Ultra pure aluminum

At about the same time, electrolytes containing aluminum alkyls were utilized by YAW (Bonn) for the production of ultra pure aluminum [142]. Fig. 18 shows the closed electrolysis cell used which already contains several hundred liters of bath. 

Although some of this is used for the production of ultra-pure silicon for semiconductors and for alloys with iron, aluminum, and magnesium, 98% goes for the production of methyl silicon chlorides ... 

Considering more complex samples or samples that demand a more laborious pretreatment, a more laborious contamination control should be adopted. Slavin and coworkers [104], in order to determine aluminum in bone, wore powderless gloves and used tantalum knives and scrapers (made from ultra-pure tantalum, relatively free from aluminum) to remove adhering tissue from bone. They also used a diamond-disc saw to cut small segments of the sample for analysis, besides using only plasticware and sub-boiling distilled HN03. 

Elemental silicon is frequently used in steel and aluminum industries for the preparation of aluminum alloys. In the production of semiconductors, amplifiers, photovoltaic and solar cells, ultra-pure silicon is needed. The world s computers and all computer-controlled equipment have, at their heart, silicon chips - crystals of silica... 

At the same time Hass [29] invented the silicon oxide protected aluminum surface mirror. Protection against mechanical damage became important in mirror fabrication with the exception of Al mirrors for astronomical applications. And finally, for use in the near ultra violet range, pure aluminum films have to be protected primarily against degrading oxidation on exposure to air by covering them with layers of MgF, or LiF, as was found out by Hass et al. [30] in the time between 1955 and 1961. 

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