The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 30, 1991
Filed:
May. 24, 1990
Jurgen Schmidt, Jena, DD;
Thomas Furche, Jena, DD;
Roland Erdmann, Jena, DD;
Marion Reichert, Jena, DD;
Ullrich Bayer, Jena, DD;
Peter Kurze, Oberlichtenau, DD;
Thomas Schwarz, Karl Marx Stadt, DD;
Joachim Schreckenbach, Limbach-Oberfrohna, DD;
Hans-Jurgen Kletke, Karl Marx Stadt, DD;
Andreas Hoffmann, Karl Marx Stadt, DD;
Martin Heppner, Jena, DD;
Anja Hasse, Berlin, DD;
Dorith Schmidt, Jena, DD;
Annette Klaus, Jena, DD;
Jenoptik Jena GmbH, Jena, DE;
Abstract
The invention relates to a cyanide-free electrolyte being harmless to the environment and to health which makes feasible the production of black surface layers on light metals or on alloys of the latter, preferably titanium, remaining deeply-black and adhesive even after extreme changes in the ambient temperature and having nearly equal values of the optical absorptivity of radiation and of the thermal emission capability (the .alpha./.epsilon.-ratio is about 0.95) by means of the anodic oxidation by spark discharge (ANOF-method). These layers are absolutely X-amorphous and show, hence, an ideal optically isotropic behavior regarding the reflection of radiation. Due to their minimum evolution of gases they offer a high thermovacuum stability. The electrolyte consists of an ammoniacal solution of K.sub.2 H.sub.2 PO.sub.4 potssium dihydrogenphosphate and K.sub.2 CRO.sub.4 potassium chromate. The homogeneity of the optically black layers is ensured by not using fluoride ions and employing acetate ions. Such layers comprise titanium, chromium and copper following ratios of CR:Ti=1:(1.9 to 2.2) and CR:Cu=1:(0.8 to 1.3).