Kinetic interactions between aluminiuml_iquid and iron/steel_solid for conditions applicable to hot-dip aluminizing

Abstract

Hot-dip aluminizing of Remko iron, 0.05%C steel, and 0.17%C steel substrates has been carried out in the temperature range 673°-286° Cfor times from 5 to 300 s. Thickening of the iron-aluminium intermetallic layer obeys a parabolic time relationship at all temperatures except for the 0.17% C steel aluminized at 826°C. The temperature dependence of intermetallic layer thickening is exponential with an activation energy of the order of 170-180 kj/mol. This value is higher than that obtained in previous studies, and reasonsfor this discrepancy are given in terms of simultaneous growth and spalling of the intermetallic layer for dipping times in excess of 60 s.