<b>Corrosion resistance of laser-cladded 304L stainless steel enriched with ruthenium additions exposed to sulphuric acid and sodium chloride media

</b><br>J van der Merwe, D Tharandt

<br><br>
The corrosion behaviour of 304L stainless steel laser-cladded with various
amounts of ruthenium (Ru) was evaluated in solutions of sulphuric acid
and sulphuric acid plus sodium chloride at 25°C and 45°C by open-circuit
potential and cyclic potentiodynamic polarization tests. In general, the
addition of Ru to the stainless steel increased its corrosion resistance in
1 M H2SO4, as well as in 1 M H2SO4 plus 1 wt% NaCl. This was observed
for a number of parameters such as corrosion rate, corrosion potential,
open-circuit potential, and current density. However, increasing the
amount of Ru added beyond a certain level did not result in further
improvement in corrosion protection. For each environment there is an
optimal Ru concentration for the best corrosion protection. For example, in
1 M H2SO4 at 25°C, 2.44 wt% Ru shows the least active surface in terms of
corrosion. Further research into ruthenium coatings on stainless steels is
recommended.<br>
Keywords: corrosion protection, ruthenium, laser cladding, 304 stainless steel.