Improvement of corrosion resistance and heat dissipation of Mg-6%Al-4%Ca alloy by the addition of Mn, Mm, and the surface treatment

• Published in: Journal of Japan Institute of Light Metals Vol. 73; no. 12; pp. 646 - 650
• Main Authors: Kondo, Natsuki, Suzuki, Mayumi, Tsukeda, Tadayoshi, Ito, Mizuki, Kurihara, Hideki, Kirimoto, Yuichi, Tabata, Hironobu, Aida, Tetsuo
• Format: Journal Article
• Language: Japanese
• Published: Tokyo The Japan Institute of Light Metals 15.12.2023; Japan Science and Technology Agency
• Subjects: Alloying elements; Aluminum; Calcium; Castability; Corrosion resistance; Dissipation; Electromagnetic shielding; Electronic equipment; Emissivity; Heat conductivity; Heat transfer; Heat treatment; Housings; magnesium; magnesium alloy; Magnesium base alloys; Manganese; Mischmetal; Surface treatment; Thermal conductivity; Thermal resistance
• ISSN: 0451-5994; 0368-5306; 1880-8018; 2186-618X
• DOI: 10.2464/jilm.73.646

With the recent digitization, electronic equipment housings are required to be thin-walled and have rigidity, heat dissipation, corrosion resistance, and electromagnetic shielding properties. Magnesium alloys are promising materials that satisfy these requirements. Mg-Al alloys have good castability and high strength, but their thermal conductivity decreases. In general, adding alloying elements to magnesium decreases thermal conductivity the effect of aluminum addition is significant. It was found that adding calcium to Mg-Al alloys to form Mg-Al-Ca (AX) alloys results in higher thermal conductivity than that of Mg-Al alloys. However, AX alloys have poor corrosion resistance and require post-treatment such as surface treatment. In this study, AX64, which has high thermal conductivity among the AX series alloys, was used as the basic composition, and corrosion resistance was improved by adding manganese and misch metal, and an attempt was made to improve corrosion resistance and emissivity through surface treatment. The change in thermal conductivity by heat treatment was also investigated. Experimental results showed that the addition of manganese and misch metal improved corrosion resistance and thermal conductivity. Plasma anodization also improved corrosion resistance and emissivity. Heat treatment of these alloys at 400°C improved the thermal conductivity with longer holding time.