石墨粉表面无敏化、活化镀铜工艺

探究一种无敏化和活化过程的石墨粉化学镀铜新工艺。研究石墨粉分别在酒石酸钾钠单络合剂、EDTA·Na_2单络合剂、酒石酸钾钠和EDTA·Na_2的双络合剂3种镀液配方中的化学镀铜行为,以及温度对镀层外观、镀覆速率、镀覆前后质量增加率的影响,并采用SEM分析方法表征施镀前后的石墨粉微观形貌。结果表明:石墨粉无敏化、活化处理条件下,可镀覆上完整的铜层。施镀反应在镀液pH值为12.5,甲醛浓度为35 m L/L条件下进行。镀覆温度为75℃,络合剂配方选择在乙二胺四乙酸二钠浓度c(EDTA·Na_2)为30 g/L时,镀覆速率1.32 g/h,镀覆效果最佳。镀覆后的石墨粉外观呈玫红色,且镀层连续致密。     

Electroless nickel plating of iron powders

Summary A new method, based on the reaction of reduction of nickel ions by hypophosphite in aqueous solutions, is proposed for the electroless nickel plating of iron powders. An electrolyte and a nickel plating procedure have been developed which yield deposits of high quality.Translated from Poroshkovaya Metallurgiya, No. 11 (47), pp. 7–8, November, 1966.     

Electroless deposition of metals on alumina powders

Conclusions A study was made of the processes of electroless plating of alumina powders with nickel and copper. Electroless nickel and copper plating with full pretreatment was performed at room temperature. In nickel plating by the process investigated the number of pretreatment operations can be reduced by raising the solution temperature to 50–55°C, although nickel plating with full pretreatment is to be preferred from a practical point of view. The concentrated solutions investigated are suitable for the application of nickel and copper layers of considerable thickness to alumina powder particles.Translated from Poroshkovaya Metallurgiya, No. 5(209), pp. 14–16, May, 1980.     

Atomized copper powders

Conclusions For the first time in the Soviet Union pilot-plant batches of copper powder have been produced by the method of atomization of melts with water under high pressure. The powder produced is characterized by increased apparent density and flowability. The best compressibility (2–6 tons/cm²) is exhibited by the powder after annealing. The compressibility of the powder in the as-atomized condition is slightly poorer (2–4 tons/ cm²), while that of the powder subjected to pickling amounts to 2–3 tons/cm². The atomized powder can be successfully used for pressing in automatic presses, since it ensures stability of weights of batches and dimensions of parts and produces very little dust during pressing.Translated from Poroshkovaya Metallurgiya, No. 5(221), pp. 6–10, May, 1981.     

还原铜粉之注射成形

平均粒度约10μm的微细还原铜粉因不规则粉末形态及残留有较高的氧含量，而不易以注射成形工艺来制备高性能产品。本研究发现，采用具较多量之主干高分子为基础的多元粘结剂能克服不规则粉末形态所导致之严重粉末间之磨擦，而将这种微细还原铜粉顺利的注射成形。烧结时，若能在烧结孔洞封闭之前将粉末中的残留氧化物有效的予以还原，如在低于900℃之温度下给予适当保温，则注射成形组件之烧结密度可高达95％理论密度。在此条件下，注射成形组件的导电率可达纯铜导电率的80％以上。     

Nanocrystalline copper powders produced by electrolysis

Translated from Poroshkovaya Metallurgiya, No. 2, pp. 5–7, February, 1991.     

Injection moulding of oxide reduced copper powders

Abstract

Fine oxide reduced copper powders of about 10 μm mean grain size are irregular in particle shape and high in oxygen content, which poses a difficulty in achieving good properties from injection moulding. Injection moulding was possible when a multicomponent binder with a large fraction of the backbone polymer was used. Injection moulded parts could be sintered to a density of about 95% theoretical, if reduction of the residual oxides in the powder was effectively carried out prior to closure of pores during sintering. Under such a condition, the injection moulded parts could attain an electrical conductivity higher than 80% of pure copper. July 2004.     

Ways of increasing the flowability of electrolytic copper powders

Translated from Poroshkovaya Metallurgiya, No. 10(334), pp. 7–11, October, 1990.     

Hot rolling of blanks from copper and nickel powders

Summary The authors investigated the hot rolling of preformed blanks from electrolytic copper and carbonyl nickel powders. The blanks were prepared by cold pressing, cold rolling, wedge pressing, and sintering loosely poured powder. The hot rolling was carried out in a special mill, in a hydrogen atmosphere. The investigation showed that at high rates of deformation, a rolling temperature of 0.8–0.9 T_melt, and a reduction of 50% the hot rolling of preformed copper and nickel blanks in one pass can yield strip with a relative density of 100%, a fine-grained structure, and mechanical properties which are not inferior to those of materials obtained by sintering powder compacts or cold-rolled strip.Translated from Poroshkovaya Metallurgiya, No. 6 (66), pp. 25–28, June, 1968.     

低氧铜杆线铜粉剥离原因分析及其对策措施

表面铜粉剥离,导致铜杆线表面损伤,其对铜杆线拉伸过程具有较大影响。通过扫描电镜分析,剥离铜粉厚度可达25μm,经物相分析确定其主要成分为铜及铜的氧化物。通过对剥离物和杆线表面缺陷进行形貌分析,以铜杆线的生产、加工各环节作为研究对象,并确认了铜杆轧制工艺、无酸清洗工艺、线表擦伤、拉伸角度及拉丝模具等5方面影响因素,制定了相应的对策措施。研究表明,铜杆氧化物剥落和机械损伤是铜粉剥离的主要原因,在铜杆线生产、加工环节,防止氧化物带入铜基体和避免铜线表面损伤能有效减少铜杆线铜粉剥离。     

Hydrogen reduction of copper bleed solution from an Indian copper smelter for producing high purity copper powders

A bench scale investigation on the hydrogen reduction of a highly acidic copper bleed solution to produce high purity copper powder is discussed in this paper. A titanium lined autoclave of 1 L capacity was used for this study. The parameters optimized on the bench scale were validated by performing hydrogen reduction of copper in a larger autoclave. Effect of various parameters viz., time of reduction, temperature of reduction, pressure variation, iron dose, volume of copper solution etc. were studied. Experiments were performed with synthetic and actual solution obtained from a copper plant. A 99% copper powder recovery is achieved by hydrogen reduction at a pressure of about 2400 kPa, reaction temperature of 453 K, stirring speed of 400 rpm for a reaction time of 2 h. The fine copper powder thus obtained had a good metallic lustre. Kinetics of reduction of copper was examined by drawing samples at different times and analyzing the percent copper reduction. The copper depleted solution was further purified with respect to the residual copper and can be processed for the recovery of nickel powder by hydrogen reduction.Properties of the copper powder obtained from the large-scale experiments from actual plant and synthetic solutions have been evaluated for powder metallurgical applications. The raw and annealed copper powders obtained from the synthetic copper solution were found to have an apparent density of 3.50 g/cm³, flow rate 35.6 g/min, hydrogen loss 0.2%, purity 99.8% and green density of 8.6 g/ cm³ while the powder from actual plant solution was found to have an apparent density of 3.59 g/ cm³, flow rate 46.0 g/min, hydrogen loss 0.6%, purity 99.4% and green density 8.6 g/ cm³. Thus, the copper powder produced by hydrogen reduction was found suitable for the application.