A Reproducible model for Experimental Validation and Green-Cost Assessment of Self-Healing Nanoencapsulated Coatings to Improve the Durability of Iraqi Steel Products

Abstract

This study presents a reproducible, plant-specific framework for the experimental validation and green-cost assessment of hybrid self-healing nan encapsulated epoxy coatings intended to improve the durability, storage stability, and market quality of Iraqi iron and steel products. The study is methodological and model-based; no coating synthesis, electrochemical impedance spectroscopy (EIS), salt-spray exposure, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), adhesion testing, or concrete-bond testing was performed for the present manuscript. Five surface states are defined using fixed codes: uncoated carbon steel (B0), conventional epoxy (E1), graphene-oxide-modified epoxy (E2), IPDI-microcapsule epoxy (E3), and a hybrid self-healing nan encapsulated epoxy (E4). The proposed validation package specifies controlled substrate preparation, EIS before and after artificial scratching, potentiodynamic corrosion-rate estimation, 720 h neutral salt-spray exposure, pull-off adhesion, SEM, TGA, and a bond-performance gate for coated reinforcing steel. A durability-quality index (DQI) is formulated to guide Bayesian formulation selection, and sensitivity analysis is used to test the robustness of both technical and green-cost assumptions. The model-calibrated targets are not observed experimental results; they suggest that E4 could achieve a post-healing low-frequency impedance of  ohm cm^2, a calculated corrosion rate of 0.00075 mm  mm underfilm corrosion after 720 h, and 95% adhesion retention, subject to experimental confirmation. The central plant-scale scenario estimates a net value added of USD 32   for   of selectively protected product. All technical and financial outputs require laboratory validation and factory accounting verification before commercial adoption.