Search

High-energy continuous wave (CW) laser ablation can cause severe damage to structural materials in an extremely short time, which generates considerable concern in terms of material safety. For the purpose of reducing or even eliminating such laser-induced damage, a novel composite coating consisting of a boron-modified phenolic formaldehyde resin incorporating ZrC and SiC has been designed and prepared. The experimental results reveal that ZrC and SiC are rapidly oxidized to ZrO 2 and SiO 2 respectively, leading to the formation of a white ceramic layer consisting of ZrO 2 particles and melted SiO 2. After ablation at 1000 W/cm2 for 50 s, elemental analysis indicates that no Si can be found in the central ablation zone because of gasification. A relatively compact ZrO 2 layer is formed through the sintering of adjacent ZrO 2 particles, which effectively improves the reflectivity of the coating from 7.3% (before ablation) to 63.5% (after ablation). The high reflectivity greatly reduces the absorption of laser energy. In addition, no obvious ablation defects are observed in the composite coating. The excellent anti-laser ablation performance of the coating makes it a promising system for protecting a material against the effects of long-term CW laser ablation. [ABSTRACT FROM AUTHOR]

High-energy continuous-wave (CW) lasers can cause severe damage to traditionally structured materials within several seconds because of the formation of an extremely high temperature field. To prevent laser damage, zirconium carbide (ZrC)-modified short-carbon-fiber-reinforced phenolic-resin matrix composites have been successfully prepared. The micro-morphologies and elemental distributions of the composites were investigated and phase detection was performed to study their laser-ablation behavior. The results reveal that the ZrC particles are oxidized rapidly, forming ZrO 2 , during laser ablation. Owing to binding of the short carbon fibers and sintering of neighboring ZrO 2 particles, a compact ZrO 2 layer was obtained. Owing to the formed ZrO 2 layer, the reflectivity increased from 8.0% to 52.5% following irradiation at 500 W/cm2 for 180 s. This greatly mitigates the absorption of the laser energy. In addition, no distinct ablation pits were observed. This indicates that the composites exhibit excellent anti-laser ablation performance, and could be potentially applied as protective shields for materials exposed to high-energy CW lasers. [ABSTRACT FROM AUTHOR]