Kinetics of oxidation of Ba–Ge based melts by air oxygen

N. S. Olimov, I. N. Ganiev. 

ABSTRACT

The kinetics of oxidation of Ba-Ge melts by atmospheric oxygen has been studied by thermogravimetry, IR spectroscopy and X-ray phase analysis (XPA). It is shown that the addition of germanium up to 50.0 wt. % increases the oxidation stability of the melt. An increase in temperature promotes an increase in the rate of oxidation of melts of the Ba–Ge system. The oxidation process of liquid alloys obeys a parabolic law. The true oxidation rate is of the order of 10^-4 kg/m²·s. The apparent activation energy of oxidation, depending on the composition of the alloys, is 39.08-262.0 kJ/mol. The oxidation products of the alloys are BaGe₄O₉ and GeO₂. The mechanism of the influence of germanium on the kinetics of oxidation of Ba–Ge melts has been established. The dominant role in the formation of a protective oxide film is played by the BaGe₄O₉ oxide.

KEY WORDS:

 Ba-Ge alloys, thermogravimetry, oxidation kinetics, oxidation rate, activation energy, oxidation products.

DOI: 10.31857/S0235010621050108