Tantalum cladding

A more detailed investigation of the mechanical and electrical properties was made using a series of conductors in which the v/o of stabilizing copper was increased to 62 v/o. These conductors were all made from a monolithic 102,163-filament composite rod consisting of 19 tantalum-clad modules in a copper matrix (Fig. 3). Each module contained 5,377 niobium filaments in a Cu-14 w/o Sn bronze matrix. The initial composite contained 34v/oCu, 4v/oTa, 15.9 v/o Nb, and 46.1 v/o bronze. The types of conductors were ... 

Nb CORES IN OFHC COPPER 800 UNITS) TANTALUM CLAD COPPER (g) TIN ALLOY... 

The system consists of 64 top entry tantalum poison rods. Tantalum, clad in stainless steel, was selected because its cost over the life of the plant appears to be about half that of B C, and the rate of burnup is one-tenth that of B4C. The higher thermal conductivity of tantalum, as... 

Metals having widely differing melting points, eg, aluminum (660°C) and tantalum (2996°C), can be clad. 

Although stainless steel (SS) remains the most used cladding material, exotic materials such as titanium, zirconium or tantalum are finding increasing applications. Apart from plate-to-plate and tube-to-tube-plate, there are many other applications for explosive welding which are listed below. 

Corrosion-resistant metals and alloys, including stainless steels, nickel alloys, titanium, zirconium, and tantalum can be applied as linings or claddings to cheaper steel substrates. Most (>90%) are applied by roll bonding, but weld overlaying and explosive bonding are also used, as appropriate. Particularly expensive metals, such as tantalum, can be used as very thin ( 0.5 mm) loose linings. 

PTFE is resistant to liquid chlorine and to both wet and dry chlorine gas up to 200°C. Tantalum, Hastelloy C, PTFE, PVDF, Monel, and nickel are recommended for membranes, rupture discs, and bellows. The materials of construction for heat exchangers and tanks are generally titanium or Ti-clad, rubber-lined carbon steel, PTFE-lined carbon steel to handle wet chlorine gas or aqueous solutions containing chlorine. 

Whiting, K.A. (1964) Cladding copper articles with niobium or tantalum and platinum outside. US Patent 3,156,976. 

Explosive bonding" and cladding. In this method, the controlled energy of a detonating explosive is used to create a metallurgical bond between tantalum and the base metal. A copper intermediate layer is used when tantalum is clad onto carbon steel in order to avoid brittle intermetallic formation at the interface. The limitations of the explosive bonding are as follows ... 

Schleicher, H.W. (1963) Electrodes for electrolytic processes. British Patent 941,177 November 6,1963. Whiting, K.A. (1964) Cladding copper articles with niobium or tantalum and platinum outside. US Patent 3,156,976 November 17,1964. 

There are, however, two characteristics, ready oxidation at high temperatures and, in the case of molybdenum and tungsten, brittleness at low temperatures, which limit their applications. Of the refractory metals, tantalum has the widest use in the chemical process industries. Most applications involve acid solutions that cannot be handled with iron or nickel-base alloys. Tantalum, however, is not suitable for hot alkalis, sulfur trioxide, or fluorine. Hydrogen will readily be absorbed by tantalum to form a brittle hydride. This is also true of titanium and zirconium. Tantalum is often used as a cladding metal. 

The autoclaves, internally clad with tantalum, had a capacity of 1.5 L. The volume of test solution was 1.3 L, leading to a volume/surface sample ratio ranging from 5.9 to 7.2 mL/cm. Taking into consideration the autoclave surface as well, the ratio became 1.7 to 1.8mL/cm, which is similar to the volume/ surface ratio for 73 mm (2 7/8 inch) tubing. Special care was taken to avoid galvanic contact between the samples and the tantalum autoclave surface, by hanging the specimen in suitable glass devices. 

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