Theory and technology of sintering, heat, and chemical heat-treatment processes - Synthesis and sintering of nanocrystalline barium titanate powder under nonisothermal conditions. V. Nonisothermal sintering of barium titanate powders of different dispersion

A comparative study has been made of the processes involved in the consolid ation of nanosized barium titanate powders by nonisothermal sintering at a linear heating rate, by rate-controlled sintering, and high-pressure sinter ing (up to 5 GPa). The use of linear heating and high-pressure has been fou nd to be ineffective for obtaining nonporous ceramics (residual porosity of about 2%) and for miniziming grain growth. The application of external pre ssure does not prevent coalescent grain growth controlled by surface diffus ion. When rate-controlled sintering is employed a densification/grain growt h optimum can be attained with a relative density of 99,9% of the theoretic al value and a grain size of about 100 nm.