Isothermal Oxidation Behavior of Aluminized AISI 1020 Steel at the Temperature of 700 Derajat Celsius
ABSTRACT: The AISI 1020 steel
was coated by dipping it into the molten Al bath at 700 °C for 16s. The coating
layer formed on the steel substrate is consisting of Al with a little Fe, FeAl3
and Fe2Al5 layers. The morphologies of the FeAl3 and Fe2Al5 layers are platelet
and columnar structures, respectively. The oxidation test was carried out
isothermally at 700 °C for a various time of 149 h in static air. The
oxidation behaviors of both of the bare steel and the aluminized steel were studied
by the oxidation kinetics, surface morphologies and phase transformation after
oxidation testing. The oxidation
products were characterized
using Optical Microscope
(OM), Scanning Electron Microscopy
with Electron Dispersive
Spectroscopy (SEM/EDS) and
X-ray diffraction analysis. The
magnitude of the rate constant (kp) of the aluminized steel is two order lower
than the bare steel. The formations of intermetallic phases on the steel
substrate for a shorter time are dominated
by the interdiffusion between
the inward diffusion
of Al-atoms into
the steel substrate and
outward diffusion of
Fe-atoms. The constituent
phases in the
aluminide layer compose of
FeAl2, Fe2Al5 and
FeAl. The formation
of FeAl phase
is controlled by
the inward diffusion of Fe- atoms
into the Fe2Al5 phase. The improvement of the oxidation resistance of the aluminized
steel subjected to severe oxidation is due to the formation of protective Al2O3
scale.
Author: Mohammad Badaruddin,
Suharno, Hanif Ari Wijaya
Journal Code: jptmesingg140002
