Aluminium- and magnesium-based

Both metals are applied to copper-base alloys, stainless steels and titanium to stop bimetallic corrosion at contacts between these metals and aluminium and magnesium alloys, and their application to non-stainless steel can serve this purpose as well as protecting the steel. In spite of their different potentials, zinc and cadmium appear to be equally effective for this purpose, even for contacts with magnesium alloys Choice between the two metals will therefore be made on the other grounds previously discussed. 

As another example, the titanium-based alloys may be mentioned. Their application in the aircraft industry permitted the barrier imposed by elevated temperature at high speed to be overcome, which had previously ruled out the use of aluminium and magnesium alloys, and new generations of airplanes were built with technical success. 

B. M. Mikhailov, Yu. N. Bubnov, A. V. Tsyban, and K. Base. Synthesis of allyl(alkyl) boranes using aluminium and magnesium compounds. Izvest. Akad. Nauk S.S.S.R. Ser. khim., 1978, 27, 1586. 

Theoretically, most inhibitors only selectively inhibit the corrosion of certain metals. Coolants developed for aluminium and cast iron may not always be suitable for magnesium alloys. Nevertheless, the possibility eannot be excluded that some inhibitors used in particular commercial coolants for aluminium and iron-based alloys may fortuitously also have some inhibition effect on magnesium. 

Recent progress in the development of synthetic routes to metal fluorides, particularly those of aluminium and magnesium, which have high surface areas, has been described in earlier chapters of this volume. The significant catalytic properties of these high surface area (HS) materials have also been emphasized. Here we examine the surface acidities, both Lewis and Brpnsted, of newly synthesized fluorides based on Al and Mg centres and pose the question What is meant by a strong acid in an heterogeneous context ... 

Inorganic compounds such as aluminium hydroxide, sodium bicarbonate, and magnesium and calcium carbonates are commonly used as antacids. There is much scope for the redesign of these agents to achieve fine control of local pH values in the gastrointestinal tract via control of the rate of release of the active bases (e.g., from insoluble compounds). 

If the percentage base saturation as defined above is 60%, this provides an indication of the need for estimation of exchangeable aluminium and hydrogen, in addition to calcium and magnesium, by the ECEC procedure. 

A number of cylindrical and flat magnesium-based cells have been developed on a commercial scale, mainly for military applications where high discharge currents and low unit weight are important. However, for most of these applications, magnesium batteries have now been replaced by various lithium/organic systems. There are no commercial aluminium-based Leclanchd cells. Magnesium and aluminium are both exploited as anodes in metal-air cells which are considered below. 

Conventional thin-layer chromatography (TLC) in our experience, known under the name planar chromatography, uses horizontal or vertical glass or Teflon chambers for the development of chromatograms. As stationary phases, commonly known adsorbents or supports based on silica gel, aluminium oxide, magnesium silica, cellulose, and so forth are used particle sizes are about 20 jitm. The migration of the mobile phase is based on the phenomenon of capillary forces. This chromatographic method is described, in detail, in other sections of this volume. 

Intergranular corrosion occurs in stainless steels and alloys based on nickel, aluminium, magnesium, copper and cast zinc. In the following sections we shall look at the three former groups in some detail. 

A synthetic or man-made diamond material is now available which is extremely tough with a hardness approaching that of natural diamond. A layer of this synthetic diamond material is bonded to a tough shock-resisting base of cemented carbide for use in the form of tips. The range of application is on non-ferrous metals such as aluminium alloys, magnesium alloys, copper, brass, bronze and zinc alloys and non-metallic materials such as ceramics, porcelain and plastics. This material will also machine fully sintered tungsten carbide. 

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