Glazing comprising a functional coating

A process for the preparation of a material comprising a transparent substrate coated with a stack of thin layers deposited by cathode sputtering, optionally magnetic-field-assisted cathode sputtering, the process comprising the sequence of following stages:

• depositing on the transparent substrate at least one functional coating comprising a silver-based metal functional layer exhibiting a thickness of between 2 and 6 nm, optionally at least one blocking layer chosen from metal layers, metal nitride layers, metal oxide layers and metal oxynitride layers of one or more elements chosen from titanium, nickel, chromium and tantalum,
• a first and second niobium-based functional layers each selected from a niobium-based metal functional layer or from a niobium-based nitride functional layer and each located:
• in contact with at least a portion of the silver-based functional layer or separated from at least a portion of the silver-based functional layer by one or more blocking layers, a sum of thicknesses of the one or more blocking layers is less than 5 nm, the silver-based metal functional layer arranged between the first and second niobium-based functional layers,
• a sum of thicknesses of the first and second niobium-based functional layers, located directly in contact with or separated by a thickness of less than 5 nm from at least a portion of the silver-based functional layer, is between 4 and 20 nm,
• wherein the niobium-based metal functional layer comprises at least 95.0% by weight of niobium with respect to the weight of the niobium-based metal functional layer and the niobium-based nitride functional layer comprises at least 95% by weight of niobium, with respect to the weight of elements other than nitrogen constituting the niobium-based nitride functional layer,
• wherein the sum of thicknesses of the first and second niobium-based functional layers is greater than the thickness of the silver-based metal functional layer and the thickness of the second niobium-based functional layer is greater than the thickness of the first niobium-based functional layer, the first niobium-based functional layer being arranged closer to the transparent substrate than the second niobium-based functional layer, and
• wherein a ratio of the sum of the thicknesses of the first and second niobium-based functional layers to the sum of the thickness of the silver-based metal functional layer of the functional coating is greater than 1 and lower than 4;
• depositing a coating based on dielectric materials is deposited above the functional layer,
• subjecting the substrate thus coated to a heat treatment.

A material comprising a transparent substrate coated with a stack of thin layers comprising at least one functional coating comprising:

• a silver-based metal functional layer exhibiting a thickness of between 2 and 6 nm,
• optionally at least one blocking layer chosen from metal layers, metal nitride layers, metal oxide layers and metal oxynitride layers of one or more elements chosen from titanium, nickel, chromium and tantalum,
• a first and a second niobium-based functional layer each selected from a niobium-based metal functional layer or from a niobium-based nitride functional layer
• and each separated from at least a portion of the silver-based functional layer by one or more blocking layers, a sum of thicknesses of the one or more blocking layers is less than 5 nm,
• the silver-based metal functional layer arranged between the first and second niobium-based functional layers,
• wherein the niobium-based metal functional layer comprises at least 95.0% by weight of niobium with respect to the weight of the niobium-based metal functional layer and the niobium-based nitride functional layer comprises at least 95% by weight of niobium with respect to the weight of elements other than nitrogen constituting the niobium-based nitride functional layer
• a sum of thicknesses of the first and second niobium-based functional layers separated by a thickness of less than 5 nm from at least a portion of the silver-based functional layer, is between 4 and 20 nm,
• wherein the sum of thicknesses of the first and second niobium-based functional layers is greater than the thickness of the silver-based metal functional layer and the thickness of the second niobium-based functional layer is greater than the thickness of the first niobium-based functional layer, the first niobium-based functional layer being arranged closer to the transparent substrate than the second niobium-based functional layer, and
• wherein a ratio of the sum of the thicknesses of the first and second niobium-based functional layers to the sum of the thickness of the silver-based metal functional layer of the functional coating is greater than 1 and lower than 4.