Synthesis and Spheroidization of Disperse High-Melting (Refractory) Powders in Plasma Discharge

One of the areas of using arc and radio-frequency induction (RFI) plasma in metallurgy is to obtain refractory metals and materials with spherical shape of particles. The main advantages of using spherically shaped particles are high purity of particle surface, high bulk density (minimum surface/volume ratio) and ability to gain control on porous article properties and to separate the particles in fractions. Spherical particles are needed in the formation of powder-metallurgy elements with desired and uniform porosity, which are operated at high temperature, in highly aggressive media and at high velocity fluid flows. The present work considers the possibilities of using arc and RFI-plasma in metallurgy to obtain high-melting point metals and materials with spherical shape of particles

Investigation of Titanium Hydride Produced from Titanium Waste

The work presents an original method for titanium hydride production by hydrogenation and dehydrogenation of titanium waste in a specially designed for this purpose vacuum chamber. Laboratory quantities of titanium hydride were prepared using LaNi5 hydrogen accumulator as a source of pure hydrogen. Chemical, X-ray, DTA, TG and granulometric analysis of the obtained hydride were made. The analyses carried out in the temperature range, 680-1070 К, DTA, TG and mass-spectrometry analysis allowed determining the activation energy of decomposition of the obtained TiH2 which was approximately E = -135.5 kJ/mol and the standard enthalpy of formation ΔH = -140 kJ/mol

Study of the Sintering Process of Iron Powders Coated with Nano-Hydrocarbon and the Resulting Microstructure at Temperatures up to 1200°C

The objective of the research is development and study of a new ecologically friendly and technologically advanced method for introduction of carbon during sintering of low alloyed iron powders ASC 100.29. The method is based on using hydrocarbon coating of the green powder, which transforms into carbon nanolayers between the powder particles, during the sintering process. The method avoids the use of graphite as alloying element and reductant, and allows for a much better homogenization, less porosity and overall increase of the quality of the final sintered product. The research presented is focused on the processes related to apparent density, fluidity and compressibility of the coated powder and resulting porosity after pressing and sintering. The aim is to determine the optimal coating conditions, and to acquire experimental data concerning key processes during the sintering and the originated microstructure. The sintering process was monitored in situ through DTA measurements and measurement of the exhaust gases pressure. Results obtained so far show better handling conditions for the green coated powders, compared to those using classical approach and higher homogeneity of the sintered specimens