The attack of molten zinc on steels

Abstract

CaS und CaS04 bei pH = 12,6 hergestellt worden waren. Die Passivierungszeiten variierten zwischen 20 min und einigen Stunden, die Passivierungspotentiale zwischen E = -200 mVh und +800 mVh.Hauptbestandteil der Schichten sind nicht nur Fe und 0, sondern ebenfalls Ca; der Gehalt an schwefelhaltigen Spezies ist nur geringfugig. Die Tiefenprofile zeigen, da8 die Konzentration von Ca, Fe und 0 relativ konstant innerhalb der Passivschicht sind, unabhangig vom Passivierungspotential Unterschiede in den Tiefenprofilen in Abhangigkeit von der Passivierungszeit deuten auf einen strukturellen Einflua hin. Vergleiche mit Mischoxiden lassen vermuten, daO die Konzentrationen von Ca, 0 und Fe in der Passivschicht etwa der Zusammensetzung von 2Ca0 . Fez 0 3 entsprechen. Hinweise auf eine mogliche ,,Sandwich-Struktur" der Passivschichten bedurfen einer genaueren, experiment ellen Uberprufung. DanksagungEiner der Autoren (M. J.-C.) dankt der Humboldt-Stiftung fur ein Stipendium fur einen Studienaufenthalt am Max-Planck-Institut fur Eisenforschung, Dusseldorf.

Liquid metal corrosion of 316L, Fe3Al, and FeCrSi in molten Zn-Al baths

“…The linear nature of the thickness reduction rate is evident from this graph and the previous graphs. This linearity, however, contradicts the study by Lampe et al [10] in which it was stated that, in a zinc melt containing 4 pct aluminum, the time law for the corrosion of steel was found to be parabolic up to 500 °C. Our study indicates a linear time law at 490 °C in a zinc bath containing 5 pct aluminum.…”

The corrosion of intermetallic alloys in liquid zinc

“…The diffusion coefficient of chromium in Fe 3 Al is very low at 450 • C (D v (Cr/Fe 3 Al) 450 • C = 3.2 × 10 −31 m 2 s −1 ) [10]. The present study suggested that the chromium dissolution occurred before the new phase formation [8]. Indeed, if the Cr diffusion appeared from the metallic blocks of the corrosion layer, a concentration gradient should be observed between the "liquid metal/corrosion layer" interface and the "corrosion layer/solid matrix" one; at the first interface the Cr content should be much lower than at the second one.…”

“…Liquid metal corrosion can proceed via various processes: dissolution, formation of intermetallic compounds at the interface, penetration of liquid metal along grain boundaries, which depend on experimental factors such as: temperature, thermal gradients, solid and liquid compositions, velocity of the liquid metal [8]. The corrosion of Fe 3 Si, Fe 3 Al and Ni 3 Al in molten zinc was controlled by the dissolution mechanism.…”

Stability investigation of electrodeposited zirconium diboride ceramic coatings in molten zinc

“…After processing in molten zinc, steel components exhibit excellent anti‐corrosion properties in corrosive environments like atmosphere, sea water, and soil. However, working parts like sink rolls, stability rolls and bearings in continuous galvanizing lines suffered rigorous attack by molten zinc at 460–650 °C and their service life was greatly shortened as a consequence of corrosion . Therefore, it is of great practical significance to promote the corrosion resistance of steels in molten zinc, which can reduce the frequent maintenance and replacement of components in galvanizing lines.…”