuity equations and theheat transfer equation is obtained. The formula of calculating the flow conductance and the pressure equation... A mathematical model of two-dimensional flows of PIM derived from the momentum, continuity equations and theheat transfer equation is obtained. The formula of calculating the flow conductance and the pressure equation arededuced when the no slip boundary condition is employed at the wall, and the pressure equation is a non-linearelliptic partial differential equation. The flow front locations, distribution of velocities, temperature and pressure aresimulated by the finite element analysis software ANSYS. Simulation results indicate that it is in the final filled partthat defects appear easily. The region in which the defects may occur during the PIM process can be predicted. 展开更多
关键词 NUMERICAL simulation powder injection molding MATHEMATICAL model ANSYS
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Sintering Mechanism of Stainless Steel in Powder Injection Molding
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作者 Chengchang Jia Shimin Fan +4 位作者 Ying Peng Xiaojie Zhao Xiaosen lu Material Science and Engineering School, University of Science and Technology Beijing, Beijing 100083, China Beijing Tungsten and Molybdenum Factory, Beijing 102206, China Beijing Hard Me 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2000年第1期51-54,共4页
Stainless steel samples were made by Powder injection Molding (PIM) process with-400 mesh powder in order to investigate the sintering mechanism in this system and develop the PIM of stainless steels. The process incl... Stainless steel samples were made by Powder injection Molding (PIM) process with-400 mesh powder in order to investigate the sintering mechanism in this system and develop the PIM of stainless steels. The process included mixing, injection molding, debin- ding and sintering. Neck growth model was used to analyze the sintering mechanism. The results show that lattice (volume) diffusion is the main mechanism in the sintering process, the products with higher density (>95%) and properties are obtained. At lower temperatures, grain boundary diffusion may play a role in the sintering densification. 展开更多
关键词 sintering mechanism powder injection molding stainless steel volume diffusion
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Chemistry principles for thermoplastic polymer binder formula selection for powder injection molding
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作者 梁叔全 唐艳 +1 位作者 黄伯云 李少强 《中国有色金属学会会刊:英文版》 CSCD 2004年第4期762-768,共7页
The polymer binder selection is one of the very important aspects for the powder injection molding. However,even nowadays the binder selection is still mainly performed by try and error method. Six commercial or inten... The polymer binder selection is one of the very important aspects for the powder injection molding. However,even nowadays the binder selection is still mainly performed by try and error method. Six commercial or intensive studied binder fo rmulas were analyzed according to state diagram and chemical characteristics of ingredients in each binder formula. In addition,the interactions between the bi nder components and additives were also taken into account. Based on the analysi s,the optimum binder formula was selected and some selection criterions were pu t forward for the binder and additives. 展开更多
关键词 粉末注射成型 粉末冶金 pim 热塑性成型 冶金原理
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Fractal phenomena in powder injection molding process
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作者 郑洲顺 曲选辉 +2 位作者 李云平 雷长明 段柏华 《中国有色金属学会会刊:英文版》 CSCD 2003年第5期1112-1118,共7页
The complicated characteristics of the powder were studied by fractal theory. It is illustrated that powder shape, binder structure, feedstock and mold filling flow in powder injection molding process possess obvious ... The complicated characteristics of the powder were studied by fractal theory. It is illustrated that powder shape, binder structure, feedstock and mold filling flow in powder injection molding process possess obvious fractal characteristics. Based on the result of SEM, the fractal dimensions of the projected boundary of carbonylic iron and carbonylic nickel particles were determined to be 1.074±0.006 and 1.230±0.005 respectively by box counting measurement. The results show that the fractal dimension of the projected boundary of carbonylic iron particles is close to smooth curve of one dimension, while the fractal dimension of the projected boundary of carbonylic nickel particle is close to that of trisection Koch curve, indicating that the shape characteristics of carbonylic nickel particles can be described and analyzed by the characteristics of trisection Koch curve. It is also proposed that the fractal theory can be applied in the research of powder injection molding in four aspects. 展开更多
关键词 粉末注射成型 不规则破碎理论 pim NAVIER-STOKES方程
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Numerical simulation of tungsten alloy in powder injection molding process
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作者 郑振兴 夏伟 +1 位作者 周照耀 朱权利 《中国有色金属学会会刊:英文版》 EI CSCD 2008年第5期1209-1215,共7页
The flow behavior of feedstock for the tungsten alloy powder in the mold cavity was approximately described using Hele-Shaw flow model. The math model consisting of momentum equation, consecutive equation and thermo-c... The flow behavior of feedstock for the tungsten alloy powder in the mold cavity was approximately described using Hele-Shaw flow model. The math model consisting of momentum equation, consecutive equation and thermo-conduction equation for describing the injection process was established. The equations are solved by the finite element/finite difference hybrid method that means dispersing the feedstock model with finite element method, resolving the model along the depth with finite difference method, and tracking the movable boundary with control volume method, then the pressure equation and energy equation can be resolved in turn. The numerical simulation of the injection process and the identification of the process parameters were realized by the Moldflow software. The results indicate that there is low temperature gradient in the cavity while the pressure and shear rate gradient are high at high flow rate. The selection of the flow rate is affected by the structure of the gate. The shear rate and the pressure near the gate can be decreased by properly widening the dimension of the gate. There is a good agreement between the process parameters obtained by the numerical simulation and the actual ones. 展开更多
关键词 散剂注入模式 钨合金 数字模式 有限元方法
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Injection molding of micro-porous titanium alloy with space holder technique 被引量:4
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作者 Gülsah Engin Bülent Aydemir H.zkan Gülsoy 《Rare Metals》 SCIE EI CAS CSCD 2011年第6期565-571,共7页
The powder space holder (PSH) and powder injection molding (PIM) methods have an industrial competitive advantage because they are capable of the net-shape production of micro-sized porous parts. In this study, mi... The powder space holder (PSH) and powder injection molding (PIM) methods have an industrial competitive advantage because they are capable of the net-shape production of micro-sized porous parts. In this study, micro-porous Ti6Al4V alloy (Ti64) parts were produced by the PSH-PIM process. Ti64 alloy powder and spherical polymethylrnethacrylate (PMMA) particles were used as a space holder material. After molding, binder debinding was performed by thermal method under inert gas. Debinded samples were sintered at 1250℃ for 60min in a vacuum (10-4 Pa). Metallographic studies were conducted to determine densification and the corresponding microstructural changes. The surface of sintered samples was examined by SEM. The compressive stress and elastic modulus of the rificro-porous Ti64 samples were determined. The effects of fraction of PMMA on the properties of sintered micro-porous Ti64 alloy samples were investigated. It was shown that the fraction of PMMA could be controlled to affect the properties of the Ti alloy. 展开更多
关键词 powder injection molding titanium powder porous metal SINTERING
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Effects of heat treatment on the properties of powder injection molded AlN ceramics 被引量:1
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作者 DU Xueli QIN Mingli +2 位作者 Akhtar Farid FENG Peizhong QU Xuanhui 《Rare Metals》 SCIE EI CAS CSCD 2008年第1期70-73,共4页
The effects of two different heat-treatment atmospheres,nitrogen atmosphere and reducing nitrogen atmosphere with carbon,on the properties of Y2O3-doped aluminum nitride(AlN) ceramics were investigated.The AlN powde... The effects of two different heat-treatment atmospheres,nitrogen atmosphere and reducing nitrogen atmosphere with carbon,on the properties of Y2O3-doped aluminum nitride(AlN) ceramics were investigated.The AlN powder as a raw material was synthesized by self-propagating high-temperature synthesis(SHS) and compacts were fabricated by employing powder injection molding technique.The polymer-wax binder consisted of 60 wt.% paraffin wax(PW),35 wt.% polypropylene(PP),and 5 wt.% stearic acid(SA).After the removal of binder,specimens were sintered at 1850°С in nitrogen atmosphere under atmospheric pressure.To improve the thermal conductivity,sintered samples were reheated.The result reveals that the heat-treatment atmosphere has significant effect on the properties and secondary phase of AlN ceramics.The thermal conductivity and density of AlN ceramics reheated in nitrogen gas are 180 W·m^-1·K^-1 and 3.28 g·cm^-3 and the secondary phase is yttrium aluminate.For the sample reheated in reducing nitrogen atmosphere with carbon,the thermal conductivity and density are 173 W·m^-1·K^-1 and 3.23 g·cm^-3,respectively,and the secondary phase is YN. 展开更多
关键词 powder injection molding AIN ceramics heat treatment thermal conductivity
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Effect of sintering parameters on powder injection molded Ti(C, N)-based cermets
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作者 范畴 熊惟皓 《中国有色金属学会会刊:英文版》 CSCD 2005年第S3期153-156,共4页
Effect of two-stage sintering parameters such as heating rate, top sintering temperature and holding time, sintering temperature and holding time at the second stage on relative density, transverse rupture strength(TR... Effect of two-stage sintering parameters such as heating rate, top sintering temperature and holding time, sintering temperature and holding time at the second stage on relative density, transverse rupture strength(TRS) and microstructures of powder injection molded Ti(C, N)-based cermets were investigated, by means of Archimedes’s method, three-point bending test and micrographic analysis. The results show that the optimum sintering cycle for powder injection molded Ti(C, N)-based cermets comprises rapid heating (10℃/min) at low temperatures, slow heating (5℃/min) at intermediate temperatures, holding at the highest sintering temperature (1420℃) for a short time (10min), and holding at the second stage (1360℃) for a longer time (6h) to avoid grain coarsening, and that its TRS reaches 624MPa, and there are little pores in their microstructures. 展开更多
关键词 Ti(C N)-based cermets powderING injection molding sintering parameters relative density transverse rupture strength
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Rheological properties of metal injection molding feedstock
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作者 李松林 李益民 +1 位作者 曲选辉 黄伯云 《中国有色金属学会会刊:英文版》 CSCD 2002年第1期105-108,共4页
Viscosity of a polyethylene glycol polymethyl methacrylate (PEG PMMA) binder and PEG PMMA/Fe 2Ni feedstock in powder injection molding was measured and calculated. A logarithmic additivity between viscosity of the bin... Viscosity of a polyethylene glycol polymethyl methacrylate (PEG PMMA) binder and PEG PMMA/Fe 2Ni feedstock in powder injection molding was measured and calculated. A logarithmic additivity between viscosity of the binder and that of its constituents was found. Other factors, such as temperature, powder loads, content and type of surface active agents and those of polymers, in relation to rheological properties of feedstock were discussed as well. The results showed that with increasing viscosity of surface active agent, polymer melt index or temperature, the feedstock viscosity decreased while higher polymer content and powder loading would lead to additional feedstock viscosity. The relationship mentioned above is expressed and effectively explained why the change rate of feedstock viscosity will slow down with the increase of shear rate. 展开更多
关键词 粉末注射成型 流变学 给料特性 胶合剂
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INJECTION MOLDED TUNGSTEN HEAVY ALLOY 被引量:5
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作者 Li Yimin, Qu Xuanhui, Li Zhilin and Huang Baiyun State Key Laboratory for Powder Metallurgy, Central South University of Technology, Changsha 410083, P. R. China 《中国有色金属学会会刊:英文版》 CSCD 1998年第4期45-50,共6页
INTRODUCTIONMetalInjectionMolding(MIM),whichisderivedfromplasticinjectionmolding,isakindofnewlydevelopedpowd... INTRODUCTIONMetalInjectionMolding(MIM),whichisderivedfromplasticinjectionmolding,isakindofnewlydevelopedpowdermetalurgyformin... 展开更多
关键词 injection molding HEAVY ALLOY powder loading
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Influence of binder composition on the rheological behavior of injection-molded microsized SiC suspensions 被引量:2
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作者 Islam S.Humail 《Journal of University of Science and Technology Beijing》 CSCD 2008年第3期297-301,共5页
The influence of four kinds of binders consisting of paraffin wax (PW), random-polypropylene (RPP), high-density polyethylene (HDPE), and stearic acid (SA) on the theological behavior of injection-molded SiC f... The influence of four kinds of binders consisting of paraffin wax (PW), random-polypropylene (RPP), high-density polyethylene (HDPE), and stearic acid (SA) on the theological behavior of injection-molded SiC feedstocks was investigated over a temperature range of 150℃ to 180℃ and a shear rate range of 4 s^-1 to 1259 s^^-1. The results showed that all the feedstocks exhibited pseudoplastic flow behavior. The wax-based binder of multipolymer components (PW-RPP-HDPE) exhibited better comprehensive rheological properties compared with the binder of monopolymer components (PW-RPP or PW-HDPE). The addition of 5wt% SA to the binder could reduce the viscosity of the feedstock but enhance the rheological stability by improving the wettability between the binder and the SiC powder. The binder of 65wt% PW + 15wt% HDPE + 15wt% RPP + 5wt% SA was found to be a better binder for microsized SiC injection molding. 展开更多
关键词 SIC powder injection molding RHEOLOGY BINDER
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