Book Description

Because of the refractory nature of zirconium hydride and zirconium oxide, analysis of these materials for trace amounts of boron may be affected adversely by loss of boron or contamination from the container during decomposition. Both sources of error may be obviated by a direct spectrochemical analysis employing either copper fluoride or sodium carbonate as pyroelectric distillation carriers. Since both the hydride and oxide appear to behave similarly in the arc with these carriers, easily prepared zirconium oxide standards were useable for analysis of both materials. Acid or fusion decompositions of the two compounds to allow separation of boron as trimethyl borate were studied. Decomposition was successful with refluxing sulfuric acid, and partly successful with sodium carbonate melts. Loss of boron during conversion of zirconium hydride to the oxide was indicated during a study of the ignition conditions, and shown conclusively by spectrographic examination of the off-gases. Contamination of the sample material by boron from new platinum ware was also found. Agreement of spectrochemical and curcumin colorimetric determinations of boron zirconium hydride was fairly good, but both methods lacked precision. The low precision may be attributable to inhomogeneity of the sample material.