Progressive Feedback Control Strategies for Thermal Spray Processes: Particle Injection, Process Maps, and In-situ Sensing Properties

ReliaCoat Technologies, LLC, a Stony Brook University based spin-off company, in conjunction with program advisors GE, Sulzer Metco, PTI and Chromalloy proposes to design, develop and commercialize an advanced process control strategy for thermal spray along with user-friendly analysis and decision software. The innovation is based on a progressive control strategy from feedstock-to-coating, incorporating feedback gates within each operational sub-domain of the process while simultaneously considering integrated effects. A product (coating) based process-control strategy is envisaged to address the core issues of reliability and performance. Critical parameters under consideration include thermal spray system variables, particle injection, comprehensive assessment of particle states through maps, deposit formation dynamics and advanced coating properties. The program will be aided by emerging capabilities in thermal spray process maps, robust integration of diagnostics information as well as novel in situ measurement of design relevant coating properties. The principle focus of the work will be advanced thermal barrier coatings, with potential for expansion into other materials and thermal spray processes. In concert with program partner Sulzer Metco, integration of advanced concepts and software to existing and new process controllers will be considered along with field demonstration at production sites such as Tinker Air Force Base. BENEFIT: Thermal spray coatings are crucial to economic, safe and reliable operation of gas turbine engines used for propulsion and energy generation. Both US military and commercial turbine industry uses a vast array of thermal spray coatings both in original equipment manufacture and in overhaul and repair and represents a multi-billion dollar industry. Thermal spray processes as they are applied in many sites around the country and the world have a number of issues with process reliability and control which affect the performance and durability of this important class of coatings. Enhancements in process understanding and control through science derived strategies will be of great benefit to both military and civilian applications of thermal spray coatings. Not withstanding performance and durability benefits, process enhancements can pay for itself through cost savings associated with reduced rework, increased efficiency and productivity.