Wetting-resistant materials and articles made therefrom

A ceramic coating with specific oxide compositions promotes stable dropwise condensation and reduces thermal resistance, addressing the need for durable, low-wettability materials in heat transfer and weather-exposed surfaces.

DE102008055502B4Active Publication Date: 2025-07-31GENERAL ELECTRIC TECH GMBH
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Patent Information

Application Number
DE102008055502
Authority / Receiving Office
DE · DE
Patent Type
Patents
Current Assignee / Owner
Priority Date
2007-12-18
Filing Date
2008-12-10
Publication Date
2025-07-31
Estimated Expiration
2028-12-10

AI Technical Summary

Technical Problem

There is a need for oxide ceramics that exhibit lower liquid wettability than conventional oxides, are stable at elevated temperatures, and have good mechanical properties, suitable for coating applications, particularly in heat transfer equipment to promote stable dropwise condensation.

Method used

A coating material comprising a primary oxide with a cation selected from cerium, praseodymium, terbium, or hafnium, and a secondary oxide with lower intrinsic surface energy, such as rare earth elements like yttrium or scandium, is applied to form a dense ceramic layer with minimal porosity, enhancing hydrophobic properties.

Benefits of technology

The coating stabilizes dropwise condensation, reducing thermal resistance and maintaining mechanical durability, suitable for applications like heat transfer equipment and weather-exposed components to prevent liquid accumulation and ice formation.

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Abstract

An article (200) comprising:a coating (202) comprising a material comprising a primary oxide and a secondary oxide, wherein the secondary oxide is different from the primary oxide and has a lower intrinsic surface energy than the primary oxide, wherein(i) the primary oxide comprises at least one cation selected from the group consisting of cerium, praseodymium, terbium, and hafnium, and(ii) the secondary oxide comprises at least one cation selected from the group of rare earth elements,wherein the material of the entire coating (202) on the article (200) has a total porosity of less than 5 vol%.
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Claims

[1] Item (200) which has: a coating (202) comprising a material comprising a primary oxide and a secondary oxide, wherein the secondary oxide is different from the primary oxide and has a lower intrinsic surface energy than the primary oxide, wherein (i) the primary oxide comprises at least one cation selected from the group consisting of cerium, praseodymium, terbium and hafnium, and (ii) the secondary oxide has at least one cation selected from the group of rare earth elements, wherein the material of the entire coating (202) on the article (200) has a total porosity of less than 5 vol%. [2] The article (200) of claim 1, wherein the coating (202) further comprises a surface structure (206) for increasing the wetting resistance of the article (200). [3] The article (200) of claim 1, wherein the primary oxide comprises a cation selected from the group consisting of cerium and hafnium. [4] The article (200) of claim 1, wherein the secondary oxide comprises a cation selected from the group consisting of lanthanum, praseodymium, and neodymium. [5] The article (200) of claim 1, wherein the primary oxide comprises cerium oxide. [6] The article (200) of claim 5, wherein the secondary oxide comprises lanthanum oxide. [7] The article (200) of claim 6, wherein the cerium cation constitutes at least 25 mol% of the cations present in the material. [8] The article (200) of claim 5, wherein the secondary oxide comprises praseodymium oxide. [9] The article (200) of claim 8, wherein the cerium cation constitutes at least about 7 mole percent of the cations present in the material. [10] The article (200) of claim 5, wherein the secondary oxide comprises neodymium oxide. [11] The article (200) of claim 10, wherein cerium cation constitutes at least about 20 mole percent of the cations present in the material. [12] The article (200) of claim 1, wherein the primary oxide comprises a plurality of oxides, each oxide having a cation selected from the group consisting of cerium, praseodymium, terbium, and hafnium. [13] The article (200) of claim 12, wherein a ratio of the mole fraction of the primary oxide cation to the mole fraction of the secondary oxide cation is 1. [14] The article (200) of claim 13, wherein the material has a composition of the chemical formula S2Z 2-x Z' x O 7+ / y wherein S denotes all cations of the secondary oxide, Z or Z' denotes a cation of the primary oxide, y is a number less than 1 and x is a number in the range from 0.01 to 1.

99. [15] The article (200) of claim 14, wherein S comprises lanthanum, Z is cerium, and Z' is hafnium. [16] Capacitor (500) comprising the article (200) of claim 1. [17] A turbine assembly comprising the article (200) of claim 1. [18] The article (200) of claim 1, wherein the article (200) is a component of a steam turbine assembly. [19] An aircraft engine assembly comprising the article (200) of claim 1. [20] A wind turbine assembly comprising the article (200) of claim 1.

Citation Information

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