In addition, to ascertain a high strength of the whole length, the fiber is to
be proof-tested (rewound from one reel to another) at some load (strain).
However, the process of proof-testing itself at loads over approximately
5–10 N (for a 125-mm fiber) can damage the metal coating and the fiber.
Moreover, tin- or indium-coated fibers survive proof-testing only in the case of
an additional polymer coating applied over the metal. This problem is less acute,
if only bending at low tension on a certain set of wheels is used as the proof-test
procedure instead of tensile load.
15.4 DEGRADATION AT HIGH TEMPERATURE
Ideally, in the absence of corrosion or oxidation effects, a metal coating
remains at work at temperatures close to the melting temperature of ...