Development of Bituminous Paint from Agbabu Natural Bitumen for Coat-Protecting the Underparts of Automobile Chassis against Corrosion and Wear

Abstract

To date, there has been continued demand for more effective, less expensive, and accessible coating systems for durable corrosion and wear protection of auto-bodies, with a research need to meet the demands. The rationale behind this study was to create a high-quality, low-cost bituminous paint for use in protecting the underparts of automobile chassis against corrosion and wear, particularly in Nigeria. Five paint blends containing various proportions of 70–100% Agbabu natural bitumen, 02–5% kerosene, 0–8.5% cobalt, 0–1% pigment, and 0–2.1% lead drier were produced and characterized by their basic physicochemical properties. The blends were brush-coated to a 1.78-mm average thickness on plate samples of mild steel, a commonly and widely applied but highly corrosion-susceptible chassis material type. Corrosion and wear tests performed on the steel samples under 1.78-mm-thick hard-dried coatings of the paint blends revealed that the blend with 75% bitumen, 15% kerosene, 8% cobalt, 0.6% pigment, and 1.4% lead drier content could perform exceptionally well in protecting the steel at the coating thickness. X-ray fluorescence and scanning electron microscopy analyses of that paint blend were conducted to understand its distinct chemical compositions and microstructural homogeneity level. The 1.78-mm-thick coatings of that paint blend's adhesion adequacy to the steel was also investigated. Analyses of the collected data revealed that the blend contained 25 different chemical species that are benign to steel corrosion, had a more or less uniform microstructure demonstrating its homogeneity, had minimal interangular boundaries indicating minimal ingress of corrosion-causing agents to the steel underneath its coatings, and its hard-dried thin coatings would have excellent adhesion to any ferrous chassis material.