Siemens Aktiengesellschaft

Richard Doetzer

Georg Iwantscheff

Johann Gehring

Klaus Stoeger

Paul Hini

The invention provides a high-purity electroaluminum layer having a purity of greater than 99.99% and, preferably, a thickness of 10 to 20 .mu.m which serves as a gas barrier layer, particularly for hydrogen, oxygen, tritium and water vapor, for metallic materials and nonmetallic materials such as glass, quartz, ceramic and cermets with an electroconductive surface as well as for conductive plastics. By post-treatment, the electroaluminum layer can be compacted. The electroaluminum layer is precipitated by electroplating from aprotic oxygen-free and anhydrous electrolyte media of the general formula M.sup.I X.2AlR.sub.3.nLsm, wherein M.sup.I is an alkali metal ion or a quaternary onium ion, X is a halogen ion, preferably F.sup.- or Cl.sup.-, R is an alkyl radical, preferably CH.sub.3, C.sub.2 H.sub.5, C.sub.3 H.sub.7 or C.sub.4 H.sub.9, Lsm is an aromatic solvent molecule, preferably toluene, ethyl benzene, xylene or a mixture thereof, and n=0 to 12, at a bath temperature of 50.degree. to 110.degree. C. and a current density of 0.5 to 10 A/dm.sup.2 under intensive bath agitation. Electroplating may be conducted in the presence of an aromatic solvent.

Gas barrier layer for metallic and nonmetallic materials

The invention provides an ion barrier formed of a high-purity electroplated aluminum layer (purity &gt;99.99%) which preferably has a thickness of 10 to 20 .mu.m for use on structural parts and shapes of metals and nonmetals, in particular on polyolefins. If desired, the electroplated aluminum layer can be compacted and/or anodically oxidized by post-treatment. The electroplated aluminum layer prevents the intrusion of metal and nonmetal ions into nonmetals, particularly plastic (for example polyolefins), and their penetration to metal surfaces. The deposition of the electroplated aluminum layer occurs from aprotic, oxygen-free and anhydrous electrolyte media of the general formula M.sup.I X.2AlR.sub.3.nLsm, wherein M.sup.I is an alkali metal ion or a quaternary onium ion, X is a halogen ion, preferably F.sup.- or Cl.sup.-, R is an alkyl radical, preferably CH.sub.3, C.sub.2 H.sub.5, C.sub.3 H.sub.7 or C.sub.4 H.sub.9, Lsm is an aromatic solvent molecule, preferably toluene, ethyl benzene, xylene or a mixture thereof, and n=0 to 12, at a bath temperature of 50.degree. to 110.degree. C. and a current density of 0.5 to 10 A/dm.sup. 2 under intensive bath movement. The media may possibly be in the presence of an aromatic solvent.

Ion barrier layer on metals and nonmetals

A system for the galvanic deposition of aluminum incorporating a tubular cell through which goods to be treated can be moved in the axial direction. An electrolyte is pumped through the tubular cell preferably with the aid of an electrolyte circulating system which is self-contained. The electrolyte is gated out by means of T-shaped connecting components which are adjoined by airlock arrangements associated with the tubular cell.

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Nuernberg, Germany

Richard Doetzer