CORROSION OF A ZINC-ALUMINUM-COPPER ALLOY BY FLUORINE-GAS

Corrosion of a commercial two-phase eutectoid zinc-aluminium alloy mod ified by 2% Cu (Zinalco(TM)) was performed at high temperature in a dr y fluorine environment. This environment was kept at a pressure of 10( 3) mbar for 100 and 300 h. The exposed samples were studied by resonan t nuclear reaction, Auger electron spectroscopy, scanning electron mic roscopy and X-ray diffraction. The Knoop micro-hardness of the samples was measured before and after the exposure. Intergranular corrosion o f the zinc-rich phase that tends to consume the material is observed, while the aluminium bonds to the fluorine forming a superficial AlF3 c ompound.