Microstructural evolution during sintering of CoO doped SnO2 ceramics

Addition of 0.5 mol% of CoO into SnO2 promotes densification of this oxide to 99% of the theoretical density during sintering. TEM in this system reve als that after sintering at 1210 degrees C a secondary phase of Co2SnO4 is precipitated at the SnO2 grain boundaries during cooling. This phase is for med by diffusion of Co ions from the bulk to the grain boundary during sint ering leaving needle-like defects at the grain bulk. The high resolution TE M micrograph of this system sintered at 1210 degrees C and 1400 degrees C s howed an amorphous grain boundary region low in cobalt, indicating that the Co2SnO4 phase is precipitated from this region. (C) 1999 Elsevier Science Limited and Techna S.r.l. All rights reserved.