Laser Ablation Propulsion Performance of Surface-Modified Polyoxymethylene

摘要

The effects of the micrometer-scale surface morphology of polyoxymethylene on propulsion performance induced by transversely excited atmospheric CO_2 laser pulse ablation were investigated. Two methods were examined for producing a surface structure on the same order as the laser wavelength, 10.6 um: hydraulic compaction of powder and etching using microelectromechanical systems technology. With the compacted powder, the fluence for maximum momentum coupling coefficient C_m shifted to a smaller value of 7 J/cm~2 from the corresponding value of 15 J/cm~2 for bulk material. However, mass consumption was increased, thereby lowering specific impulse I_(sp). Three surface patterns were examined with the microelectromechanical systems etching, obtaining an up to 20% increment, both in C_m and I_(sp).