Evaluation of Corrosion Performance of Zinc-Plated Underhood Automotive Fasteners Using Salt Spray Test

Abstract:

Mechanical fasteners such as screws, nuts, bolts, and washers are integral components in a vehicle. Rust or corrosion mechanisms of fasteners in the automotive industry is complex and may probably due to many factors includes temperature, pH, ion concentrations, coatings compositions as well as fastener geometry. Most of underhood fasteners used by PROTON models are Zinc coated fasteners. PROTON requires interior fasteners are coated to a minimum of 5 μm, while exterior fasteners are of 8 μm minimum thickness. There is a need to understand the corrosion performance of such fasteners in order to improve cosmetic and functional performances of these fasteners. The main objective of this study is to evaluate corrosion performance of three different compositions of Zinc-coated underhood fasteners using laboratory test. Samples were subjected to salt spray test with 5% NaCl for specific periods of time, in accordance ASTM B117-90 and JIS Z 2371:2000 conforming to their corrosion resistance requirements based on coating type and thickness. Results of the study revealed that Zn-Ni and Zinc-flake platings exhibit superior corrosion resistance characteristics with rating number (RN) of 10 compared to conventional 8 μm hexavalent-chrome free plated fasteners.

• Periodical: Key Engineering Materials (Volume 659)
• Pages: 560-564
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.659.560
• Online since: August 2015
• Authors: Amrin Astuty, Syairah Mohamad Zubir Dalila, Mohd Anuar Liza, Mohd Faim Aezal
• Keywords: Automotive Underhood Fasteners, Rating Number (RN), Zinc-Flake Plating, Zn-Ni Plating

References

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