TEXTURE FORMATION IN AL2O3 SUBSTRATES

The formation of textures (preferred crystal orientation) in Al2O3 sub strates by green forming and subsequent sintering was studied. The obs erved texture type was always characterized by the basal plane paralle l to the substrate plane. Crystal orientation within this plane was ne arly axially symmetric. The c-axis pole distribution was obtained by a n indirect method from several (hkil) pole distribution functions meas ured by X-ray diffraction. Texture formation starts in the very first stages of green forming, the essential process being rigid particle ro tation. Small texture changes were observed also in the initial stages of sintering. The strongest increase of texture, however, took place during grain coarsening at high sintering temperatures. The texture st rength factor can be expressed quantitatively in terms of the green te xture as well as the sintering time and temperature.