Beverage containers corrosion

Various materials are used in dental prosthetic practice for the preparation of dental implants, crowns, and bridges. Some of these materials contain copper, which is added in order to improve mechanical or/and chemical properties, but some of them may contain the copper as an impurity. Considering the fact that dental implants remain in the oral cavity for a long time, and that they are exposed to the corrosive action of oral fluids and various kinds of food and beverages, it is necessary to check their possible harmful effects upon the human health. 

The chief advantage of wood for containers is that many common species are free from harmful contaminants. For this reason wood had widespread use in the food and beverage industries, but it has now suffered severe competition from corrosion-resistant metals, plastics and paper products. Oak had a very extensive use in tight cooperage in the brewing industry, and its use for barrels still survives in the maturing of whisky and brandy and in the wine industries. Wood is particularly useful where acetic acid is present as this acid is corrosive to most common metals. 

Corrosion has been encountered infrequently to date and has been a surface type, as opposed to pitting corrosion that can result in perforations. Entrapped air in the beverage or in the cans headspace increases the corrosive action of the product according to Koehler et at (21). As with beer and other canned foods, aluminum ends provide electrochemical protection when combined with tinplate or tin-free-steel can bodies. The level of iron pickup is reduced while the amount of aluminum dissolved in soft drinks increases without detrimental effect. Aluminum containers with vinyl epoxy and vinyl organosol coatings are compatible with carbonated soft drinks. 

Some of the factors that contribute to the internal corrosion of tin plate cans are (i) the ratio and concentrations of citric to malic acids which in turn depend upon the strain of fruit, the extent of ripeness (ii) nitrate present in the fertilizers may find its way into fruits and vegetables and the nitrate may be reduced to hydroxylamine and support the detinning process (iii) pesticides containing dithiocarbomates may find their way in and attack iron (iv) phosphates, citrates and the low pH of cola-type beverage may dissolve iron (iv) meats, fish and peas contain sulfur-bonded protein molecules, which can decompose to H2S and attack the tin and iron, forming the respective sulfides. Hydrogen sulfide can react with Sn and Fe, yielding FeS and SnS, which are not poisonous, but impart some color to the canned product. 

Tin and lead are often used together in a variety of useful alloys, partly because the presence of a few percent of tin mixed with lead causes the alloy to be considerably harder than lead is alone. For example, common solder consists of about 50% Sn and 50% Pb. Type metal consists of about 82% Pb, 15% Sb, and 3% Sn. Pewter, an alloy used to make ornamental objects and vessels for food and beverages, consists of about 90% Sn with the remainder consisting of copper and antimony. Large quantities of tin are used as a coating for other metals, particularly steel, to retard corrosion. Alloys used as bearings often contain tin, antimony, and copper or aluminum. One such alloy is babbit, which consists of 90% Sn, 7% Sb, and 3% Cu. Several other commonly encountered alloys have various specialty uses. 

The energy of a corrosion reaction is used to prepare a meal that has a self-contained heat source. The heat comes from a packet containing a powder made of a magnesium-iron alloy and a separate packet of salt water. When the contents of the two packets mix, the reaction between the metal, salt water, and oxygen in the air releases enough energy to heat the food by 100°C in 15 minutes. The process is used to provide heated food or beverages to military personnel, truck drivers, and sports fans. 

Uses Preservative for foods, margarine, beverages, adhesives, cosmetics antimicrobial, preservative in pharmaceuticals lubricant for pharmaceutical tablets pyrotechnic ingred. corrosion inhibitor for aq. systems, antifreeze in closure-sealing gaskets for food containers... 

Metal cans that contain food or beverages employ a thin film of an epoxy polymer on its inside surface to control corrosion of the metal and to limit food contact with metal. Epoxy is ideally suited for this application, and the type of epoxy used is predominantly (over 98%) BPA-based. Both aluminum and steel beverage cans are typically sprayed with a water-based epoxy-acrylic system, often with an amino resin (or phenolic resin) to cross-link the lining (Oldring and Nehring, 2007). 

Figures 7 and 8 show two examples where aluminium is used in building industry The Place Ville Marie building in Montreal and a barn with painted aluminium siding at some ranch in the USA. The lustrous appearance and high resistance to corrosion is achieved by a special electrolytic process of anodization. The automobile industry is making extensive use of anodized aluminium, as exemplified by the automotive trim parts. In one of its major uses, that for cans containing various beverages, it has already penetrated every home practically all over the world.

CC. This also common grade contains 16 to 18% chromium and 11 to 14% nickel (316 SS). It also has molybdenum added to the nickel and chromium of the 304 material. The molybdenum is added to control pitting corrosion. Type 316 is used in chemical processing the pulp and paper industry for food and beverage processing and dispensing and in more corrosive environments. The molybdenum content must be a minimum of 2%. 

---