Effects of Micro-Sized Ferrite and Austenite Grains on the Pitting Corrosion Behavior of Lean Duplex Stainless Steel 2101

Abstract

Abstract:The connection between the austenite transformation and pitting corrosion of lean duplex stainless steel LDX 2101 was investigated at different annealing temperatures in the range 950-1200 • C. Optical microscopy, scanning electron microscopy, and electrochemical techniques were employed in the present work. Results indicated that micro-sized ferrite and austenite grains, formed with the increase of annealing temperature, influenced the pitting corrosion resistance of the studied stainless steel. As the austenite phase transformed into ferrite, the micro-sized ferrite grains were produced in austenite domains with temperature increase from 1000 • C to 1100 • C, especially at 1050 • C. In these conditions, the corrosion resistance of LDX 2101 was reduced by the micro-sized ferrite grains. A further increase of annealing temperature to 1150 • C produced the presence of micro-sized austenite grains in the ferritic phase, due to an incomplete transformation of austenite to ferrite. They represent new sites for severe pitting attacks and therefore the corrosion resistance of LDX 2101 was the weakest. The sample annealed at 1200 • C, with few micro-sized austenite grains in the ferritic matrix, exhibited excellent corrosion resistance. Moreover, a schematic was used to illustrate the pitting corrosion of the samples annealed at different temperatures.

Patterns of differentiation of the old arable horizon of fallow soils according to the content of mobile forms of manganese and copper

“…The study of the patterns of changes in the content of various HM forms in fallow soils can be very informative for predicting their behavior under the influence of fallow plant communities in the long term. The further use of HM-contaminated lands is becoming an increasingly serious problem in agriculture [11] and the conversion of lands to fallow land, if it is impossible or expensive to clean 1045 (2022) 012059 IOP Publishing doi:10.1088/1755-1315/1045/1/012059 2 them up, may turn out to be an increasingly popular practice in the future. At the same time, pollution of fallow soils with high concentrations of available forms of toxic HMs can affect the state of vegetation and soil microorganisms [8;12] and, as a consequence, determine sequestration processes of atmospheric carbon in fallow lands.The goal of the work: to study the patterns of differentiation of the old arable horizon of fallow soils in terms of the content of mobile forms of manganese and copper and the influence of changes in the content of alkali-soluble organic matter (OM P ) and exchange acidity on this process.…”