NEI Corp. has completed development of Nanomyte PT-20, a chromate-free pretreatment designed to improve the adhesion and corrosion resistance of painted steel while reducing surface preparation.
The environmentally friendly, waterborne pretreatment promotes adhesion between the metal substrate and overlying paint layer by acting as a double-sided bonding agent, while improving corrosion resistance, the manufacturer says.
|Shipyard trials of the product used steel panels prepared according to SSPC SP-10 and SP-6. The SP-6 panels were then treated with Nanomyte PT-20. Despite less surface preparation, the manufacturer says, the treated panels later showed less corrosion.|
NEI says the new product reduces the level of surface preparation required before painting bridges, ships and other steel structures. It is also suitable for coil, spray coating and other industrial painting operations.
Nanomyte PT-20 has been extensively tested at a major U.S. shipyard, according to NEI. In one test, steel panels were blasted to an SSPC SP-10 (near white blast cleaning) and SP-6 (commercial blast cleaning). The SP-6 preparation took less than half the time of the SP-10 and generated only a fraction of the powdery hazardous waste from blasting.
PT-20 was then applied to the SP-6 panels only. Both types of panels were then painted with two coats (8 mils thick) of a U.S. Navy-specified epoxy primer (MIL-PRF-23236D) and subjected to salt spray testing (ASTM B117).
After four weeks, the SP-6 panels with PT-20 exhibited half of the scribe creep detected on the untreated SP-10 panel.
In another shipyard trial, steel parts were blasted to SP-10 and SP-6, and PT-20 was applied to the SP-6 panels. The parts were painted with a full US Navy-specified paint system: two coats of epoxy primer and one coat of a silicone alkyd topcoat. After six months of outdoor exposure in a severe marine environment, the SP-10 parts are showing rust, while the SP-6 plus PT-20 parts are rust free, NEI said.
“Our chromate-free pretreatment for steel represents a significant advancement in the state-of-the-art for corrosion-resistant technologies,” says Dr. Ganesh Skandan, CEO of NEI Corp.
Development of the PT-20 coating was funded by the U.S. Navy Small Business Innovative Research Program.
Founded in 1997 and based in Somerset, NJ, NEI Corp. develops, manufactures, and distributes advanced protective coatings and other nanoscale materials for a broad range of industrial customers worldwide.