Flux-assisted wetting and spreading of Al on TiC

The effect of a K–Al–F-based flux on the spreading of Al on TiC, at temperatures up to 900 °C, in Ar and in air has been studied. Whilst obtuse contact angles were observed without flux, the flux facilitated rapid spreading to a perfect wetting condition, in both Ar and in air. The atmosphere was found to have a weak effect on the spreading kinetics as the liquid flux provides a locally protective atmosphere by spreading over the TiC surface and also on the solid surface of Al. The flux dissolves the aluminium oxide, covering Al, so that when Al melts, and the oxide layer has been removed or weakened, intimate contact occurs between liquid Al and the TiC substrate facilitating spontaneous spreading and instantaneous wetting of liquid Al on TiC. Since flux-assisted spreading is very rapid and occurs without the formation of a reaction layer at the Al/TiC interface, this process is very different to the reactive wetting behaviour previously reported in the Al–TiC system.

The figure above shows the effect of a K–Al–F-based flux on the spreading of Al on TiC. The rapid spreading times and absence of thick reaction layers at the Al/TiC interface are very different to the reactive wetting behaviour previously reported in the Al–TiC system.Figure optionsDownload high-quality image (91 K)Download as PowerPoint slide