Influence of Implanted Aluminum Ions on the Oxidation Behavior of M5 Alloy at 500°C

Abstract

The beneficial effect of aluminum-ion implantation on the oxidation behavior of M5 alloy at 500°C has been studied. M5 alloy specimens were implanted with aluminum ions with fluences ranging from 1 × 1016 to 1 × 1018 ions/cm2, using a MEVVA source at a voltage of 40 kV at maximum temperature of 380°C. The weight-gain curves were measured after oxidation in air at 500°C for 120 min, which showed that a significant improvement was achieved in the oxidation behavior of M5 alloy implanted with aluminum compared with that of the as-received M5 alloy. The valences of elements in the implanted surface of M5 alloy were analyzed by X-ray photoemission spectroscopy (XPS), and the depth distributions of the elements in the surface of the samples were obtained by Auger-electron spectroscopy (AES). Scanning-electron microscopy (SEM) was used to examine the micro-morphology of oxidized samples. The color of the oxidized samples was checked by a scanner. Glancing-angle X-ray diffraction (GAXRD) at 0.3° incident angles was employed to examine the phase transformations of implanted samples before and after oxidization in air at 500°C for 120 min. It was found that when the fluence is 1 × 1018 ions/cm2the implanted M5 alloy is slightly oxidized. The mechanism of the improvement during oxidation is discussed.