Bell Telephone Laboratories

Theodore J Louzon

Franz T Geyling

Alloys comprising copper, nickel and tin, when appropriately processed, exhibit high levels of tensile strength and ductility. Processing has been by cold working and aging or, when cold working is impracticable, by aging of alloys which are modified by the addition of a refractory element. It has been discovered that, even without cold working and even in the absence of additives, strong and ductile Cu-Ni-Sn alloys can be produced when a body of the alloy is subjected to a characteristic heat treatment to develop an alpha plus essentially nonlamellar gamma structure. This is followed by cooling and aging at a temperature and for a time corresponding to a predominantly spinodal alpha-1 plus alpha-2 structure. Typical properties are a 0.01 percent offset yield strength of 128 Kpsi and an elongation to fracture of 5 percent in an alloy comprising 15 weight percent Ni, 8 weight percent Sn, and remainder essentially Cu.

Cu-Ni-Sn Alloy processing

Fibers are coated with a metal layer by applying onto the fiber a relatively high viscosity slurry comprising an alloy in the form of liquid and solid phases. This allows application of metal coatings on layers that do not 'wet' with the liquid metal. For example, an optical fiber having a soft polymer layer to reduce microbending losses is coated with a metal to prevent moisture entry. An alloy of Bi-Sn or In-Sn, among others, allows coating at a relatively low temperature to prevent polymer degradation. Other fibers for various uses can also be advantageously coated with this technique.

Metal coating of fibers

Fibers, including optical fibers, are coated under pressure to reduce the amount of bubbles entrapped in the coating. Fluid coating material is directed radially toward the fiber, typically through a porous material or radial channels in a coating applicator. The passage diameter for the fiber is large enough to prevent contacting the fiber, while the pressure of the fluid coating material is high enough to substantially prevent air from entering the applicator. Fiber coating speeds up to at least several meters/second are possible.

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Bridgewater, NJ, United States of America

Theodore J Louzon