Mesoporous fibrous silicon nitride by catalytic nitridation of silicon

Abstract

[EN] The catalytic effect of metal oxide/alumina whiskers (CeO2,Mn3O4, NiO, Co3O4,Fe2O3,Cr2O3/AW) was eval-uated on their ability to drive the nitridation of silicon and to generate mesoporousfibrous silicon networks.Silicon powder with different particles size along with the catalyst was nitridized at 1300 °C for 5 h in nitrogenand nitrogen diluted with 10 vol% ammonia atmospheres. Nitridation degree of silicon up to 99% was recordedusing 1.5 wt% CeO2and Fe2O3catalysts in nitrogen-ammonia atmosphere. The catalyzed samples containsubmicronic silicon nitridefibres with a diameter of 400–500 nm and a length of up to few micrometers. Thecompressive strength of 46 ± 1 MPa was measured for silicon samples catalyzed with nickel oxide/aluminawhiskers and nitridized in N2/10 vol%NH3atmosphere. Porous silicon nitride networks were produced with45–52% porosity, pore sizes in the range of 370–1200 nm and median pore in the range of 495–1655 nm.