The effect of sulfate reducing bacteria (SRB) on electrochemical corrosion behavior of 16Mn steel, and galvanic corrosion behavior of the steels in the juncture area between bacterial and bacteria free sea mud was stu...The effect of sulfate reducing bacteria (SRB) on electrochemical corrosion behavior of 16Mn steel, and galvanic corrosion behavior of the steels in the juncture area between bacterial and bacteria free sea mud was studied in laboratory under simulated conditions. Sea mud dense with SRB was taken from the Qingdao beach. Part of the sea mud was sterilized and the rest was kept in the original condition. The sterilized and original sea mud was put respectively into two plastic testing troughs electrically connected by an agar potassium chloride salt bridge. Galvanic and non galvanic 16Mn steel samples were put into the trough at the same intervals. The SRB number measured by the MPN tri tube method was about 2.4×10 5 per 100 g mud and was kept basically the same during the experimental period. The ρ, pH, eH, T, S (salinity) were measured simultaneously. The galvanic current was measured with zero resistance galvanometer and the corrosion rate was measured with the weight loss method.The results showed that (1) the corrosion rate of 16Mn steel in bacterial sea mud was 4.0 times that in bacteria free sea mud; (2) galvanic corrosion occurs between steel samples buried in different (bacterial and bacteria free) sea mud. The steel sample in the bacterial sea mud was the anode of a galvanic couple and had higher corrosion rate than that of the non galvanic sample. The existence of the galvanic couple increased the corrosion rate of the sample in bacterial sea mud by 4.1%.展开更多
To save freshwater, people want to replace freshwater with seawater for cooling in industry. However, in seawater cooling system, the corrosion of the outlet of heat-exchanger and its following steel components is ver...To save freshwater, people want to replace freshwater with seawater for cooling in industry. However, in seawater cooling system, the corrosion of the outlet of heat-exchanger and its following steel components is very serious. Application of Al sacrificial anode is one effective method to prevent steel equipment in seawater from corrosion, but at 50℃, Al anodes in common use are not applicable. So it is important to study the relevant rules governing Al anode performance at high temperature. Since the working potential is an important factor affecting the performance of Al anode, we try to find the rules governing how additional elements affect the working potential at various temperature. Twenty-eight kinds of Al sacrificial anode were made for the experiment by the method of the Chinese National Standard GB4948—85. The interrelation of additional elements in the Al anode and the working potential of anode were studied by the method of grey box analysis. The results showed that the influencing order of elements on the working potential was the same on the whole; and that In, Zn, Mg and Ga were good additional elements for aluminum sacrificial anode in order to get negative working potential.展开更多
基金supported by the"Ninth-Five Plan"Great Project of the Chinese Academy of Sciences(KZ951-A1-405-04).
文摘The effect of sulfate reducing bacteria (SRB) on electrochemical corrosion behavior of 16Mn steel, and galvanic corrosion behavior of the steels in the juncture area between bacterial and bacteria free sea mud was studied in laboratory under simulated conditions. Sea mud dense with SRB was taken from the Qingdao beach. Part of the sea mud was sterilized and the rest was kept in the original condition. The sterilized and original sea mud was put respectively into two plastic testing troughs electrically connected by an agar potassium chloride salt bridge. Galvanic and non galvanic 16Mn steel samples were put into the trough at the same intervals. The SRB number measured by the MPN tri tube method was about 2.4×10 5 per 100 g mud and was kept basically the same during the experimental period. The ρ, pH, eH, T, S (salinity) were measured simultaneously. The galvanic current was measured with zero resistance galvanometer and the corrosion rate was measured with the weight loss method.The results showed that (1) the corrosion rate of 16Mn steel in bacterial sea mud was 4.0 times that in bacteria free sea mud; (2) galvanic corrosion occurs between steel samples buried in different (bacterial and bacteria free) sea mud. The steel sample in the bacterial sea mud was the anode of a galvanic couple and had higher corrosion rate than that of the non galvanic sample. The existence of the galvanic couple increased the corrosion rate of the sample in bacterial sea mud by 4.1%.
文摘To save freshwater, people want to replace freshwater with seawater for cooling in industry. However, in seawater cooling system, the corrosion of the outlet of heat-exchanger and its following steel components is very serious. Application of Al sacrificial anode is one effective method to prevent steel equipment in seawater from corrosion, but at 50℃, Al anodes in common use are not applicable. So it is important to study the relevant rules governing Al anode performance at high temperature. Since the working potential is an important factor affecting the performance of Al anode, we try to find the rules governing how additional elements affect the working potential at various temperature. Twenty-eight kinds of Al sacrificial anode were made for the experiment by the method of the Chinese National Standard GB4948—85. The interrelation of additional elements in the Al anode and the working potential of anode were studied by the method of grey box analysis. The results showed that the influencing order of elements on the working potential was the same on the whole; and that In, Zn, Mg and Ga were good additional elements for aluminum sacrificial anode in order to get negative working potential.
