再生高密度钨合金的性能

采用氧化-还原法回收钨合金切削废料,用回收粉末及镍、铁元素粉配制成91W-6Ni-3Fe系高密度合金的混合粉,经压制、脱胶、烧结制得再生高密度钨合金.结果表明:所得再生合金的性能同非回收粉末所制备的合金性能相当,再生钨合金的密度随着烧结温度的升高而先升高后有所降低,最大密度为17.12 g/cm3,硬度随着烧结温度的升高而降低;当烧结温度为1 440℃时再生合金的强度和塑性达到较好的配合,抗拉强度为922.95MPa,延伸率为20.18%;经真空热处理后,再生钨合金性能得到改善,抗拉强度和延伸率得到不同程度的提高,抗拉强度比热处理前提高了约6.44%,延伸率比热处理前提高了约43.42%.     

高性能再生硬质合金的短流程回收制备

以WC-16%Co(质量分数)废旧硬质合金块体为原料,采用氧化-原位还原碳化的方法对其进行回收制备再生WC-16%Co复合粉,并对再生复合粉进行低压烧结制备再生硬质合金块体材料.通过热力学计算确定氧化物粉末和炭黑发生原位还原碳化反应的温度范围,采用实验方法系统研究了原料粉末中配C量对再生复合粉和再生硬质合金的物相组成、力学性能等的影响,并对再生合金的显微组织与性能的关系进行了分析.结果表明:随着原料粉中配C量的增加,再生复合粉中的Co6W6C相逐渐减少,总C和游离C含量增加;当配C量为16.60%时,可制备出化学成分符合原生WC-16%Co复合粉要求的再生复合粉,经低压烧结可得到物相纯净,断裂韧性达到23.05 MPa·m1/2,横向断裂强度达到4020 MPa的高性能再生硬质合金;再生硬质合金的Co相分布是否均匀,对再生硬质合金的综合性能优良与否起到至关重要的作用.     

再生料制备的硬质合金组织与性能研究

以电解法回收的WC粉和Co粉为原料,通过高能球磨、压制成型和1400℃真空烧结制成YG6、YG8、YG11三种合金,检测了合金的硬度、密度、抗弯强度、金相等力学性能及微观组织。分析讨论了回收WC粉、Co粉与原生WC粉、Co粉在化学成分、颗粒形貌等方面的不同,通过断口观察测量断裂源缺陷尺寸,分析讨论再生料制备的硬质合金缺陷尺寸与强度的关系。     

铝基PS版的生产与再生利用工艺（5）

铝基ＰＳ版的生产与再生利用工艺（５）东北轻合金加工厂王祝堂４ＰＳ版的再生利用资源的回收与再生利用对于环境保护和国民经济的发展都有着重要的意义。铝基ＰＳ版的回收与再生利用有着双重的意义：一是回收的ＰＳ版经处理后仍是ＰＳ版，与新ＰＳ版一样用于印刷制版，不...     

金属再生利国利民

所谓再生金属,是指由废旧金属、合金或含金属的废料经重新提炼得到的金属产品,例如熔炼废杂铜得到的再生铜。 世界上许多发达国家,都很重视金属再生或废品回收利用。再生或回收在次发达国家,甚至在发展中国家亦越来越受到人们的重视。     

氧化-还原碳化法回收再生高性能硬质合金的研究

以废旧WC-Co硬质合金为原料,采用氧化和原位还原碳化的短流程方法合成再生WC-Co复合粉末,随后对再生复合粉低压烧结得到再生硬质合金。利用XRD、SEM和TEM等对再生复合粉和再生硬质合金的物相和显微组织形貌进行观察和分析,系统研究了原料粉末中配碳量对再生复合粉和再生合金的物相组成和力学性能的影响。配碳量为16.60%时制备的再生WC-16%Co(质量分数,下同)硬质合金的断裂韧性为24.80 MPa·m1/2、横向断裂强度达到3860MPa,并且分析了再生硬质合金的显微组织与性能之间的关系。     

铜金粉的颜色及其影响因素

利用分光光度计对国内外铜金粉的颜色进行了测试，研究了铜金粉的成分、微观状态对颜色的影响。结果表明：铜金粉颜色可以用色彩三要素进行描述，其中铜金粉的色相只与合金成分有关，而与铜金粉片的大小、形状及粒度分布无关；明度和纯度与铜金粉片在油墨层中定向排列状态、片的大小、形状及粒度分布有关，而与成分无关；合金成分的微小波动不会引起铜金粉色相的明显改变。     

世界最大废旧全铝易拉罐再生中心投产

正诺贝丽斯铝业公司(Novelis)是全球最大的平轧铝产品(FRPs)生产者,也是最大的全铝易拉罐带材生产者,所生产的罐料(罐身料、罐盖料、拉环料)达2800kt/a,约占世界总产量4300kt的65%。此外,它还是全球最大的废旧全铝易拉罐回收与再生者,它在美国、德国、巴西、韩国等国都建有回收再生中心或生产线,其中德国纳希特斯特(Nachterstedt)轧制厂的回收再生中心是世界最大者,再生3104合金锭的生产能力400kt/a。2013年,诺贝丽斯公司在其生产的罐身料中(3104合金),用再生料生产的占45%以上,公司规划2020年生产的罐身料的80%以上是用回收的废料生产的。纳希特斯特轧制厂回收中心已于     

混合稀土氧化物与再生WC-Co粉制备YG8硬质合金的研究

以混合稀土和再生WC-Co粉混合制备YG8硬质合金为研究对象,对合金性能和组织进行检测。结果表明:混合稀土的加入对合金样品的密度和硬度无影响,对合金的矫顽磁力、钴磁和抗弯强度产生一定的影响,但并不明显。与原生WC粉末制备的硬质合金相比,再生粉末制备的硬质合金,其钴磁和抗弯强度等性能下降严重,而且组织中出现明显的脱碳现象。     

世界最大废旧全铝易拉罐再生中心投产

正诺贝丽斯铝业公司(Novelis)是全球最大的平轧铝产品(FRPs)生产者,也是最大的全铝易拉罐带材生产者,所生产的罐料(罐身料、罐盖料、拉环料)达2800kt/a,约占世界总产量4300kt的65%。此外,它还是全球最大的废旧全铝易拉罐回收与再生者,它在美国、德国、巴西、韩国等国都建有回收再生中心或生产线,其中德国纳希特斯特(Nachterstedt)轧制厂的回收再生中心是世界最大者,再生3104合金锭的生产能力400kt/a。2013年,诺贝丽斯公司在其生产的罐身料中(3104合金),用再生料     

MICROSTRUCTURE OF REGENERATED HIGH DENSITY TUNGSTEN ALLOYS MADE BY OXIDATION-REDUCTION

The mechanical properties of regenerated W-alloys relating to the chemical purity and size ofreclamation powders of 93W-Ni-Fe-Co(Mn)alloy chips,the structure of main constituentsof the powders,as well as microstrueture and fractograph of regenerated W-alloys made bythe reclamation powders,composition of W particle and binder phase,content,structure anddistribution of main impurity elements have been studied by means of optical microscope,SEM,XRES.XRD,TEM,AES and chemical analysis.The feasibility of oxidation-reduc-tion process for reclamation and the possibility of praetical application of regenerated W-al-loys have been discussed.     

Preparation of nickel-coated tungsten carbide powders by room temperature ultrasonic-assisted electroless plating

In this paper nickel (Ni)-coated tungsten carbide (WC) composite powders have been synthesized by ultrasonic-assisted electroless plating with a simplified pretreatment at room temperature as the conventional sensitization and activation steps have not been employed. The growth mechanism of Ni layers and surface morphologies and composition of initial WC powders, pretreated WC powders and Ni-coated WC powders were analyzed by field emission scanning electron microscopy, and energy dispersion spectrometry. The results shows that uniform Ni-coated WC composite powders were successfully synthesized without conventional sensitization and activation steps by ultrasonic-assisted electroless plating at room temperature. The growth mechanism of Ni layers appears as follows: the surfaces of pretreated WC powders appear step-like defects which act as activated sites. Nucleation and the growth of nickel grains take place on the activated sites of pretreated WC powder, and the process repeats continuously on the lath particles with reticulate structure on the as-coated surfaces of previously deposited Ni-cells, finally Ni cells grow up and merge into a layer.     

振动式旧砂再生机结构及其改进

介绍了振动式旧砂再生机的基本结构,以及旧砂再生过程的能量传递规律.讨论了现有的几种振动再生机的结构与性能特点,以及借鉴振动磨原理提高旧砂再生效果的方法,并介绍了离散元法(DEM)引入到旧砂再生研究中的可能.     

Characteristics of Fe powders prepared by spray pyrolysis from a spray solution with ethylene glycol as the source material of heat pellet

Fe powders as the heat pellet material for thermal batteries are prepared from iron oxide powders obtained by spray pyrolysis from a spray solution of iron nitrate with ethylene glycol. The iron oxide powders with hollow and thin wall structure produce Fe powders with elongated structure and fine primary particle size at a low reducing temperature of 615 °C. The mean size of the primary Fe powders with elongated structure decreases with increasing concentration of ethylene glycol dissolved into the spray solution. The heat pellets prepared from the fine-size Fe powders with elongated structure have good ignition sensitivities below 1 watt. The heat pellets formed from the Fe powders obtained from the spray solution with 0.5 M EG have an extremely high burn rate of 26 cms^?1.     

Surface characteristics of rapidly solidified nickel-based superalloy pow-ders prepared by PREP

The surface microstructure and the surface segregation of FGH95 nickel-based superalloy powders prepared through plasma rotating electrode processing (PREP) have been investigated by using SEM and AES. The results indicate that the surface microstructure of powders changes from dendrite into cellular structure as the particle size of powders de-crease, and the predominant precipitates solidified on the particle surfaces were identified as MC' type carbides enriched with Nb and Ti. It was also indicated that along with the depth of particle surfaces, the segregation layer of S, C and O ele-ments are thick, and that of Ti, Cr elements are thin for large size powders while they are in reverse for median size parti-cles.     

铸造旧砂再生回用技术现状及进展

本文对近5年来铸造旧砂再生回用技术研究及应用的进展进行了概述.对目前广泛使用的再生回用技术、设备的研究及应用进行了分析.认为铸造废旧砂的再生回用是铸造工业实现绿色可持续发展的必然要求,低成本高效率地再生回用铸造旧砂是铸造技术进步的重要方向.     

雾化气体和冷却速度对镍基合金粉末凝固特性的影响

镍基合金粉通过氩气雾化和氮气雾化制得。利用扫描电镜及其借助EDS能谱仪研究了雾化粉末的凝固微观结构特性。基于牛顿冷却模型,计算了雾化融滴的冷却速度和飞行速度。计算结果表明,雾化介质和融滴尺寸对冷却速度有影响,冷却速度也影响粉末的微观结构。对于氩气雾化粉,发达的枝晶结构在较低的冷速下获得;在较高的冷却速度下,得到混合的微观结构（枝晶和包晶）。对于氮气雾化粉,较低的冷速下得到枝晶;在较高的冷速下得到包晶。通过理论计算,氩气雾化粉末的冷却速度是10000K/s到424000 K/s,氮气雾化粉的冷却速度是10000K/s到480000 K/s。随着融滴尺寸的减小,两种雾化粉末的冷却速度则逐渐增加。元素Cr, Co, W, Ni 和 Al主要集中于晶轴,然而Ti主要集中于枝晶区域。     

酯硬化碱性酚醛树脂旧砂的再生工艺

论述了酯硬化碱性酚醛树脂旧砂中树脂与有机酯等有机物和氧化钾无机物共存的特点,试验研究了不同的再生方法.结果表明:采用热法与多次机械法组合武再生工艺,可使酯硬化碱性酚醛树脂旧砂的灼烧减量降至1.5%以下,残留氧化钾含量降至0.12%以下,旧砂再生率可达约80%,从而大幅度降低铸件的生产成本.     

Application of nanotechnology in a silver／graphite contact material and optimization of its physical and mechanical properties

By applying nanotechnology, a new type of silver/graphite (AgC) electrical contact was fabricated and charac-terized. The AgC coating powders were obtained through high-energy ball milling and reducer liquid spraying-coating method. The as-prepared powders were examined by transmission electron microscope (TEM), scanning electron micro-scope (SEM), and X-my diffraction (XRD). The results show that the thickness of graphite flakes milled for 10 h is about 50-60 nm and the AgC coating powders exhibit flocculent structure with quite free and homogeneous intemal micropores.XRD implies that the average crystalline size of silver in coating powders is about 50 rim. The mechanical and physical properties of this newly developed AgC contact made from the above-mentioned nanocrystalline powders by traditional powder metallurgy technique were measured. Compared with its counterparts made from other techniques, the properties of this new AgC contact have been optimized. High surface energy and high-energy interfaces of the nanocrystalline AgC coating powders provide powerful driving force for sintering densification. Moreover, the flocculent structure of the pow-ders is also an important factor to acquire fine density ratio.     

Fe-Ni-B超细非晶粉表面不同处理后的组成和性能

本文对Fe—Ni—B超细非晶粉表面加以单宁酸和重铬酸钾处理，并采用了XPS和TEM等对处理后超细粉的表面组成和结构进行了分析。结果表明，单宁酸和重铬酸钾处理均可以提高Fe—Ni—B超细非晶粉的饱和磁化强度，但后者的提高幅度远大于前者。原因在于二种表面处理均使超细粉的表面状态发生了有利于饱和磁化强度的变化，在表面形成了复合型氧化物NiFe2O4；而重铬酸钾处理还在超细粉表面形成了致密的Cr2O3层，阻挡了氧原子从表面向体内的扩散，减少了超细粉的氧化态数量，而使其饱和磁化强度得以大大提高。