Oxidation kinetics of aluminum alloy AZh5K10, modified by calcium in solid state

The solution of many problems of modern technology is associated with the use of materials with high resistance to oxidation. In this series, a special place is given to aluminum alloys with calcium, strontium, barium and other metals. The oxidation process of the alloys has been studied in air under isothermal conditions by means of thermogravimetric method with continuous fixation of sample mass during an hour. Based on experimental data, the kinetic curves of oxidation of AZh5K10 aluminum alloy with calcium have been constructed, which were used to determine the specific weight gain from the amount of calcium, time and temperature. According to research results, it has been found that calcium additions up to 1.0 wt.% increase the oxidation rate of the AZh5K10 aluminum alloy, which is accompanied by a decrease of apparent activation energy of oxidation process. By constructing the quadratic dependences of the specific weight gain of the alloys on duration of oxidation time, the oxidation mechanism of alloys has been defined. It has been shown that oxidation process of alloys in studied temperature range 773-873 K obeys to hyperbolic dependence. (author)