The ammonia generally used as a buffer in alkaline electroless nickel and cobalt plating baths has been shown to have a significant effect on both the rate of deposition of thin metal films and the magnetic and physical properties of such films. These effects have been studied on both metallic and nonmetallic substrates, using both ammonia and nonammine buffer systems, and attempts have been made to correlate them with spectral and polarographic observations.
Mischungen von LaCl3 (SmCl3, GdCl3, YbCl3) mit SrCl2 (BaCl2) wurden differenzthermoanalytisch und röntgenographisch untersucht. In den Zustandsdiagrammen wurden die peritektoid bzw. Peritektisch zerfallenden Verbindungen BaLnCl5, M2InCl7 und Ba3LnCl9 nachgewiesen, die Existenz der Phase Sr4LnCl11 wird vermutet. Eine Mischkristallbildung auf der Basis der Erdalkalihlogenide wurde beobachtet. Sr2SmCl7 und Sr2GdCl7 sind isotyp und wegen der sehr ähnlichen Reflexmuster der Guinier‐Aufnahmen strukturverwandt mit Sm3Cl7. Die Systeme ähneln bei gleichen Radienquotienten der Kationen den Zustandsdiagrammen LnCl7LnCl2.
Die Mischungsenthalpien der Systeme LaCl3(GdCl3, YbCl3)SrCl2 wurden calorimetrisch bestimmt. Alle Mischungsenthalpien sind exotherm, die Minima liegen bei etwa 65 Mol‐% SrCl2.
ions. Because chromium is the only element listed which is normally found associated with vanadium in analytical samples, such as steels, the problem is not too serious.The interference of iron, due to the color of the ferric ion, can be easily eliminated by the addition of fluoride ion, as shown in Table V. Care must be taken to avoid a large excess of fluoride, as large quantities of this ion interfere.The interference of organic acids, if any are present, can easily be removed by destroying the organic material with nitric acid.
CONCLUSIONSThe proposed 3-tungstovanadic acid method is very sensitive, exceeding the sensitivity of the well-known method based upon tungstovanadophosphoric acid. In addition, the results obtained are precise and accurate. Chromium, the most serious interference, must be completely removed. Interference of iron is eliminated by complexation with fluoride.Because of the necessity of removing chromium, if present, the determination of vanadium by this method may be lengthy, but no more so than by other standard colorimetric methods under the same conditions. A minor disadvantage is the rather narrow pH range that must be maintained. As pH meters are now commonplace, this requirement is not a serious defect.
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