Cost effective, multifunctional thermal spray coatings for protection of metal combustors

A significant number of world population use some form or low-grade biomass based heat from cooking to heating to incineration. Biomass is a carbon neutral energy source and as such attractive for sustainable living. A major challenge in using biomass is the equipment used to generate and confine the heat during the combustion process. Given the diversity of constituents and contaminants in biomass the containment vessels typically can experience unpredictable chemical corrosion. In addition, thermal management of the system is also of critical interest to enhance the efficiency of their utilization. Coatings offer and exciting method to mitigate against corrosive and thermal degradation of metal combustors used in biomass thermal furnaces. Coatings can provide low cost and life extension solution with the ability to tailor the surface to meet required resistance to corrosion deposits and provide reduced thermal impact to the containment metal. In comparison to other materials or protection technologies, porcelains, vapor deposition, plating, etc), thermal spray offers a flexible, scalable and cost effective method to address the criteria set forth in the solicitation. Thermal spray allows unprecedented materials tunability e.g. graded metal-ceramic composites) which allows multi-functionality and location specific optimization. In addition, existing factories can be used to transition the technology reducing large dedicated investments and allowing scalable manufacturing. In this phase I program, a thermal spray coatings based on metal-ceramic composites is proposed as a potential solution to meet the above mentioned functional requirements. The choice of metal-ceramic composite is two-fold: to meet the thermal and corrosion requirements while also reducing costs. Oxide ceramics alumina, zirconia) and their mineral grade versions zircon) are an economical means to provide high temperature coatings and while minimizing use of advanced high temperature alloys. Damage tolerance is achieved through the presence of tough metallic phases and control of residual stresses. In Phase I, several combinations of such metal ceramic composites will be developed, fabricated and tested under relevant thermo-chemical environments. Cost will be incorporated as a design variable weaving this parameter into developing efficient and reliable process as well as minimize use of expensive materials. An STTR partnership between ReliaCoat Technologies and Stony Brook University has been established to bring necessary expertise to address the program requirements. Although the focus of the STTR is to develop cost effective coatings, given the broader application portfolio of biomass energy convertor a range of coating applications will be contemplated in the technology transition. Successful deployment of such coatings can have far reaching impact not only for the specific listed application but across a spectrum of biomass convertors and incinerators by expanding the operational limits, enhancing efficiencies and extending service life of key components. A concomitant beneficiary is the US thermal spray coating industry as it will enhance its penetration into cost sensitive industry sectors.