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

ABSTRACT: ReliaCoat Technologies, LLC, a Stony Brook University based spin-off, in conjunction with program advisors GE Aviation, Sulzer Metco, Cincinnati Thermal Spray and other spray applicators proposes to design, develop and commercialize an advanced thermal spray process control strategy with user-friendly software. The innovation is based on a progressive control strategy from feedstock powder to coating properties, incorporating decision 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 particle injection, comprehensive particle properties, deposit stress evolution dynamics and advanced coating properties. The program will be aided by emerging capabilities in control systems, process and coating diagnostics and mapping strategies for design and reliability. The principle focus of the work will be advanced thermal barrier coatings, with potential for expansion into other materials (CrC-NiCr, Tribaloy, abradabes) and range thermal spray processes (e.g. HVOF). 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 CTS and eventually 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. This represents a multi-billion dollar industry in the US. 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.