In the presence of biofilms, stainless steels （SS） exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential （Eco,） behavior of the duplex SS UNS S32760 was rec...In the presence of biofilms, stainless steels （SS） exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential （Eco,） behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo, Southeastern Brazil. The biofilm at Forno Harbor （an anthropogenically disturbed area） was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms （especially Navicula sp.） on day 10 and dinoflagellates on day 18, whereas no clear trend was recorded at Cabo Frio Island （an undisturbed area）. The ennoblement of Ecor values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Eco values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in imnortant gaps in this knowledge.展开更多
The microstructure of hot-dip galvanized Zn-ll%A1-3%Mg-0.270Si alloy coating was studied in this article. X-ray diffraction analysis revealed the coating is composed by Zn, A1 and MgZn2 phase. Optical microscope （OM...The microstructure of hot-dip galvanized Zn-ll%A1-3%Mg-0.270Si alloy coating was studied in this article. X-ray diffraction analysis revealed the coating is composed by Zn, A1 and MgZn2 phase. Optical microscope （OM） and scanning electron microscope （SEM） observations showed the coating is occupied by snowflake-like dendrite, double hexagonal organization and eutectic. The coating backbone was the dendrite considered to be a phase of hexagonal close-packed （HCP） structure judging form its morphology according to the crystal growth way in the coating. Transmission electron microscopy （TEM） and energy dispersive spectroscopy （EDS） researches on the dendrite suggested that an intermediate Zn-A1 phase was formed at high temperature, then decomposed into a type of Zn-A1 granular eutectoid after cooling down to room temperature, while the eutectoid Zn and A1 had a certain crystallographic relationship. The coating solidification process and the grain crystal structure were discussed.展开更多
文摘In the presence of biofilms, stainless steels （SS） exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential （Eco,） behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo, Southeastern Brazil. The biofilm at Forno Harbor （an anthropogenically disturbed area） was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms （especially Navicula sp.） on day 10 and dinoflagellates on day 18, whereas no clear trend was recorded at Cabo Frio Island （an undisturbed area）. The ennoblement of Ecor values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Eco values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in imnortant gaps in this knowledge.
文摘The microstructure of hot-dip galvanized Zn-ll%A1-3%Mg-0.270Si alloy coating was studied in this article. X-ray diffraction analysis revealed the coating is composed by Zn, A1 and MgZn2 phase. Optical microscope （OM） and scanning electron microscope （SEM） observations showed the coating is occupied by snowflake-like dendrite, double hexagonal organization and eutectic. The coating backbone was the dendrite considered to be a phase of hexagonal close-packed （HCP） structure judging form its morphology according to the crystal growth way in the coating. Transmission electron microscopy （TEM） and energy dispersive spectroscopy （EDS） researches on the dendrite suggested that an intermediate Zn-A1 phase was formed at high temperature, then decomposed into a type of Zn-A1 granular eutectoid after cooling down to room temperature, while the eutectoid Zn and A1 had a certain crystallographic relationship. The coating solidification process and the grain crystal structure were discussed.
