# US 2021/0340677 A1 · A method to increase the thermal stress capability of a porous ceramic coating and a layer system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0340677 A1 - Document ID: US20210340677A1 - Status: Published application - Kind: A1 - Application number: 17/282,295 - Filed: 2019-06-14 - Published: 2021-11-04 - Earliest claimed: 2018-10-12 - Assignees: Siemens Energy Global GmbH & Co. KG - Applicants: Siemens Energy Global GmbH & Co. KG - Inventors: Peter Stuart Hollingsworth; Alexandr Sadovoy; Dimitrios Zois - Web page: https://patentgrep.com/patent/US20210340677A1 ## CPC - C23C 4/18: After-treatment - C04B 38/0074: {expressed as porosity percentage} - C04B 41/0081: {characterised by the subsequent cooling step} - C23C 4/02: Pretreatment of the material to be coated, e.g. for coating on selected surface areas - C23C 4/11: Oxides - C23C 4/134: Plasma spraying - 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 (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE ## Abstract A method to increase the thermal stress capability of a porous TBC and layer system. Due to a post treatment step to a pose TBC coating cracks are produced inside the post TBC advantages manner to increase the thermal stress capability of the ceramic coating by only heating the surface of the ceramic coating. ## Claims ### Claim 1 A method to produce cracks into a porous ceramic coating in order to increase the thermal stress capability of the ceramic coating, the method comprising: coating or providing a component with a porous ceramic coating, wherein the ceramic coating shows no or almost no vertical microcracks, wherein the component comprises a substrate and a bond coat, and the ceramic coating is on the bond coat, heating up in a first step the surface of the ceramic coating to sinter the ceramic coating at the surface so that vertical cracks are produced starting from a surface rim, force cooling in a final step the sintered rim and the coating. ### Claim 2 (depends on 1) The method according to claim 1, wherein the porosity of the ceramic coating is 8% to 22%. ### Claim 3 (depends on 1) The method according to claim 1, wherein the material of the ceramic coating is a zirconia based. ### Claim 4 (depends on 1) The method according to claim 1, wherein the component is forced cooled from inside after the coating step. ### Claim 5 (depends on 1) The method according to claim 1, wherein a heat source, or a laser or a plasma burner is used to heat up the ceramic coating at the surface. ### Claim 6 (depends on 2) The method according to claim 2, wherein after the coating step the component is forced cooled from inside and heated up with a rate≤50 K/s, wherein the cooling from inside is maintained. ### Claim 7 (depends on 6) The method according to claim 6, wherein the temperature of the coating is raised until a high temperature between 1000° C. and 1500° C. ### Claim 8 (depends on 7) The method according to claim 7, wherein the high temperature is maintained for a residence time from 5 min to 2 hours, in order to allow a sintering process to occur. ### Claim 9 (depends on 1) The method according to claim 1, wherein the heating up to sinter step is directly performed after the coating step, in the same equipment. ### Claim 10 (depends on 9) The method according to claim 9, wherein cooling from inside is stopped and wherein the sintered rim is forced cooled from outside. ### Claim 11 (depends on 1) The method according to claim 1 wherein the heat source is focused on the section of the layer system where the ceramic coating is required to demonstrate high thermal strain capacity. ### Claim 12 (depends on 1) The method according to claim 1, wherein a thermal camera or other monitoring device is used to monitor the temperature of the coating. ### Claim 13 (depends on 1) The method according to claim 1, wherein the depth and frequency of vertical cracks are adjusted by manipulating heat rate, residence time and/or cooling rate. ### Claim 14 (depends on 1) A layer system, produced by the method of claim 1, comprising: a substrate, optionally a bond coat, an outermost ceramic coating, wherein the outer surface is partially sintered, so that a surface rim is present, and wherein the ceramic coating has vertical cracks. ### Claim 15 (depends on 1) The method according to claim 1, wherein the substrate comprises a metallic substrate, and/or wherein the bond coat comprises a metallic bond coat. ### Claim 16 (depends on 1) The method according to claim 1, wherein the heating up comprises heating up for several minutes up to 2 hours. ### Claim 17 (depends on 3) The method according to claim 3, wherein the material of the ceramic coating comprises a partially or fully stabilized zirconia (ZrO2). ### Claim 18 (depends on 6) The method according to claim 6, wherein the component is forced cooled until a low temperature of 600° C. ### Claim 19 (depends on 7) The method according to claim 7, wherein the temperature of the coating is raised until a high temperature between 1300° C. and 1500° C., with a heating rate of max 50 K/s. ### Claim 20 (depends on 8) The method according to claim 8, wherein the high temperature is maintained for a residence time from 15 min to 2 hours. ### Claim 21 (depends on 11) The method according to claim 11, wherein the heat source is focused on the section(s) of the layer system where the ceramic coating is required to demonstrate high thermal strain capacity, comprising a leading edge, a suction side, and/or a pressure side of a turbine blade or vane. ### Claim 22 (depends on 14) The layer system according to claim 14, wherein the substrate comprises a metallic substrate, and/or wherein the bond coat comprises a metallic bond coat.