US Patent 10183287 Method of applying a multilayer wet-on-wet coating to a substrate

A method of coating a substrate includes distributing a first catalyst slurry having a first catalytic composition and a first initial viscosity within the substrate to form a first catalyst layer within the substrate; adjusting the viscosity of the first catalyst layer such that the first catalyst layer is made to have a first adjusted viscosity that is greater than the first initial viscosity of the first catalyst slurry; distributing a second catalyst slurry having a second catalytic composition and a second initial viscosity within the substrate to form a second catalyst layer within the substrate, the second initial viscosity being made to be less than the first adjusted viscosity; the second catalyst slurry being distributed within the substrate while the first catalyst layer is in a wet state such that the second catalyst layer is formed as a wet-on-wet coating that at least partially overlaps the first catalyst layer.