Nickel alloys, density, thermal conductivity

Phillips and Timms [599] described a less general method. They converted germanium and silicon in alloys into hydrides and further into chlorides by contact with gold trichloride. They performed GC on a column packed with 13% of silicone 702 on Celite with the use of a gas-density balance for detection. Juvet and Fischer [600] developed a special reactor coupled directly to the chromatographic column, in which they fluorinated metals in alloys, carbides, oxides, sulphides and salts. In these samples, they determined quantitatively uranium, sulphur, selenium, technetium, tungsten, molybdenum, rhenium, silicon, boron, osmium, vanadium, iridium and platinum as fluorides. They performed the analysis on a PTFE column packed with 15% of Kel-F oil No. 10 on Chromosorb T. Prior to analysis the column was conditioned with fluorine and chlorine trifluoride in order to remove moisture and reactive organic compounds. The thermal conductivity detector was equipped with nickel-coated filaments resistant to corrosion with metal fluorides. Fig. 5.34 illustrates the analysis of tungsten, rhenium and osmium fluorides by this method. 

Zirconium is a lustrous, grayish white, ductile metal. A listing of the physical properties of zirconium is given in Table 22.1. However, a few comments can be made. First, zirconium s density is considerably lower than those of iron-and nickel-based stainless alloys. Second, zirconium has a low coefficient of thermal expansion, favoring equipment that requires a dose tolerance. The coefficient of thermal expansion of zirconium is about two-thirds that of titanium, about one-third that of type 316 stainless steel (S.S.), and about one-half that of Monel. Third, zirconium has high thermal conductivity that is more than 30% better than those of stainless alloys. These properties make zirconium very fabricable for constructing compact, efficient equipment. 

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