摘要:
An article which is covered with a nickel-phosphorus alloy is covered on its outer surface with a protective layer which comprises CrPO.sub.4, Cr(OH).sub.3 and may also comprise Cr.sub.2 (SO.sub.4).sub.3 and in which no nickel is present. The layer provides excellent corrosion protection. In a particular embodiment the layer is black, scratch-resistant in normal use, cannot be wiped off and is not sensitive to finger prints and is extremely suitable for decorative applications. The layers can be obtained electrolytically in a bath which comprises chromic acid and optionally phosphoric acid and sulfuric acid using reversed current in a given frequency range, a given range of current densities and a given range of ratios of cathodic to anodic pulse durations. In order to obtain the black layers the cathodic time duration is only a fraction of the anodic time duration.
摘要:
A metal article which covered with a nickel-phosphorus alloy and which is covered on its outer surface with a protective layer which comprises CrPO.sub.4, Cr(OH).sub.3 and may also comprise Cr.sub.2 (SO.sub.4).sub.3 and in which no nickel is present. The layer provides an excellent corrosion protection. In a particular embodiment the layer is black, scratch-resistant in normal use, cannot be wiped off and is not sensitive to finger prints and is extremely suitable for decorative applications. The layers can be obtained electrolytically in a bath which comprises chromic acid and optionally reversed current in a given frequency range, a given range of current densities and a given range of ratios of cathodic to anodic pulse durations. In order to obtain the black layers the cathodic time duration is only a fraction of black layers the anodic time duration.
摘要:
Treating objects of which at least the surface consists of tin in order to obtain a satisfactory corrosion resistance. To this end the objects are subjected in a tungstate solution of at least 0.02 M and having a pH of 4-11 alternately to a cathodic and an anodic polarity (so-called periodically reversed current). The frequency with which the current reverses must be between 0.2 and 2 Hz and the current density must be between 0.2 and 1 A/dm.sup.2, the ratio of the anodic to the cathodic density being from 0.5-1.
摘要:
A master suitable for the manufacture of electroplated negative metal copies. The master comprises a preform which on at least one side has a layer of electroplated aluminum. The surface has a precisely machined profile and is coated with a titanium nitride layer.
摘要:
An optically readable information disc having a reflective optical structure which comprises a reflective layer which is composed of a nitride, carbide or boride of a transition metal selected from the group consisting of titanium, zirconium, hafnium, vanadium, chromium, niobium, molybdenum, lanthanum, tantalum and tungsten.
摘要:
The invention provides a method by means of which it becomes possible to produce emblems or wordmarks having three-dimensional symbols, both the front face and the raised side faces of which are metallized, while the substrate is not metallized. For that purpose, the symbols are injection molded with a carrier and they are not secured to a separately manufactured substrate until after the metallizing operation.
摘要:
A coating solution and a method of manufacturing a magnesium-oxide layer on a glass substrate. The layer obtained is characterized by a satisfactory adhesion and a high secondary electron emission coefficient. The curing temperature can remain below 250.degree. C., so that the method is suitable for the customary types of glass.Said coating solution comprising a solvent and partially acetylated and partially hydrolyzed Mg(OR).sub.2 of the formula Mg(OH).sub.x (OR).sub.y (OAc).sub.z.