MILDLY ALKALINE THIN INORGANIC CORROSION PROTECTIVE COATING FOR METAL SUBSTRATES

摘要

Disclosed is a neutral to alkaline inorganic chrome-free conversion coating composition that can be applied directly to a metal surface without a phosphatizing pre-treatment and that provides significant corrosion protection to the surface. The conversion coating composition preferably has a pH of from about 6 to 11 and more preferably from 8 to 10. The coating composition includes at least one element from group IVB of the Periodic table and at least one element from group VB of the Periodic Table. Preferably, the coating composition includes from 1 to 7% by weight of the at least one element from group IVB and from 0.20% to 2.00% by weight of the at least one element from group VB. The conversion coating composition is a dry in place coating and being chrome free it does not have the environmental issues associated with chrome-based coatings. The coating composition is very versatile and can accommodate addition of a wide variety of organic coating resins which can be added directly to the coating composition thus eliminating multistep coating processes.