Showing papers on "Rust published in 2022"

Optimize Ni, Cu, Mo element of low Cr-steel rebars in tropical marine atmosphere environment through two years of corrosion monitoring

Abstract: To optimize Ni, Cu, Mo element content of low Cr steel rebars in tropical marine atmosphere environment, five newly steel rebars were exposed in Dalat to carry out the outdoor exposure tests including weight loss method, surface characterization method and electrochemical test. The results show that when 0.15 wt% Mo is added in the steel rebar, the corrosion resistance is 31.8% higher than that of the steel rebar with 0.3 wt% Cu. The corrosion resistance of 0.3 wt% Cr added steel rebar is 63.4% higher than that of 0.2 wt% Ni added steel rebar. With the addition of 0.3 wt% Cu and 0.3 wt% Cr, the corrosion resistance is 46.3% higher than that of the steel rebar with 0.2 wt% Ni and 0.15 wt% Mo. Mo and Cr are the main elements to improve the protection of steel rebar rust layer. The corrosion products of the five steel rebars are composed of α-FeOOH, γ-FeOOH and Fe2O3 or Fe3O4. The higher the content of Cr is, the higher the ratio of α - FeOOH to γ-FeOOH (α/γ) in the rust layer becomes. The protective layer composed of CaMoO4 and Fe2(MoO4)3, formed by molybdate in alkaline environment hinders the further corrosion of steel rebars. Cr(OH)3 produced by hydrolysis of Cr in low alloy steel inhibits the growth of FeOOH in rust, resulting in the decrease of FeOOH particle size and the rust layer more compact. On the whole, the newly designed low alloy steel rebar with a little of 1.6Cr-0.15Mo elements can be well used in tropical marine atmospheric environment.

Operational Control of Wheat Leaf Rust in a Hyper-continental Climate

Abstract: Observations of the infection of spring wheat with the leaf rust pathogen in the hyper-continental climate of the Ural region of the Russian Federation showed that the moderate and epiphytotic development of the phytopathogen took place in 58% of the years. It was during these years that the use of fungicidal plant protection products was mandatory to preserve wheat productivity and grain quality. The biological effectiveness of more than 90% against the local racial composition of leaf rust was provided by chemical preparations, especially the variants with combinations of active ingredients “propiconazole + tebuconazole” and “thiophanate-methyl + epoxiconazole” were distinguished. A microbiological preparation based on the bacterium Bacillus subtilis during the years of epiphytes provided a decrease in the development of this infection by only 35–47%. The yield of spring wheat for the period of research on the control variant of the experiment varied from 9–12 dt/ha in severely arid years to 39 dt/ha, on average during the research period it was 21.3 dt/ha. The use of chemical fungicidal plant protection during the years of epiphytes retained 32–45% of the yield or 7.0–9.4 dt/ha. In years with moderate leaf infections, the increase in productivity averaged 2.8 dt/ha. In arid years, in the second half of the growing season, the manifestation of leaf rust was single and had no economic significance.