Metal coated fibers
Silica–silica fibers require a coating to prevent ingress of moisture that leads to early failure. The most common coatings are polymers. An acrylate coating is low cost and allows use up to about 100ºC. Polyimide coatings allow use up to about 300ºC.For higher temperatures metal-coated fibers are available.
Suitable metals include aluminium and copper. An aluminium coated fiber will allow use up to about 400ºC and copper coated fibers with additional trace elements added to reduce oxidisation will allow use up to 700ºC. The copper alloy we use (CuBALL) has the advantage of being solderable or for higher temperatures it can be brazed. These fibers are suitable for a variety of high temperature uses such as engine probes.
Distributed sensor systems where the fiber is used as the sensing element can be constructed using these metal coated fibers allowing higher temperature use than is possible with polyimide coated fibers.
