Preparation And Properties Of High-absorption Coating Based On Hollow Carbon Spheres

High-absorptive coating generally refers to a class of materials that can achieve high absorption of incident light in a specified wavelength band by constructing a nano-or micro-scale structure.With the development of my country's aerospace industry,higher requirements have been placed on the accuracy of space optical systems.However,due to the interference of stray light,the imaging accuracy of the optical system is adversely affected.Therefore,this paper conducted a series of simulations and experimental studies on high-absorptive coatings applied to aerospace optical systems to eliminate stray light.Traditional high-absorptive coatings often have problems such as low solar absorption,poor adhesion to the substrate,and high vacuum gas release.Therefore,in this paper,the solution to achieve high absorption of materials is used as the starting point,and hollow carbon spheres are used as fillers to build a hierarchical structure with both micro-level light trapping effect and sub-wavelength hollow structure,so as to achieve high absorption of light.The effects of the particle size of the hollow carbon sphere,the thickness of the carbon shell and the thickness of the coating on the light absorption performance were studied by FDTD simulation.The simulation results show that the hollow carbon sphere coating with a particle size of less than 200 nm,a carbon shell thickness of about 20 nm,and a thickness of more than 15 ?m has the best light absorption performance,and the solar absorption ratio is higher than 99%.By comparing with the light absorption performance of different carbon structure simulation models,it is confirmed that the hollow carbon sphere structure has more excellent absorption capacity for incident light in the range of 0.25-2.5 ?m.In order to prepare a highly light-absorbing coating that can be applied to the aerospace optical system with a solar absorption ratio higher than 98%,the calcination and grinding processes of phenolic-coated polystyrene(PS@RF)microspheres and hollow carbon spheres were optimized to prepare particles Monodisperse hollow carbon spheres with a diameter of 190 nm and a carbon shell thickness of 20 nm.By optimizing the binder resin and coating preparation process,a hollow carbon sphere high light absorption coating with a solar absorption ratio higher than 98.5% was prepared.The design of the vacuum ultraviolet irradiation device and the vacuum ultraviolet irradiation test of the coating confirmed that the prepared high absorbance coating will not affect its performance in space due to ultraviolet irradiation.The binding force,thermal cycle and vacuum gas release performance of the high light absorption coating were tested.The coating's binding force,thermal cycle performance was stable and the vacuum gas release amount was less than 1%.The coating of fluororesin hollow carbon spheres prepared by using hollow carbon spheres meets the requirements of aerospace optical systems.