Papers by Keyword: Microbiological Corrosion

Abstract: The article considers malfunctions in operation of sewage collectors and their causes. A system is presented for forecasting the critical technical condition of the sewage system pipeline. An example is supplied of using a measuring complex on operating sewage facilities of St Petersburg.

Abstract: The microbiological corrosion of cement based composite material is increasingly acute, which has caused great economic losses. To improve cement based composite material's performance, by using compound modification technology, selecting cement type, more suitable admixture and additive to make up concrete, improving concrete's comprehensive performance of corrosion resistance. Meanwhile through the performance comparison test validate the modified effect.

Abstract: Hydroquinone derivatives are studied as inhibitors of microbiological corrosion and hydrogen absorption by mild steel in water salt media that supports development of sulfate reducing bacteria (SRB). The chosen composition of the media is close to sea water containing biogenic H2S. Н2S content, bacterial titer in corrosive media, its pH, Redox potential Eh, and φ of steel together with the quantity of hydrogen absorbed by surface steel sub-layers, were measured. Protective action against corrosion achieved by the best compounds studied, reached the values of 65…84%, while against hydrogen absorption by steel samples − 60…72%. The presence of the studied derivatives of hydroquinone at concentration C= 5 mMoldm–3 resulted in the decrease of SRB cell count at the rate of 48…84%, the suppression rate being at the values of 29…57%.

Abstract: The growth and the corrosion behaviors of thermophilic sulfate reducing bacteria (SRB), desulfotomaulum thermocisternum strain ST90, were studied in this work. It was found that the growth curves and the main reduction products were influenced greatly by the growth temperatures. The time of the exponential phase and the stable phase decreased with the increase of growth temperatures. The reduction product of this kind of SRB was mainly H2S when it grew at 60°C. With the decrease of growth temperatures, thiosulfate came up as an internal reduction product. The thiosulfate was re-reduced by SRB at the growth temperatures of 40 and 50°C. When the growth temperature came to 30°C, no H2S was generated. The regulation of corrosion rate changed was coincident with the changes of the main reduction products of the SRB. This kind of SRB could accelerate the corrosion rate of carbon steel when grew at higher temperature. But the corrosion rate of carbon steel could be inhibited when it grew at 30°C.

Abstract: The new high-strength stainless steels alloyed by copper and nitrogen and possessing high resistance to corrosion by active micro-organisms in carbon-oxidizing, heterotrophic and sulfate-regenerating bacteria mediums are developed. The introducing of small addition of nitrogen (about 0.22 %) to the corrosion resistant steel С0.5Cr15Ni5Cu2NMoNbTi results in a decrease of adhesive micro-organisms quantity on a sample surface by 8 times, while increasing of nickel content to 9 % results in their decrease only by 2 times. It is supposed that the effect of nitrogen can be related to formation of biocide substances. High copper (Cu = 2.5-5 %) nitrogen-containing cast steels are in austenitic (non-magnetic) condition. Due to a dendritic segregation, the structure of steel corresponds to a natural composite structure, and it is preserved on heating to high temperatures. After cold deformation with up to 85 % reduction, the steels preserve austenitic structure, and its hardness attains a level close to the hardness level of the martensitic structure. The developed corrosion-resistant antimicrobial steels with the increased hardness can be used as a material for the surgical instrument.