247 magnesium-copper galvanic

Decreased numbers of red blood cells and hemoglobin were found in several workers with 7-20 years of experience in the galvanizing industry (McCord et al. 1926). However, there were excess tobacco use and alcohol consumption by workers and possible concurrent exposure to other chemicals (chloride, sulfide) which limit the study results. No anemia was detected among 12 workers exposed for 4-21 years to zinc oxide fumes in the production of brass alloys (Hamdi 1969). These workers may have also been exposed to magnesium, copper, and aluminum. 

Adhesives of HP type have been shown to bond bronze, lead, nickel, magnesium, copper, aluminum, steel, and stainless steel, in addition to most of the other substrates that earher offerings were capable of bonding. They did, however, continue to show weaknesses when zinc surfaces were bonded. So these adhesives may not be well suited for certain appKcations in the automobile area where galvanized steel is being bonded (Note that later generations covered in this chapter do not necessarily have this shortcoming). 

Vanadium is resistant to attack by hydrochloric or dilute sulfuric acid and to alkali solutions. It is also quite resistant to corrosion by seawater but is reactive toward nitric, hydrofluoric, or concentrated sulfuric acids. Galvanic corrosion tests mn in simulated seawater indicate that vanadium is anodic with respect to stainless steel and copper but cathodic to aluminum and magnesium. Vanadium exhibits corrosion resistance to Hquid metals, eg, bismuth and low oxygen sodium. 

The cathodic protection of plain carbon and low-alloy steels can be achieved with galvanic anodes of zinc, aluminum or magnesium. For materials with relatively more positive protection potentials (e.g., stainless steels, copper, nickel or tin alloys), galvanic anodes of iron or of activated lead can be used. 

Contact of brass, bronze, copper or the more resistant stainless steels with the 13% Cr steels in sea-water can lead to accelerated corrosion of the latter. Galvanic contact effects on metals coupled to the austenitic types are only slight with brass, bronze and copper, but with cadmium, zinc, aluminium and magnesium alloys, insulation or protective measures are necessary to avoid serious attack on the non-ferrous material. Mild steel and the 13% chromium types are also liable to accelerated attack from contact with the chromium-nickel grades. The austenitic materials do not themselves suffer anodic attack in sea-water from contact with any of the usual materials of construction. 

METAL FUME FEVER Non-specific, Self-limiting illness resembling an attack of influenza caused mainly by exposure to fumes of zinc, copper, or magnesium and less frequently due to exposure to other metal fumes. Exposures occur from molten metals, e.g. in smelting, galvanizing, welding. 

Isothiazoline is a widely used biocide, but it is not effective against anaerobic bacteria. It is deactivated by hydrogen sulfide leaks. Also, do not dose to closed systems (because of the presence of 0.2% copper and 2 to 3% magnesium salts, which are used as product stabilizers and can increase the risk of galvanic corrosion). Additionally, the high pH of closed-loop systems will hydrolyze isothiazoline. Automated feed systems may be useful for dosing isothiazolines due to the severe skin irritant nature of this material. 

The same overall redox reaction occurs if the magnesium metal is placed directly into a solution of copper sulfate, Figure 17.12. However, this is not a galvanic cell because the electrons do not flow through an external circuit. Instead, the electrons move directly from the magnesium metal to the copper ions, forming copper metal. This is a way to make copper metal from copper ions, but it is not a way to make electrical power. 

When a simple galvanic cell does useful work, it is called a battery. If the external circuit is connected with a wire, electrons flow from the site of oxidation at the magnesium strip and through the LED to the surface of the copper strip, where reduction of Cu + ions takes place. The voltage pushes electrons through the LED, causing it to light up. 

FERMC(III) SULFATE (10028-22-5) Fej(S04)3 Light sensitive. Hygroscopic hydrolyzed slowly in water , forming acid solution and precipitates hydroxide and phosphate salts. Violent reaction with strong bases. Aqueous solution (often shipped as 73% solution) is incompatible with sulfiiric acid, aluminum, caustics, alkylene oxides, ammonia, aliphatic amines, alkanolamines, amides, epichlorohydrin, organic anhydrides, isocyanates, magnesium, methyl isocyanoacetate, vinyl acetate. Corrosive to copper, copper alloys, and both mild and galvanized steel. 

A-(2-AMINOETHYL) PIPERAZINE (140-31-8) Combustible liquid (flash point 199°F/ 93°C). Aqueous solution is a strong base. Incompatible with strong oxidizers, organic anhydrides, acrylates, alcohols, aldehydes, alkylene oxides, substituted allyls, cellulose nitrate, cresols, caprolactam solution, epichlorohydrin, ethylene dichloride, isocyanates, ketones, glycols, nitrates, phenols, vinyl acetate. Exothermic decomposition with maleic anhydride. May increase the explosive sensitivity of nitromethane. Attacks aluminum, copper, magnesium, nickel, zinc, or their alloys, and galvanized steel. 

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