Department - Author 1

Materials Engineering Department

Degree Name - Author 1

BS in Materials Engineering



Primary Advisor

Trevor Harding


This project investigates the performance benefits of polysiloxane and polyurethane coating systems for corrosion protection in marine environments. PPG Industries Amercoat 450H and International Paint Interthane 990HS were the polyurethane topcoats tested. PPG Industries Ameron PSX 700 (New Blend) and International Paint Interfine 878 were the polysiloxane topcoats tested. Each coating was sprayed onto carbon steel panels that were prepared through hand blasting with glass beads. Scribed and unscribed panels were tested in a salt fog chamber for 1,200 hours according to ASTM Standard B0117-11 and in a UV/Humidifier for 1,650 hours according to ASTM Standard D4587-11. Panels were tested for impact resistance according to ASTM D2794-93R10. Panels were also placed at the Cal Poly pier for over 3 months. In Salt Fog Testing, both PPG and International Paint polyurethane systems outperformed their polysiloxane counterparts. Polyurethanes also performed better in gloss retention at 93% for Interthane 990HS and 85% for Amercoat 450H. Impact test results concluded, on average, that Amercoat 450H failed at 33 in-lbs, Ameron PSX 700 (New Blend) failed at 63 in-lbs, Interthane 990HS failed at 31 in-lbs, and Interfine 878/879 failed at 41 in-lbs. Testing will continue at the Cal Poly pier through NACE at Cal Poly.