Multi-metal protection

What s more, inhibited films protecting ferrous as well as nonferrous metals exist in the range of anticorrosion materials [8] films for multi-metal protection are also known. 

Uses Detergent base with rust inhibitor for multi-metal protection against flash rusting... 

In modern practice, inhibitors are rarely used in the form of single compounds — particularly in near-neutral solutions. It is much more usual for formulations made up from two, three or more inhibitors to be employed. Three factors are responsible for this approach. Firstly, because individual inhibitors are effective with only a limited number of metals the protection of multi-metal systems requires the presence of more than one inhibitor. (Toxicity and pollution considerations frequently prevent the use of chromates as universal inhibitors.) Secondly, because of the separate advantages possessed by inhibitors of the anodic and cathodic types it is sometimes of benefit to use a formulation composed of examples from each type. This procedure often results in improved protection above that given by either type alone and makes it possible to use lower inhibitor concentrations. The third factor relates to the use of halide ions to improve the action of organic inhibitors in acid solutions. The halides are not, strictly speaking, acting as inhibitors in this sense, and their function is to assist in the adsorption of the inhibitor on to the metal surface. The second and third of these methods are often referred to as synergised treatments. 

Each metal or alloy in a multi-metal circuit must be protected by its own inhibitor(s). This explains the complexity of certain formulations of liquid inhibitors used for certain circuits. 

Thermoplastic acrylics are used in a variety of applications for metal, both directly (e.g. in Light Industrial) and as part of a multi-coat system (e.g. in Off-shore and Marine). Fast drying, water-white colour and good compatibility with other polymers as well as exterior durability are the properties which attract their use in coatings for metal protection. 

Many plastic products are decorated to make them multi-colored, add distinctive logos, or allow them to imitate wood, metal and other materials. Some plastic products are painted since their as-molded appearance is not satisfactory, as may be the case with reinforced, filled or foamed plastics. Painting or coating is also for product protection. The following section will discuss some of the secondary operations frequently used with plastics. Since plastics vary widely in their ability to be machined and to accept finishes,... 

It is generally known that only a very limited number of packaging materials such as glass or metal provide absolute protection properties concerning the penetration of chemical compounds from layers behind or from the environment. In the case of multi-layers with plastics materials as functional barriers there occurs, in most cases to a certain extent, an unavoidable mass transfer from the plastics layers into the product. This must be understood as a functional quantity which, however, must comply with food regulations. Therefore it is necessary firstly to understand functional barrier characteristics and mechanisms and, secondly, to define the functional barrier efficiency in relation to food safety and to establish appropriate test methods. This is especially important with those food packaging applications where recycled plastics are covered by plastics functional barriers. 

A basic concept of the catalyst combination system is that pretreatment catalyst, such as HDM catalyst, loaded in the upper section of a reactor removes the deactivation components included in feed residual oils, and it protects the desulfurization catalyst and the hydroconversion catalyst loaded in the latter section of reactor. Several bench plants which had multi-reactor systems and intermediate product sampling systems were operated to investigate the deactivation behavior and metal accumulation of each catalyst. The required temperature and the metal accumulation can be calculated through the analysis of each intermediate product for sulfur levels and metal levels. 

Another method by which metals can be protected from corrosion is called alloying. An alloy is a multi-component solid solution whose physical and chemical properties can be tailored by varying the alloy composition. 

---