Abstract: Powders of the Al-3.2Li-1.1Mg-0.3Cu-0. 2Zr alloy were produce by USGA(Ultra Sonic Gas Atomization) with Ar gas. Powders of 50-56μm size were degassed at 350℃(lower temp.).450℃(intermediate temp.)and 500℃(elevated temp. )in vacuum(10(-3)Pa)for 2h.The surface feaction product, formed during atomization and degassing were studied using ESCA(Electron Spectroscopy fof Chemical Analysis)quantitatively. The as-received powder particles exhibit an outer hydrocarbon layer,a surface hydrousoxider layer and an oxide laver.The oxide layer is 97A thick,consisting of Al2O3, Li2O and MgO(mole ratio is Al(3+) Li(+) : Mg(2+)=1:0. 86: 0. 09).When degassing at lower temperature(350℃),the hydrocarbon and dydroxides are e-vaporated and dehydrated partly, but of them the Li2O· H2O can not be decomposed; at the sametime,the lithium is oxidized continously,making the thickness of oxide layer increase to 130A(Al(3+): Li(+):Mg(2+)=1:3. 06 : 0. 09 ).When degassing at intermediate temprature(450℃), the hydrocarbon can be decomposed to the limit,Li2O· H2O dehydrates completely but the metallie aluminum and Li2O,at the same time,be oxidized continuously also,which results in a thicker oxide layer 108A(Al(3+): Li(+): Mg(2+)=1:3.42:0.11).When degassing at elevated temperature(500℃) in addition to the reactions of degassing of 450℃,there are some complicat-ed reactions takirtg place;the thickness of oxide film adds up to 119A(Al(3+):N(+):Mg(2+)=1:4. 72:0.15).

Key words: solidification, powder metallurgy, aluminiun-lithium alloys, surface stability alloys