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In this study a-phase-rich Si3N4 powders were synthesized containing the sintering additive (CaO) using carbothermal reduction and nitridation. The starting agent for the silicon source was high-purity (99 %) synthetic silica. Carbon was added to the high-purity SiO2 above the stoichiometric amount of oxygen. CaCO3 (for the silicon nitride containing the mass fraction of CaO w = 10 %) was premixed in the starting reactants depending on the final powder composition and the type and amount of the secondary phases required for sintering. The synthesis was carried out in a tube furnace in different temperature ranges (1400 °C, 1450 °C and 1475 °C for 3h) under a nitrogen-gas atmosphere. Having completed the synthesis process, the powder properties were examined using standard characterization techniques (XRD, SEM,etc.). V tej študiji so bili sintetizirani s karbotermično redukcijo in nitridacijo z a-fazo bogati prahovi Si3N4 z dodatkom za sintranje (CaO). Začetni izvir silicija je bil zelo čisti (99 %) sintetični SiO2. Ogljik je bil dodan zelo čistemu SiO2 nad stehiometrično količino kisika. CaCO3 (za silicijev nitrid jevseboval 10 % CaO) je bil primešan začetnim reaktantom, odvisno od končne sestave prahu in vrste ter količine sekundarnih faz, potrebne za sintranje. Sinteza je bila izvršena v cevni peči pri različnih temperaturah (1400 °C, 1450 °C in 1475 °C, 3 h) v atmosferi dušika. Po sintranju so bile lastnosti prahu ugotovljene z uporabo navadnih tehnik za karakterizacijo (XRD, SEM itd.). |
