In this study, thermogravimetric analysis (TG) testing is used to measure the mass loss of polished Al-6Zn-XMg (X = 0 and 2 mass%) alloy samples heated at 773 K for 6 h in dry air or nitrogen gas. The progressive development of thermally formed oxides on an Al-6Zn-XMg (X = 0 and 2 mass%) alloy as shown by X-ray diffractometer analyses is discussed. Zn-spinel and Mg-spinel are detected on the Al-6Zn and Al-6Zn-2Mg alloy samples, respectively, and then heated in the dry air atmosphere; AlN and Mg(3)N(2) are detected in alloy samples heated in nitrogen gas. The chain reactions that cause the serrated change in the mass loss curve are proposed and discussed.
