Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/0215—Coating
  • B01J37/0221—Coating of particles
• • 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
  • C23C24/00—Coating starting from inorganic powder
  • C23C24/02—Coating starting from inorganic powder by application of pressure only
  • C23C24/04—Impact or kinetic deposition of particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
  • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
  • B01J21/063—Titanium; Oxides or hydroxides thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
  • B01J35/39—Photocatalytic properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
  • B05B7/16—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed
  • B05B7/1606—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed the spraying of the material involving the use of an atomising fluid, e.g. air
  • B05B7/1613—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed the spraying of the material involving the use of an atomising fluid, e.g. air comprising means for heating the atomising fluid before mixing with the material to be sprayed
  • B05B7/162—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed the spraying of the material involving the use of an atomising fluid, e.g. air comprising means for heating the atomising fluid before mixing with the material to be sprayed and heat being transferred from the atomising fluid to the material to be sprayed
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G23/00—Compounds of titanium
  • C01G23/04—Oxides; Hydroxides
  • C01G23/047—Titanium dioxide
• • 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
  • C23C24/00—Coating starting from inorganic powder
  • C23C24/08—Coating starting from inorganic powder by application of heat or pressure and heat
• • 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
  • C23C24/00—Coating starting from inorganic powder
  • C23C24/08—Coating starting from inorganic powder by application of heat or pressure and heat
  • C23C24/082—Coating starting from inorganic powder by application of heat or pressure and heat without intermediate formation of a liquid in the layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00743—Feeding or discharging of solids
  • B01J2208/00761—Discharging

Definitions

• the invention relates to a method for cold gas spraying, in which a spray powder containing photocatalytically active spray particles is accelerated by means of a carrier gas in a nozzle and forms a coating when hitting a substrate. Furthermore, the invention relates to coatings and articles with
• metallic spray particles are typically accelerated to high velocities in a relatively cold gas stream, a carrier gas, so that they form a coating upon impact with a substrate or workpiece by plastically deforming the particles upon impact.
• the particles For a coating to form, the particles must have a minimum impact velocity.
• the acceleration of the carrier gas and the particles is usually carried out in a Laval nozzle.
• the carrier gas is often heated because the particles ductile in the warm carrier gas, so that the layer formation is supported on impact.
• higher carrier gas velocities are achieved.
• the temperature of the carrier gas is therefore relatively low, so that one speaks of cold gas spraying or kinetic spraying.
• photocatalytically active coatings have a catalytic effect on incidence of light. This manifests itself for example in an antibacterial or antiviral effect or in the initiation of redox reaction. So it is a disinfection and cleaning possible by removing pollutants and killed bacteria and viruses.
• photocatalytically active layers are often titanium dioxide. For example, by doping the titanium dioxide it can be achieved that a titanium dioxide coating, which is normally photocatalytically active only in UV light, also becomes active in visible light.
• EP 2 302 099 includes a coating of sanitary, kitchen and medical-technical objects by means of cold gas spraying with photocatalytically active Titanium dioxide.
• EP 1 785 508 discloses a cold gas spraying of photocatalytically active titanium dioxide, wherein the spray powder consists of photocatalytically active titanium dioxide with a metallic component.
• DE 10 2004 038 795 is the
• EP 2 257 656 also describes cold gas spraying of photocatalytically active coatings.
• a matrix material with nanocrystalline titanium dioxide is used as the spray powder, wherein it is achieved during the cold gas spraying that the photocatalytic activity shifts into the visible by irradiating the processing point with UV or laser light.
• a method for cold gas spraying in which a spray powder containing photocatalytically active spray particles accelerated by means of a carrier gas in a nozzle and forms a coating when hitting a substrate, characterized in that at least a portion of the photocatalytically active spray particles from nanocrystalline agglomerates having a porosity of 200 to 800 m 2 / g, wherein the porosity is determined by means of a BET measurement with nitrogen.
• the coatings are characterized by a high photocatalytic activity. Furthermore, they show little abrasion in use and a high resistance to scratches and others
• the coatings advantageously show a rich yellow, so it is immediately apparent that the coatings absorb parts of visible light.
• the method according to the invention it is thus possible to produce very high quality, photocatalytically active coatings, which are particularly excitable by wavelengths of visible light and this in a very economical manner.
• the photocatalytic activity and in particular the photocatalytic activity in the visible light of the spray particles is not reduced by the process according to the invention but instead
• Temperatures such as those used in cold gas spraying, is destroyed, since such activity is based on a shift in the band structure of the electrons.
• the shift of the band structure is in turn most advantageously achieved by doping with foreign atoms. The Applicant believes that this is probably due to the fact that in the inventive method, an interaction of carrier gas and spray particles takes place, which to the desired
• the carrier gas before the nozzle throat at a temperature of more than 400 ° C, preferably of more than 800 ° C, more preferably of more than 900 ° C. Even temperatures of more than 1000 ° C, even more than 1100 ° C are possible. Despite the high temperature in the cold gas spraying process, which suvantt that in the hot carrier gas and the spray particles are heated, the remains
• the carrier gas can even be one high temperature, and it still creates a coating with high photocatalytic activity.
• nitrogen is used as a carrier gas.
• the nitrogen can penetrate into the nanocrystalline agglomerates, as they are open-pored for nitrogen.
• the nanocrystalline agglomerates thus have a very high surface area. The nitrogen can thus attach to the nanocrystallites on a large scale and interact with them. Because now
• the temperature of nitrogen and spray particles is high (see previous paragraph), the reaction of nitrogen with the nanocrystallites is very much supported. Surprisingly, it has now been shown that, despite the high temperature, the reaction proceeds in such a way that during the cold gas spraying process, the photocatalytically active, and even in the visible light, photocatalytic active form of the nanocrystallites is formed.
• helium can be used as a carrier gas.
• This carrier gas has also proved to be particularly advantageous in the experiment.
• mixtures of the two gases may also be used as the carrier gas.
• the price of the carrier gas can also be influenced, since an increase in the nitrogen content in a carrier gas
• the nanocrystalline agglomerates advantageously contain titanium dioxide (TiO 2 ), tungsten trioxide (WO 3 ), strontium titanate (SrTiO 3 ), tin dioxide (SnO 2 ), silicon carbide (SiC),
• Bismuth vanadate (BiVO 4 ), tantalum oxide nitride (TaON), (III) tantalum (V) nitride (Ta 3 N 5 ), indium tantalum (IV) oxide (lnTa0 4 ) or / and indium niobium (IV) oxide (lnNb0 4 ).
• titanium dioxide TiO 2
• anatase a bismuth vanadate
• Compounds have a photocatalytic activity, in particular a photocatalytic activity in visible light.
• photocatalytic activity in particular a photocatalytic activity in visible light.
• Titanium dioxide in the modification anatase converts to the rutile modification at a temperature of more than 700 ° C and with higher temperature.
• rutile titanium dioxide is, however, photocatalytically inactive.
• photocatalytically active in particular photocatalytically active, feeds, which are photocatalytically active, in particular in the visible light, despite a temperature which is well above 700 ° C. and thus above the transition temperature observed under otherwise conventional processes. So it does not occur due to the high temperature of carrier gas and spray particles expected conversion of
• the nanocrystalline agglomerates have a porosity of 250 to 600 m 2 / g (square meters per gram), preferably from 280 to 450 m 2 / g.
• the porosity is determined by means of a BET measurement with nitrogen. So that a photocatalytically active layer is formed, so a powder with
• Spray particles are used which have a porosity according to claim 1, preferably as just stated. It must therefore be used very open-pore agglomerates.
• the nanocrystalline agglomerates preferably have a hardness between 0.1 and 4 GPa (gigapascal), preferably between 0.2 and 2 GPa, the hardness being determined using nanoindenter. On the one hand, such a hardness is sufficient that the nanocrystalline agglomerates can be used for cold gas spraying and, on the other hand, the hardness is sufficiently low that the necessary porosity is present.
• a powder is thus used which contains spray particles which contain titanium dioxide in the modification anatase.
• the spray particles thus advantageously consist at least partially of nanocrystalline particles of titanium dioxide in the modification anatase. These advantageously have a size of 5 to 30 nanometers. These nanocrystalline particles were processed into nanocrystalline agglomerates.
• the nanocrystalline particles are thus agglomerated to Nanocrystalline agglomerates and these advantageously sintered.
• the nanocrystalline agglomerates become harder, so they withstand the stresses of cold gas spraying.
• the nanocrystalline agglomerates preferably have a size of from 5 to 150 ⁇ m, more preferably from 10 to 30 ⁇ m.
• Nanocrystalline agglomerates meet the requirements for porosity and hardness, so that they are on the one hand sufficiently porous, so that the nitrogen with the
• Spray particles can interact and on the other hand have sufficient hardness, so that they can be accelerated in the gas jet of the cold gas spraying.
• Impact on the object to be coated forms a photocatalytically active in the visible light layer.
• Coating leads. This formation of the coating is thus due to the properties of the spray powder.
• the spray powder consists almost exclusively of nanocrystalline agglomerates.
• the spray powder so no metallic or other additional component is added, so it contains in addition to the
• Nanocrystalline agglomerates only impurities. Additional components are not required because the properties of the spray particles are such that they can be cold-sprayed as spray powder.
• At least the photocatalytically active spray particles are heated from nanocrystalline agglomerates in a pre-chamber and / or in an extended convergent region by means of the carrier gas.
• Prechamber is an area that is in front of the convergent area of the nozzle.
• An extended convergent area means that the nozzle is extending to the nozzle throat over a wide range.
• Such a cold gas spraying nozzle which has a high residence time of spray particles in the warm carrier gas, is shown, for example, by EP 1 791 645.
• the spray particles are particularly well warmed by the warm carrier gas, since the residence time in the hot gas is long, so that a heat transfer can take place on the spray particles.
• the carrier gas cools down again due to the expansion, so that the spray particles are no longer warmer here.
• Coatings made with photocatalytic activity in visible light If the coatings also exhibit photocatalytic activity in visible light, the desired reactions for, for example, cleaning and disinfection take place when only visible light is present. UV light is therefore not necessary. This is advantageous if the coatings are to be used in rooms and rooms that are artificially illuminated or in the daylight through windows. Such light has, in contrast to daylight, no or only a very small proportion of UV. Consequently, the layers produced by the method according to the invention can also be used indoors.
• the coatings are at least 80 ⁇ , preferably at least 100 ⁇ thick. With the method according to the invention can thus produce thick layers.
• the coatings have a thickness of at least 80 ⁇ , preferably of at least 100 ⁇ .
• Thick coatings are characterized by being thicker than a layer of spray particles. So they have more than one layer of spray particles.
• the ductility of the material pairing is obviously of
• Thick layers are, when they are photocatalytically active in visible light, richly yellow and can be easily recognized as such.
• the coatings advantageously receive no metallic component. Also, the coatings advantageously contain no other components. With the method according to the invention it is thus possible to produce a coating which, apart from usual impurities, consists exclusively of titanium dioxide.
• coatings which are produced by the process according to the invention are claimed.
• the coatings produced by the process according to the invention are distinguished by their homogeneity and their layer thickness. These properties, which have only the coatings produced by the process according to the invention, can be recognized, for example, in the micrograph. In the light microscope, homogeneity and thickness can be determined in the
• the coating also shows the additional nitrogen taken up during the injection process or its influence on the nitrogen
• the coating has a photocatalytic activity in visible light.
• the coatings advantageously consist of titanium dioxide.
• an adhesion-promoting layer which is suitable for a
• Adhesion between the object to be coated and the coating provides, applied. This improves the durability of the coating.
• the inventive method is thus in an advantageous embodiment
• a cold gas spray gun is shown schematically and designated overall by 1.
• the cold gas spray gun 1 has a cold gas spray nozzle 10, which will now be explained in more detail.
• the cold gas spray gun 1 is directed onto a substrate S and has gas inlets 2, 3, via which a carrier gas G, in particular a heated gas stream of a
• Carrier gas G can be provided.
• a gas heater arranged upstream of the spray gun 1 is provided.
• Further gas inlets 3 can be used for setting a gas mixture and / or a gas temperature of the gas stream G.
• a powder inlet 4 is provided, by means of which the spray powder P in the
• Spray gun 1 is fed.
• an upstream of the spray gun 1 provided, but not shown powder conveyor is provided.
• the carrier gas G and the powder P enter a mixing chamber 5, which is arranged within a multi-part housing 6 of the spray gun 1.
• the multi-part housing 6 is shown partially open.
• a cold gas spray nozzle 10 has a spray gun side nozzle inlet 11 and the substrate side, a nozzle orifice 12. Between nozzle inlet 11 and
• Nozzle opening 12 extends a nozzle channel 13.
• the nozzle channel 13 has a nozzle neck 14. From the nozzle inlet to the nozzle throat 14 tapers
• correspondingly heated spray powder P is directed to the substrate S as a gas-powder mixture GP.
• This powder is heated in the carrier gas G, which preferably consists of nitrogen, in the convergent region of the nozzle up to the nozzle throat 14. In the divergent region of the nozzle behind the nozzle throat 14 gas and powder are accelerated to sufficiently high speeds. The powder then hits the substrate with high kinetic energy.
• the coating according to the invention forms on the substrate S, so that the substrate S is the coated article or a part of the coated article.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Environmental & Geological Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Inorganic Chemistry (AREA)
• Catalysts (AREA)
• Paints Or Removers (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Laminated Bodies (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)

Priority Applications (6)

Applications Claiming Priority (4)

Publications (1)

Family

ID=46146507

Family Applications (1)

Country Status (8)

Cited By (1)

Families Citing this family (10)

Citations (11)

Family Cites Families (5)

• 2012
  • 2012-01-24 DE DE102012001361A patent/DE102012001361A1/de not_active Withdrawn
  • 2012-04-24 EP EP12002885.7A patent/EP2620525A1/de not_active Withdrawn
• 2013
  • 2013-01-17 WO PCT/EP2013/000121 patent/WO2013110441A1/de active Application Filing
  • 2013-01-17 EP EP13700462.8A patent/EP2807287A1/de not_active Withdrawn
  • 2013-01-17 BR BR112014018034A patent/BR112014018034A8/pt not_active IP Right Cessation
  • 2013-01-17 US US14/369,002 patent/US9527069B2/en not_active Expired - Fee Related
  • 2013-01-17 AU AU2013212183A patent/AU2013212183B2/en not_active Ceased
  • 2013-01-17 CA CA2860720A patent/CA2860720A1/en not_active Abandoned
  • 2013-01-17 JP JP2014553658A patent/JP6104281B2/ja not_active Expired - Fee Related

Patent Citations (11)

Non-Patent Citations (3)

Also Published As

Similar Documents

Legal Events