Correlation between the particle size, pore size, and porous structure of sintered tungsten
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It has been established that the maximum size of pore channel constrictions D1 is close to the mean size of pore sections in microsections of porous skeletons (γ-=22–44%) from tungsten powders of 1- to 5-μm mean particle size. A rapid method of assessment of an integral fineness characteristic of a tungsten powder is proposed consisting in the determination of the pore size D1 in a compact (γ-c=25–45%), followed by the calculation of the mean size of agglomerated particles with Kozeny's formula. The densification of compacts from tungsten powders of 4-μm particle size at sintering temperatures of about 0.6 Tmelt is a result of decrease in the number of pores and increase in the equivalent size of agglomerated particles. In this process the mean pore section size determined by the metallographic method remains unchanged during sintering, which corresponds to a statistical model of a porous solid in the rheological theory of sintering.
KeywordsParticle Size Pore Size Tungsten Statistical Model Porous Structure
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