Praxair S.t. Technology, Inc.

Zhihong Tang

Kevin E Garing

Thomas F Lewis, Iii

James Kent Knapp

Thomas D Findlay

Irina Belov

Daryl Copeland

Brian D Fitzwater

John Foster

Albert Feuerstein

Jeffrey J McConnell

Mark W Perpall

Bradley J Burton

James K Knapp

Thomas F Lewis

Hexavalent chromium-free slurry formulations which are suitable in the production of inorganic overlay coating systems are described. The formulations provide superior hot corrosion and high-temperature oxidation protection for superalloy substrates. A basecoat slurry and topcoat slurry are provided. The basecoat slurry includes an aluminum phosphate based aqueous solution having a molar ratio of Al:P higher than about 1:3 with the incorporation of pigments of either metallic particles, or metal oxide particles, or both in combination. The topcoat slurry includes an aluminum phosphate based aqueous solution having a molar ratio of Al:P higher than about 1:3. An inorganic overlay coating formed on substrate made from the slurry formulation of present invention for hot corrosion protection on superalloy substrate against hot corrosion. Furthermore, a multilayer coating comprises a metallic bond coat and an inorganic overlay coating formed on superalloy substrate to further enhance high-temperature oxidation and hot corrosion protection.

Chromate-free inorganic coating systems for hot corrosion protection of superalloy substrate

Hexavalent chromium-free slurry formulations which are suitable in the production of ceramic overlay coating systems are described. The formulations provide superior hot corrosion and heat oxidation protection for superalloy substrates. A basecoat slurry and topcoat slurry are provided. The basecoat slurry includes an aluminum phosphate based aqueous solution having a molar ratio of Al:POhigher than about 1:3 with the incorporation of metal oxide particles. The topcoat slurry includes an aluminum phosphate based aqueous solution having a molar ratio of Al:POhigher than about 1:3. Both of the basecoat slurry and the topcoat slurry are hexavalent chromium-free.

Chromate-free ceramic coating compositions for hot corrosion protection of superalloy substrates

Novel slurry formulations and processes for forming improved protective coatings used in the hot section components of gas turbine engines are provided. The process includes a unique two-step deposition methodology whereby the required concentration of reactive element within an improved reactive element doped aluminide coating can be consistently produced in a reproducible manner.

Slurry formulations for formation of reactive element-doped aluminide coatings and methods of forming the same

A novel dual layer mask formulation is provided. In particular, the mask has a unique composition that protects the integrity of an underlying chromide coating, prevents chromium depletion from the chromide coating and prevents a subsequent aluminide coating from being deposited thereon.

Mask formulation to prevent aluminizing onto the pre-existing chromide coating

Unique and improved chromizing processes are disclosed. The processes involve forming localized chromizing coatings onto selected regions of a substrate. The chromium diffusion coatings are locally applied to selected regions of substrates in a controlled manner, in comparison to conventional chromizing processes, and further in a manner that produces less material waste and does not require diffusion-stop-off masking. Prior to or after a localized slurry chromizing process of the present invention, a layer of a platinum-group-metal (PGM) is applied to produce a PGM-modified chromium diffusion coating onto selected regions of a substrate. A second coating can be selectively applied onto other regions of the substrate.

Methods of applying chromium diffusion coatings onto selective regions of a component

Unique and improved chromium coatings derived from modified chromium-containing slurry formulations are disclosed. The slurry formulation includes a combination of a selected halide activator and buffer material that synergistically interact with each other to form chromium diffusion coatings with improved microstructure in comparison to chromium diffusion coatings produced from conventional chromizing processes. The coatings may be locally applied in a controlled manner with accuracy onto various parts, including those having internal sections with complex geometries, without masking any portion thereof.

Modified slurry compositions for forming improved chromium diffusion coatings

A modified electroplated nickel-based metallic alloy coating and method of forming the same is provided. The electroplated coatings exhibit unique microstructure and composition which improves performance over conventional metallic materials. The coatings have significantly higher strength at elevated service temperatures.

Electroplated coatings

Unique and improved chromizing processes are disclosed. The processes involve forming localized chromizing coatings onto selected regions of a substrate. The chromium diffusion coatings are locally applied to selected regions of substrates in a controlled manner, in comparison to conventional chromizing processes, and further in a manner that produces less material waste and does not require masking. A second coating can be selectively applied onto other regions of the substrate.

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Carmel, IN, United States of America

Zhihong Tang