Electrolytic Copper Powder Research Articles

The effect of particle structure on apparent density of electrolytic copper powder

The quantitative microstructural analysis and the sieve analysis of copper powder as well as the scanning electron microscopy analysis of the copper powders particles were performed. It was found that the structure of the copper powder particles determines the apparent density of copper powder. The powder particles from the same fractions of different powders occupy approximately the same volume, but the structure of metallic copper is very different. This causes the difference in apparent densities of copper powder obtained under different conditions. The more dendritic is the structure of powder particles the smaller is the apparent density of copper powder.

The Effect of Some Parameters of Electrolysis on Apparent Density of Electrolytic Copper Powder in Galvanostatic Deposition

The investigation on some properties of electrochemically deposited copper powders from copper sulphate - sulphuric acid has been performed. Relations between conditions of electrolysis of powder storage, apparent density as well as hydrodynamic regime, temperature and deposition time are established. It is shown unambiguously that apparent density depends on conditions of powder production as well as of duration of electrodeposition;it increased on decreasing of working current density and with increasing of copper ion concentration, temperature, electrolyte circulation rate and brush down interval.

A new lease of life for electrolytic copper powder : G.A.Mowbray, B.Mais. (Norddeutsche Affinerie AG, Hamburg, Germany.)

A new lease of life for electrolytic copper powder : G.A.Mowbray, B.Mais. (Norddeutsche Affinerie AG, Hamburg, Germany.)

The influence of microstructure on the sintering process in crystalline metal powders investigated by positron lifetime spectroscopy: I. Electrolytic and spherical copper powders

We investigate the influence of microstructure (dislocations, and grain and subgrain boundaries) on the sintering process in compacts of electrolytic and spherical copper powders by means of positron lifetime spectroscopy. We compare the lifetime data obtained to the kinetics of the annealing out of vacancy clusters after low-temperature electron irradiation, and the kinetics of recovery and recrystallization after plastic deformation. The change of powder-particle and grain sizes with temperature is determined in a complementary study by metallography and x-ray line-profile analysis. At the intensive-shrinkage stage, the effective powder-particle size in electrolytic copper powder is and the grain size is . Due to the dendritic morphology of the powder, the effective powder-particle size is much smaller than that determined by particle-size analysis . Because of the small powder-particle and grain sizes, a measurable fraction of positrons annihilate at grain boundaries and in surface states, i.e. at inner pore surfaces. At higher temperatures , grain boundaries are, besides a small surface component for compacts of electrolytic powder, the only detectable lattice defects in both powders. We find that the observed shrinkage rates can be explained - at least qualitatively - by Coble creep, while Nabarro-Herring and Kosevic (dislocation) creep seem to play only a minor role in the systems investigated.

Effect of cobalt hard alloy additions on copper-tin-lead bearing alloys: M.Fujita et al. (NDC Co Ltd, Narashino, Japan.) J. Jpn Soc. Powder Powder Metall., vol 44, no 6, 1997, 585–589. (In Japanese.)

The inert gas atomised prealloyed copper powders containing 3.5 wt.% Al were milled up to 20 h in the planetary ball mill in order to oxidize aluminium in situ with oxygen from the air. In the next procedure compacts from milled powder were synthesized by hot-pressing in argon atmosphere. Compacts from as-received Cu-3.5 wt.% Al powder and electrolytic copper powder were also prepared under the same conditions. Microstructural and morphological changes of high energy milled powder as well as changes of thermal stability and electrical conductivity of compacts were studied as a function of milling time and high temperature exposure at 800 °C. Optical, scanning electron microscopy (SEM) and X-ray diffraction analysis were performed for microstructural characterization, whereas thermal stability and electrical conductivity were evaluated by microhardness measurements and conductometer Sigmatest, respectively. The prealloyed 5 h-milled and compacted powder showed a significant increase in microhardness reaching the value of 2600 MPa, about 4 times greater than that of compacts synthesized from as-received electrolytic copper powder (670 MPa). The electrical conductivity of compacts from 5 h-milled powder was 52% IACS. The results were discussed in terms of the effect of small grain size and finely distributed alumina dispersoids on hardening and thermal stability of compacts.

Injection moulding of electrolytic copper powder: N.Wada et al. (Ritsumeikan University, Kusatsu, Japan.) J. Jpn Soc. Powder Powder Metall., vol 44, no 6, 1997, 596–603. (In English.)

Injection moulding of electrolytic copper powder: N.Wada et al. (Ritsumeikan University, Kusatsu, Japan.) J. Jpn Soc. Powder Powder Metall., vol 44, no 6, 1997, 596–603. (In English.)

Electrolytic copper powder : B.Mais, G.A.Mowbruy. (Mowbray Industrial Consultants, UK.)

Electrolytic copper powder : B.Mais, G.A.Mowbruy. (Mowbray Industrial Consultants, UK.)

Electrolytic Cu powders ready for the 21 st century

Electrolytic copper powders have a long history in the powder metallurgy (PM) industry. Recent developments have addressed concerns relating to waste, ensuring that the materials will continue to play an important role in the industry in the next century. Bernhard Mais of Norddeutsche Affinerie (NA) and Geoffrey A. Mowbray, of Mowbray Industrial Consultants in Hebden Bridge, UK, review the technique with particlular reference to NA's plant in Hamburg, Germany.

粉末プロセスの制御と製品評価 機械構造部品用焼結材料のヤング率について

Method for determination of Young's modulus of sintered metal materials is dynamic testing method by the longitudinal oscillations of the specimens, which has been provided in the standard of Japan Powder Metallurgy Association JPMA M 10 in March 1997. This paper shows the testing results of Young's modulus of various sintered metal materials for machine parts of the iron base, the stainless steel base and the bronze base materials, which are introduced in Japanese Industrial Standard JIS Z 2550. For example, the specimens of the iron base (6×8×60mm) were made from reduced iron powder, atomized iron powder, electrolytic copper powder, natural graphite powder and carbonyl nickel powder, by compressing with 300-600 MPa and sintering at 1423K for 1.8ks in cracked ammonia atmosphere. Consequently, the values of Young's modulus and relations between the values of Young's modulus and the sintered densities of various sintered metal materials could be obtained.

Characteristics of Electrolytic Copper Powder Compaction by Differential Speed Rolling.

Differential speed rolling of electrolytic copper powder is conducted under conditions of carefully controlled powder feed volume. Roll speed ratios are changed in the range of 1.00 to 1.50 by choosing different combinations of roll diameters. The rolling load increases with an increase in the ratio of the powder feed volume to the strip speed. The strip thickness increases with an increase in the rolling load for each roll gap, regardless of the roll speed ratio. The relative density of the strip is greater than that achieved using conventional powder rolling.

Injection Molding of Electrolytic Copper Powder.

In this study, products obtained using Cu-Ni alloy powder and a Cu, Ni powder mixture in injection molding were compared. Both the alloy powder and the powder mixture were composed of 69.4 mass% Cu and 30.6 mass% Ni. Both feedstocks were composed of 56.0 vol% metal powder and 44.0 vol% organic binder. The binder system consisted of 25.0 vol% polybutylmethacrylate (PBMA), 35.0 vol% ethylene-vinyl acetate copolymer (EVA), and 40.0 vol% paraffin wax (PW) for both feedstocks. Sintered bodies of Cu-Ni alloy were produced from Cu-Ni alloy powder or Cu, Ni powder mixture using metal injection molding (MIM) technology. In nitrogen sintering, the density of sintered bodies produced using the Cu, Ni powder mixture was higher than that of sintered bodies produced using the Cu-Ni alloy powder. In vacuum sintering, the density of sintered bodies produced using the alloy powder was higher than that of sintered bodies produced using the powder mixture. Contents of oxygen and carbon in sintered bodies, and density depended on hydrogen treatment temperature. The maximum density, tensile strength and Vickers hardness (Hv) of sintered bodies produced using alloy powder were 8.39 g⋅cm-3, 213 MPa and 56.9-87.2, respectively. On the other hand, those of sintered bodies produced using the powder mixture were 8.36 g ⋅CM-3, 199 MPa and 86.9-123, respectively.

Technology of processing electrolytic copper powder by low temperature vacuum drying: H. Wenxian, W. Limin (Central Inst. of Non-Ferrous Metals, Beijing, China). PM Technol., vol 13, no 4, 1995, 265–267h. (In Chinese.)

Many food materials are dried to enhance shelf-life. Drying is an energy-intensive process, and accurate drying models could be used in real time process control of drying equipment to drive cost optimizations. However, most physics-based models suffer from two shortcomings: they require thermo-physical properties of the food materials to be known a priori, and they usually neglect material shrinkage due to moisture loss. In this work, we first develop a simplified physics-based transport model to predict temperatures and moisture content and corresponding spatial and temporal shrinkage during low temperature air drying process, where volumetric shrinkage is dominated by moisture loss. This model agrees well with experiments conducted by us (reported in this paper) as well as with those conducted by others (taken from the literature) on food samples. Further, using the validated modelling framework, we have developed an experimentally validated deep learning-based artificial neural network (ANN) model for properties' estimation. This ANN model is designed to estimate solid density, initial porosity, and initial water saturation of a given food material, using temperature and moisture data from a set of simple experiments with error less than 1%. Using these predicted parameters as input, the physics-based model can predict temperature and moisture for real-time drying to within 5% accuracy. The method proposed in this work could play an important role in industrial drying process optimisation and will find wide applications in the food processing industry.

The influence of the hot deformation and heat treatment on the properties of P/M Al-Cu composites

The development of the automotive industry requests the light construction materials, which can guarantee optimal mechanical and usable properties of the products. The aluminium is one of such materials, which, however, has a low hardness and a poor wear resistance. Aluminium-based composites, strengthened by dispersion or by hard ceramic particles, may fulfil demands made to the new materials. The problem of manufacturing Al-Cu composites by the hot closed-die forging of the compacts made of metal powders is investigated in present paper. The aim of presented researches is the evaluation of an influence of the hot deformation of the Al-5.5%Cu composite - based on the home-grown, sprayed aluminium powder and electrolytic copper powder on their final density and mechanical properties. As the result of the hot closed-die forging of the compacts, materials with a high degree of density were obtained. Mechanical properties of the composites were evaluated after heat treatment and ageing. It is proved, that the conditions of the heat treatment have an essential influence on the mechanical properties. Metallographic analysis was made on the materials after heat treatment. After the hot deformation, precipitations were observed in the material. Their size decreases after heat treatment. The fractures are plastic and proceed through the grains. It is proved, that hot deformation of the compacts lets us to: i) obtain products with a high degree of density, ii) apply semiproducts with porosity of 20–30%, which can be obtained by compacting with comparatively low unit pressure, what has an influence on the tool life, iii) apply such composite materials, based on powders, to construction elements, iv) eliminate expensive hot isostatic pressing process.

Changes in specific surface area during sintering of electrolytic copper powder : H. Frydrych, M. Sowa (Academia Gorzniczo-Hutnicza, Krakow, Poland), Metal. Proszkow, vol 27, no 3/4, 1994, 14–19. (In Polish)

In this paper, we present a new and powerful method to increase the specific surface area of nanocrystalline ball milled materials. The method consists of using a lixiviation technique to increase the surface area. The element to be lixiviated is ball milled with the hydrogen-absorbing alloy. After complete mixing, the lixiviated element is leached in an appropriate solution. The end product is a porous metal hydride with high specific surface area. The system magnesium–lithium is presented as an example. The results show that before lixiviation, the alloys absorb hydrogen slowly and the hydrogen capacity is reduced due to the presence of lithium. After lixiviation, the specific surface area shows a ten-fold increase and the hydrogen sorption kinetics are faster.

A microscopic investigation of electrolytic copper powders deposited by reversing currents

The copper powders electrodeposited by reversing current were investigated using a scanning electron microscope. The effects of the current amplitude, cathodic to anodic time ratio and period of the current wave are discussed. It is shown that the parameters determining the reversing current wave determine the micromorphology of the copper powder particles deposited.

ニッケル 水素化物二次電池用銅 水素吸蔵合金複合粉の製造とその放電容量

A new composite powder composed of hydrogen storage alloy and electrolytic copper powders was prepared by the use of mechano-fusion system. The composite powder was almost spherical and had porous surface with particle diameters from 10 to 50μm . Discharge capacites of electrodes using this composite powder were larger than those using mixed powders prepared by the conventional process, and increased by the addition of small amounts of cuprous oxide powder and cobalt powder in the preparation process of the powder.Addition of a small quantity of oxidation-protective agents to the powder was effective for preventing the composite powder from oxidation. The powder was produced even in an atmospheric condition when the oxidation-protective agents was added. It has been found that this new copper-alloy composite powder can be used for improving of discharge capacities of hydrogen storage alloy anodes.

Factors influencing the quality of electrolytic copper powder : A. Durisinova, (Slovak Academy of Sciences, Kosice Czechoslovakia), Powder Metallurgy, Vol 33, No 2, 1991, 139–141

Factors influencing the quality of electrolytic copper powder : A. Durisinova, (Slovak Academy of Sciences, Kosice Czechoslovakia), Powder Metallurgy, Vol 33, No 2, 1991, 139–141

Production and handling of electrolytic powders

Norddeutsche Affinerie AG (NA) of Hamburg, Germany, one of the world's major copper producers, celebrates its 125th anniversary this year. The company's name is closely connected with the invention of electrolysis. In 1876 the first electrolytic refinery commenced production in Hamburg, and in the 1930s copper powder was added to NA's product family. Today, the company says that it is not only the largest European manufacturer of electrolytic copper powders, but also leads in the production of atomized copper powder and alloy powders. A new production plant for atomized copper powder is currently under construction. The following article deals with the present state of metal powder production by electrolytic methods.

Factors Influencing Quality of Electrolytic Copper Powder

AbstractThe quality of electrolytically produced copper powder is influenced in the course of electrolysis by a number of factors. The most important of these include time of powder growth, current density, electrolyte concentration, concentration of sulphuric acid, temperature and circulation of the electrolyte, and the presence of foreign ions. The influence of these factors on the quality of copper powder has been studied. Changes in properties of the powder were followed, and metallographic analysis was performed. PM/0498

An X-Ray Diffraction Study of Compacted Metal Powders

In this study electrolytic copper powder and atomised high purity iron powders of various size, fractions were consolidated to comparable densities by two very different processes (quasistatic pressing and dynamic, or shook wave, compaction). The resulting pairs of compacts had densities of approximately 0.96 of the theoretical density. These specimens were analysed by X-ray diffraction in order to determine the effect of particle size on the response to compaction.