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Search Results: 1 - 10 of 29584 matches for " 左孝青 "
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挤压Fe-25Cr-5Al金属蜂窝的烧结和组织结构研究
周芸,,梅俊,张喜秋,孙加林
材料工程 , 2006,
Abstract: 以纯铁粉、铬粉、铝粉为原料,采用粉体增塑挤压-烧结工艺制备Fe-25Cr-5Al金属蜂窝,研究不同的烧结温度和时间条件下烧结蜂窝的收缩率、表观密度和组织结构特征。研究表明,随烧结温度的升高,蜂窝的收缩率和表观密度增大,径向收缩率的范围为5.6%~12.3%,表观密度的范围为0.98~1.09g/cm3。在1250℃烧结时,随烧结时间的延长,蜂窝的收缩率和表观密度也随之增大,径向收缩率的范围为6.5%~12.1%,表观密度的范围为0.85~1.02g/cm3。烧结组织为Fe-Cr固溶体(-αFe)基体,少量Fe-Al,Cr-Al间化合物及Cr2O3,Al2O3。
多孔青铜过滤片的制备工艺及结构特性探究
李和汀,杨一群,谢波,孙亚东,周芸,
- , 2018, DOI: 10.11951/j.issn.1005-0299.20170029
Abstract: 开发一种工艺简单、重复性好、孔形孔径易控制、制取成本低的铜基多孔材料制备工艺是当前的研究热点之一.本文以青铜粉为原料,K2CO3为造孔剂,采用烧结溶解法制备多孔青铜过滤片,研究了造孔剂、烧结温度对样品孔隙率的影响,分析了烧结温度、压制压力对样品最大孔径和透气系数的影响,以及孔隙率与抗压强度的关系.研究结果表明:当造孔剂体积分数为20%~40%时,所制备样品的孔隙率为22.8%~44.4%,开孔孔隙率为18.5%~37.2%;随着烧结温度的升高,样品孔隙率和透气系数下降;随着压制压力增加,最大孔径和透气系数均减小;随着样品孔隙率增大,抗压强度减小.当选择造孔剂体积分数30%、压制压力150 MPa、烧结温度800 ℃的工艺参数下,制备出孔隙率32.2%、最大孔径4.6 μm、透气系数9.27 m3/(h·kPa·m2)、压缩强度27.9 MPa的多孔青铜过滤片.
The development of preparation processing of a copper based porous material with simple procedure, excellent repeatability, easy control of pore size and low cost is one of the current research hotspots. Bronze powders were used as the raw material and K2CO3 as pore-forming agent, the porous bronze samples were fabricated by a sintering-dissolution process. The effect of pore-forming agent and sintering temperature on the porosity of samples was studied. The effects of compacting pressure and sintering temperature on maximum pore size and permeability of samples was also examined. The relationship between porosity and compressive strength were discussed. The experimental results indicate that the whole porosity of samples is 22.8%~44.4%, and the porosity of open pore is 18.5%~37.2%, for the case of 20%~40% volume fraction of pore-forming agent. Both the porosity and permeability of samples decrease with increasing the sintering temperature. Both the maximum pore size and permeability of samples decrease with increasing the compacting pressure. The compressive strength of samples decreases withincreasing porosity. The porosity, the maximum pore size, permeability, and compressive strength of porous bronze filter sample is 32.2%, 4.6 μm, 9.27 m3/(h·kPa·m2), and 27.9 MPa, respectively at sintering temperature of 800 ℃, compacting pressure of 150 MPa, and the volume fraction of pore-forming agent of 30%.
粉末增塑挤压制备Al2O3/Fe复合型蜂窝材料的组织与性能
Structures and properties of Al2O3/Fe composite honeycombs fabricated by plasticizing powder extrusion

李明超,龚泉,杨一群,余娇,周芸,
- , 2016, DOI: 10.13801/j.cnki.fhclxb.20160308.005
Abstract: 为制备性能优良的Al2O3/Fe复合型蜂窝材料,首先以316 L合金粉末、Al2O3粉末和黏结剂为原料,通过粉末增塑挤压及在1 200℃氩气气氛中烧结2 h获得了Al2O3/Fe复合型蜂窝材料;然后,借助SEM、XRD及万能试验机研究了添加Al2O3对Al2O3/Fe复合型蜂窝材料组织与性能的影响。结果表明:金属粉末颗粒在烧结过程中结合形成γ-Fe基体网状组织,表面有呈多边形几何状形态的Cr2O3形成;添加少量的Al2O3可以抑制Cr从基体中析出,降低表面Cr2O3的含量,使金属颗粒烧结结合更为紧密,组织表面更加光滑;随着Al2O3含量的增加,蜂窝材料表面与催化活性涂层的结合能力增强,复合型蜂窝材料的抗压强度先升高后降低;在Al2O3含量为5.0wt%时,抗压强度达26 MPa。所得结论表明5.0wt% Al2O3/Fe复合型蜂窝材料力学性能最佳,表面涂覆性能优良。 In order to fabricate Al2O3/Fe composite honeycombs with high-performances, 316L alloy powder, Al2O3 powder and binder were used as raw materials, Al2O3/Fe composite honeycombs were obtained by plasticizing powder extrusion and sintering at 1 200℃ for 2 h in argon atmosphere firstly. Then, the effects of adding Al2O3 on the structures and properties of Al2O3/Fe composite honeycombs were investigated by SEM, XRD and universal testing machine. The results show that metal powder particles bind together to form γ-Fe matrix network structure during sintering process, and Cr2O3 with polygon geometric shape is formed on the surface. Adding a small amount of Al2O3 can inhibit the precipitation of Cr from matrix and reduce the amount of Cr2O3 on the surface, which makes the sintering combination of metal powder particles more compact and the surface of structure more smooth. With Al2O3 content increasing, the bonding capacity for the surface of honeycomb materials with catalytic activity coating enhances, compressive strength of the composite honeycomb increases at first and then decreases, and when Al2O3 content is 5.0wt%, the compressive strength reaches 26 MPa. The conclusions obtained show that the mechanical properties of 5.0wt% Al2O3/Fe composite honeycomb are the best, and the surface paintability is preferable. 国家自然科学基金(51264024)
原位合成TiB2/ZL205A复合材料的组织及流动性
Microstructure and fluidity of In-situ TiB2/ZL205A composites

孔德昊,,卢锴,李威威,郑翰
- , 2017, DOI: 10.13801/j.cnki.fhclxb.20161115.006
Abstract: 采用原位合成法制备了TiB2/ZL205A复合材料,对所合成复合材料的物相、TiB2颗粒形貌及分布、流动性进行了研究。结果表明:TiB2/ZL205A复合材料主要由α-Al、Al2Cu和TiB2组成,TiB2颗粒呈多边形或卵圆形,平均颗粒尺寸500 nm左右,大部分沿晶界分布,少量分布在晶粒内部。TiB2/ZL205A复合材料的流动性与浇铸温度及TiB2质量分数的关系均可用指数阻尼模型进行描述。当浇铸温度由710℃提高到750℃时,7wt% TiB2/ZL205A复合材料的流动性提高了30.4%;当浇铸温度在750℃以上时,7wt% TiB2/ZL205A复合材料的流动性随浇铸温度的提高而提高的速率降低。与基体合金相比,在730℃浇铸时,3wt% TiB2/ZL205A复合材料的流动性降低了21.8%,7wt% TiB2/ZL205A复合材料的流动性降低了36.4%。 The in-situ TiB2/ZL205A composites were prepared by the method of mixed salt reaction in aluminum alloy melt. The phases, morphology and distribution of TiB2 particles and the fluidity of the fabricated composites were studied. The results show that the main phases of the TiB2/ZL205A composites are α-Al, Al2Cu and TiB2. The TiB2 particles with an average size of 500 nm and the shape of polygon or ovoid distribute mostly along the grains boundary and a few in the grains. The two relationships, that is the fluidity and casting temperature and the fluidity and mass fraction of Ti2B particles, can all be described by the exponential damping model. When the casting temperature raises from 710℃ to 750℃, the fluidity of 7wt%TiB2/ZL205A composites increases by 30.4%. When the casting temperature increases above 750℃, the increasing rate of the 7wt%TiB2/ZL205A composites fluidity is decreased with the increasing of casting temperature. Compared with the matrix alloy, the fluidity of 3wt%TiB2/ZL205A composites decreases by 21.8%, and the fluidity of 7wt%TiB2/ZL205A composites decreases by 36.4%. 国家自然科学基金(51164019);云南省应用基础研究重点项目(2010CC004);昆明理工大学创新团队项目;昆明理工大学-沾益锴晟特种金属有限公司合作项目
粉末增塑挤压制备Al2O3/430L复合型蜂窝材料的组织与性能
杨一群,李和汀,孙亚东,周芸,,桓源峰,刘沁曦
- , 2017, DOI: 10.11951/j.issn.1005-0299.20160389
Abstract: 为制备性能优良的Al2O3/430L复合型蜂窝载体材料,本文以430L不锈钢合金粉末、Al2O3粉末、粘结剂为原料,采用粉末增塑挤压技术挤压成形,并在1 100 ℃真空中烧结2 h获得Al2O3/430L复合型蜂窝材料.借助SEM、XRD及万能试验机, 研究了添加Al2O3对Al2O3/430L复合型蜂窝材料的组织与性能的影响.研究表明:金属粉末颗粒在烧结过程中结合形成的基体组织为α-Fe(Cr),在基体晶粒间孔隙处和表面弥散分布着Al2O3颗粒.添加少量的Al2O3可提高烧结密度,制件表面光滑.随着Al2O3添加量增加,蜂窝材料表面负载催化涂层的能力增强;抗压强度随Al2O3添加量的增加先升高后降低,在Al2O3含量为2.5wt.%时,最大抗压强度达27 MPa.添加2.5wt.%Al2O3所制备的Al2O3/430L复合型蜂窝材料力学性能最佳、表面负载催化涂层的能力优良.
To fabricate Al2O3 /430L composite honeycombs with high-performance, with pure 430L powder, Al2O3 and a binder as raw materials, Al2O3 /430L composite honeycombs were fabricated by plasticizing powder extrusion and sintering at 1 100 ℃ for 2 h under vacuum conditions. The effect of adding Al2O3 on the microstructure and properties of Al2O3 /430L composite honeycombs has been investigated by SEM, XRD and universal testing machine.The results show that, by sintering at 1 100 ℃ for 2 h in a vacuum, metal powder particles were jioned together to form α-Fe matrix, and Al2O3 is distributed on the surface and pore of matrix. Adding a small amount of Al2O3 can improve the density of sintered part, and make the part surface smooth. Increasing the amount of Al2O3can improve the surface bonding strength of honeycomb carriers with catalytic coating. Compressive strength of the part increases at first and then decreases with the increase of the content of Al2O3, and the peak value reaches at 2.5wt.% Al2O3 and maximum compressive strength 27 MPa.The Al2O3 /430L composite honeycombs with 2.5wt.% Al2O3 have best mechanical properties and high surface coating adhesion.
庭院资源的开发与庭院经济

中国农业资源与区划 , 1991, DOI: 10.7621/cjarrp.1005-9121.19910606
Abstract: 按全国2亿农户估算,农村庭院占地约1亿亩左右,相当于全国耕地总面积的1/15。这1亿亩庭院除去宅基地、道路、水沟等等难以开垦利用的土地外,约有6000万亩可以开发利用。充分利用农村庭院资源,对加速我国农村经济发展,提高农副产品的产量,增加农民收入都有着极为重要的意义。
农业综合开发探讨

中国农业资源与区划 , 1991, DOI: 10.7621/cjarrp.1005-9121.19910206
Abstract: 随着社会对农业的普遍重视,农业综合开发正作为一项崭新的事业,提到各级领导的议事日程。本文拟从理论和实践上对农业综合开发问题进行探讨。一.农业综合开发是相对常规农业而言自党的十一届三中全会以来,以家庭联产承包责任制为突破口的农村经济体制改革,取得了举世瞩目的成就,推动了我国农村经济及农业生产的发展。
《清代皇帝传略》前言

清史研究 , 1990,
Abstract: ?
如何正确的编制地质勘探设计
,凤岐
地质与勘探 , 1959,
Abstract: 编制??的目的在于根据国家对地?勘探工作的要求,妥善地安排全盘地?工作,使其能够有节奏地进行,因而只有在??思想是先进的,作法是正确合理的条件下,其最?效果才能表现为获得?量多,耗?投资少,勘探时间短,?量勘探成本低。因此勘探??编制的好坏是地?勘探部?开展增产节约运的动代有根本性?题。?根据我?的体会,??怎样正确?制勘探??的??。
自然保护区生态旅游开发与保护浅析

世界林业研究 , 2002,
Abstract: 分析了自然保护区生态旅游产生的背景,认为生态旅游是中国大多数自然保护区发展的最佳策略,概述了自然保护区生态旅游及自然保护区生态旅游开发与保护之间的关系。在此基础上,提出了自然保护区生态旅游开发与保护的对策。
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