On the kinetics of modified CVD in porous ceramics

This paper reports a kinetic study on modified CVD process in porous ceramic substrates by both theoretical analysis and experimental approach. The theoretical analysis indicates that with a heterogeneous chemical reaction the decrease of the pore size is proportional to the deposition time and the pore closure time is proportional to the original pore size. While for a homogeneous reaction the pore size decreases exponentially with the deposition time and it is very difficult to achieve pore closure. The experimental results indicate that the deposition of YSZ in porous ceramics is a heterogeneous reaction.