By using surface sol–gel method with perhydropolysilazane (PHPS) as a precursor, a silica coating was prepared?on a Kapton substrate as an atomic oxygen (AO) protective coating. The AO exposure tests were conducted?in a ground-based simulator. It is found that the erosion yield of Kapton decreases by about three?orders of magnitude after the superficial application of the coating. After AO exposure, the surface of the coating?is smooth and uniform, no surface shrinkage induced cracks or undercutting erosion are observed. This is?because that during AO exposure the PHPS is oxidized directly to form SiO2 without through intermediate reaction?processes, the surface shrinkage and cracking tendency are prohibited. Meanwhile, this PHPS derived?silica coating also presents self-healing effect due to the oxidation of free Si. Compared with other kinds of?silica or organic polymer coatings, this PHPS derived silica coating exhibits a superior AO erosion resistance.
Longfei Hu,Meishuan Li,Caihong Xu,Yongming Luo
Thin Solid Films