[en] In order to judge the efficiency of an added P/M lubricant the ejection force needed to remove a powder compact from the tool used for its production is normally measured. The author has elaborated an alternative method whereby the work needed for the compression of the compact is determined

[en] Nano ceramics have special properties: they are superhard, frictionless and have very fine pores. These special properties are shown only with grain sizes below 100 nanometers (nm). It is very difficult to retain this small grain size during conventional consolidation of powders and subsequent sinter processes. A key to solve this problem could be the explosive consolidation with shock pressures up to ∼30 GPa. Experiments with nano Al₂O₃ - powder which was produced by the 'exploding wire technique' with a mean crystallite size of ∼60 nm showed that almost 100 % of crystalline density is achievable by explosive consolidation. By SEM - and XRD - analysis is found that phase transitions occur and as a result of high shock wave treatment lattice distortion in the material decreases and subgrain size increases. (author)

[en] Powder metallurgy is increasingly widely used in the manufacture of complex machine parts, details of high hardness, high friction and super high working temperatures in the nuclear industry, rocket technology and jet engines. With the advantage over conventional metals, the authors have researched, tested created new friction materials promising to manufacture brake pads for the railway. The paper presents the process of theoretical and empirical research from the initial component powder metals, casting and sintering process specifications to create samples with different metal components. The samples were then tested to test the friction, micro structure, hardness of the material. Combined with simulation programs Solid works and Qform-VX to analyze stress in the mold, suitable shape of rail brake pads. Based on the experience gained, the research team developed a technology diagram to produce brakes for the railway. The research results have created friction materials from metal powder with outstanding characteristics and on this basis developed the technology for braking production for the railway. (author)

[en] Two carbonyl nickel powders of the same purity, one spherical, the other of very irregular shape, were isostatically compacted at pressures from 0.5 to 13Kbars with two compacting speeds: 1Kbar/s and 1Kbar/15s. The influence of the powder shapes on the electrical resistivity, tensile strength and microcalorimetric measurements was studied

[en] This report covers the broad outlines of gas atomization methods of current importance to produce rapidly solidified metal/alloy powders ranging from pilot scale to commercial ones and several innovative methods in the exploratory or laboratory-scale stage of development. Processes, advantages, limitations and relationships between processing parameters and primary powder characteristics are also summarized. (author)

[en] The technology of indium powder production using the method of sputtering, permitting to increase the yield of acceptable fraction (<45 μm) up to 70-98 %, is described. The gist of the process is in the sputtering of molten indium by compressed air

[en] First, significance and advantages of sintered materials consisting of two layers are pointed out. By means of the two layer powder pressing technique metal powders are formed resulting in compacts with high accuracy of shape and mass. Attributes of basic powders, different filling methods and pressing techniques are discussed. The described technique is supposed to find further applications in the field of two layer compacts in the near future

[en] The feasibility of powder production, applying an electrochemical method using solutions of a very low metallic ion concentration, that's presents as a polluted material at the industrial practice is discussed. In this way, is possible to increase the product value or to treat an effluent, and at the same time, to transform an polluted material in a useful spice. An example of this idea is showed with the arsenic elimination in a technical quality phosphoric acid, in order to improve it purity. To do this, the arsenic is deposited over a cathode, separated by ultrasound and recuperated in a powder form. A continuous electrochemical reactor, at the pilot plant scale, with a tri-dimensional cathode constructed with cupper nets and a continuous flow of the electrolyte has been used. Another case studied, is the deposition of cadmium from a diluted solution resembled to be an industrial effluent. A continuous electrochemical reactor with a rotating cylindrical electrode was employed. The cadmium deposited on the electrode is recovery in the form of a metal powder. Typical parameters obtained are: In the arsenic conversion 24% per step, specific energetic consumption 250 kWh kg^-1; in the cadmium conversion 35% per step with an specific energetic consumption of 3 kWh kg^-1 depending on the operation conditions. For the arsenic, on account of the deposit isn't a conductive material, is necessary to promote it separation from the cathode preventing current blockade. However for cadmium, the more time is elapsed, larger is the electrode wrinkled condition on account of the metal deposit formation. For this reason, for a give applied potential, an increase of the current is generated. In order to represent this behavior a mathematical model is developed that takes into account the temporary variation of the product between the mass transference coefficient and the specific area of the electrode, getting an adequate correlation of the experimental results (AG)

No abstract available

[en] The main purpose of powder metallurgy is to obtain semi-finished products with very small changes of thickness after machining. Ti-Al-Si alloys based on γ - TiAl and α₂ - Ti₃Al compounds has some unique like high fusion temperature, low density and high temperature mechanical strength. Hot isostatic press (HIP) technology has been used to remove internal porosity and involves subjecting components to simultaneous elevated and pressure for a period of time. (author)