Influence of alloying with elements of subgroups IV, V, and VI on the oxidation of vanadium in heating in air

Abstract

It is established that unalloyed vanadium has the lowest oxidation resistance in air; it is resistant in air up to 523 K. Further heating leads to a marked increase in weight, especially at 737 K, and subsequently at 1000 K. X-ray diffraction analysis of the scale formed (573 - 737 K) indicates the presence on the surface of the oxides VO and V/sub 2/O/sub 3/ or of those close to them stoichometrically. In all cases the layer of metal directly adjoining the scale is characterized by an increased hardness and poor etchability. Composite derivatograms are shown which were obtained in heating of typ VnM-2 unalloyed vanadium and its alloys. It is shown that alloying of vanadium with niobium, tungsten, titanium, chromium, and zirconium increases its scaling resistance but has little influence on the temperature of the transition of the oxidation products to the liquid phase.