Abstract
The effect of ultrasonic waves on the anodizing of aluminum was studied in terms of synergism in the presence of glass beads.
The baths used were sulfuric acid (1∼15w/v%) at 20∼40°C, frequencies of 28∼1000kHz, power outputs of 100∼60W and current densities of 1∼2A/dm2.
It was found that the coatings formed under ultrasonic waves were thicker and much harder than those formed without ultrasonic waves.
The best results were obtained with a 15w/v% bath at 400kHz and a 1w/v% bath at 28kHz.
Dissolution of the coatings in 5∼15w/v% baths by 28∼100kHz ultrasonic waves was also investigated.
It is suggested that effects of ultrasonic waves during anodizing were to increasing the dissosiation of aluminum ions and to promote the decomposition of oxygen supplyers (OH-).
