Textures of Silver‐Halide Infrared Fibres

Fibres consisting of a silver chloride core, a silver bromide cladding and a metallic silver coating were produced by co-extrusion followed by wire drawing and annealing. In most cases the core material was initially single crystalline. Together with the different flow stresses of core and cladding this may lead to inhomogeneous, non-axially symmetric flow. Particularly it may lead to a non-circular shape of the boundary between core and cladding which must be avoided when the fibres are to be used as infrared light conductors. The deviation from axially symmetric flow was studied with the help of texture investigations using neutron diffraction. The high penetration depth of neutrons allows the simultaneous measurement of the textures of all three phases of the composite fibres. Using neutron diffraction texture analysis as a sensitive flow indicator, coated “core-cladding” as well as “graded” fibres with sufficient axial symmetry could thus be obtained. The fibres are well suited as infrared light conductors.