The electro-negativities

Gibbs free energy of oxidation reaction and physical properties of some alloying elements and their oxides were compared. It is pointed out that alkaline earth and rare earth elements are dominant in ignition-proof of is used to

especially Be element. RE elements is used to substituting Be and Ca due to high toxicity of Be and be inferior to mechanical properties of the Mg alloy with Ca. The oxidation and ignition temperatures of AZ91 magnesium alloy with somew hat Ce addition were measured. The results show that although the oxidation and ignition temperatures of the alloy are raised

their increasing velocity is slowed with Ce addition increase

increasing by 33 ℃ and 61 ℃

respectively

with 1% Ce addition

compared with those of the AZ91 magnesium. The advisable Ce addition is about 0.6% for ignition-proof AZ91Mg alloy.