Corrosion-Resistant Coating Composition
The present invention provides a chromate-free coating composition having excellent corrosion resistance. The coating composition includes a binder system comprising a resin and a pigment system including a metal alloy pigment component and optionally, a carbonaceous component. Coated articles with the coating composition applied to at least a portion of a surface thereof are also provided.
1 . A corrosion-resistant coating composition, comprising:
a binder system including
a resin component;
a crosslinking component; and
a cure catalyst; and
a pigment system including
a metal alloy pigment component; and optionally, a carbonaceous component,
wherein the ratio of the pigment system to the binder system is about 1:1 to 9:1.
2 . The composition of claim 1 , wherein the resin component is selected from polyesters, modified polyesters, polyurethanes, polyacrylates, epoxies, modified polyacrylates, and combinations thereof.
3 . The composition of claim 1 , wherein the crosslinking component is selected from melamine, isocyanate, and combinations thereof.
4 . The composition of claim 1 , wherein the cure catalyst is selected from acid catalysts, acid precursors, amines, and combinations thereof.
5 . The composition of claim 1 , wherein the metal alloy pigment is in the form of metal flake.
6 . The composition of claim 1 , wherein the metal alloy pigment is in the form of metal dust.
7 . The composition of claim 1 , wherein the metal alloy pigment is a Zn Mg alloy pigment.
8 . The composition of claim 1 , wherein the carbonaceous material is graphene.
9 . The composition of claim 1 , wherein the carbonaceous material is mixed with the metal alloy pigment.
10 . The composition of claim 1 , wherein the graphene is present in an amount of about 0.1 to 10 wt % based on the total weight of the composition.
11 . The composition of claim 7 , wherein the ZnMg alloy pigment has Zn content of about 70 to 95 wt % based on the total weight of the composition.
12 . The composition of claim 7 , wherein the ZnMg alloy pigment has Zn content of about 74 wt % and Mg content of about 26 wt % based on the total weight of the alloy pigment.
13 . The composition of claim 1 , wherein the metal alloy pigment is in the form of 30 to 70 wt % metal flake and 30 to 70 wt % metal dust, based on the total weight of the composition.
14 . A method of making a corrosion-resistant coated article, comprising:
providing a substrate or portion thereof made of metal;
providing a coating composition according to claim 1 ;
applying the coating composition to the substrate; and
curing the composition to obtain a cured coating having dry film thickness of about 0.1 to 0.5 mil.
15 . A coated article prepared by the method of claim 14 .