The peculiar alterations of the optical and mechanical characteristics of the quartz glass plates with a reinforcing coating under the collision with a hyper-velocity flux of microparticles

Abstract

This article experimentally investigates the collision of a high-velocity (5–8 km/s) flux of iron microparticles with quartz-glass plates and the effect of such collisions on the optical and mechanical properties of the plates protected by In–Sn–O-based coatings. Such coatings are used to protect the optical systems of spacecraft from the impacts of micrometeoroids and fragments of space debris. To ensure the safety of the optical systems of manned vehicles is crucial for the future of space exploration. This requires special protective materials that can resist external factors.In the present article, thin and thick protective coatings were formed by pulsed reactive magnetron sputtering of a tin-doped (7.5 wt%) indium target.The collision of the particles with the target's surface forms craters. The surface density of the craters ρ depends on the thickness of the coating and its physical and mechanical properties. The increased thickness up to ∼6 μm decreases the crater density 3.3 times, which is due to increased elastic modulus and crack resistance and decreased microhardness of the coated glass. For the quartz-glass specimens without the protective coating, the bombardment by the high-speed flux of iron microparticles decreases the visible-region light transmittance by ~ 6 %. The bombardment of quartz-glass specimens with thin protective In–Sn–O coating reduces the light transmittance to a lesser extent, while there is no reduction in the case of a thick coating. The transmittance linearly depends on the crater density and is inversely proportional to the total area occupied by the craters on the surface under study. This effect is due to the partial shading of the glass working area when rays of light pass through the zones occupied by the craters.