Very High Laser-Damage Threshold of Polymer-derived Si(B)CN- Carbon Nanotube Composite Coatings

We study the laser irradiance behavior and resulting structural evolution of polymer-derived silicon–boron–carbonitride (Si(B)CN) functionalized multiwall carbon nanotube (MWCNT) composite spray coatings on copper substrate. We report a damage threshold value of 15 kWcm-2and an optical absorbance of 0.97 after irradiation. This is an order of magnitude improvement over MWCNT (1.4 kWcm-2, 0.76), SWCNT (0.8 kWcm–2, 0.65) and carbon paint (0.1 kWcm–2, 0.87) coatings previously tested at 10.6 μm (2.5 kW CO2laser) exposure. Electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy suggests partial oxidation of Si(B)CN forming a stable protective SiO2phase upon irradiation.