Highly dispersed composite iron—Copper powders obtained from oxalates by a thermochemical method

The preparation of highly dispersed composite iron—copper powders with various concentrations of copper from mixed iron and copper oxalates was studied. The physico-chemical properties of the powders were determined. The powders were corrosion resistant, hydrophilic, practically monodispersed, bacteriocidal and tolerated the sterilization at elevated temperatures. Their magnetic properties could be regulated in the process of forming the initial components. Such powders can be useful in medicine, biology and technology. Institute of Colloid and Water Chemistry, Ukraine National Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 7–8(402), pp. 1–4, July–August, 1998.     

Finely divided Fe-Co-Ni powders made by a thermochemical method

It is shown to be possible to make finely divided Fe-Co-Ni powders with given physicochemical properties. Iron, cobalt, and nickel oxalates have been made by chemical methods. Hydrogenous media have been used in the thermal decomposition of the iron oxalates to give finely divided powder that are nonpyrophoric and corrosion resistant and which have high contents of the metallic phase and given magnetic properties. These powders have been used in sealing composites for pipelines, and also as fillers in lacquers and magnetic liquids for general purposes.Institute for Colloid Chemistry and Water Chemistry, Ukrainian National Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 3/4(384), pp. 111–113, March–April, 1996. Original article submitted June 20, 1994.     

Nanodimensional ferromagnetic powders fabricated by a thermochemical method. Possible approaches for biomedical applications of the powders

Thermochemical methods of fabricating nanodimensional composite powders of ferromagnetic substances are developed. Ferromagnetic substances are the single magnets that possess a controlled set of physical, physico-chemical, and biomedical properties, which are also realized simultaneously. A physico-chemical principle for the fabrication of colloid-chemical systems as a foundation for nanostructural materials based on nanodimensional ferromagnetic substances is proposed. The ranges of application of such systems, i.e., biology and medicine, are established. __________ Translated from Poroshkovaya Metallurgiya, Nos. 7–8(450), pp. 116–121, July–August, 2006.     

Properties of iron and low-alloy powders produced by the Sulinsk Metallurgical Plant

Translated from Poroshkovaya Metallurgiya, No. 2(350), pp. 101–106, February, 1992.     

Properties of fine metal powders produced by the formate pyrolysis method

Conclusions Optimum parameters have been determined for the processes of preparation of fine copper, nickel, and cobalt powders by the pyrolysis of formates in a protective argon atmosphere. Use of fine copper, nickel, and cobalt powders prepared by this method as interlayers in the vacuum diffusion welding of copper and steel parts enables the temperature of the process to be substantially lowered. Copper coatings can be applied to metallic and nonmetallic materials in the course of the pyrolysis of copper formate.Translated from Poroshkovaya Metallurgiya, No. 3(207), pp. 1–6, March, 1980.     

Electron-microscopic investigations of highly dispersed iron powders obtained by the electroemulsion method

Conclusions Depending upon the electrolysis conditions and the rate of movement of the emulsion the form, dispersion, degree of aggregation, and specific surface of highly dispersed iron particles change. The electroemulsion method makes it possible to obtain 0.15–0.25~m metal particles close to monodispersed.Translated from Poroshkovaya Metallurgiya, No. 6(258), pp. 68–72, June, 1984.     

Nanocrystalline copper powders produced by electrolysis

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

Properties and sintering behaviour of fine spherical iron powders produced by new hydrogen reduction process

Abstract

The most important use of fine spherical iron powders is for metal injection moulding (MIM). For many applications, the high costs of powder based on the carbonyl or atomising production route are a limiting factors. An alternative two-step hydrogen reduction process using a granulated hematite powder, which is a recycling product from steelmaking, has been developed to produce <25 µm spherical powder. The morphology and properties of the powder have been found to depend strongly on the second temperature step of the reduction process. A further important step is enclosed powder processing by milling and sieving to remove agglomerates. The powder properties and sintering behaviour as a function of heat treatment and processing parameters are reported and discussed.     

Microporosity of powders produced by centrifugal sputtering

Conclusions The nature of the liquid-metal film flow about the end of the pulverized billet is defined by its rotational velocity. In the case of a turbulent film flow regime gas is captured and pores are formed in individual powder particles.The greatest number of porous particles produced in a single pulverization regime is found in a large-fraction powder while the smallest quantity is found in the finely dispersed powder with grain sizes less than 100n.Increasing the helium content in the pulverization medium to 100% produces a discontinuous increase in the number of porous particles as a result of the reduced viscosity of the gaseous medium and the high penetration power of the helium. The smallest number of porous particles is formed when pulverization takes place in a medium with a volumetric argon content in excess of 30%.The pore size in the powder particles is virtually independent of the production regime and usually amounts to about 25–35 % of the particle diameter. The average gas-pore volume is 2–3% of the volume of the powder particle.To achieve minimum microporosity in compacted billets fabricated by the methods of powder metallurgy, it is expedient to use 100m powder fractions, produced at a billet rotation velocity of 35–40 m/sec.Translated from Poroshkovaya Metallurgiya, No. 12(348), pp. 1–7, December, 1991.