Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
  • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
  • C23C16/40—Oxides
  • C23C16/405—Oxides of refractory metals or yttrium
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/02—Pretreatment of the material to be coated
  • C23C16/0272—Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
  • C23C16/50—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
  • C23C16/448—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for generating reactive gas streams, e.g. by evaporation or sublimation of precursor materials
  • C23C16/4481—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for generating reactive gas streams, e.g. by evaporation or sublimation of precursor materials by evaporation using carrier gas in contact with the source material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

• the present invention relates to a process for depositing a coating based on titanium oxide with photocatalytic properties on a substrate, in particular transparent. It also targets the substrate thus obtained.
• Glass-based, ceramic or glass-ceramic substrates are known, more particularly glass, in particular transparent, which are provided with coatings with photocatalytic properties, with a view to manufacturing glazing of various applications, such as utility glazing, glazing for vehicles. or for buildings.
• the photocatalytic properties imparted to the substrate due to the coating based on titanium oxide give the latter an anti-fouling function.
• the substrate retains appearance and surface properties over time, which in particular make it possible to space cleaning times and / or to improve visibility, by succeeding in eliminating progressively the soiling gradually deposited at the surface of the substrate, in particular soiling of organic origin such as fingerprints or volatile organic products present in the atmosphere, or even soiling of the fogging type.
• this cleaning results from the fact that certain semiconductor materials, based on metal oxide, such as for example titanium oxide, are capable, under the effect of radiation of adequate wavelength (in the visible and / or in the ultraviolet), to initiate radical reactions causing the oxidation of organic products: we generally speak of "photocatalytic" or even "photo-reactive" materials.
• pyrolysis techniques liquid pyrolysis, powder pyrolysis, pyrolysis in value phase called CVD (Chemical Vapor Deposition), techniques associated with sol-gel: soaking or dipping, cell-coating, etc.
• CVD Chemical Vapor Deposition
• sol-gel soaking or dipping, cell-coating, etc.
• a vacuum technique reactive or non-reactive sputtering
• the decomposition of the precursors takes place directly at the level of the float line, and any modification as to the nature of the substrate (composition, property) on which the coating is deposited necessarily requires a slow adaptation of the loading conditions for raw material. float.
• a certain difficulty as regards the control of the surface temperatures and the temperatures of the means of injection of the precursors (nozzle), the high temperatures being one of the most important parameters. more fundamental to obtaining a titanium oxide coating having optimal photocatalytic properties.
• the deposition can only be carried out on substrates that are not very sensitive to temperature (for example plastic).
• the second technique mentioned above called vacuum deposition (using a magnetron line for example), necessarily requires a heat treatment phase of the titanium oxide coating previously deposited under vacuum in order to allow obtaining 'an adequate crystallographic phase. This heating is difficult to implement directly within the magnetron which is under vacuum and it is then necessary to carry out a recovery operation outside the deposit enclosure. Indeed, for the latter to have photocatalytic properties, the titanium oxide should be in an anatase crystallized form, in rutile form or in the form of a mixture of anatase, rutile, brookite with a rate crystallization of at least 25%, especially around 30 to 80%, especially near the surface, (the property being rather a surface property).
• the crystallization rate includes the amount by weight of T O2 crystallized relative to the total weight amount of TIO2 in the coating).
• the object of the invention is therefore to develop a process for depositing photo-catalytic coatings on the substrate, which have a marked “anti-fouling” effect on the substrate and which can be manufactured from industrially, which does not have the drawbacks of the previously mentioned techniques.
• the inventors have discovered that it is possible to use the so-called PECVD technique for (Plasma Enhanced Chemical Vapor Deposition) to deposit a photocatalytic coating on a glass substrate or not.
• This particular technique is known for depositing titanium oxide for waveguide applications (US5295220), or for fission product trapping applications (FR2695507).
• the subject of the invention is therefore a method of depositing on a substrate a coating based on semiconductor materials based on metal oxides, in particular titanium oxide, which are capable, under the effect of radiation of adequate wavelength, to initiate radical reactions causing the oxidation of organic products so as to confer photocatalytic properties on said coating which is characterized in that the coating with photocatalytic property is deposited by chemical deposition in the gas phase , in particular from a gas mixture comprising at least one organometallic precursor and / or a metal halide of said metal oxide, the deposition being assisted by a plasma source.
• a photocatalytic coating which does not necessarily require heat treatment at high temperature (beyond 300-350 ° C) to reveal the desired properties, during or after deposition and which is also very flexible, the optimal deposition conditions no longer being dependent on the presence of a nearby heat source ( float).
• at least one carrier gas or a mixture of carrier gases chosen from air, nitrogen, helium, argon.
• An oxidizing agent or a mixture of oxidizing agents is incorporated into the gas mixture.
• a reducing agent or a mixture of reducing agents is incorporated into the gas mixture.
• the reaction and deposition phase is carried out at reduced pressure.
• the reaction and deposition phase is carried out at atmospheric pressure.
• At least one sublayer is deposited prior to the coating with photocatalylic property, making it possible to provide another functionality to said coating with photocatalytic property and / or to reinforce said properties of said coating.
• At least one other type of mineral material is incorporated into the gas mixture comprising at least the organometallic precursor and / or a metal halide of said metal oxide, in particular in the form of an amorphous or partially crystallized oxide, for example a silicon oxide ( or mixture of oxides), titanium, tin, zirconium, vanadium, antimony, zinc, tungsten, cobalt, nickel, aluminum, these oxides can be mixed or doped.
• the photocatalytic coating is deposited on the substrate within the plasma discharge.
• the photocatalytic coating is deposited on the substrate outside the plasma discharge. According to another aspect of the invention, it also relates to a substrate obtained according to the previously mentioned method, as well as its variants.
• This glass-based, ceramic or vitro-ceramic, or plastic substrate provided on at least part of at least one of its faces with a coating with photo-catalytic property comprising at least partially crystallized titanium oxide is characterized in that the crystallized titanium oxide is in anatase form, in rutile form, in brookite or in the form of a mixture of anatase, rutile, brookite.
• the crystallized titanium oxide is in the form of crystallites of average size between 0 , 5 and 60 nm, preferably 1 to 50.
• the coating also comprises an inorganic material, in particular in the form of an oxide or mixture of amorphous or partially crystallized oxides of the silicon oxide, titanium oxide, tin oxide type , zirconium oxide, aluminum oxide, vanadium, antimony, zinc, tungsten, cobalt, nickel oxide, these oxides can be mixed or doped.
• the coating comprises additives capable of extending the photocatalytic phenomenon due to titanium oxide, in particular by increasing the absorption band of the coating and / or by increasing the number of charge carriers by doping the crystal lattice of the oxide or by surface doping of the coating and / or by increasing the yield and kinetics of the photocatalytic reactions by covering at least part of the coating with a catalyst.
• the crystal lattice of the titanium oxide is doped, in particular by at least one of the metallic or non-metallic elements, - the thickness of the coating is between 5 nm and 1 micron, preferably from 5 to 100 nm the photocatalytic activity of the coating is at least 5.10 - 3 cm - 1 min ⁇ 1 measured using the TAS test, the RMS roughness of the photocatalytic coating is between 2 and 20 nm, in particular between 5 and 20 nm. the light reflection of the photocatalytic coating is less than 30%, preferably less than or equal to 20%, with a neutral color.
• the absorption of the photocatalytic coating is less than 10%, preferably less than 5%, it is arranged under the coating with photocatalytic property at least one thin layer with anti-static, thermal, optical function, or acting as a barrier to the migration of alkalis originating from of the substrate.
• the thin layer with anti-static function, optionally with controlled polarization, and / or thermal and / or optical is based on conductive material of the metal type or of the doped metal oxide type such as ITO, SnO: F, SnO 2 : Sb, ZnO: ln, ZnO: F, ZnO: AI, ZnO: Sn or metallic oxide sub-stoichiometric in oxygen as Sn ⁇ 2- ⁇ ⁇ u Zn ⁇ 2-x with x ⁇ 2.
• the thin layer with optical function is based on an oxide or of a mixture of oxides whose refractive index is intermediate between that of the coating and that of the substrate, in particular chosen from the following oxides: AI2O3, Sn ⁇ 2, ln2 ⁇ 3, or based on oxycarbide or oxynitride of silicon, or possibly based on a mixture of a high refractive index material with a low refractive index material (AI2O3 / TiO 2 , AI 2 ⁇ 3 / SiO 2 , AI2O3 / SnO, SnO 2 / TiO .).
• the thin or multilayer layer with barrier function to alkali is for example based on oxide, nitride, oxynitride or oxycarbide of silicon, of AbO ⁇ : F or Sn ⁇ 2: F of aluminum nitride, of silicon nitride.
• the substrate is transparent, flat or curved, the substrate is a glass substrate.
• the substrate is based on a polymer-based substrate, in particular PMMA, polycarbonate, PEN.
• the latter relates to a glazing “anti-fouling and / or anti-fogging”, monolithic, multiple of the double type.
• the orientation of the growing T O2 crystals on the substrate had an influence on the photo-catalytic performances of the oxide: there is a preferred orientation (1, 1, 0) which clearly promotes photocatalysis.
• the coating is produced in such a way that the crystallized titanium oxide which it contains is in the form of “crystallites”, at least near the surface, that is to say of single crystals, having a size average between 0.5 and 100 nm, preferably 1 to 50 nm. It is indeed in this dimension range that titanium oxide seems to have an optimal photocatalytic effect, probably because the crystallites of this size develop a large active surface.
• the coating may also comprise, in addition to crystallized titanium oxide, at least one other type of mineral material, in particular in the form of an amorphous or partially crystallized oxide, for example a silicon oxide (or mixture of oxides), titanium, tin, zirconium or aluminum.
• This mineral material can also participate in the photocatalytic effect of crystallized titanium oxide, by itself presenting a certain photocatalytic effect, even weak compared to that of crystallized Ti ⁇ 2, which is the case of tin or amorphous titanium oxide.
• a “mixed” oxide layer thus combining at least partially crystallized titanium oxide with at least one other oxide may be advantageous from the optical point of view, especially if the other or the other oxides are chosen with a lower index.
• the coating by lowering the refractive index " overall ”of the coating, one can play on the light reflection of the substrate provided with the coating, in particular lower this reflection.
• a layer of T.O2 / AI2O3 is chosen, one method of obtaining which is described in patent EP-0 465 309, or in Ti ⁇ 2 / Si ⁇ 2.
• the coating however contains a content of TIO2 sufficient to maintain a notable photocatalytic activity and that T O2 remains crystallized. It is thus considered that it is preferable for the coating to contain at least 40% by weight, in particular at least 50% by weight of TiO 2 relative to the total weight of oxide (s) in the coating.
• the coating according to the invention it is possible first of all to increase the absorption band of the coating, by incorporating into the coating other elements, in particular metallic and based on cadmium, tin, tungsten, zinc, cerium, or zirconium, possibly doped as well as non-metallic elements.
• the coating actually has not one property but two, as soon as it is exposed to adequate radiation as in the visible range and / or ultraviolet, such as solar radiation: by the presence of photocatalytic titanium oxide, as already seen, it promotes the gradual disappearance, as and when they accumulate, of dirt of organic origin, in causing their degradation by a radical oxidation process.
• the coating of the invention which is permanently self-cleaning, also preferably has an outer surface with a pronounced hydrophilic and / or oleophilic character, which induces three very advantageous effects: • a hydrophilic nature allows perfect wetting of the water which can be deposited on the coating. When a phenomenon of water condensation occurs, instead of a deposit of water droplets in the form of a mist which impairs visibility, there is in fact a thin continuous film of water which forms on the surface of the coating. and which is completely transparent. This “anti-fog” effect is demonstrated in particular by measuring a contact angle with water of less than 5 ° after exposure to light, and,
• the coating can also have an oleophilic character, allowing the "wetting" of organic dirt which, as for water, then tends to be deposited on the coating in the form of a continuous film less visible than well localized “spots".
• an “organic anti-fouling” effect which takes place in two stages: as soon as it is deposited on the coating, the soiling is already hardly visible. Then, gradually, it disappears by radical degradation initiated by photo-catalysis.
• the coating can be chosen to have a more or less smooth surface. A certain roughness can be sought: • it makes it possible to develop a larger active photocatalytic surface and therefore it induces greater photocatalytic activity, • it has a direct influence on the wetting.
• the roughness indeed enhances the wetting properties.
• a smooth hydrophilic surface will be even more hydrophilic when roughened.
• the term “roughness” is understood here to mean both the surface roughness and the roughness induced by a porosity of the layer or of the sublayer in at least part of its thickness. The above effects will be all the more marked when the coating is porous and rough, hence a superhydrophilic effect of the rough photoreactive surfaces. However, too pronounced, the roughness can be penalizing by favoring the incrustation, the accumulation of dirt and / or by making appear a level of blurring optically unacceptable.
• the coating if it consists only of TIO2, it preferably has a porosity of the order of 65 to 99%, in particular from 70 to 90%, the porosity being defined here indirectly by the percentage of the density theoretical T102, which is about 3.8.
• the thickness of the coating according to the invention is variable, it is preferably between 5 nm and 1 micron, preferably between 5 and 100 nm, in particular between 10 and 80 nm, or between 15 and 50 nm. In fact, the choice of thickness may depend on different parameters, in particular on the envisaged application of the glazing type substrate, or on the size of the UO2 crystallites in the coating or on the presence of alkalies in high proportion in the substrate.
• the coating according to the invention constituting the last layer of the stack.
• the coating has a relatively low refractive index, which is the case when it consists of a mixed oxide of titanium and silicon.
• the layer with an anti-static and or thermal function can in particular be chosen based on a conductive material of the metal type, such as l silver, or of the metal oxide type doped like indium oxide doped with tin ITO, tin oxide doped with a halogen of the fluorine type Sn ⁇ 2: F, or with antimony Sn ⁇ 2: Sb, or zinc oxide doped with indium ZnO: ln, fluorine ZnO: F, aluminum ZnO: AI or tin ZnO: Sn.
• a conductive material of the metal type such as l silver
• the metal oxide type doped like indium oxide doped with tin ITO, tin oxide doped with a halogen of the fluorine type Sn ⁇ 2: F, or with antimony Sn ⁇ 2: Sb or zinc oxide doped with indium ZnO: ln, fluorine ZnO: F, aluminum ZnO: AI or tin ZnO: Sn.
• the layer with anti-static function preferably has a square resistance value of 20 to 1000 ohms / square. Provision may be made to provide it with current leads in order to polarize it (supply voltages for example between 5 and 100V). This controlled polarization makes it possible in particular to combat the deposit of dust of size on the order of a millimeter capable of being deposited on the coating, in particular dry adherent dust only by electro-static effect: by brutally reversing the polarization of the layer, "Ejects" this dust.
• the thin layer with an optical function can be chosen in order to reduce the light reflection and / or make the color in reflection of the substrate more neutral.
• it preferably has an intermediate refractive index between that of the coating and that of the substrate and an appropriate optical thickness, and may consist of an oxide or a mixture of oxides of the aluminum oxide type.
• AI2O3, tin oxide SnO 2) indium oxide ln2 ⁇ 3, oxycarbide or silicon oxynitride it is preferable that this thin layer has an index of refraction close to the square root of the product of the squares of the indices of refraction of the two materials which surround it, that is to say say the substrate and the coating according to the invention.
• the thin layer with an alkali barrier function may in particular be chosen based on silicon oxide, nitride, oxynitride or oxycarbide, in aluminum oxide containing fluorine A OsiF, or in aluminum nitride or based on SnO 2 .
• silicon oxide, nitride, oxynitride or oxycarbide in aluminum oxide containing fluorine A OsiF, or in aluminum nitride or based on SnO 2 .
• the nature of the substrate or of the sub-layer is also of additional interest: it can promote the crystallization of the photocatalytic layer which is deposited, in particular in the case of CVD deposition assisted by a plasma source, preferably at reduced pressure. , or even more preferably at atmospheric pressure (called in English APPECVD (Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition) All these optional thin layers can, in known manner, be deposited by vacuum techniques of the sputtering type or by other techniques of the thermal decomposition type such as pyrolysis in the solid, liquid or gas phase, each of the aforementioned layers can combine several functions, but they can also be superimposed.
• the invention also relates to "anti-fouling" glazing
• the invention therefore relates to the manufacture of glass, ceramic or vitro-ceramic products, and very particularly the manufacture of "self-cleaning" glazing.
• These can advantageously be building glazing, such as double glazing (it is then possible to arrange the coating “outside side” and / or “inside side”, that is to say on face 1 and / or on face 4). This is particularly advantageous for glazing that is difficult to access for cleaning and / or that needs to be cleaned very frequently, such as roof glazing, airport glazing, etc.
• This coating can thus be placed on windshields, lateral or rear windows of the car, in particular on the face of the glazing facing towards the interior of the passenger compartment. This coating can then prevent the formation of fogging, and / or remove traces of soiling of the fingerprint type, nicotine or organic material of the volatile plasticizer type "released" by the plastic coating the interior of the passenger compartment, in particular that of the dashboard (release sometimes known under the English term "fogging").
• Other vehicles such as planes or trains may also find advantage in using glazing provided with the coating of the invention.
• All these glazings being generally made up of p the plurality of transparent substrates between which the “active” elements are arranged, it is then advantageously possible to arrange the coating on the external face of at least one of these substrates.
• electrochromic glazing when the latter is in the colored state, its absorption leads to a certain heating on the surface, which, in fact, is capable of accelerating the photocatalytic decomposition of the carbonaceous substances depositing on the coating according to the invention.
• the coating according to the invention can preferably be arranged in side 1.
• This metal oxide coating is therefore produced using the so-called APPECVD technique which consists of chemical deposition in the gas phase, in particular from a mixture of gases comprising at least one organometallic precursor. and / or a metal halide of said metal oxide (titanium oxide for example in our case), the deposition being assisted by a plasma source.
• the photocatalytic semiconductor material chosen is titanium oxide. There are others that can be used. Reference may be made to the applicant's patent (FR2738813).
• the semiconductor material can be doped (N, F, Pt, Pd, Metals ...) to improve its photocatalytic performance or adapt the optical gap and thus be adapted to different wavelengths of the solar spectrum (UV, visible) .
• the gas mixture used incorporates an organometallic precursor and / or a metal halide.
• an organometallic precursor for titanium oxide, mention may be made of TiCI, TiPT, Ti ethoxide (butoxide, etc.), Ti diisopropoxide (acetylacetonate), Titanium (III) tris (2,2,6,6-tetramethyl-3 , 5-heptanedionate.
• This gaseous mixture can also incorporate at least one oxidant or a mixture of oxidants (air, O 2 , CO 2 , N2O, organic: alcohol, ester, etc.) or at least one reducing agent or a mixture reducing agent (H2, hydrocarbons, etc.) and the carrier gas used is air, nitrogen, helium or argon or a mixture of these gases. Preferably, it will mainly consist of helium and / or nitrogen and / or argon.
• the same ranges of precursors organometallic / halides
• metals for dopants or mixed deposits, the same ranges of precursors (organometallic / halides) can be used for metals.
• fluorine trifluoroacetic acid is used for example ( TFA), HF, NF3 ...
• NH3 or amines primary, secondary or tertiary
• precursors containing both titanium and dopant for example: Tétrakisdiethylamino titane, Tétrakisdimethylamino titane or tetrachlorodiamminotitanium .
• the reaction gas mixture is then dissociated, by a plasma source, either directly within the plasma, or remotely, blown out (indirectly).
• the metal oxide with photocatalytic property is deposited continuously and uniformly in at least part of at least one of the faces of the substrate.
• the substrate and the deposition zone incorporating the plasma source having a relative displacement.
• the coating may also be advantageous to deposit the coating not at once, but by at least two successive stages, which seems to favor the crystallization of titanium oxide over the entire thickness of the coating when it is chooses relatively thick.
• the treatment temperature chosen can also allow better control of the crystallization rate and the crystalline, anatase and / or rutile nature of the oxide.
• the deposition process which is the subject of the invention is advantageous because the plasma source can be sufficient to provide thermal energy (without having to heat the substrate) sufficient to obtain the desired crystallographic properties at the level of the metal oxide.
• a barrier layer will be interposed between the substrate and the photocatalytic property layer.
• a barrier layer between the substrate, if it is standard glass, and the coating, or the choice of a glass substrate of suitable composition, or the choice of a soda-lime glass whose surface is dealkalized, eliminating this risk.
• the coating comprises additives capable of extending the photocatalytic phenomenon due to titanium oxide, by avoiding the recombination of charge carriers in the material.
• a transparent, clear silica-soda-lime glass substrate 4 mm thick is used. It goes without saying that the invention is not limited to this specific type of glass. The glass may also not be flat, but curved.
• a layer of Ti ⁇ 2 from TiCI4 is deposited by homogeneous discharge operating at atmospheric pressure. The thin layer of TiO2 was deposited on a clean glass substrate heated to a temperature of 260 ° C.
• the gas mixture which is introduced consists of helium (He) and oxygen (O 2 ).
• the respective flow rates of these gases are 14 slpm and 1 sccm.
• the organometallic precursor titanium tetrachloride (TiCU)
• TiCU titanium tetrachloride
• This bubbler is heated to 10 ° C and a gas vector (He) is injected into the bubbler with a flow rate of 140 sccm to transport the organometallic vapors.
• He gas vector
• the total pressure in the reactor is maintained at 1013 mbar ⁇ 50 mbar.
• the electrodes, covered with a dielectric barrier of alumina 0.5 mm ⁇ 0.1 mm
• they are 5 mm apart and they are supplied with a sinusoidal alternating voltage of 1.1 Volt rms at a frequency of 25 kHz.
• the thin layer of TiO 2 was deposited on a clean glass substrate heated to a temperature of 235 ° C.
• the gas mixture which is introduced consists of helium (He) and oxygen (O2).
• the respective flow rates of these gases are 11 slpm and 20 sccm.
• the organometallic precursor, TipT titanium tetraisopropoxide
• This bubbler is heated to 50 ° C. and a carrier gas (He) is injected into the bubbler with a flow rate of 500 sccm for transport organometallic vapors.
• He carrier gas
• the total pressure in the reactor is maintained at 1013 mbar ⁇ 50 mbar.
• the electrodes covered with an alumina dielectric barrier (0.5 mm ⁇ 0.1 mm), are 6 mm apart and they are supplied with a sinusoidal alternating voltage of 1.1 Volt rms at a frequency of 10 kHz. Under these conditions, a homogeneous deposit of Ti ⁇ 2 is obtained.
• the thin layer thus deposited of ⁇ O2 has a thickness of 260 nm and has a photo-catalytic activity.
• a RAMAN analysis shows that TiO 2 is crystallized in rutile form.
• a layer of TiO 2 from TiCI4 is deposited by homogeneous discharge operating at atmospheric pressure. The deposition conditions are identical to those of the first example, the duration is reduced so as to obtain a greater layer thickness.
• This thin layer of ⁇ O2 54 nm thick and deposited under the conditions of Example 1 has a photo-catalytic activity.
• the layer of Ti couche2 was deposited on a clean glass substrate heated to a temperature of 260 ° C.
• the gas mixture which is introduced consists of nitrogen (N2) and oxygen (O2).
• the nitrogen flow is 10 slpm with 150 ppm of O2.
• the organometallic precursor, titanium tetrachloride (TiCU) is poured into a 0.5 I bubbler. This bubbler is heated to 10 ° C. and a carrier gas (He) is injected into the bubbler with a flow rate of 140 sccm for transport organometallic vapors.
• the total pressure in the reactor is maintained at 1013 mbar ⁇ 50 mbar.
• the electrodes covered with an alumina dielectric barrier (0.5 mm ⁇ 0J mm), are 5 mm apart and they are supplied with a sinusoidal alternating voltage of 1.1 Volt rms at a frequency of 5 kHz. Under these conditions have obtained a homogeneous deposit of Ti ⁇ 2. Crystallized in anatase form and having a photocatalytic activity of 11.10 -3 cm-1.min-1, the thickness of the layer being approximately 150 nm.

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• 2003
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