メッキにおける超音波の応用

Abstract

Various workers have reported the effects of ultrasonic waves on the electro-deposition of metal. In this paper, the effect of ultrasonic irradiation on bright nickel plating in watt type bath, as shown table 1., and particulary the effect of the frequency and intensity of ultrasonic waves were studied. For this purpose, two sorts of generator which have frequency of 20kc. and 450kc, were used, and the measurement of accoustic pressure, instead of the intensity, were observed before the experiment was begun. The ultrasonic weves ware irradiated striking parallel to the specimen surface as shown in fig. 2..The following results concerning charactaristics of the deposite were obtained.1. It was seemed that no changes of the decomposition potential was observed as compare to the ordinary plating.2. The cathodic current efficiency with the use of high frequency was slightly higher than the efficiency with the use of low, but details of them were not clearly. However, the use of ultrasonics rised the upper limit of the effective current density.3. Pinholes at the electro-deposition was certainly less with the use of low frequency, especially, it was remarkable at high current density.4. The higher intensity brought out the larger hardness of the deposite in the range of considerablly high intensity side. This large hardness was considered as the effect of certain work due to alternating changes of pressure caused by ultrasonic wave motion.5. An excellent brightness was observed with the use of low frequency, but, some times, the stripes pattern caused by standing wave appeared with the use of high frequency.6. Generally, the effect of combination of ultrasonic irradiation and mechanical stirring was superposed the each good charactaristics of the two respectively.From the above, we can say that the precision measurement of intensity in the plating bath and intensites which variate in wider range especially lower side are neccessery. These two are important on the dractical utilization to cut down the initial cost of the instrument. Effect on the changing of the direction of ultrasonic irradiation to specimens, hydrogen brittleness, throwing power, and leveling power will be studied as next work.