Aluminum anodizing applications

Pure aluminum is used in the electrolysis protection process, which does not passivate in the presence of chloride and sulfate ions. In water very low in salt with a conductivity of x < 40 yUS cm" the polarization can increase greatly, so that the necessary protection current density can no longer be reached. Further limits to its application exist at pH values < 6.0 and >8.5 because there the solubility of Al(OH)3 becomes too high and its film-forming action is lost [19]. The aluminum anodes are designed for a life of 2 to 3 years. After that they must be renewed. The protection currents are indicated by means of an ammeter and/or a current-operated light diode. In addition to the normal monitoring by service personnel, a qualified firm should inspect the rectifier equipment annually. 

Cobalt(II) acetate is used for bleaching and drying varnishes and laquers. Other applications are as a foam stahihzer for beverages in sympathetic inks as a mineral supplement in animal feed and as a catalyst for oxidation. It also is used in aluminum anodizing solutions. 

Cokes derived from resids or blends of resids with other petroleum feedstocks give high CTE values and are utilized as fillers for aluminum anodes and certain specialty carbon and graphite products. The remaining properties differ depending on the final application. Alow ash content is required for... 

The preparation of three-, five- and six-membered rings in modest yield by the elec-trochemically induced coupling of activated olefins with dihalides has been reported (equation 35)98. Use of an aluminum anode was critical for the formation of cyclized product. Application of this technique to the preparation of four-membered rings was unsuccessful. 

Chromium trioxide is used in the following applications in chromium plating, in copper stripping, in aluminum anodizing, as an anticorrosive, in photography, in hardening microscopic preparations, and in purifying oil and acetylene. 

However, none of these new applications of dialysis, with the possible exception of acid recovery in aluminum anodizing, appears to have progressed beyond the pilot-plant scale, and today the only mejor application of dialysis remeins hemodialysis for the treatment of renal failure. 

AFM investigation of aluminum surface after anodic treatment was performed. It was shown that electropolishing in HCIO4 based solutions and long-time anodic oxidation result in formation of highly ordered nanorelief on the aluminum surface. Applications of such treatments in nano- and optoelectronics are discussed. 

Aluminum and aluminum-zinc alloy anodes have become the preferred sacrificial anodes for the cathodic protection of offshore platforms. This preference is because aluminum anodes demonstrate reliable long-term performance when compared with magnesium, which might be consumed before the platform has served its useful hfe. Aluminum also has better current/weight characteristics than zinc. Weight can be a major consideration for large offshore platforms. The major disadvantage of aluminum for some applications, for example, the protection of painted ship hulls, is that aluminum is too corrosion resistant in many environments. Aluminum alloys will not corrode reliably onshore or in freshwater [37]. In marine... 

Hydrogen produced from the decomposition of anunonia (600 °C) can be often used for feeding alkaline fuel cells, particularly suited for portable power applications. The performance of this reaction was developed by Ganley et al. [79] over a proper MSR configuration (Ru supported on aluminum-anodized alumina microchannels) resulting in a H2 production equivalent to 60W with an ammonia conversion of 99%, all in a volume of 0.35 cm, which exceeded the specifications for practical use laid out until that moment. 

Rechargeable lithium batteries have been introduced into the market on a limited scale. Coin cells, using lithium-aluminum anodes, are available for special applications mainly for low-power portable applications where they can be conveniently recharged, in some instances by solar cells. A small cylindrical cell, using a lithium anode, was briefly, and perhaps prematurely, introduced in the 1980s for consumer electronics applications, but was withdrawn when safety problems arose. More recently, the lithium-ion cell, which has a safety advantage over other lithium secondary cells as it does not contain lithium in a metallic form, has been marketed as a power source for consumer electronics such as cellular phones and camcorders. This technology has become dominant in the market. 

Applications of Alkaline Aluminum/Air Batteries. The alkaline aluminum/air batteries being developed cover a wide range of applications from emergency power supplies to field-portable batteries for remote power applications and underwater vehicles. Most of these are designed as reserve batteries, which are activated before use, or mechanically recharged by replacing the exhausted aluminum anodes. 

These are mostly employed for seawater applications. The base metal contains 98-99% of aluminum. Elements commonly added in different types of aluminum anodes are shown in Table 5.4a. Table 5.4b shows the solution potential of various classes of anodes. 

Finishes are applied to aluminum alloys for aesthetic reasons and to provide protection against corrosion. TTiese finishes include nonfinished (bare) aluminum, anodized aluminum, conversion coatings, painted aluminum, porcelain finishes, and plated finishes. In retarding corrosion, these finishes naturally minimize the buildup of corrosion products to which airborne dirt particles can adhere. In most applications, aluminum with an applied finish presents no maintenance or cleaning problem for a considerable period of time subsequently, when cleaning is required, it is much easier to do. Many (if not most) of these finishes... 

---