Papers by Keyword: Spherical Powder

Abstract: Titanium alloy powders were prepared from titanium rods by plasma rotating electrode process (PREP). The effects of powder preparation technology on the morphology and properties of titanium alloy powders were studied by laser particle size analyzer, scanning electron microscope (SEM), X-ray diffraction, powder comprehensive property tester and oxygen nitrogen analyzer. The results shown that the titanium alloy powder prepared by PREP had uniform particle size distribution, sphericity >93% and oxygen content <1000 ppm. For TA1 powder, the phase’s structure was mainly composed of HCP-α phase, while the TC4 powder mainly composed of α' phase. During the preparation process, the particle size and sphericity of the alloy powder increased with the increase of electrode speed. The smaller the particle size and the higher the sphericity of the alloy powder, the larger the compacting density and bulk density, but the powders fluidity became worse. At the same time, the oxygen content of the titanium alloy powder increased with the decrease of the particle size, while the nitrogen content was not affected by the powder size. The oxygen content of the titanium alloy powder increased as the particle size became smaller, and the nitrogen content was not affected by the powder size.

Abstract: Powder metallurgy technologies require specific powders to ensure a good quality to the manufactured parts. The critical properties are; the powder chemistry, flow ability, packing density, and the absence of porosity. This review highlights the capability of Tekna’s Inductively Coupled Plasma (ICP) technology for the production of high quality powders for the additive manufacturing industry.

Abstract: The manufacture technology of spherical WC powder has been studied by using of induction plasma. We can get spherical powder above 85% in the powder through changing several parameters. And the hall flow-ability, the oxygen content , particle size of powder before and after plasma treatment have been compared. The results were shown that oxygen contents was deduced markedly, and the plasma method can control the particle size easily.

Abstract: Titanium alloy powder provides manufacturing variants to produce a variety of titanium intermediate materials and final products. However, titanium alloy powder is quite expensive at fifteen to thirty times the cost of sponge thus limiting the utilization of titanium powder to produce titanium products. The standard state-of-the-art processing to produce alloy powder results in very high cost of alloy powder. Three new processes have been demonstrated to produce titanium alloy powder at a cost of only 2-5 times the typical cost of sponge. The processes are (1) one step melting of sponge/alloying and gas blowing alloy powder, (2) metallothermic reduction of mixed chloride precursors to produce alloy powder and (3) electrolytic reduction in a fused salt of mixed alloying (TiCl₄-AlCl₃-VCl4) chlorides. These processes have bee_{Subscript text}n demonstrated to produce low cost titanium alloy powder which can serve as feeds for the variant manufacturing processes to produce low cost titanium products.

Abstract: In this paper, α-Si₃N₄ was mixed with Y₂O₃ and MgO by ball milling. Spray granulation was adopted to fabricate spherical powder. The influence of the sintering temperature and the holding time on the thermal conductivity of the powder was studied. The results show that α-Si₃N₄ raw powder was transformed into β-phase after sintering. Spherical powder, of which the diameter is about 20 μm, was fabricated. Some compounds such as YMgSi₂O₅N, Y₄Si₂N₂O₇ and Y₂Si₃N₄O₃ were generated in the samples. The thermal conductivity of the pressed powder first increased then decreased with the sintering temperature rising, showing a maximum at 1800°C. Also the thermal conductivity first increased then decreased as the holding time getting longer, showing a maximum at a sintering time of 2 hours.