Improving the Predictability of Thermal Spray Coating Process Outcome

This proposal is aimed at demonstrating the feasibility of developing a control system for the plasma spray process that will compensate for the plasma spray variations as well as enable achieving a desired set of coating properties. Our control strategy is to directly control the particle sub-distributions that most directly determine the coatings structure and thus the related coating properties. Essential to developing such a system is identifying a set of particle-plume based measurements that are tightly correlated to the desired coating characteristics. Once the critical set of sensor measurements are identified as appropriate control objectives, the input-output coupling will be experimentally determined, providing the basis for developing a multiple degree of freedom control system that is robust for typical torch variations and operating conditions. In Phase I, the feasibility of our control approach will be determined based on experimental performance evaluation from both laboratory experiments and based on observations from production booth measurements. To ensure that our system is effective under production conditions and would be accepted by industry, this project will be conducted in collaboration with a leading turbine OEM, coating manufacturing company, and a plasma equipment company. BENEFIT: This research will lead to the development of a system that more directly provides the ability to engineer plasma sprayed coating structures as well as reducing coating variation. Such a system will not only benefit the manufacture of aircraft turbines, but also the broader plasma spray coating process used in industrial gas turbines, electronic manufacturing systems, and other industrial applications including pumps and large scale rollers. Development of such a control system will also benefit the plasma sensor market since it provides a basis for increasing the value for industry to incorporate sensors into their production booths.