GOALI: Engineering Coating Microstructure Through Advanced Plasma Spray Processing: Fuel Cell and Thermal Barrier Applications

Trustees Of Boston University, Boston

Investigators

Abstract

This research is focused on developing enhanced plasma spray processing capabilities that will enable meeting the advanced materials and manufacturing requirements in two important areas: the emerging fuel-cell industry and advanced thermal barrier coatings (TBC) for engine and power applications. The research is directed at both expanding the science base needed to better understand the process-structure-property relationships critical for these applications, as well as utilizing this knowledge to develop an advanced real-time control system that more directly controls the process physics that determines the resulting microstructure. The benefit will be both in expanding the ability to engineer advanced coating systems as well as improving manufacturing capabilities. Our research approach is designed to bridge the gap between extensive parametric design of experiments studies and more fundamental studies of the process physics involving highly "idealized" conditions, such as single splats on smooth interfaces. Plasma spray is a high-throughput, economical, low environmental impact process that can be used to custom engineer coating microstructure to meet specific performance requirements. However, fuel-cell and advanced TBC applications, important to improving energy efficiency and reducing environmental impact, require the ability to engineer coating structure and meet manufacturing requirements (yield and variation levels) that are beyond today's current plasma spray capabilities. We focus on these two applications not only because of their importance, but because they involve the same ceramic material (yitria stablized zirconia, YSZ) but with significantly different microstructural requirements. We believe that by basing our development effort on a deeper knowledge of the process-structure relations, we will develop a control system that is generalizable and widely applicable. This research will be conducted by an interdisciplinary team of academic-industry researchers with expertise in materials, thermal-fluids, controls, manufacturing, and the application areas. We will take a combined modeling-experimental approach in order to better understand the complex process-structure issues under real processing conditions. Research areas include: a) developing a more complete understanding of the underlying physics that determines the process-structure relationships for critical coating features, b) developing non-dimensionalized models to relate the process physics and measurable process characteristics to production objectives such as coating thickness and deposition rate, c) investigating the distributed nature of the process in terms of its impact on coating structure and control requirements, and d) incorporating these elements explicitly into the architecture of an advanced control system. Guided by expertise from our industry co-PI's (GOALI Partners: Siemens-Westinghouse and Engelhard Surface Technologies), we will then evaluate these new capabilities in meeting the fuel-cell and TBC requirements. Building on our record over the past 9 years (50% of 38 undergraduate researchers were from underrepresented groups), we intend to continue actively involving underrepresented groups and undergraduate students in our research.