Instrumentation for Understanding and Controlling Surface Chemistry During Femtosecond Laser Surface Processing (FLSP)
Abstract
The proposed DURIP instrumentation, coupled with a tunable femtosecond laser source, will allow UNL researchers to obtain a fundamental understanding of FLSP contributions and the enhancements from surface chemistry. FLSP surfaces are very reactive as the functionalization process exposes new virgin surfaces that can contain both typical grain boundaries as well as nanoscale grain boundaries. The DURIP instrumentation provides a tremendous added value to the research effort by being able to perform laser surface processing and the analysis of such surfaces without ever breaking the vacuum; thus eliminating environmental contamination issues being experienced in the current research. The proposed DURIP equipment allows researchers to independently control and tune the surface wetting properties of virtually any bulk material, but especially metallic surfaces that exhibit permanency without coatings. By having an understanding of FLSP micron/nanoscale features along with surface chemistry, UNL researchers will be able to design material systems from the ground up without compromising bulk properties for desired surface features (or vice versa). For example, a surface can be functionalized to enhance heat transfer, reduce drag, limit biofouling and enhance corrosion resistance, while the bulk material can be independently selected for weight, strength, and or cost. AbstractIn our current ONR research program, femtosecond laser surface processing (FLSP) of about 50-100 microns of the top metallic surfaces have demonstrated 7 times the enhancement of heattransfer in pool boiling experiments and about 28% decrease in drag in annular flowexperiments. FLSP surfaces have huge implications to thermal management, anti-fouling anddrag reduction applications for DoD. In order for UNL to take this research to even greaterlevels of achievement, it is necessary for our research team to be able to decouple FLSPmicroscale/nanoscale bulk effects from surface chemistry effects as both are occurringsimultaneously. The proposed DURIP instrumentation, coupled with a tunable femtosecond lasersource, will allow UNL researchers to obtain a fundamental understanding of FLSP contributionsand the enhancements from surface chemistry. FLSP surfaces are very reactive as thefunctionalization process exposes new virgin surfaces that can contain both typical grainboundaries as well as nanoscale grain boundaries. The DURIP instrumentation provides atremendous added value to the research effort by being able to perform laser surface processingand the analysis of such surfaces without ever breaking the vacuum; thus eliminatingenvironmental contamination issues being experienced in the current research. The proposedDURIP equipment allows researchers to independently control and tune the surface wettingproperties of virtually any bulk material, but especially metallic surfaces that exhibit permanencywithout coatings. By having an understanding of FLSP micron/nanoscale features along withsurface chemistry, UNL researchers will be able to design material systems from the ground upwithout compromising bulk properties for desired surface features (or vice versa). For example,a surface can be functionalized to enhance heat transfer, reduce drag, limit biofouling andenhance corrosion resistance, while the bulk material can be independently selected for weight,strength, and or cost.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 03, 2017
- Source ID
- N000141712238
Entities
People
- Dennis R. Alexander
Organizations
- Office of Naval Research
- United States Navy