The ability to develop coatings with specific attributes such as thermal shock, oxidation, wear, and corrosion resistance depend both on the design and the ability to produce a coating of specific composition and microstructure. CVD is widely used to manufacture such coatings since it can economically produce a range of different material microstructures. The difficulty in using such an approach in developing new coatings is the inherent complexity of the process. Development of a measurement based feedback system, can provide the capability to control coating microstructure. The objective of this research is to develop both the knowledge base and technology to implement real-time control of coating microstructure.
Temperature is proposed since it affects particle mobility on the surface.
Growth rate is proposed since if there is higher growth rate relative to the ability to migrate along the surface, growth of finer grain material is promoted. Control Strategy Need independent control of both the local temperature and growth rate to control coating microstructure. Our strategy is to implement a hierarchy of control objectives, starting with control of deposition rate and progressing to microstructure control. Achievable performance for MIMO systems may be limited due to the cross-coupling. Extend original Low Order Model to include multiple species, depletion, and delay dynamics.