Application of Jatropha Oil in Heat Treatment of Aluminium Alloy 6061 and Corrosion Study of Anodized Alloy

摘要

The application of Jatropha oil in heat treatment of aluminium alloy 6061 and corrosion behaviour of anodized alloy have been studied. The aim was to examine the effectiveness of Jatropha oil as alternative to mineral oil quenching media and also to examine the effectiveness of tartaric-sulphuric acid as alternative to chromic acid electrolyte for the anodization process. The aluminium alloy 6061 was prepared by melting high purity aluminium and other alloying elements at temperature 660°C and cast into a cylindrical shape at 730°C. The physicochemical properties (viscosity, acid value, iodine value and flash point) of Jatropha oil were evaluated. The aluminium alloy 6061 was heated to 530°C for 2 hrs and quenched in Jatropha oil and mineral oil (SAE 20W/50) respectively and then age hardening at 120°C for 5 hrs, anodization was conducted in a mixture of 80 g/1 tartaric acid (C_4H_6O_6) and 40 g/1 sulphuric acid (H_2SO_4) electrolyte under operating conditions of 13 V, period of 20 min and temperature of 37°C.. The results of these experiment shows that the composition (in wt. %) of alloy sample prepared was 95.93Al-1.1Mg-0.7Si, the physicochemical properties of Jatropha oil was characterized to be 162, 2.16 mg KOH/g sample, 13 gl/100g sample and 228°C for the viscosity index, acid. number, iodine value and flash point respectively. samples heat-treated to 530°C and quenched in Jatropha oil has the highest tensile strength of 330 Mpa and yield strength of 284 Mpa Increase solution treatment temperature was found in improved soluble precipitates in the alloy, and the heat extraction capacity of the quenching medium also contributed to the formation of fine precipitates. Improvements in properties may be correlated with a more refined metallurgical structure. High values of strength were associated with fine precipitate distribution.