Phase reactions in a hot pressed TiC/Si powder mixture

• This work investigated the possibility of producing dense Ti3SiC2 by hot pressing TiC/Si powders. A hot press with graphite heating elements was used for densification and the phase reactions of some hot pressed samples were further evaluated by pressureless heating in a dilatometer. The density and phase composition of the heat treated samples were evaluated using Archimedes principle and by x-ray diffractometry respectively. Hot pressing resulted in a low Ti3SiC2 yield; the main phases were TiC and TiSi2 regardless of starting powder composition, temperature, holding time or pressure. A second heating without pressure resulted in Ti3SiC2 formation, but only in samples initially hot pressed at 1300 °C or lower. At higher hot pressing temperatures, thin oxide layers on particle surfaces were locked into the structure. Acting as diffusion barriers, they prevented the Ti3SiC2 forming reaction. In hot pressed samples the density was significantly higher than in samples sintered without pressure.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Annan materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Other Materials Engineering (hsv//eng)

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Engineering Materials

Materialteknik

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