Wah Chang, with a capacity of 100,000 Ibs./month, has been producing ingots of niobium/45%-55% titanium alloy for over 25 years. In recent years, various programs have been outlined for large superconducting devices which will require thousands of pounds of fine composite wire.

The alloy is fabricated in all forms, although it is generally used in multifilamentary cables. Quantities of the various alloys and types are generally available. The alloys are manufactured in both Grade 1 and Grade 2 types. The primary difference is that the Grade 2 material has a higher allowable tantalum content which has no effect on the superconducting properties.

One of the major improvements in Nb/Ti superconducting alloys has been the development of high homogeneity (Hi-Ho) grade alloys, which have improved the current density of the final material, while permitting smaller diameters to be drawn with less fabrication difficulties. While not intended for all applications, Hi-Ho grade is necessary for 10-micron sized filaments. Wah Chang also manufactures copper clad Nb/Ti alloys which can be made with or without a barrier of vanadium or niobium. This monofilamentary material can be furnished as extruded rod or drawn to whatever final size is specified.

A special high purity grade of niobium, known as Residual Resistivity Ratio (RRR), has been developed for use in radio frequency (RF) accelerator cavities. The RRR is the ratio of the resistance of Nb at 273 Kelvin (ice point) to the normal-state resistance at 4.2 Kelvin extrapolated to zero field. Ratios of 250 and up are routinely produced at Wah Chang in all the standard forms and shapes.

The niobium/55% titanium alloy is also used in the aircraft industry for rivets. The alloy requires approximately one quarter of the bucking force necessary to head a CP titanium rivet of the same size. The Nb/55% Ti alloy, as specified in AMS 4982, is stronger than CP titanium at temperatures in excess of 600° F. Material can be manufactured into all rivet shapes and forms, including the composite types.

For more detailed information regarding either the superconducting Nb/Ti alloys or the rivet grade material, contact Wah Chang.

Page 18 of 34 Next

INDEX  •  CORROSION RESISTANCE PROPERTIES  •  FABRICATION   
NIOBIUM PRODUCTS   •  SPECIFICATIONS of NIOBIUM   
NIOBIUM ELECTRONICS APPLICATIONS