Mechanical and chemical characteristics of hermetically coated silica optical fibre

• Published in: Surface & coatings technology Vol. 202; no. 11; pp. 2494 - 2499
• Main Authors: Severin, Irina, El Abdi, Rochdi, Poulain, Marcel
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 25.02.2008; Elsevier
• Subjects: Applied sciences; Chemical reliability; Chemical Sciences; Cross-disciplinary physics: materials science; rheology; Dynamic fatigue; Exact sciences and technology; Fatigue; Fluorinated reagents; Hermetically coated optical fibre; Material chemistry; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Physics; SEM; Surface treatments; Chemical reliability; Hermetically coated optical fibre; SEM; Dynamic fatigue; Fluorinated reagents; Scanning electron microscopy; Mechanical properties; Fatigue; Surface treatments; Silica
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2007.08.005

The mechanical strength of carbon hermetically coated fibres, compared to standard single mode silica optical fibre, has been investigated through chemical exposure to fluorinated vapour reagents, known as the harshest reagents for silica. Two reagents were used: ammonium hydrogenofluoride and hydrofluoric acid. Dynamic fatigue tests for different stress rates were implemented using a two-point bending testing device in order to determine n-stress corrosion parameter from Weibull statistics. As-received and chemically etched fibres were compared. Hermetically coated fibres appeared extremely durable in harsh chemical conditions. No significant change in the Weibull distribution and the mean fibre strength was observed after 6 days of chemical exposure to hydrofluoric vapours. In the same conditions, the mechanical strength of the epoxy-acrylate polymer coated standard fibres has decreased to nearly 50% of the initial strength value. SEM observations revealed crystal deposition on the chemical exposed fibres. Chemical analysis provides partial information on the complex mechanisms of fibre corrosion.