Study On The Wettability Of Molten Aluminum On Non Metallic Substrates

Wetting of liquid on solid is a common phenomenon in the preparation and processing of materials. The sessile drop method was used to test the wetting behavior of the molten aluminum on graphite, titanium coated graphite, zirconium coated graphite and zirconium coated alumina in vacuum condition. This paper mainly studied the effect of film thickness on the wetting behavior of molten aluminum on nonmetallic substrates. The mechanism of the Ti and Zr film on wetting of molten aluminum on nonmetallic substrates was analyzed.The wetting behavior and interfacial phenomena of plain and zirconium-deposited alumina and bulk zirconium with liquid aluminum at 700?C was investigated by the sessile drop technique. Zirconium film deposited on alumina improved the wettability with aluminum and promoted the formation of the precursor film. With the increase of zirconium film thickness from 160 nm to 670 nm, final contact angle decreases gradually and spreading rate increased and the precursor film became wider and thicker. Marangoni flow resulting from the surface tension gradient due to the interfacial interaction is a major factor resulting in the formation of the precursor film.The wetting of molten Al on Zr-coated graphite was studied at 700?C and 750?C. The experimental results showed that Zirconium film deposited on graphite improved markedly the wettability with aluminum. Complete wetting of molten Al on Zr-coated graphite with thickness of 580 nm was achieved at 750?C within 2 minutes. With the increase of zirconium film thickness from 170 nm to 580 nm, final contact angle decreases gradually and spreading rate increased and the precursor film became wider. The increase of wetting temperature from700?C to 750?C may accelerate markedly the spreading of molten Al and decrease the final contact angle to a certain extent.The wetting of molten Al on Ti-coated graphite was studied at 750?C and 800?C. The experimental results showed that Ti film deposited on graphite improved markedly the wettability with aluminum and promoted the formation of the precursor film. The thickness of Ti film deposited on graphite has an important influence on the wettability with molten Al.With the increase of Ti film thickness from 310 nm to 590 nm, final contact angle decreases gradually and spreading rate increased and the precursor film became wider. The increase of wetting temperature from 750?C to 800?C may accelerate markedly the spreading of molten Al and decrease the final contact angle to a certain extent.