Influence of application parameters on stability of Pyromark® 2500 receiver coatings

• DOI: 10.1063/1.5117514
• Publication Date: 2019-07-27T13:00:36Z
• Authors: Andrea Ambrosini; Antoine Boubault; Clifford K. Ho; Lam Banh; John R. Lewis
• Keywords: [SDU.STU] Sciences of the Universe [physics]/Earth Sciences; 0211 other engineering and technologies; 02 engineering and technology; 7. Clean energy

Pyromark ® 2500, manufactured by Tempil, is currently the industry standard for high solar absorptive receiver coatings for concentrating solar power towers. However, Pyromark has been reported to degrade if not applied properly or exposed to temperatures exceeding 700 °C over a period of time. However, it is not apparent if such degradation is due to a particular aspect or aspects of the deposition process, which may vary from plant to plant. Many variables factor in to the performance of Pyromark, e.g. deposition method, drying time, curing parameters (ramp rate, homogeneous heating, time at temperature…), and coating thickness. Identifying the factors with the most influence on coating performance and durability will help guide the application of Pyromark to receivers to minimize degradation over time. The relationships between coating quality and optical properties with deposition/curing parameters on Haynes 230 substrates were assessed using statistical analysis of variance (ANOVA) techniques for repeated measures. These ANOVA techniques were designed to detect differences in treatment effects on the response at each of the aging cycles. The analyses found that coating thickness, curing ramp rate, and dwell time had the most effect on coating quality.