Abstract
The effects of, concentration of nitric acid and temperature were examined on hard rolled aluminium (Purity=99.70%) by dip method corrosion test. The corrosion test was carried out in 5_??_98% HNO3 at 30_??_70° by measuring the weight loss for 10 hours, and the corrosion rate was expressed as g/m2hr.
The results obtained were as follows. (1) In 98% HNO3; the resistivity is excellent up to 70° (2) In 94% HNO3; the resistivity is excellent at 30°, and even at 50_??_70° the resistivity is good. (3) in 92% HNO3; the resistivity is good at 30°. (4) In bellow 90% HNO3; the resistivity is rot good even at 30° and is minimum in. 30% HNO3.
II. The effect of purity of aluminium was examined on virgin ingot (Purity=99.980, 99.74, 99.60, 99.38, 99.18 and 98.40%) by dip method corrosion test. The corrosion test was carried out in 30%, 90% HNO3 at 30° by measuring the weight loss for 10 hours, and the corrosion rate was expressed as g/m2hr.
The results. obtained were as follows. (1) In cone. HNO3 the effect of purity of aluminium is very small. (2) In dil HNO3, the effect is small as far as purity of aluminium is above 9938%.
