	US 12,434,264 B2
	Method for forming silica-based multilayer coating on substrate from polysilazane-containing compositions
Takaomi Tanabe, Hyogo (JP); Seiichiro Kawachi, Hyogo (JP); and Kosaku Hiyama, Hyogo (JP)
Assigned to TOCALO CO., LTD., Hyogo (JP)
Appl. No. 18/269,082
Filed by TOCALO CO., LTD., Hyogo (JP)
PCT Filed Nov. 11, 2021, PCT No. PCT/JP2021/041604 § 371(c)(1), (2) Date Jun. 22, 2023, PCT Pub. No. WO2022/137873, PCT Pub. Date Jun. 30, 2022.
Claims priority of application No. 2020-213363 (JP), filed on Dec. 23, 2020.
Prior Publication US 2024/0116076 A1, Apr. 11, 2024
Int. Cl. B05D 1/38 (2006.01); B05D 3/02 (2006.01); B05D 7/00 (2006.01); B05D 7/14 (2006.01)

CPC B05D 1/38 (2013.01) [B05D 3/0209 (2013.01); B05D 7/14 (2013.01); B05D 7/54 (2013.01); B05D 2202/15 (2013.01); B05D 2518/12 (2013.01)]

5 Claims

1. A method for forming a coating comprising:

a first step of applying a first solution comprising a polysilazane consisting of perhydropolysilazane to a surface of a metal substrate and heating the first solution at a first temperature to form a first coating on the surface of the metal substrate, and

a second step of applying a second solution comprising a polysilazane consisting of perhydropolysilazane to a surface of the first coating and heating the second solution at a second temperature lower than the first temperature to form a second coating on the surface of the first coating, wherein

a density of the first coating is less than 2.00 g/cm³, and

a density of the second coating is 2.00 g/cm³or more.