Gray low-radiation refrigerator door glass

Abstract

The invention provides gray low-radiation refrigerator door glass. The gray low-radiation refrigerator door glass comprises a first dielectric layer, a first metal layer, a second dielectric layer, a second metal layer, a third dielectric layer, a third metal layer and a fourth dielectric layer which are sequentially compounded outwards from a glass substrate, the first metal layer comprises a nickel-chromium alloy layer; the second metal layer comprises a nickel-chromium alloy layer or a superposition layer; the third metal layer comprises a superposition layer; the superposed layer comprises a silver layer and a nickel-chromium alloy layer which are arranged in sequence; and the silver layer in the laminated layer is arranged on one side close to the glass substrate. By optimizing the structural design of the film layer, the reflectivity of the film surface is reduced, the transmission color is improved, the overall performance of the product is improved, the requirements of high-end consumer groups for the display effect and high-grade texture of the wine cabinet are met, and the wine cabinet is suitable for large-scale production and application.

Description

Technical Field

[0001] This invention relates to the field of glass manufacturing technology, and in particular to a gray low-emissivity refrigerator door glass. Background Technology

[0002] In the application of low-emissivity glass for refrigerators, black / grey glass low-emissivity products, with their soft color and high-end texture, are particularly suitable for wine refrigerators, which have high requirements for display effect and storage function. They are applicable to a variety of places and decoration styles, and the demand continues to rise.

[0003] However, existing grey-glazed low-emissivity (GED) glass products suffer from numerous problems: long procurement cycles, unreliable raw material quality, potential surface defects such as film marks, scratches, bubbles, and pitting during production, resulting in low yields and unreliable delivery times. These issues severely restrict the promotion and application of GED glass products in the high-end market. Furthermore, traditional low-emissivity coated glass, while ensuring energy efficiency, often struggles to balance optical and mechanical properties, especially in temperable triple-silver low-emissivity glass, where the complex film structure, challenging process control, and high costs contribute to its high efficiency.

[0004] CN106186724A discloses a high-transmittance, light green, bendable steel triple-silver low-emissivity coated glass, comprising a glass substrate layer and a coating layer. The coating layer consists of sixteen layers sequentially arranged from the glass substrate layer outwards: the first layer is a SiNx layer, the second is a ZnO layer, the third is an Ag layer, the fourth is a NiCr layer, the fifth is an AZO layer, the sixth is a SiNx layer, the seventh is a ZnO layer, the eighth is an Ag layer, the ninth is a NiCr layer, the tenth is an AZO layer, the eleventh is a ZnSnO layer, the twelfth is a ZnO layer, the thirteenth is an Ag layer, the fourteenth is a NiCr layer, the fifteenth is an AZO layer, and the sixteenth is a SiNx layer. However, this patent still has shortcomings in optimizing the coating structure, making it difficult to effectively control the glass's light transmittance and energy efficiency.

[0005] CN112159116A discloses a neutral gray temperable double-silver Low-E coated glass, comprising a glass substrate on which fourteen layers are sequentially deposited using a vacuum magnetron sputtering method. The fourteenth layer is a ZrO2 film, with the following layers: ZTO, AZO, Ti, Ag, Ti, AZO, ZTO, AZO, Ti, Ag, Ti, AZO, ZTO, Ti, Ag, Ti, AZO, ZTO, and ZrO2. However, this patent still has shortcomings in optimizing the film structure, making it difficult to achieve better optical and thermal performance.

[0006] Therefore, there is an urgent need to develop a new type of tempered low-emissivity refrigerator door glass product that can not only meet the demand of the high-end market for gray glass low-emissivity products, but also solve many problems in the production and quality of existing products. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides a gray low-emissivity refrigerator door glass, which is made by sequentially compounding a first dielectric layer, a first metal layer, a second dielectric layer, a second metal layer, a third dielectric layer, a third metal layer and a fourth dielectric layer from the glass substrate outwards. This makes the gray low-emissivity refrigerator door glass have excellent optical and mechanical properties, as well as good oxidation resistance and processability, thus meeting the needs of large-scale production and application.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] The present invention provides a gray low-emissivity refrigerator door glass, the gray low-emissivity refrigerator door glass comprising a first dielectric layer, a first metal layer, a second dielectric layer, a second metal layer, a third dielectric layer, a third metal layer and a fourth dielectric layer sequentially laminated from the glass substrate outwards;

[0010] The first metal layer includes a nickel-chromium alloy layer;

[0011] The second metal layer includes a nickel-chromium alloy layer or a superimposed layer;

[0012] The third metal layer includes a stacked layer;

[0013] The superimposed layer includes a silver layer and a nickel-chromium alloy layer arranged sequentially; the silver layer in the superimposed layer is disposed on the side close to the glass substrate.

[0014] The gray low-emissivity refrigerator door glass of this invention comprises, sequentially from the glass substrate, a first dielectric layer, a first metal layer, a second dielectric layer, a second metal layer, a third dielectric layer, a third metal layer, and a fourth dielectric layer. The second metal layer comprises a nickel-chromium alloy layer or a superimposed layer; the third metal layer comprises a superimposed layer; and the superimposed layer comprises a silver layer and a nickel-chromium alloy layer arranged sequentially. Through a single-silver or double-silver tempered steel structure, surface problems such as film marks, scratches, bubbles, and pitting in traditional gray low-emissivity glass products during production are effectively solved, significantly improving the product yield, ensuring product quality stability, shortening the delivery cycle, and overcoming the problem of long procurement cycles for gray glass in existing technologies. The function of the first metal layer in the gray low-emissivity refrigerator door glass of this invention is to adjust the visible light transmittance and color. The function of the second metal layer is to reduce the visible light reflectance. The function of the third metal layer is to protect the functional silver layer and adjust the color. Omitting any of these layers will cause the color to deviate. If the third metal nickel-chromium layer is too thin, the functional layer will be prone to oxidation and lose its low-emissivity performance. However, if it is too thick, it will also lead to adverse effects such as a decrease in emissivity. Adding more metal layers will increase the manufacturing cost of the gray low-emissivity refrigerator door glass.

[0015] The gray low-emissivity refrigerator door glass of the present invention includes a film layer of specific thickness and specific composition, which improves the optical performance of the film layer while ensuring reduced glass surface reflection.

[0016] Preferably, the thickness ratio of the nickel-chromium alloy layer in the first metal layer, the second metal layer and the third metal layer is (4-7):(7-9):(1-2), for example, it can be 4:7:1, 4.2:7.5:1.2, 4.5:8:1.5, 5:8.5:1.8 or 7:9:2, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0017] The present invention preferably uses a nickel-chromium alloy layer thickness ratio of (4-7):(7-9):(1-2) in the first metal layer, the second metal layer and the third metal layer, which can improve the transmission color while ensuring the color of the glass surface.

[0018] Preferably, the glass substrate comprises silicate glass.

[0019] Preferably, the thickness of the glass substrate is 2-6mm, for example, it can be 2mm, 3mm, 4mm, 4.5mm, 5.2mm or 6mm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] Preferably, the thickness of the glass substrate is 3.2-4mm, for example, it can be 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.8mm or 4mm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] Preferably, the first dielectric layer, the second dielectric layer, the third dielectric layer, and the fourth dielectric layer each independently include one or more combinations of silicon nitride, zirconium silicon nitride, aluminum zinc oxide, or tin zinc oxide, wherein typical but non-limiting combinations include a combination of silicon nitride and zirconium silicon nitride, a combination of aluminum zinc oxide and tin zinc oxide, or a combination of silicon nitride and aluminum zinc oxide.

[0022] Preferably, the first dielectric layer, the second dielectric layer, or the third dielectric layer includes a zinc-aluminum oxide layer. In particular, when the metal stack includes a functional silver layer, the antioxidant properties of the film can be increased.

[0023] Preferably, the zinc oxide aluminum layer is disposed on the side away from the glass substrate. Its function is to form a flat metal seed layer, making the metal layer more flat and stable, and optimizing the emissivity of the product. If the zinc oxide aluminum layer is disposed on the side closer to the glass substrate, the continuity and flatness of the metal layer will decrease, which will easily lead to adverse effects such as delamination and oxidation during subsequent steel cutting and grinding processes.

[0024] Preferably, the thickness of the zinc-aluminum oxide layer is 5-15 nm, for example, it can be 5 nm, 7 nm, 9 nm, 11 nm, 13 nm or 15 nm, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable. When the zinc-aluminum oxide layer is thicker, the coating efficiency will decrease.

[0025] Preferably, the thickness of the first dielectric layer is 45-60 nm, for example, it can be 45 nm, 48 nm, 50 nm, 52 nm, 56 nm or 60 nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] Preferably, the thickness of the second dielectric layer is 40-60 nm, for example, it can be 40 nm, 44 nm, 48 nm, 52 nm, 56 nm or 60 nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, the thickness of the third dielectric layer is 80-95nm, for example, it can be 80nm, 83nm, 85nm, 88nm, 92nm or 95nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the thickness of the fourth dielectric layer is 30-40 nm, for example, it can be 30 nm, 32 nm, 34 nm, 36 nm, 38 nm or 40 nm, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0029] The thickness of the third dielectric layer described in this invention is 80-95nm, which is thicker than other dielectric layers. Its function is to adjust the glass surface and transmit color. When the thickness of the third dielectric layer is set to 40-60nm, the reflectivity will be too high, resulting in poor product display effect inside the refrigerator and the inability to achieve neutral gray color, among other adverse effects.

[0030] Preferably, the fourth dielectric layer further includes a zirconium oxide layer, which can improve the wear resistance of the gray low-emissivity refrigerator door glass.

[0031] Preferably, the zirconium oxide layer is disposed on the side away from the glass substrate.

[0032] Preferably, the thickness of the zirconium oxide layer is 2-4 nm, for example, it can be 2 nm, 2.4 nm, 2.8 nm, 3.2 nm, 3.6 nm or 4 nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] The present invention preferably uses a zirconium oxide layer with a thickness of 2-4 nm, which is the most economical thickness to ensure that the gray low-emissivity refrigerator door glass has anti-damage and anti-oxidation properties.

[0034] Preferably, the thickness of the first metal layer is 5-10 nm, for example, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm or 10 nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Preferably, the thickness of the second metal layer is 5-15nm, for example, it can be 5nm, 7nm, 9nm, 11nm, 13nm or 15nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, the thickness of the silver layer in the third metal layer is 10-18 nm, for example, it can be 10 nm, 12 nm, 14 nm, 16 nm, 17 nm or 18 nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] The thickness of the nickel-chromium alloy layer is 1-3 nm, for example, it can be 1 nm, 1.4 nm, 1.8 nm, 2.2 nm, 2.6 nm or 3 nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] This invention enhances the anti-oxidation performance of the film by controlling the thickness of the silver layer and nickel-chromium alloy layer in the metal layer and setting a dielectric layer with zinc-aluminum oxide layer. It achieves low light transmittance and low surface resistivity while ensuring excellent optical performance, and solves the problem in the prior art where the silver layer thickness setting affects the film thickness and structure.

[0039] The gray low-emissivity refrigerator door glass described in this invention undergoes tempering delay testing in a single-chamber flat bending furnace during production. The upper furnace temperature is 710-715℃, the lower furnace temperature is 690-705℃, and the tempering time is 180-270s. By controlling the tempering temperature and time during the tempering process, oxidation of the film surface can be prevented.

[0040] Compared with the prior art, the present invention has at least the following beneficial effects:

[0041] (1) The gray low-emissivity refrigerator door glass provided by the present invention reduces the reflectivity of the film surface and improves the transmittance by optimizing the film layer structure design, thereby improving the overall performance of the product and meeting the needs of high-end consumers for the display effect and high-end texture of the wine cabinet.

[0042] (2) The gray low-emissivity refrigerator door glass film layer provided by the present invention has a simple structure, low production cost, and is suitable for large-scale production. It can meet the market's demand for high-end gray glass low-emissivity products and provide new options for decoration and design in related fields. Detailed Implementation

[0043] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0044] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0045] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the shown orientation or positional relationship, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0046] Example 1

[0047] This embodiment provides a gray low-emissivity refrigerator door glass, which includes a first dielectric layer, a first metal layer, a second dielectric layer, a second metal layer, a third dielectric layer, a third metal layer, and a fourth dielectric layer sequentially laminated from the glass substrate outwards.

[0048] The first metal layer is a nickel-chromium alloy layer;

[0049] The second metal layer is a nickel-chromium alloy layer;

[0050] The third metal layer is a stacked layer; the stacked layer consists of a silver layer and a nickel-chromium alloy layer arranged sequentially; the silver layer in the stacked layer is disposed on the side closest to the glass substrate.

[0051] The glass substrate is silicate glass with a thickness of 3.2 mm.

[0052] The first dielectric layer, the second dielectric layer, and the third dielectric layer are all stacks of silicon nitride and aluminum zinc oxide layers, and the fourth dielectric layer is a silicon nitride layer; the aluminum zinc oxide layer is disposed on the side away from the glass substrate.

[0053] The total thicknesses of the first dielectric layer, the second dielectric layer, the third dielectric layer, and the fourth dielectric layer are 47 mm, 45 mm, 86 mm, and 30 mm, respectively, wherein the thicknesses of the zinc-aluminum oxide layers in the first dielectric layer, the second dielectric layer, and the third dielectric layer are 14 nm, 7 nm, and 10 nm, respectively.

[0054] The thicknesses of the nickel-chromium alloy layers in the first, second, and third metal layers are 6 nm, 13 nm, and 1.5 nm, respectively. The thickness of the silver layer in the third metal layer is 17 nm.

[0055] In this embodiment, the gray low-emissivity refrigerator door glass is tempered in a single-chamber flat bending furnace during the production process. The upper furnace temperature is 712°C, the lower furnace temperature is 702°C, and the tempering time is 230 seconds, which ensures that the film surface does not oxidize.

[0056] The optical properties of this tempered low-emissivity refrigerator door glass are as follows: 3.2mm clear glass with a visible light transmittance of 37% after tempering, a film reflectance of 9%, and a glass surface a* value of -0.39 and b* value of -4.88, both negative. The thermal properties are: emissivity of 0.04 and surface resistivity of 2.9Ω after tempering.

[0057] Example 2

[0058] This embodiment provides a gray low-emissivity refrigerator door glass, which includes a first dielectric layer, a first metal layer, a second dielectric layer, a second metal layer, a third dielectric layer, a third metal layer, and a fourth dielectric layer sequentially laminated from the glass substrate outwards.

[0059] The first metal layer is a nickel-chromium alloy layer; the second metal layer is a stacked layer; the third metal layer is a stacked layer; the stacked layer includes a silver layer and a nickel-chromium alloy layer disposed sequentially; the silver layer in the stacked layer is disposed on the side close to the glass substrate.

[0060] The glass substrate is silicate glass with a thickness of 3.2 mm.

[0061] Both the first and fourth dielectric layers are silicon nitride layers, and both the second and third dielectric layers are stacks of silicon nitride and aluminum zinc oxide layers; the aluminum zinc oxide layer in the second and third dielectric layers is disposed on the side away from the glass substrate.

[0062] The total thicknesses of the first dielectric layer, the second dielectric layer, the third dielectric layer, and the fourth dielectric layer are 52 nm, 60 nm, 83 nm, and 39 nm, respectively; wherein the thicknesses of the zinc-aluminum oxide layers in the second dielectric layer and the third dielectric layer are 15 nm and 10 nm, respectively.

[0063] The thickness of the first metal layer is 9 nm; the thickness of the second metal layer is 8 nm, wherein the thickness of the silver layer is 5 nm; and the thickness of the third metal layer is 15 nm, wherein the thickness of the silver layer is 11 nm.

[0064] In this embodiment, the gray low-emissivity refrigerator door glass is tempered in a single-chamber flat bending furnace during the production process. The upper furnace temperature is 713°C, the lower furnace temperature is 703°C, and the tempering time is 260 seconds, which ensures that the film surface does not oxidize.

[0065] The optical properties of this tempered low-emissivity refrigerator door glass are as follows: 3.2mm clear glass with a visible light transmittance of 30% after tempering, a film reflectance of 7%, and a glass surface a* value of -0.38 and b* value of -4.82, both negative. The thermal properties are: emissivity of 0.03 and surface resistivity of 2.5Ω after tempering.

[0066] As can be seen from Examples 1 and 2, by reasonably setting the thickness and stacking order of the metal layer and the dielectric layer, the present invention obtains gray low-emissivity refrigerator door glass with low film surface reflectivity and excellent overall product performance, which can meet the needs of high-end consumers for wine cabinet display effect and high-end texture.

[0067] Example 3

[0068] This embodiment provides a gray low-emissivity refrigerator door glass, wherein the fourth dielectric layer of the gray low-emissivity refrigerator door glass further includes a zirconium oxide layer; the zirconium oxide layer is disposed on the side away from the glass substrate; the thickness of the zirconium oxide layer is 3 nm, and the rest are the same as in Embodiment 1.

[0069] In this embodiment, the addition of a zirconium oxide layer on the fourth dielectric layer effectively improves the wear resistance of the gray low-emissivity refrigerator door glass.

[0070] Example 4

[0071] This embodiment provides a gray low-emissivity refrigerator door glass, which is the same as that in Embodiment 1 except that the thickness of the silver layer in the third metal layer is 8nm.

[0072] Example 5

[0073] This embodiment provides a gray low-emissivity refrigerator door glass, which is the same as that in Embodiment 1 except that the thickness of the silver layer in the third metal layer is 20nm.

[0074] As can be seen from Examples 1 and 4-5, the silver layer in the third metal layer of Example 4 is relatively thin, which leads to an increase in the emissivity of the gray low-emissivity refrigerator door glass, making the glass surface prone to fogging and frost, and deteriorating its performance. The silver layer in the third metal layer of Example 5 is relatively thick, which leads to a decrease in the processing resistance of the gray low-emissivity refrigerator door glass, making it prone to defects such as film oxidation and cracking, and the color deviates from the neutral color, while also increasing the manufacturing cost.

[0075] Example 6

[0076] This embodiment provides a gray low-emissivity refrigerator door glass. Except for adjusting the zinc oxide aluminum layer in the first dielectric layer to be located on the side close to the glass substrate, the gray low-emissivity refrigerator door glass is the same as that in Embodiment 1.

[0077] In this embodiment, because the zinc oxide aluminum layer in the first dielectric layer is located on the side close to the glass substrate, there will be adverse effects such as decreased emissivity and poor oxidation resistance of the film layer.

[0078] Comparative Example 1

[0079] This comparative example provides a gray low-emissivity refrigerator door glass, which is the same as that in Example 1 except that it does not have a third metal layer and a fourth dielectric layer.

[0080] Because this comparative example does not have a third metal layer and a fourth dielectric layer, the glass loses its low-emissivity performance, the emissivity increases to 0.7, and there is no defrosting or defogging function.

[0081] Comparative Example 2

[0082] This comparative example provides a gray low-emissivity refrigerator door glass, which is the same as that in Example 1 except that it does not have a first dielectric layer and a first metal layer.

[0083] Because this comparative example does not have a first dielectric layer and a first metal layer, it will have the disadvantage of high glass surface reflectivity and a noticeably yellowish color.

[0084] Comparative Example 3

[0085] This comparative example provides a gray low-emissivity refrigerator door glass, which is the same as that in Example 1 except for changing the order of the first metal layer and the third metal layer.

[0086] Due to the change in the order of the first and third metal layers, this comparative example will have adverse effects such as increased glass surface reflectivity, reddish-yellow color, and decreased emissivity during subsequent cutting and tempering processes.

[0087] In summary, by rationally setting the thickness and stacking order of each film layer of the gray low-emissivity refrigerator door glass, this invention achieves gray low-emissivity refrigerator door glass with excellent overall product performance and low film reflectivity. It can meet the needs of high-end consumers for wine cabinet display effect and high-end texture, and is suitable for widespread application.

[0088] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A gray low-emissivity refrigerator door glass, characterized in that, The gray low-emissivity refrigerator door glass comprises, sequentially from the glass substrate, a first dielectric layer, a first metal layer, a second dielectric layer, a second metal layer, a third dielectric layer, a third metal layer, and a fourth dielectric layer. The first metal layer includes a nickel-chromium alloy layer; The second metal layer includes a nickel-chromium alloy layer or a superimposed layer; The third metal layer includes a stacked layer; The superimposed layer includes a silver layer and a nickel-chromium alloy layer arranged sequentially; the silver layer in the superimposed layer is disposed on the side close to the glass substrate.

2. The gray low-emissivity refrigerator door glass according to claim 1, characterized in that, The thickness ratio of the nickel-chromium alloy layer in the first metal layer, the second metal layer and the third metal layer is (4-7):(7-9):(1-2).

3. The gray low-emissivity refrigerator door glass according to claim 1 or 2, characterized in that, The glass substrate includes silicate glass; Preferably, the thickness of the glass substrate is 2-6 mm; Preferably, the thickness of the glass substrate is 3.2-4 mm.

4. The gray low-emissivity refrigerator door glass according to any one of claims 1-3, characterized in that, The first dielectric layer, the second dielectric layer, the third dielectric layer, and the fourth dielectric layer each independently include one or more combinations of silicon nitride layer, zirconium silicon nitride layer, aluminum zinc oxide layer, or zinc tin oxide layer.

5. The gray low-emissivity refrigerator door glass according to claim 4, characterized in that, The first dielectric layer, the second dielectric layer, or the third dielectric layer includes a zinc-aluminum oxide layer; Preferably, the zinc oxide aluminum layer is disposed on the side away from the glass substrate; Preferably, the thickness of the zinc oxide aluminum layer is 5-15 nm.

6. The gray low-emissivity refrigerator door glass according to any one of claims 1-5, characterized in that, The thickness of the first dielectric layer is 45-60 nm; Preferably, the thickness of the second dielectric layer is 40-60 nm; Preferably, the thickness of the third dielectric layer is 80-95 nm; Preferably, the thickness of the fourth dielectric layer is 30-40 nm.

7. The gray low-emissivity refrigerator door glass according to any one of claims 1-6, characterized in that, The fourth dielectric layer also includes a zirconium oxide layer.

8. The gray low-emissivity refrigerator door glass according to claim 7, characterized in that, The zirconium oxide layer is disposed on the side away from the glass substrate; Preferably, the thickness of the zirconium oxide layer is 2-4 nm.

9. The gray low-emissivity refrigerator door glass according to any one of claims 1-8, characterized in that, The thickness of the first metal layer is 5-10 nm; Preferably, the thickness of the second metal layer is 5-15 nm.

10. The gray low-emissivity refrigerator door glass according to any one of claims 1-9, characterized in that, The thickness of the silver layer in the third metal layer is 10-18 nm, and the thickness of the nickel-chromium alloy layer is 1-3 nm.