Anti-Corrosive Coating Using Recycled High Density Polyethylene for Automotive Chassis

Both high corrosion costs and an over-abundance of plastic waste have significant global impacts. This research seeks to help in both areas by utilizing recycled plastic as an anticorrosive coating. Many plastic-based coatings, especially those developed in more recent years, already contain recycled content. This research, which utilizes 100% recycled high density polyethylene (HDPE) as a powder coat, will add to the increasingly sustainable catalog of anti-corrosive coatings. The HDPE was applied to mild steel samples with traditional electrostatic powder coating equipment. The coating thickness was measured using scanning electron microscope (SEM) characterized and was found to be roughly 116 μm. The SEM analysis did not reveal any porosity in the coating. The immersion corrosion test in 5% H₂SO₄ for 2–3 days showed corrosion products at the bottom of the beaker. The maximum corrosion obtained was 424.4 mills/year (mpy) after 70.45 hours of immersion and the minimum corrosion obtained was 0.0 mpy after 5.58 hours of immersion. The acid immersion tests indicated that the corrosion started from the edges and advanced towards the inner surfaces. The coating on the edges was not uniform and may be porous. The salt immersion test in 5% NaCl solution by mass showed the sign of corrosion products after 5.5 hours and increased with time. A few samples showed corrosion over 25% of the surface after 70.5 hours of immersion. This is again attributed to the fact that the edges were not coated completely. The corrosion resistance can be improved by avoiding the sharp edges on the part.