COLOURED GLAZING AND METHOD FOR OBTAINING SAME

Abstract

A glazing includes a glass substrate on which is deposited a coating including at least one layer, the layer being formed from a material including metal nanoparticles dispersed in an inorganic matrix of an oxide, in which the metal nanoparticles are made of a metal chosen from the group formed by silver, gold, platinum, copper and nickel or of an alloy formed from at least two of these metals, in which the matrix including an oxide of at least one element chosen from the group of titanium, silicon and zirconium and in which the atomic ratio M/Me in the material is less than 1.5, M representing all atoms of the elements of the group of titanium, silicon and zirconium present in the layer and Me representing all of the atoms of the metals of the group formed by silver, gold, platinum, copper and nickel present in the layer.

Claims

1. A glazing comprising, a glass substrate on which is deposited a coating comprising at least one layer, said layer being formed from a material comprising metal nanoparticles dispersed in an inorganic matrix of an oxide, in which said metal nanoparticles are made of a metal chosen from the group formed by silver, gold, platinum, copper and nickel or of an alloy formed from at least two of these metals, said matrix comprises, is formed essentially from or is formed from an oxide of at least one element chosen from the group of titanium, silicon and zirconium, and the atomic ratio M/Me in said material is less than 1.5, M representing all of the atoms of the elements of the group of titanium, silicon and zirconium present in said layer and Me representing all of the atoms of the metals of the group formed by silver, gold, platinum, copper and nickel present in said layer.

2. The glazing as claimed in claim 1, in which said material has a plasmon absorption peak whose maximum is between 350 and 800 nm.

3. The glazing as claimed in claim 1, in which the metal atoms Me represent between 20% and 50% of all of the atoms M, Me and O present in the material constituting the layer.

4. The glazing as claimed in claim 1, in which the atoms of the element(s) M together represent between 10% and 40% of all of the atoms M, Me and O present in the material constituting the layer.

5. The glazing as claimed in claim 1, in which the thickness of the layer is between 5 and 100 nm.

6. The glazing as claimed in claim 1, in which the inorganic matrix is formed or formed essentially from titanium oxide TiOx, with 1x2.

7. The glazing as claimed in claim 1, in which the metal is silver Ag.

8. The glazing as claimed in claim 1, in which the metal nanoparticles have a globular form, the longest dimension of which, measured by transmission electron microscopy (TEM), is on average between 2 and 20 nm.

9. The glazing as claimed in claim 1, in which the metal nanoparticles are distributed in the layer in an increasing concentration gradient, from each surface of the layer to the center of said layer, the concentration of silver particles being at a maximum substantially at the center of the layer.

10. The glazing as claimed in claim 1, in which said glazing also comprises at least one overlayer deposited onto said layer relative to the glass substrate, said overlayer being formed from a dielectric material.

11. The glazing as claimed in claim 1, in which said dielectric material constituting said overlayer is formed essentially from a silicon and/or aluminum nitride.

12. The glazing as claimed in claim 10, in which said dielectric material constituting said overlayer is formed essentially from an oxide of at least one element chosen from silicon, titanium, zinc and tin.

13. The glazing as claimed in claim 1, in which said glazing also comprises at least one underlayer deposited under said layer relative to the glass substrate, said underlayer being formed from a dielectric material.

14. The glazing as claimed in claim 1, in which said dielectric material constituting said underlayer is formed essentially from a silicon and/or aluminum nitride.

15. The glazing as claimed in claim 13, in which said dielectric material constituting said underlayer is formed essentially from an oxide of at least one element chosen from silicon, titanium, zinc and tin.

16. A process for depositing a layer of a material having a plasmon absorption peak whose maximum is between 350 and 800 nm onto a glass substrate, said process comprising: a) passing said substrate into a cathode sputtering vacuum deposition device, b) introducing a plasma-generating gas into said vacuum deposition device and a plasma is generated from said gas, c) simultaneously sputtering the following, in the same chamber of the vacuum deposition device: a first target comprising an oxide of at least one element chosen from the group of titanium, silicon and zirconium, a second target made of an oxide of at least one element chosen from the group of titanium, silicon and zirconium and of particles of a metal included in the group formed by silver, gold, platinum, copper and nickel or particles of an alloy formed from at least two of these metals, said target having an M/Me atomic ratio of less than 1.5, M representing all of the atoms of the elements of said group of titanium, silicon and zirconium and Me representing all of the atoms of the metals of the group formed by silver, gold, platinum, copper and nickel, said sputtering being obtained by said plasma, said sputtering being obtained by said plasma, d) recovering a glazing comprising said substrate covered with said layer, said layer being formed from metal nanoparticles of said metal or of said alloy dispersed in an inorganic matrix of the oxide and having a plasmon absorption peak in the visible range, or d) recovering a glazing comprising said substrate covered with said layer and at least said layer is heat-treated, under conditions suitable for obtaining a layer formed from metal nanoparticles of said metal or of said alloy dispersed in an inorganic matrix of the oxide and which has a plasmon absorption peak in the visible range.

17. The process as claimed in claim 16, in which the elements chosen for the oxide of the first target and for the oxide of the second target are identical.

18. The process as claimed in claim 17, in which the oxide of the first target and of the second target is essentially titanium oxide.

19. A process for depositing a layer of a material having a plasmon absorption peak whose maximum is between 350 and 800 nm onto a glass substrate, said process comprising: a) passing said substrate into a cathode sputtering vacuum deposition device, b) introducing a plasma-generating gas into said vacuum deposition device and a plasma is generated from said gas, in the presence of oxygen, c) sputtering a target in a chamber of said device, said target comprising an oxide of at least one element chosen from the group of titanium, silicon and zirconium, and of particles of a metal included in the group formed by silver, gold, platinum, copper and nickel or particles of an alloy formed from at least two of these metals, said target having an M/Me atomic ratio of less than 1.5, M representing all of the atoms of the elements of said group of titanium, silicon and zirconium and Me representing all of the atoms of the metals of the group formed by silver, gold, platinum, copper and nickel, said sputtering being obtained by means of said plasma, d) recovering a glazing comprising said substrate covered with said layer, said layer being formed from metal nanoparticles of said metal or of said alloy dispersed in an inorganic matrix of the oxide and having a plasmon absorption peak in the visible range, or d) recovering a glazing comprising said substrate covered with said layer and at least said layer is heat-treated, under conditions suitable for obtaining a layer formed from metal nanoparticles of said metal or of said alloy dispersed in an inorganic matrix of the oxide and which has a plasmon absorption peak in the visible range.

20. The process as claimed in claim 19, in which the oxide of the target is formed essentially from titanium oxide.

21. The process as claimed in claim 19, in which the metal is silver, gold or platinum, more preferably silver.

22. The process as claimed in claim 19, in which the plasma-generating gas is a neutral gas essentially comprising argon, krypton on or helium, alone or as a mixture.

23. The process as claimed in claim 19, in which said process comprises, during step d), heating of the substrate up to a temperature above 400 C. and below the softening point of the glass substrate.

Description

IMPLEMENTATION EXAMPLE NO. 1: FLAT TARGET WITH ME=AG AND M=TI

[0131] This implementation example according to the invention relates to the preparation of a flat target, formed from a combination of sub-stoichiometric titanium oxide TiO.sub.x (with x=1.95) and of silver particles, the two constituents being distributed in the microstructure homogeneously, said target being intended to be used in magnetron sputtering in AC, DC or RF mode.

[0132] This flat TiO.sub.xAg target was produced by the plasma spraying process described previously after optimization of the distribution of the various materials in the plasma jet. The main steps of the process are as follows: [0133] Production of the intermediate support plate (tile) by machining, intended to be subsequently brazed on the target support. [0134] Preparation of the surface of the support plate by abrasive spraying (alumina-zirconia AZ grit 24). [0135] Deposition of a bonding underlayer by plasma spraying of a CuAl alloy (90% by mass of Cu), about 150 m thick. [0136] Premixing of TiOx and Ag powders in proportions calculated as a function of the differential yields (57.3% by mass of TiOx and 42.7% by mass of Ag). The mixture is stirred (in a Turbula mixer) systematically for 1 hour. The powders used for preparing the target are powders respectively having the following characteristics: [0137] TiO.sub.x powder: Powder of ground molten TiO.sub.x type (x=1.98) with a particle size (d.sub.50) of 75 m and a purity of 99.7% [0138] Silver powder produced by atomization of liquid metal, with a particle size (d.sub.50) of 45 m and a purity of 99.95% [0139] Construction of the TiO.sub.xAg active layer on the target by plasma spraying under the following conditions: [0140] Plasma torch of DC type with a maximum power of 60 kW, placed in a chamber under air [0141] Use of cooling jets placed under the copper support plate, and also on either side of the plasma torch, and directed toward the target to control the temperature and the stresses induced during the plasma spraying. [0142] Plasma spraying performed with the following parameters:

TABLE-US-00007 Arc Spraying Material H.sub.2 content intensity distance flow rate Parameters (%) (A) (mm) (g/min) Values used 13.4 450 120 80 [0143] Surface finishing by polishing and/or machining to obtain a roughness such that Ra<5 m

[0144] An optimized device for injecting the powder mixture allows suitable injection into the plasma without segregation of the powders in flight, making it possible to ensure homogeneous distribution of Me and of MO.

[0145] The main characteristics of the target thus produced are given below:

[0146] a. Chemical Composition:

[0147] The chemical analysis of the target thus produced corresponds to an M/Me ratio of about 0.6.

[0148] b. Electrical Resistivity

TABLE-US-00008 Resistivity per unit volume measured at 20 C. <100 .Math. cm by the Van Der Pauw method (ASTM F76)

[0149] c. Me Dispersion Homogeneity in the Structure:

TABLE-US-00009 Homogeneity criteria (Max min) on mean Standard deviation on on all of the ROIs Me content mean Me content Flat target 44% 19%

[0150] d. Microstructure and Degree of Porosity

[0151] The evaluation of the degree of porosity by image analysis, according to the method described hereinbelow, is 1%.

[0152] The microstructure of the target obtained is illustrated by the SEM image reported in FIG. 7 of a cross section thereof, which reflects the excellent homogeneity of distribution of the silver particles in the titanium oxide.

EXEMPLARY EMBODIMENT NO. 2

[0153] rotating tubular target with Me=Ag and M=Ti This implementation example relates to a rotating tubular target, formed from a combination of sub-stoichiometric titanium oxide TiO.sub.x (with x=1.95) and of silver particles, the two constituents being distributed in the microstructure homogeneously, said target being intended to be used in magnetron sputtering in AC, DC or RF mode.

[0154] This tubular TiO.sub.xAg target is produced by the plasma spraying process after optimization of the distribution of the various materials in the plasma jet. The main steps of the process are as follows: [0155] Use of a support tube made of austenitic stainless steel, for instance X2CrNi18-9. [0156] Preparation of the surface of the support tube by abrasive spraying (alumina-zirconia AZ grit 24). [0157] Preparation of a bonding underlayer via the electric arc process (twin wire arc spraying), performed in air, bonding layer of NiAl composition (95% nickel), about 150-200 m thick. Alternatively, the wire flame spray or projection plasma (air plasma spray) processes may also be used to produce this bonding underlayer. [0158] Premixing of TiOx and Ag powders in proportions calculated as a function of the differential yields (62% by mass of TiOx and 38% by mass of Ag). The mixture is stirred (in a Turbula mixer) systematically for 1 hour. [0159] The powders used for preparing the target are powders respectively having the following characteristics: [0160] TiO.sub.x powder: Powder of ground molten TiO.sub.x type (x=1.98) with a particle size (d.sub.50) of 75 m and a purity of 99.7% [0161] Silver powder produced by atomization of liquid metal, with a particle size (d.sub.50) of 45 m and a purity of 99.95% [0162] Construction of the TiO.sub.xAg active layer on the target by plasma spraying under the following conditions: [0163] Plasma torch of DC type with a maximum power of 60 kW, placed in a chamber under air [0164] Use of cooling jets placed under the copper support plate, and also on either side of the plasma torch, and directed toward the target to control the temperature and the stresses induced during the plasma spraying. [0165] Plasma spraying performed with the following parameters:

TABLE-US-00010 Parameters Arc Spraying Material H.sub.2 content intensity distance flow rate (%) (A) (mm) (g/min) Values used 12.3 550 150 160 [0166] Surface finishing by polishing and/or machining to obtain a roughness such that Ra<5 m.

[0167] An optimized device for injecting the powder mixture allows suitable injection into the plasma without segregation of the powders in flight, making it possible to ensure homogeneous distribution of Me (Ag) and of MOx (TiOx).

Essential Characteristics of the Target Thus Produced:

[0168] a. Chemical Composition:

[0169] The chemical analysis of the target thus produced corresponds to an M/Me ratio=0.92

[0170] b. Electrical Resistivity

TABLE-US-00011 Resistivity per unit volume measured at 20 C. 28.5 .Math. cm by the Van Der Pauw method (ASTM F76)

[0171] c. Me Dispersion Homogeneity in the Structure:

TABLE-US-00012 Homogeneity criteria (max min) Standard deviation on all of the ROIs on mean Me content on mean Me content Tubular target 42% 24%

[0172] d. Microstructure and Degree of Porosity

The evaluation of the degree of porosity by image analysis, according to the method described hereinbelow, is 1%.
The microstructure of the target obtained is illustrated by the image reported in FIG. 8 below of a cross section thereof, which reflects the excellent homogeneity of distribution of the silver.

IMPLEMENTATION EXAMPLE NO. 3: TARGET FORMED FROM A TIOX PREFORM

[0173] According to a third embodiment of a process for manufacturing a target according to the invention not making use of thermal spraying, the targets according to the invention are prepared by the process described below via its main steps directed toward producing a target with M=Ti and Me=Ag and x=1.8 to 2.0):

[0174] 1. Preparation of a Preform of the Porous TiO.sub.x Target.

The geometry of the preforms corresponds to the geometry of the segments intended to be bonded to the support plate (backing plate), namely plates, or to the support tube (backing tube), namely sleeves (hollow cylinders).
The desired degree of porosity for the preform depends on the final targeted volume content of TiO.sub.x. If A % is the targeted volume content of silver in the target, then the preform TiO.sub.x has a degree of porosity of P %=A %.
For high porosity values, the preform may be, for example, a ceramic foam produced according to the techniques of the art. Alternatively, to achieve the desired porosity levels, recourse may optionally be made to the addition of a furtive material intended to act as a pore generator during the thermal sintering cycle, this furtive material possibly being, for example, a polymer. For porosity levels which are lower but which can be reached by standard sintering, the preform may be made by imperfect sintering of a block of pressed powder.

[0175] 2. Impregnation of Said Preform

The porous preform or ceramic foam is impregnated with liquid Ag via one of the following methods: [0176] Preheating of the preform to 1000 C. followed by pouring liquid Ag onto the preform placed in a case (mold) so as to impregnate it completely [0177] Immersion of the preform (which is itself preheated to 1000 C.) in a bath of liquid Ag followed by extraction of the preform [0178] Immersion by capillarity by placing the preform above and in contact with the bath of liquid Ag so that the Ag impregnates the preform by capillarity.

[0179] 3. Fixing to the Support:

After light machining to bring the segments made to the targeted perfect geometry, the segments prepared are fixed to the support (tube or plate) via the soft brazing methods usually used for fixing magnetron targets, for example the indium brazing technique.
This third embodiment, performed as stated here, will also make it possible to produce the target according to the invention with the characteristics corresponding to the criteria stated previously (resistivity, homogeneity of distribution of Me, porosity).
The measurement techniques for measuring the essential characteristics of the targets described previously are given below:

AMethodology for Characterizing the Homogeneity of Distribution of the M Oxide and Metal Me Phases in the Structure of the Target:

[0180] The methodology for characterizing the homogeneity of distribution of the M oxide phase, on the one hand, and the metal Me phase, on the other hand, are illustrated in the particular case of a target with M=Ti and Me=Ag. The element M is introduced in the form of sub-stoichiometric titanium oxide TiO.sub.x (with x=1.95) and the element Me in the form of metallic silver particles.

[0181] It is thus a matter of characterizing the homogeneity of distribution of these two phases present.

[0182] To ensure the homogeneity of distribution of these two phases present, a sample representative of the microstructure of the target in its entirety is analyzed via an image analysis protocol which makes it possible to map the presence of Me within the microstructure of the sample. The representative sample must be sampled in a representative zone of the target, encompass the entire thickness of the target and have side dimensions of a few mm. The analysis protocol is applied on images of the microstructure of the target in cross section, images taken on the representative sample with a magnification of 200 or even, preferentially, 100 so as to cover a wider zone.

[0183] Zones of analysis (or ROI, Region Of Interest) having the same areas (for example 100100 m.sup.2), ideally 7070 m.sup.2, and which are uniformly distributed on the analysis screen are defined (see image 1). This screen, endowed with the definitions of the ROIs thus made, will act as an analysis grille on the microstructure images taken and presented facing this grille. In order thus to cover all of the microstructure sample representative of the whole target, a succession of translations is applied to successively position a sufficient number of images facing the analysis grille. Grayscale thresholding may then be applied to detect the metal phase Me (which is lighter in optical microscopy) and to determine the content thereof per unit area. The operation is repeated on at least 10 different images, taken from the target in cross section. Thus, for each ROI, a minimum of 10 images will be analyzed, which thus makes it possible to obtain the mean of the area percentage of the Me phase per ROI and the associated standard deviations.

[0184] A target thus obtained is considered as being a sufficiently homogeneous structure according to the invention if the following conditions are met: [0185] the difference A between the measured maximum content of Me phase and the measured minimum content of Me phase (counted on all of the ROIs chosen randomly) less than 50%, ideally less than 40% of the nominal contents T of Me phase (i.e. the mean content of Me observed on all the ROIs) [0186] preferably, the overall standard deviation calculated on the total number of measurements (=number of ROIs x number of images) less than 25% of the content T.
The images obtained illustrate the positioning of the ROIs and the detection of the Me phase is performed by grayscale thresholding.
Case of a Target with Non-Homogeneous Distribution:

[0187] To evaluate the pertinence of this protocol, analyses were performed by applying this homogeneity characterization protocol on various tests of preparation of targets of MOx-Me type having very different homogeneities of distribution of Me within the MOx.

[0188] Table 7 reports the area contents of Me (silver) per ROI and the associated standard deviations, the criteria identified above (A and standard deviations) of such targets, which make it possible to reflect the homogeneity of distribution.

TABLE-US-00013 TABLE 7 Homogeneity criteria (max min) Standard deviation on all of the ROIs on mean Me content on mean Me content Sample Test A 69% 37% Sample Test B 121% 53%

B Measurement of the Degree of Porosity

[0189] Evaluation of the degree of porosity is performed fire the standard image analysis techniques using images obtained by electron microscopy.

[0190] More precisely, the volume content of the porosities contained in the targets is determined from the measurement of the area content of these porosities by means of the stereology relationships developed by J. C. Russ, R. T Dehoff, Practical Stereology, 2nd edition, Plenum Press, New York, 1986. Consequently, this section describes the protocol for measuring the surface content of the porosities, determined on images (at magnification 100 to 500) of microstructures of cross sections (metallographic cross sections).

Evaluation of this content is performed by image analysis, the main objective which is to separate the porosities from the rest of the microstructure to be able subsequently to take measurements on the characteristics of the selected parts.

[0191] More precisely, the analysis comprises several successive steps to be applied to each representative sample of the target, which has been polished beforehand: [0192] Acquisition of the images to be analyzed using acquisition software, coupled with an optical microscope and high-resolution camera assembly. The images are preferentially taken in grayscale. [0193] Selection of the working zone which will define the area of the sample on which the measurements will be taken. [0194] Binarization of the image by thresholding, which consists in conserving from the initial image only the pixels whose grayscale is between two predetermined thresholds. Given that the pixels representative of the porosity are very dark, the lower level may be chosen equal to 0. It then remains to set the upper threshold value, generally interactively, by using a representative histogram of the distribution of the pixels according to their grayscale value (from 0, black, to 255, white). The conserved pixels representative of the porosity are then coded as black (0) and the others as white (1) and give a binary image. [0195] Determination of the area content of the porosities relative to the area of the pixels coded as black (0) representative of the porosity on the area of the working zone. This value can be calculated automatically by the image analysis software.
The mean porosity content finally retained according to the invention is the mean value of the porosity contents obtained on a sufficient number of microstructure images taken randomly (5 to 10 images) via the method described previously.

[0196] A cathode sputtering target for performing the present invention is formed, on the one hand, from an oxide of at least one element chosen from the group of titanium, silicon and zirconium and, on the other hand, of particles of a metal included in the group formed by silver, gold, platinum, copper and nickel or particles of an alloy formed from at least two of these metals, the M/Me atomic ratio in said target being less than 1.5, M representing all of the atoms of the elements of said group of titanium, silicon and zirconium present in said layer and Me representing all of the atoms of the metals of the group formed by silver, gold, platinum, copper and nickel present in said layer.

[0197] Preferred characteristics for the targets for performing the present invention are given below, and may, of course, be combined together, where appropriate: [0198] the M/Me atomic ratio is less than 1.2, especially less than 1.0 and very preferably less than 0.8. [0199] M represents a single element. [0200] Said oxide is a titanium oxide of formula TiO.sub.x, with x2, in particular a titanium oxide of formula TiO.sub.x, with x<2 and more preferably in which 1.70<x<2.0. [0201] The metal is silver, gold or platinum, copper or nickel; more preferably, the metal is silver, gold or platinum and, very preferably, it is silver. [0202] The target is made of a mixture of titanium oxide and of silver particles, the Ti/Ag atomic ratio in said target being less than 1.5, preferably less than 1.4, more preferably less than 1.0 and very preferably less than 0.8 or even less than 0.6. [0203] The electrical resistivity, as measured according to standard ASTM F76, is less than 5 .Math.cm. [0204] The porosity is less than 10%. [0205] The distribution of Me relative to M is such that the difference D between the maximum content of Me phase measured in said target and the minimum content of Me phase measured in said target, on a plurality of analysis zones of the same area 7070 m.sup.2, is less than 50%, preferably less than 40%, of the mean content of Me phase measured on said target. [0206] The global standard deviation calculated on the total number of measurements is less than 25% of the mean content of Me phase measured on said target.