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Modification of particle size distribution for high sintered density
Metal powders are found everywhere! They’re used for a diversity of applications, such as iron fortification of cereals and flour, electromagnetic components in motors, for surface coating of valves and for net shape manufacturing of structural steel components in power tools and the automotive industry.Höganäs AB is the world’s leading producer and developer of metal powders, with sales and active business relations on all continents except Antarctica.
More information is available on www.hoganas.com
Iron powders for sintering of structural components often have a particle size distribution where the main part of the particles are found between 45 and 150 µm. The distribution is controlled in order to make sure that specified product properties can be guaranteed. E.g. powder compressibility and dimensional change during sintering will be affected by the particle size distribution. The sintering activity of small particles, often referred to as fines, is higher than the sintering activity of coarse particles, and by a modification of the fine fraction a higher sintered density might be achieved. High fines content does, however, also lead to segregation problems and reduced compressibility.
The project objective is to investigate the effect of the size distribution of powder particles on sintered density, especially to investigate the possibility to increase density by a modification of the fine fraction of particles.
The project involves getting familiar with powder mixing, pressing and sintering, selection of fine powders to use for modification of particle size distributions, and production of specimens for the trials.
On a theoretical level the project covers experimental planning and basic understanding of the effect of fines on powder handling, compressibility, and sintered properties.
Experimental work will include characterization of powder mixes with modified fine contents, investigation of possible mixing routes to avoid segregation in powder mixes, sintering with different holding times, evaluation of mechanical properties, and metallographic investigation of specimens.
Questions regarding the scope of the project may be directed to:
Informationen om uppsatsförslag är hämtad från Nationella Exjobb-poolen.