Advanced protection against environmental degradation of silver mirror stacks for space application

Rajendra Kurapati (1) , Vincent Maurice (1) , Antoine Seyeux (1) , Lorena H Klein (1) , Dimitri Mercier (1) , Grégory Chauveau (2) , Catherine Grezes-Besset (2) , Loic Berthod (3) , Philippe Marcus (1)

1 IRCP - Institut de Recherche de Chimie Paris
2 CILAS - Compagnie industrielle des lasers
3 CNES - Centre National d'Études Spatiales [Toulouse]

Protection of silver mirror stacks from environmental degradation before launching is crucial for space applications. Hereby, we report a comparative study of the advanced protection of silver mirror stacks for space telescopes provided by SiO2 and Al2O3 coatings in conditions of accelerated aging by sulfidation. The model silver stack samples were deposited by cathodic magnetron sputtering on a reference silica substrate for optical applications and a surface-pretreated SiC substrate. Accelerated aging was performed in dry and more severe wet conditions. Optical micrographic observations, surface and interface analysis by Time-of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and reflectivity measurements were combined to comparatively study the effects of degradation. The results show a lower kinetics of degradation by accelerated aging of the stacks protected by the alumina coating in comparable test conditions.

Mots clés: Mirror layers; protection layers; silver; atmospheric corrosion; accelerated aging; surface analysis; space applications

Domaines: Matériaux; Science des matériaux [cond-mat.mtrl-sci]

Rajendra Kurapati, Vincent Maurice, Antoine Seyeux, Lorena H Klein, Dimitri Mercier, et al.. Advanced protection against environmental degradation of silver mirror stacks for space application. JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY, 2020, Advanced Corrosion-Resistant Materials and Emerging Applications, 64, pp.1-9. ⟨10.1016/j.jmst.2020.01.019⟩. ⟨hal-02489359⟩