Room temperature impact consolidation and application to ceramic coatings: aerosol deposition method

Coating processes that purely use collision pressure or impact force such as the aerosol deposition (AD) method and cold spray method have been attracting attention. These methods accelerate microparticles and ultrafine particles into a beam at velocities of several hundreds of m/s or more that impacts a substrate, thus forming dense films with good adhesion forces by only providing purely mechanical energy. It is thought that microparticles of metals and ceramics can thus be macroscopically bonded at room temperature while remaining in a virtually solid state. In fact, the AD method has been commercialized as an important coating process in the field of semiconductor fabrication equipment which has been confirmed to be able to form thin or thick dense films of ceramics with microcrystal structures on the scale of several tens of nm or less at room temperature that offer excellent electromechanical properties. This is called room temperature impact consolidation (RTIC), and is thought to have different principles of film growth from thermal spray coating and shock compaction techniques which obtain bonding by putting the raw material particles into a molten or semi-molten state. This paper describes the deposition mechanism of AD processes that use RTIC and the importance of this as a coating technique for the future. (C) 2020 The Ceramic Society of Japan. All rights reserved.