ABSTRACT
Abstract. Like many ceramic materials, Si3N4 contains amorphous intergranular films (IGFs). These films affect or even dominate the properties of the ceramic material. As a result of the sintering process the amorphous IGFs in Si3N4 ceramics contain oxides of silicon and other elements. These additional elements are also observed in amorphous pockets where three or more grains meet. To obtain information about the local atomic structure of the IGFs we employ electron diffraction with a convergent probe focussed on the IGF. This method provides the reduced radial distribution function G(r) within the films and thereby a fingerprint of the atomic structure. We have studied Si3N4 containing oxygen as an additional element. Our first results show that the order in both pockets and IGFs is closely related to amorphous Si02, with little if any nitrogen. This suggests Si02 as the main constituent in the pockets as well as in the interfaces. In Y 20 3 doped material, the G(r) indicates the presence of yttrium in the IGF.
