青铜合金粉松装烧结温度的确定

总结了确定青铜合金粉松装烧结温度的经验和对炉膛的颜色进行观察的经验。     

超固相线液相烧结

简略地介绍了超固相残液相烧结的特点、发展和影响因素。     

Nitrogen Ceramics: Liquid Phase Sintering

Abstract

The role of a minor silicate eutectic liquid phase as a transport medium in sintering hot–pressed silicon nitride (β Si₃N₄) ceramics was identified in the 1970s. A similar mechanism is applicable to hot–pressed Si–Al–O–N ceramic alloys which offer an advantage in control of the final liquid volume and hence in superior high temperature mechanical properties. By increasing the liquid volume it is possible to densify ceramic alloys without application of pressure at the sintering temperature and hence to fabricate components of complex shape. The Lucas Syalon ceramics typify the new range of pressureless–sintered ceramics based on the β Si₃N₄ structure. They are fabricated from the ultrafine compound powders α Si₃N₄, SiO₂, Al₂O₃, Y₂O₃, and a polytypoid phase (a substitute for A1N). The ceramics consist of submicrometre solid solution crystals of general composition Si_3?xAl_xO_xN_4?x(x < 1) within a minor matrix phase which may be either a glassy Y–Si–Al oxynitride or be crystallized to form yttrogarnet. Analysis of matrix glass compositions shows them to be residues of liquids near to a ternary eutectic in the Y₂O₃–SiO₂–Al₂O₃ system which is well below the sintering temperature of ～ 1800°C. Sintering models, based on particle rearrangement due to dissolution of the major α Si₃N₄ component in the eutectic liquid and its reprecipitation as a β Si₃N₄ solid solution, are discussed. Properties and current applications of Syalon ceramics are surveyed briefly. PM/0266     

钨铜复合材料的化学活化液相烧结

钨在铜中的不溶解性妨碍钨和铜混合粉末的液相烧结。在本文所述的研究中，通过往原始的粉末混合物中添加质量分数小于１％的钴而显著地改善了材料的各种性能。本文还探讨了诸如钴含量、初始均勺性、铜粉粒度、铜含量、未烧结密度、加热速率和烧结温度等工艺因素的作用．     

Effect of Graphite Content and Granularity on Mechanical and Tribological Properties of Bronze Alloyed Powder Composite

Antifrictionmaterialsofthebronze graphitetypealloyedwithdifferentmetalsareusedtomanufactureslidingelectricalcontacts.Tinandleadareaddedtopowderchargewhosemaincomponentiscopper,andthebronzecanbeformed .Theamountofgraphitetoimprovethetribologicalpropertieso…     

Fe-Sn-Cu粉末合金的液相压制

本文初步探讨了液相压制的规律和致密化机理。对实验数据进行回归分析表明,液相密度增量△D(=y),粉末比表面S及液相含量G(G/S=x)之间存在如下指数函数关系:
y=aeb x
产生液相密度增量的机理,除了液相的润滑作用、固相在液相中的溶解析出外,由镀铜铁粉和不镀铜铁粉的液相压制对比实验表明,扩散蠕变及液相对固相颗粒表面的活化作用,对液相密度增量有重要影响。     

锡青铜标准样品的研制

介绍了锡青铜标准样品的成分设计、最佳试验条件的选择,熔铸加工和均匀性初检以及定值分析、分析数据统计处理、均匀性检验和标准值及标准偏差的确定。结果表明,最佳熔铸条件为:在1 150℃炉温下,通入0.2m3/kg的氩气,以100r/min的速度搅拌1min,保温30min。本样品符合GB/T15000-2008和YS/T409-1998标准的要求,已被全国标准样品技术委员会批准为国家级标准样品。     

液相法制备纳米氧化锌粉体

以硫酸锌溶液为原料,采用液相法工艺制备纳米氧化锌,使用碳酸氢钠或碳酸氢氨作沉淀剂,调整制备工艺技术参数,以乙醇作为分散剂,可制备出高品质纳米氧化锌产品。采用比表面仪、X-射线衍射仪和透射电子显微镜对纳米氧化锌产品进行表征。产物比表面积为21.9～91.8m2/g,平均粒径为48.1～171.4nm。     

浅析锡磷青铜带材的生产技术

本文简述了锡磷青铜带材的用途和特性，综述了目前锡磷青铜带材的几种主要生产工艺及其特点对我国锡磷青铜带材的发展提出了几点建议。     

Sintering Time Dependent Supersolidus Liquid Phase Sintering Behaviour of a Metal Injection Molded Nickel-Base Superalloy

Metallurgical and Materials Transactions A - Supersolidus Liquid Phase Sintering of a high refractory metal Ni-based superalloy revealed that the liquid fraction and associated grain growth...     

纳米级球形In2O3（SnO2）粉末的制备及性能研究

采用化 学液相 共沉淀,以 铟、四氯 化锡为 原料,通过 选择沉 淀介质和 控制一定 的工艺 ,制备了球形的 Ｉ Ｔ Ｏ 粉料。用 Ｔ Ｅ Ｍ 、 Ｂ Ｅ Ｔ 等法对 所制粉料 进 行了 表征 。结 果表 明, 所制 粉料 分 散性 好,粒径约为 １６ ｎ ｍ 。     

高碳,高合金铁基材料的液相烧结

研究了烧结温度，保温时间及不同合金元素对铁基材料大液相量（质量分数２０～３０％）液相烧结及烧结后材料密度，硬度和抗弯强度的影响。结果表明，通过机械混合制成的高碳，高合金铁基体经过大液相量液相烧结后，得到的致密化程度较高，各合金元素分布较为均匀，水套冷却中形成部分马氏体。     

Distortion in a 7xxx Aluminum Alloy during Liquid Phase Sintering

The distortion in a sintered 7xxx aluminum alloy, Al-7Zn-2.5Mg-1Cu (wt. pct), has been investigated by sintering three rectangular bars in each batch at 893 K (620 °C) for 0 to 40 minutes in nitrogen, followed by air or furnace cooling. They were placed parallel to each other, equally spaced apart at 2 mm, with their long axes being perpendicular to the incoming nitrogen flow. Pore evolution in each sample during isothermal sintering was examined metallographically. The compositional changes across sample mid-cross section and surface layers were analyzed using energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy depth profiling, respectively. The two outer samples bent toward the middle one, while the middle sample was essentially distortion free after sintering. The distortion in the outer samples was a result of differential shrinkage between their outer and inner surfaces during isothermal sintering. The porous outer surface showed an enrichment of oxygen around the large pores as well as lower magnesium and zinc contents than the interior and inner surface of the same sample, while the inner surface was distinguished by the presence of AlN. The differential shrinkage was caused by different oxygen contents in local sintering atmosphere and unbalanced loss of magnesium and zinc between the outer and inner surfaces.     

锡青铜中微量铝的测定

在乳化剂ＯＰ和阴离子表面活性剂ＣＴＭＡＢ存在下，用ＣＡＳ作为显色剂光度法测定锡青铜中的微量铝，适宜的酸度范围在ｐＨ５．５～６．５，Ｃｕ用Ｎａ２Ｓ２Ｏ７掩蔽，存在于锡青铜中的其它共存金属离子不影响铝的测定。本法可测定锡青铜中１×１０－３％以上的铝。     

铈基氧化物粉体的湿化学法制备及用途

介绍了制备铈基氧化物粉体的几种湿化学合成方法、特点及研究进展，同时也介绍了铈基氧化物粉体的应用领域和研究前沿。