Chapter 10.5 - Aerosol Deposition Method for Room-Temperature Ceramic Coating and Its Applications

Abstract

The manufacturing of ceramic materials usually requires sintering at temperatures higher than 1000 °C, which makes it difficult to compound or integrate ceramics with low-melting point metals, glass, or plastics. This is a serious hindrance for upgrading electroceramic components and optical components. Up to now, numerous research works have been made to reduce the sintering temperature for the purpose of reducing energy consumption and implementing innovative functional components through integration with metal or glass materials. The aerosol deposition (AD) method is an unique coating technology, based on collision of solid-state fine ceramic powder with a substrate. This coating method has many advantages such as high deposition ratio, low process temperature, and high adhesion force with a substrate in comparison with that by conventional thin-layer coating technology. During the AD process, submicron ceramics particles are accelerated by gas flow in the nozzle up to a velocity of several hundred m/s and sprayed onto the substrate under vacuuming condition. We found interesting consolidation phenomenon of ceramic in this method over 10 years ago. During collision of fine particles and interaction with substrate, these ceramic particles, not only for oxide materials but also for nonoxide materials, formed thick, dense, and hard ceramic layers at room temperature. No additional heating for solidification of ceramic powder was required. We named this phenomenon “room-temperature impact consolidation (R.T.I.C)”. Same behavior as R.T.I.C. for metal fine particles was also observed. Consolidated ceramic powder with R.T.I.C. via AD method can be called as a high-density binder-less ceramic green. Aerosol deposition is a novel and very attractive coating method for ceramic integration. In this paper, we explain the principle of the AD method and its application to ceramic layer formation for information/communication and energy technology applications.