Wettability effect on the flattening ratio of molten metal droplets

Plasma sprayed coatings are formed by a continuous deposition of numerous and molten droplets, which lead to a lamella structure. So it is very crucial to understand the interaction between molten droplets and substrates. Wettability is one of the factors governing the interaction. This report presents the influence of wettability of substrates by molten metal droplets on the flattening degree of splats. Using a free-fall apparatus of droplets, the metals, Sn, Pb, Cu and Fe are used for the experiments. Taking an equilibrium contact angle of metals into the energy balance for impingement of molten droplets, the relationship between the theoretical and experimental results shows approximately a good agreement in some R-e and W-e regions. (C) 2001 Elsevier Science B.V. All rights reserved.