Wetting improvement of carbon or silicon carbide by aluminium alloys based on a K2ZrF6 surface treatment: application to composite material casting

• Published in: Journal of materials science Vol. 24; no. 8; pp. 2697 - 2703
• Main Authors: ROCHER, J. P, QUENISSET, J. M, NASLAIN, R
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.08.1989
• Subjects: Applied sciences; Exact sciences and technology; Metals. Metallurgy; Powder metallurgy. Composite materials; Production techniques
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/BF02385613

A surface treatment with aqueous solutions of K2ZrF6 dramatically improved the wetting of carbon (or SiC)-base ceramics by liquid light alloys at low temperatures (i.e. within the 700 to 900 C range). The mechanism which is possibly responsible for this involves two steps: K2ZrF6 reacts with Al with the formation of K3AlF6, other complex fluoride species and intermetallics; K3AlF6 dissolves the Al2O3 thin layer, coating the liquid light alloy and enables the wetting of the ceramics. The mechanism was deduced from sessile drop experiments, solid state chemistry experiments and composite casting. The K2ZrF6 surface treatment appears to be particularly suitable for processing composite materials made of carbon (or SiC) fibrous preforms and Al base matrices according to techniques directly derived from the light alloy foundry. 17 refs.