| Abstract Scope |
Additions of small amounts (>2ppm) of Be to AlMg alloys have proven to decrease their rate of oxidation. As Be can cause respiratory health issues, it is desirable to evaluate other parameters that may have the same inhibiting effect. In the present study six aluminium alloys, i.e. Al5Mg, Al5Mg5Si, Al1Mg1Si, Al5Mg1Si, Al1Si5Mg and Al5Si, have been investigated by Thermogravimetric Analysis (TGA) monitoring the mass change as a function time and temperature in atmospheres of Ar, synthetic air and an atmospheric mixture of synthetic air, Ar and CO<sub>2</sub> (<5%) at 750°C for 7h.
The TGA results revealed a two-step mass gain in synthetic air for all AlMg alloys, and the microscopic analysis showed that both MgO and MgAl<sub>2</sub>O<sub>4</sub> were present in the oxide films. For the atmospheric mixture, the mass gain was significantly lower confirming that CO<sub>2</sub> has an inhibiting effect on the overall rate of oxidation of these alloys. |