Low Temperature Photonic Curing for Ceramic Coated Heat Exchangers
An innovative high power ultraviolet (UV) photonic sintering process is proposed for low temperature sintering of ceramic materials on metallic substrates. New high power ultraviolet (UV) flash lamps developed and integrated with a system that permits complex pulse forms in which pulse energy, duration, and frequency are controlled. By delivering a series of high energy flashes having durations as short as 30 microseconds, energy densities in excess of 100 kW/cm^2 can be produced with minimal heating of the underlying substrate. This technique has been used to sinter high temperature metals printed on polymer and paper without damage to the substrates. The innovation of new UV flash lamps will allow sintering of ceramic materials such as yttria-stabilized zirconia (YSZ) that have low absorption at longer wavelengths put out by currently available flash lamps. For demonstration of technical feasibility, the UV photonic sintering process will be applied to functionally graded coatings deposited via direct-write printing. Coatings consisting of a gradual transition from 316 stainless steel to ceramic YSZ will be printed on 316 SS substrates. The new UV photonic sintering process will then be applied. Coating quality will be characterized in terms of density, strain, and grain size reduction.
PI: Denis Cormier