Effect of niobium on corrosion resistance to sulfuric acid of 430 ferritic stainless steel

Abstract

The influence of niobium on corrosion resistance to 0.5M H2SO4 of 17% Cr ferritic stainless steels, to which it was added in amounts larger than that necessary to stabilize the interstitial elements, was investigated. Their performance was compared to that of other two Fe-17%Cr alloys, one without additions and another containing 0.93% molybdenum. Through weight and electrochemical measurements and through morphologic examination of corroded surface it was found that the corrosion of these alloys, with the exception of that containing molybdenum, proceeds in two different steps. In the first step (up to about 60 min) the corrosion rate practically does not change with time, the lower rates being displayed by alloys containing larger amounts of Nb. In the second stage the corrosion rate increases with time. The corrosion rate of Mo containing alloy is constant for all times.

Microscopic examination of the 2,300‐year‐old excavated steel plowshare from northern India

“…The titanium is a strong ferrite stabilizer and strong carbide former, which could lower the effective carbon content, thereby promoting a ferritic structure of stainless steel and also improves corrosion resistance . In austenitic steels, they are added to increase the resistance to intergranular corrosion and to increase the mechanical property at high temperature . In addition, low percentage of silica, alumina, lime, magnesia, and absence of wustite (FeO) indicates that high‐quality ore, as well as efficient working during whole smelting process, was implied by the smiths in the making of the ancient plowshare.…”

“…[23] In austenitic steels, they are added to increase the resistance to intergranular corrosion and to increase the mechanical property at high temperature. [24] In addition, low percentage of silica, alumina, lime, magnesia, and absence of wustite (FeO) indicates that high-quality ore, as well as efficient working during whole smelting process, was implied by the smiths in the making of the ancient plowshare. Figures 6 and 7 show the elemental X-ray mapping of a single-phase slag inclusion and two-phase slag inclusion, respectively.…”

Application of metallization coatings for protection of submersible electric motors of pumping equipment from influence of complicating factors in oil wells

“…Порошковый материал наносился методом высокоскоростного газопламенного напыления. Было установлено, что при воздействии 3 % NaCl покрытие обладает коррозионной стойкостью в течение 7 дней, а в [25,26].…”

Low-Cost and Durable Bipolar Plates for Proton Exchange Membrane Electrolyzers

“…Especially, the use of Pt 14 and Au 29 as surface modifiers to reduce contact resistance may end up in significant higher material costs. Niobium may be used as an alternative to Pt based on the superior corrosion protecting properties and stable behavior in acid environment 30 31 . Niobium coatings for bipolar plates of PEM water electrolyzers were investigated for the first time by Russell and co-workers 32 .…”