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Verfahren zur Herstellung von Titanoxidschichten mit hoher photokatalytischer Aktivitaet und dergestalt hergestellte Titanoxidschichten

Vacuum deposition of transparent titanium oxide layer with high photocatalytic activity, follows deposition under controlled conditions by specified heat treatment
: Neubert, T.; Neumann, F.; Vergoehl, M.

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DE 102007025577 A: 20070601
DE 102007025577 A: 20070601
Patent, Electronic Publication
Fraunhofer IST ()

(A1) Die vorliegende Erfindung bezieht sich auf ein Verfahren zum vakuumbasierten Abscheiden einer Titanoxidschicht aus der Gasphase auf einem Substrat, wobei von einer titanoxidhaltigen Quelle mit einer Abscheiderate von kleiner als 25 nm/s, in einer sauerstoffhaltigen Atmosphaere und bei einer Substrattemperatur von kleiner als 500°C abgeschieden wird und wobei nach dem Abscheiden das beschichtete Substrat ueber einen Zeitraum von mindestens 30 min in einer sauerstoffhaltigen Atmosphaere bei Temperaturen zwischen 200?C und 1000?C waermebehandelt wird.


DE 102007025577 A1 UPAB: 20081217 NOVELTY - A titanium oxide-containing source with a deposition rate of less than 10 nm/s, is used for coating a substrate at a temperature of less than 500 degrees C in an oxygen-containing atmosphere. The coated substrate is then heat treated over an interval of 30 minutes or more at a temperature between 200 degrees C and 1000 degrees C. Deposition takes place at a substrate temperature less than 100 degrees C in an atmosphere containing oxygen at preferably 2 x 10-4 mbar. The preferred heat treatment temperature is 600 degrees C. DETAILED DESCRIPTION - The oxygen proportion during heat treatment is preferably 27%. The atmosphere is air and/or the heat treatment is at normal pressure, with a duration of 1 h. The deposition rate is less than 0.5 nm/s. The resultant titanium oxide layer thickness is 200-300 nm. The substrate is glass, ceramic, metal or a composite of one or more of these. The physical gas phase deposition process (PVD) is used. Sputtering is preferred, using a hollow cathode method. Alternatively a vacuum metallization technique involving thermal vaporization, electron beam vaporization, laser beam vaporization or arc vaporization is used. Heat treatment is at constant temperature. This is reached at a heating rate, exceeding 100 degrees C per minute; the same cooling rate is used subsequently. An inorganic material, V, W, Co, Bi, Nb and/or Mn, is co-vaporized from a separate source. Before titanium oxide coating, a dielectric diffusion barrier layer is deposited, comprising SiO2, Al2O3, Si3N4 and/or AlN and especially SiO2. A multiple layer system is deposited. The layer remote from the substrate is 10 nm thick and/or alternating highly-refractive layers including TiO2 and low-refractivity layers containing SiO2 are deposited. AN INDEPENDENT CLAIM IS INCLUDED FOR the deposited layer. USE - For vacuum deposition of transparent titanium oxide layers with high levels of photocatalytic activity. The disclosure also lists widely ranging industrial and domestic applications for the layer, including lamps, vehicle glass, building glazing, mirrors, vehicle mirrors, lenses and spectacle lenses. Its functions include photocatalytic air- and/or water cleaning, anti-reflection, anti-condensation, superhydrophilicity, or surface components splitting water into hydrogen and oxygen(all claimed). Further optical component applications are listed. ADVANTAGE - Known commercial vacuum coating plants can be used to deposit a titanium oxide layer of very high photocatalytic activity. This is 100 times more active, than measured in similar prior art. The layers are highly transparent in visible- and near infra-red light, hence optical applications such as filters, lenses, mirrors, sight glasses, and instrument covers can be served. The layers have high hardness, so having high resistance to mechanical wear and scratching.