镁对铝与粉煤灰润湿性的影响

Effect of magnesium on wettability of aluminium melt on fly ash

用改进的座滴法测量了铝合金在粉煤灰上的润湿角。在铝中添加Mg能减小铝对粉煤灰的润湿角,由于Mg能在液滴表面挥发,破坏铝滴表面新产生的氧化铝,从而改善润湿性。粉煤灰中的SiO2、Fe2O3与铝发生反应,促进铝合金与基片的润湿,但铝滴表面Mg的挥发变慢,导致其破坏铝滴表面氧化铝的能力逐渐变弱,表层氧化铝的生长速度变快,同时SiO2、Fe2O3与铝反应减弱,反应性润湿影响变小,非反应性润湿在润湿过程中所起作用变大。

The contect angle of the aluminium alloy on fly ash was measured by improved sessile drop technique. Owing to the fact that Mg can volatilize on the liquid droplet surface and destroy the new aluminium oxide on droplet surface, adding Mg in aluminium can reduce the contact angle of aluminium on fly ash and improve the wettability. SiO_2 and Fe_2O_3 contained in fly ash can react with aluminium alloy and promote wetting of aluminium alloy with substrate. However, Mg volatilizing becomes slow on surface and the ability to destroy the aluminum oxide becomes weak gradually, then growth speed of aluminum oxide layer on surface becomes quick with the weakening of reaction of SiO_2, Fe_2O_3 and aluminium, then the reactivity wetting influence is reduced and the non-reactivity wetting affects chiefly on the contact course.