FUNCTIONAL COATED ARTICLE

Abstract

A process to produce a scratch resistant coated article includes providing a flat glass substrate having a surface to be coated, and depositing a multilayered coating on the surface in corresponding sequence coming from the surface, a functional layer stack including at least one metallic silver inclusive layer sandwiched between two dielectric layers, a transition metal (TM) inclusive layer including carbon in a molar amount, which at least in a region of an outer surface of the TM inclusive layer equals at least the molar metal amount of TM metals, and a hydrogen containing layer in direct contact to the outer surface of the TM inclusive layer as an outermost layer of the coating.

Claims

1. A process to produce a scratch resistant coated article, the process comprising: providing a flat glass substrate having a surface to be coated; and depositing a multilayered coating on the surface in corresponding sequence coming from the surface: a functional layer stack (11, 11′, 11″) comprising at least one metallic silver inclusive layer (2, 4) sandwiched between two dielectric layers (1, 3, 5); a transition metal (TM) inclusive layer (6) comprising carbon in a molar amount, which at least in a region of an outer surface of the TM inclusive layer equals at least the molar metal amount of TM metals; and a hydrogen containing DLC (DLCH) layer (7) in direct contact to the outer surface of the TM inclusive layer as an outermost layer of the coating, wherein the functional layer stack is a low-E stack and deposition of the low-E stack comprises in corresponding sequence: sputtering a target comprising or consisting of at least one of Ti, TiZr, Zr, TiNb, Nb, Sn, SnZn, Si, or Si:Al or respective oxides thereof in an reactive atmosphere containing at least one of nitrogen and oxygen to produce an oxidic, nitridic, or oxynitridic Ti, TiZr, Zr, TiNb, Nb, Sn or SnZn, Si or Si:Al, inclusive basic layer (1′); sputtering a target comprising or consisting of at least one of Zn, Zn:Al, or respective oxides thereof in an atmosphere containing at least one of an inert gas and oxygen to produce a seed layer (1″), consisting of at least one of sub-stoichiometric zinc oxide (ZnO.sub.x), sub-stoichiometric aluminum doped zinc oxide (ZnO.sub.x:Al), directly on the surface of the basic layer; sputtering a silver containing target in an inert gas atmosphere to produce a silver inclusive layer (2, 4) directly on the surface of the seed layer (1″), between the silver inclusive layer (2) and the basic layer (1′); sputtering a target consisting of at least one of Ti, Ni, Cr, Zn, Zn:Al or respective metal oxide(s) in an atmosphere containing at least one of the inert gas and oxygen to produce a blocking layer (3′, 5′) consisting of at least one of Ti, NiCr, Zn, Zn:Al, sub stoichiometric TiO.sub.x, sub stoichiometric NiCrO.sub.x, sub stoichiometric ZnO.sub.x, sub stoichiometric ZnO.sub.x:Al directly on the surface of the silver inclusive layer; sputtering a target comprising or consisting of at least one of Nb, Sn, Ti, Zn, Zr, in an atmosphere containing at least one of the inert gas and oxygen to produce an intermediate layer (3″, 5″) consisting of at least one of TiO.sub.x, TiZrO.sub.x, TiNbO.sub.x, NbO.sub.x, SnO.sub.x, SnZnO.sub.x and ZnO.sub.x; sputtering a Si, an Si:Al, or respective oxides thereof or nitrides containing target in an reactive atmosphere containing at least one of nitrogen and oxygen to produce a silicon inclusive layer (5″′), the silicon inclusive layer comprising or consisting of an oxidic, nitridic, or oxynitridic Si, or Si:Al inclusive layer (5″″); and optionally repeating at least once complete deposition sequence or parts of the sequence of the low-E stack, wherein depositing of the TM inclusive layer comprises sputtering of a TM target consisting of at least one of following TM metals, or respective TM metal oxides of: Co, Cr, Fe, Hf, Nb, Ni, Mn, Mo, Ni, Sn, Ta, Ti, V, W, Y, Zn, Zr in a carbon gas containing atmosphere.

2. The process according to claim 1, characterized in that the depositing of the TM inclusive layer comprises sputtering the TM target in the inert gas and optionally oxygen gas containing sputter-atmosphere.

3. The process according to claim 1, characterized in that the depositing of the TM inclusive layer comprises sputtering a target consisting of at least one of Ti, TiNb, TiZr, Nb, Zr, NbZr TiO.sub.xC.sub.y, TiNbO.sub.xC.sub.y, TiZrO.sub.xC.sub.y, NbO.sub.xC.sub.y, ZrO.sub.xC.sub.y, and NbZrO.sub.xC.sub.y, in a carbon gas containing atmosphere,
wherein 0.1≤x≤3, 0≤y≤1, to deposit a TM layer consisting of at least one of TiO.sub.xC.sub.y, TiNbO.sub.xC.sub.y, TiZrO.sub.xC.sub.y, NbO.sub.xC.sub.y, ZrO.sub.xC.sub.y, NbZrO.sub.xC.sub.y,
wherein 0≤x≤2 and 1≤y≤6.

4. The process according to claim 1, characterized in that the depositing of the TM inclusive layer comprises sputtering a (Ti.sub.aZr.sub.bY.sub.cHf.sub.d) O.sub.x C.sub.y target or a (Ti.sub.aZr.sub.bY.sub.cHf.sub.d) target in a carbon gas containing atmosphere, wherein
a+b+c+d=1, 0.5≤a≤1, 0≤b≤0.5, 0≤c≤0.02, 0≤d≤0.01 and 0.1≤x≤2, 0≤y≤1 to deposit a (Ti.sub.aZr.sub.bY.sub.cHf.sub.d) O.sub.x C.sub.y layer, wherein
a+b+c+d=1, 0.5≤a≤1, 0≤b≤0.5, 0≤c≤0.02, 0≤d≤0.01 and 0≤x≤2 and 1≤y≤6.

5. The process according to claim 4, characterized in that the carbon gas is methane.

6. The process according to claim 4, characterized in that a flow of the carbon gas in the sputter atmosphere is adjusted to deposit a TMO.sub.xC.sub.y layer having a molar metal to carbon ratio of 1.0≤Me/C≤0.01 at least at the surface in direct contact with the DLCH layer.

7. The process according to claim 1, characterized in that depositing of DLCH-layer comprises exposing the carbon containing surface of the TM inclusive layer to a plasma-enhanced chemical vapor (PECVD) process using a mixture of a carbonaceous gas and an inert gas.

8. The process according to claim 7, characterized in that the PECVD process is an inductively coupled plasma process (ICPP) providing an ion current density from 0.01 mA/cm.sup.2 to 3.5 mA/cm.sup.2 to the surface.

9. The process according to claim 8, characterized in that an ion energy of the ICPP is 10 eV to 70 eV.

10. The process according to claim 7, characterized in that the carbonaceous gas is acetylene (C.sub.2H.sub.2).

11. A process to produce a scratch resistant coated article, the process comprising: providing a flat glass substrate having a surface to be coated; and depositing a multilayered coating on the surface in corresponding sequence coming from the surface: a functional layer stack (11, 11′, 11″) comprising at least one metallic silver inclusive layer (2, 4) sandwiched between two dielectric layers (1, 3, 5); a transition metal (TM) inclusive layer (6) comprising carbon in a molar amount, which at least at an outer surface of the TM inclusive layer equals at least to the molar metal amount of TM metal(s); and a hydrogen containing DLC (DLCH) layer (7) in direct contact to the outer surface of the TM inclusive layer as an outermost layer of the coating, wherein the hydrogen containing DLC (DLCH) layer (7) is deposited in direct contact to the TM inclusive layer as an outermost layer of the coating by an inductively coupled plasma process (ICPP) using a mixture of a carbonaceous gas and an inert gas, and wherein a DLCH layer (7) is produced having an average surface roughness as measured with atomic force microscopy (AFM) which is smaller 10 nm, having a hardness of the DLCH layer in a range from 6 GPa to 9 GPa, and having a mass density of the DLCH layer from 1.2 g/cm.sup.3 to 2.2 g/cm.sup.3

Description

[0100] The invention shall now be further exemplified with the help of figures and further tables. The figures show:

[0101] FIG. 1 Schematically and simplified an embodiment of an inventive glass article before and after tempering;

[0102] FIG. 2 An embodiment of an inventive article;

[0103] FIG. 3 A further embodiment of an inventive article;

[0104] FIG. 3A-N Examples of embodiments of the basic layer;

[0105] FIG. 4 Mechanical properties of an inventive article;

[0106] FIG. 5 An EDX spectroscopy plot of an TM inclusive layer;

[0107] FIG. 6 A TOF-SIMS depth profile of an TM inclusive layer;

[0108] FIG. 7A A surface area scan of AFM measurements on DLCH;

[0109] FIG. 7B A height distribution scan of an AFM measurement on DLCH;

[0110] FIG. 8A Refractive indices n of DLCH top layers;

[0111] FIG. 8B Coefficients of extinction of DLCH top layers;

[0112] FIG. 9 Raman spectra of DLCH top layers;

[0113] FIG. 10A\B Pos(G) and I(D)/I(G) with variable acetylene percentage;

[0114] FIG. 10C\D Pos(G) and I(D)/I(G) with variable ICP power;

[0115] FIG. 11A\B ATR FTIR measurements stretching and bending C—H modes;

[0116] FIG. 12 A .sup.13C NMR spectrum of a DLCH layer;

[0117] FIG. 13 A compressive stress versus DLCH thickness diagram;

[0118] FIG. 14 A water droplet on a DLCH surface.

[0119] FIG. 1 shows a basic scheme of an inventive article before and after tempering whereat on a glass substrate a low-E stack 11 is deposited comprising two silver layers 2, 3 and three dielectric layers 1, 2, 3. It should be mentioned that in an even more economical version a low-E stack with one silver layer 2 and two dielectric layers 1,2 only will also work but will not reach the same IR-blocking values as stacks comprising two or more silver layers of comparable dimensions. Following to the low-E stack 11 a TM including layer 6 with a high carbon content and a DLCH layer 7 follows for a so called intermediate product I, in this case a surface protected low-E glass. During an optional tempering process at 650 to 700° C. performed with or during finishing to produce the so called end-product II, a toughened safety glass, the DLCH-coating is burnt away and at the same time the mixed carbide containing amorphous structure 6 of the so called TM inclusive layer is transformed to a still amorphous, essentially oxidic structure 6′ as discussed in detail above. The oxidic structure 6′ having a better wear resistant with scratch and washing tests as can be seen with FIG. 4, see also respective description below. The low-E stack 11, protected below layers 6 and 7 respectively below layer 6′ after tempering essentially remains unchanged.

[0120] FIG. 2 and FIG. 3 show further inventive embodiments of intermediate products I′ and I″ comprising dielectric layers 1, 3, 5 of a defined material within the low-E stacks 11′ and 11″, namely one base layer 1′ which can be in direct contact to the surface of the substrate S and the following silver layer 2 or as shown with an innermost seed layer 1″, which may be dope with aluminum. The base layer 1′ and two intermediate layers 3″, 5″ may consist of TiO.sub.x, TiZrOx, TiNbOx, NbOx, SnOx, SnZnOx, SiN, SiON or a mixture thereof, each followed either by a seed layer 1″, 3″′ consisting of a sub-stoichiometric zinc oxide (ZnO.sub.sub) or a sub-stoichiometric aluminum doped zinc oxide (ZnO.sub.sub:Al) which is followed by two silver layers 2, 4, or in the case of the outermost intermediate layer 5″, the top layer 5″′ of the low-E stack, which is a silicon inclusive layer 5′″, the latter may follow either directly on the zinc oxide, tin oxide or ZnSnO.sub.x, inclusive intermediate layer 5″ as shown, or on an intermediate layer stack comprising a final zinc oxide inclusive layer to contact the silicon inclusive layer 5″′. Zinc oxide inclusive layers may be doped with Aluminum in both cases. Seed layers are optional but should be used when a silicon containing material is used for the base layer or the intermediate layer. On the outer surface of every silver or silver inclusive layer, sandwiched between the silver layer 2, 4 and following intermediate layer 3″ and 5″, a respective blocking layer 3′, 5′ of respective metallic and/or sub-stoichiometric oxidic material is deposited in direct contact to layers 2, 4 to protect silver from oxidation. With FIG. 2 the TM inclusive layer 6, which on its part directly supports the DLCH layer 7, follows in direct contact to the top layer of the low-E stack. With FIG. 3 an absorber layer stack 12 comprising at least one chromium nitride inclusive layer 9 sandwiched and in direct contact between two silicon nitride inclusive layers 8, 10 can be arranged between the low-E layer stack 11″ and the TM inclusive layer 6. Further, e.g., oxide and/or nitride inclusive layer may be provided instead or between the low-E stacks 11, 11′, 11″ and absorber layer 12 stack or between the latter and the TM inclusive layer 6.

[0121] Further examples of layer sequences which can be verified within the low-E stack are shown in Table 3, whereby column 3A to 3C show stacks with one silver layer 2, whereas in column 3D an example for a two silver layer 2, 4 stack is shown, which could be extended in analogy to three, four or more silver layer stacks. Therefrom it can be seen that absorber layer stacks 12, sandwiched between or comprising at least one intermediate layer 3″, 5″ in direct contact at an inner or/and outer surface of the absorber layer stack 12 can be inserted at different levels of the low-E stack 11, e.g. between the blocking layer 3′ and the silicon inclusive layer 5′″, which is the top layer 5′″ of the low-E stack, between the basic layer 1′ and the seed layer 1″, or between a blocking layer 3′ and a seed layer 3″′. Layers in bold boxes are optional for the function of the respective low-E stack example and can be omitted, replaced or accomplished by other layers. Layers below or above empty cells have to be seen as neighboring layers.

[0122] FIG. 3A to 3N show further examples of base layer stacks, which can be applied on a glass substrate S according to the present invention. Therewith only examples comprising absorber layers consisting of a Si.sub.3N.sub.4/CrN.sub.x/Si.sub.3N.sub.4 stack are shown, however other silicon inclusive layers as disclosed with the present description can be used too. It should be mentioned that basic layer stacks as shown are only examples which can be varied to a large extent by combining such basic layer stacks or introducing further layers of a basic layer material or of a further layer material as defined above between the substrate and the basic layer stack, between single layers of the basic layer stack, or between the basic layer stack and the following seed layer.

[0123] Table 1 shows exemplarily function, thickness d and composition of some of the as mentioned layer material which could be used for inventive articles.

[0124] With FIG. 4 results of a universal scratch test (UST) and a washing test (WT) on inventive articles I before tempering were combined and set into relation as surprisingly an essentially linear relation could be seen between the two tests on such coated articles, whereby the easier to perform washing test could replace the more elaborate universal scratch test in a production environment. P1 to P4 refer to inventive coatings, whereas state of the art coatings without an a-CH-protective layer delaminate with the UST at loads in the range from 0.5 to 0.7 N.

[0125] Universal scratch test (UST) of the as deposited layer stacks has been performed with Erichsen scratch hardness tester, where tip is of van Laar (∅0.5 mm) type, force can be increased from 0.1 N-10 N. Visible inspection under strong LED lamp. The maximum load value, under which coating still doesn't show any visible damage, defines its scratch-resistance.

[0126] Washing test has been performed by nylon brush of 454 g in deionized water, with a total amount of 300 runs and speed 37 cycles/min, control the sample on the subject of scratches under LED lamp. No scratches correspond to WT mark equal 1, with occasionally increasing amount of visible scratches the WT mark increases.

[0127] An energy-dispersive X-ray (EDX) spectroscopy plot of an TM inclusive layer, d=90 nm deposited on a float glass is shown in FIG. 5. The spectrum has been taken at 10 keV. The respective data are collected in Table 5. From that data a Ti/Zr atomic ratio of about 83/17 and a Me/C atomic ratio of about 0.22 could be deducted, whereby Me=Ti+Zr. Other metals as well as Si and an essential amount of the oxygen peak are assigned to the testing glass.

[0128] A time of flight secondary ion mass spectrometry (TOF-SIMS) depth profile from the same layer is displayed in FIG. 6. Elements like Si from the glass substrate, and C, Ti, Zr from the TM inclusive layer are displayed. The TiZrO.sub.xC.sub.y layer was a homogeneous TiZrO.sub.xC.sub.y layer essentially without C-gradient. Similar homogeneous layers have been proved to be successful in many applications. The depth profile has been taken with Cs.sup.+ (1 kV) and Bi.sup.+ (25 kV) ions measured in positive polarity on a surface area of 100×100 μm.sup.2.

[0129] In the following some testing results with reference to DLCH layers on top of coated articles before tempering II (intermediate products) according to the present invention are discussed. The DLCH layers 7 having been deposited by an ICP-process as described above and in Table 4.

[0130] FIG. 7A shows a surface area scan of an atomic force measurements (AFM) of a DLCH layer of 24 nm thickness, with very small nodules randomly distributed over the surface having a diameter in the sub-μm range, e.g. having a diameter of about 100 nm and 1 nm height. A one μm dimension line can be seen inserted as a lateral x, y-scale, the grey-value bar on the right side serves as a basis to determine height (z-value) of respectively toned sub-areas. FIG. 7B shows a statistical height distribution over the same 2.5 μm×2.5 μm area, and evidences an average height of about 1 nm, also the highest nodules were far below 10 nm in height, about 6 nm to the maximum with a percentage of 99.9% within the range between zero and two nm.

[0131] Therewith an extremely smooth surface of the DLCH layer 7 is shown.

[0132] FIG. 8 show optical properties of DLCH coatings from samples “a” to “e”, as deposited according to parameters given in Table 4. FIG. 8A shows the index of refraction n and FIG. 8B the extinction coefficient k, both between 300 and 1500 nm. In the IR region between 700 and 1500 nm n could be adjusted between 1.75 and 1.68, whereas k was always below 2×10.sup.−2 respectively below 1×10.sup.−2 for λ≥900 nm.

[0133] For the same test coatings samples “a” to “e” also Raman spectra were taken at an excitation wavelength of 532 nm and fitted with 2 Gaussian peaks (D and G) after background subtraction and normalizing of the date. Full width half maximum (FWHM) and intensity (I) numbers of both peaks calculated from the data were collected in Table 4, as were intensity relation I(D)/I(G) and Position of peak G. Respective curves are displayed in FIG. 9, “a” to “e”.

[0134] From the same data numbers for FIG. 10A to C were taken. FIG. 10A and FIG. 10B show variation of Position (G) respectively of relation of peak intensities I(D)/I(G) when acetylene percentage in the process atmosphere was varied from 19 to 35%, samples numbers “a” to “c”,. Inert gas as used was Argon, the ICP-power was fixed at 7 kW per source, that is 21 kW for the three sources of the source configuration as used.

[0135] FIG. 10C and FIG. 10D show variation of Pos(G) respectively of relation I(D)/I(D) when the ICP-power range in the process atmosphere was varied from 4 to 7 kW, sample numbers “d”, “e” and “a”. Inert gas as used was Argon, the acetylene range in the process atmosphere was fixed at 27 mol %.

[0136] Thereby Position (G) variations could be seen from 1520 to 1545 cm.sup.−1, whereas variation of peak intensities I(D)/I(G) varied from 0.39 to 0.61±0.05. With typical production conditions at Position (G) 1530 cm.sup.−1, at an excitation wavelength of 532 nm a comparison with a state of the art correlation diagram, showing DLC phases at different Pos(G)/λ.sub.excit positions, was made which fitted well to a ta-C:H phase of the DLCH. The diagram was from A.C. Ferrari and J. Robertson as published in Phil Trans. R. Soc. Lond. A (2004), FIG. 11.

[0137] For estimation of the hydrogen content from Pos(G) and I(D)/I(G) a further diagram of the same authors has been used which has been published in Physical Review B 72, 085401 (2005), FIG. 5. Thereby a hydrogen content of 15 to 35% could be estimated for DLCH coatings on top of an inventive “intermediate product”.

[0138] By similar correlating of respective Raman data to state of the art investigations a hardness range from about 100 to 250 GPa could be found,

[0139] ATR FTIR measurements have been performed for one of the thick single DLCH layers and are shown exemplarily. Absorbance versus wavenumber is displayed with FIG. 11A for stretching C—H modes and with FIG. 11B for bending C—H modes wherein sp.sup.3 hybridization could be seen for C—H, CH, CH.sub.2 and CH.sub.3 bonds. The presence of these FTIR features also confirms a presence of hydrogen in the DLCH film.

[0140] Quantification of the sp.sup.3 content however has been verified by solid 130 NMR. Therewith a sum signal from C—C and C—H bonds is measured at a chemical shift of about 40 and 140 ppm, wherein the C—H bonds are estimated to give a relatively stronger signal. An sp.sup.3 proportion from 51 to 55% referring to sp.sup.2/sp.sup.3 ratios from 0.8 to 0.95 could be found by fitting data from the measurement signals. An example and exemplary data of such measurements can be seen in FIG. 12, respectively looked up in Table 6. The following measurement set up was used: 10 kHz rotation, 4 mm CP/MAS Sample head at 400.2 MHz (.sup.1H), 100.6 MHz (.sup.13C). Raman parameters as shown above and in Table 4, according to respective Raman investigations from Ferrari and Robertson, correlate well with parameters as defined by NMR sp.sup.3 content.

[0141] Density of the DLCH layer material has been deducted from correlating NMR sp.sup.3 and Raman FWHM (G) data with state of the art investigations as well as from indexes of refraction measured at 635 nm (e.g. n=1.75) which estimates a density range from 1.2 to 2.2 g/cm.sup.3.

[0142] Internal layer stress as measured for some ta-C:H layers of different thickness is displayed in FIG. 13. It can be seen that internal stress grows from about 281 MPa for a 96 nm layer to 424 MPa with a 24 nm layer. Such layers have been deposited directly on to a glass substrate.

[0143] Water contact angles (WCA) for 24 nm DLCH layers have been measured within one day after deposition. Such WCA values were 53.1±0.8 as can be seen exemplarily in FIG. 14.