	US 12,252,628 B2
	Chromate-free inorganic coating systems for hot corrosion protection of superalloy substrate
Irina Belov, Zionsville, IN (US); Zhihong Tang, Carmel, IN (US); Mark W. Perpall, Indianapolis, IN (US); Daryl G. Copeland, Greenwood, IN (US); and Brian D. Fitzwater, Indianapolis, IN (US)
Assigned to Praxair S.T. Technology, Inc., North Haven, CT (US)
Filed by Irina Belov, Zionsville, IN (US); Zhihong Tang, Carmel, IN (US); Mark W. Perpall, Indianapolis, IN (US); Daryl G. Copeland, Greenwood, IN (US); and Brian D. Fitzwater, Indianapolis, IN (US)
Filed on Nov. 3, 2021, as Appl. No. 17/517,930.
Claims priority of provisional application 63/110,590, filed on Nov. 6, 2020.
Prior Publication US 2023/0340276 A1, Oct. 26, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. C09D 1/00 (2006.01); C09D 5/00 (2006.01); C09D 5/08 (2006.01); C09D 5/10 (2006.01); C09D 7/40 (2018.01)

CPC C09D 5/084 (2013.01) [C09D 1/00 (2013.01); C09D 5/002 (2013.01); C09D 5/103 (2013.01); C09D 7/69 (2018.01)]

25 Claims

1. An aqueous slurry composition for the production of a multilayer coating system for hot corrosion protection of a substrate comprising:

a basecoat slurry, comprising:

a first binder comprising an aluminum phosphate based aqueous solution having a molar ratio of Al:P higher than about 1:3, the first binder characterized by an absence of hexavalent chromium; and

metallic particles or metal oxide particles or a combination thereof incorporated into the first binder;

a topcoat slurry, comprising:

a second binder comprising an aluminum phosphate based aqueous solution having a molar ratio of Al:P higher than about 1:3, the second binder characterized by an absence of hexavalent chromium.