吹气发泡工艺中Ca对颗粒分散和泡沫稳定性的影响

摘要

The effect of Ca addition on particulate dispersion and foam stability in gas injection foaming process was investigated. The particulate size in the melt, the critical injection depth, the thickness of foam cell wall and the wetting angle of Al2O3 particulate on the bubble surface were viewed without and with Ca addition into A356 melt, respectively.The results show that the particulate size is smaller with addition of 1％ (mass fraction) Ca. Thus, it's easier to be dispersed for fine particulates with Ca addition. The critical injection depth of the melt becomes larger, so, the stability of aluminum foam becomes worse when adding calcium. The wetting angle of Al2O3 particulate on the bubble surface is about 65°, less than the ideal angle of 90°. With Ca, the wetting angle of the particulate decreases away from the ideal value. As a result, although the average size of the particulates decreases and the thickness of foam cell wall increases with Ca addition, the stability of the foam still becomes worse.%研究加入Ca元素对吹气法制备泡沫铝工艺中颗粒分散程度和泡沫稳定性的影响,考察加入质量分数为1%的Ca后A356铝合金熔体中陶瓷颗粒团聚尺寸、临界吹气深度、泡壁厚度和Al2O3颗粒在气泡界面处浸润角的变化.结果表明:加入Ca使熔体中颗粒团聚尺寸减小,令微小颗粒的分散变得容易,但使临界吹气深度增加,不利于泡沫的稳定;吹气法工艺中,Al2O3颗粒在气泡界面处的浸润角约为65°,小于理想值90°,加入Ca使颗粒的浸润性进一步远离理想值,因此,尽管加入Ca使颗粒团聚尺寸减小,但同时增大壁厚,泡沫的稳定性依然变差.