The growth kinetics of zeta-FeZn13, delta1-FeZn7, Gamma1-Fe5Zn21, and eta-Fe2Al5 phase dross particles that form in molten Zn-Al baths experimentally was investigated to propose the growth mechanism of their dross particles under the condition of no stirring. The morphologies of zeta, delta1, Gamma1, and eta-Fe2Al5 phase dross particles were an elongated rectangular shape, plate like hexagonal shape, polyhedral shape, and polyhedral shape with 14 plane faces, respectively. Every dross particle has some habit planes and grows while keeping stable planes. Their morphologies are supposed to be the equilibrium shapes by the Wullf theorem. The cubic mean particle radius of every phase dross increases linearly with holding time. The mean particle diameter of zeta at 733 K, delta1 at 843 K, Gamma1 at 713 K, and eta-Fe2Al5 phase dross at 733 K, were about 37, 20, 70 and 35 micrometers after 7 days, respectively. The growth mechanism of every dross particle is proposed as the Ostwald ripening controlled on diffusion of solute through solvent by theoretical simulations. The growth rate was found to be larger in order of Gamma1, zeta, eta-Fe2Al5, and delta1 phase dross particles at the same bath temperature by estimating the growth rate constant.
Growth mechanism of dross particles in molten ZN baths
2001
8 Seiten, 10 Bilder, 4 Tabellen, 28 Quellen
Aufsatz (Konferenz)
Englisch