Patent ID: 9739169
Date: 2017-08-22
CPC Classifications: C04B,C09D,C23C,F01D,F02C,F05D,Y02T,Y10T

Claim:
1. A coating process comprising: (A) applying to a metallic or ceramic surface an aqueous coating composition which has a shelf-life of at least about ten months, which does not contain chromium, which has a pH of about 10 to about 14, which is capable of forming on the surface a corrosion-resistant coating, and which consists essentially of an aqueous liquid phase including about 35 to about 70 wt. % of water having dissolved therein about 2.5 to about 30 wt. % of lithium or sodium silicate or a mixture thereof and having dispersed therein about 20 to about 50 wt. % of solid aluminum particles of no greater size than about 15 microns, wherein the sodium silicate has a weight ratio of SiO 2 to Na 2 O of about 1.6 to 1 to about 3.75 to 1 and the lithium silicate has a weight ratio of SiO 2 to Li 2 O of about 9.4 to 1 to about 17 to 1, to form on the surface a wet coating; and (B) drying said wet coating: (i) under conditions which convert said wet coating to an electrically conductive, corrosion-resistant, solid coating; or (ii) under conditions which form a solid coating which is not electrically conductive (non-conductive) and thereafter treating said non-conductive coating under conditions which convert said non-conductive coating to an electrically conductive, corrosion-resistant coating; a corrosion-resistant coating as referred to herein being such that a coating which has a thickness of about 0.8 mil to about 3.5 mils has corrosion-resistant properties that are characterized by no greater than about 1.6 mm loss of adhesion at scribe when subjected to 5% neutral salt spray at 95° F. for about 1000 hours according to ASTM B-117.