Ceramic to Metal Joints

High strength, high temperature ceramic to metal joining technologies are critical for leveraging the high temperature properties of ceramics in power generation systems. Ceramics enable higher operating temperatures that translate directly into higher thermal efficiency generators. More importantly, the superior corrosion resistance of ceramics compared to nickel based alloys will enable a transition to higher efficiency, higher power density generators that use supercritical carbon dioxide as a working fluid to reduce the need for the construction of additional generator capacity to incorporate carbon capture and sequestration systems. A new ceramic to metal joining technology will be developed based on an applied nanostructured layer. The unique physical structure of the nanostructures will enable a smoother transition in the coefficient of thermal expansion than current approaches using glass loaded fluxes that will improve the strength of the joint across a wider temperature range. During the Phase I program high strength (>20 MPa) joints between high purity Inconel 740 and Haynes 282 alloys and alumina will be demonstrated. The joints will have strength greater than 35 MPa at temperatures up to 800C and will be impermeable to air and carbon dioxide. The project will develop a ceramic to metal joining technology that enables next generation. High efficiency power generation systems to be built. Higher efficiency electricity generation systems will reduce greenhouse gas emissions and the nation’s reliance on fossil fuels. Commercial Applications and Other Benefits: Successful development of the proposed joining technology will impact the ceramic heat exchanger market making it possible to build higher temperature systems to boost process efficiency. Heat exchangers in power generation systems are the largest market opportunity. The proposed technology will enable greater electrical output by increasing operating temperatures to simultaneously meet increasing demand while reducing the need for new plant construction to incorporate carbon capture and sequestration systems. Additional market opportunities for ceramic heat exchangers include chemical waste treatment systems and high efficiency air conditioning and refrigeration systems using nontoxic and environmentally benign supercritical carbon dioxide.