Development and Comprehensive Study of a Novel BNP Inhibitor for Corrosion Protection of D16T Aluminum Alloy in Model Formation Water

D. Asanova, R. Vardanyan and N. Akatyev

Abstract
This study presents the development and evaluation of a novel ternary BNP corrosion inhibitor composed of boric acid (B-component), 1,4-phenylenediamine (N-component), and disodium hydrogen orthophosphate (P-component) for the protection of D16T aluminum alloy in model formation water. The inhibition performance was evaluated using gravimetric, electrochemical, and surface wettability techniques. The optimized BNP composition achieved a protection efficiency of 93.13 % at 31.2 mg dm–3 and significantly reduced the corrosion current density from 6.41·10–6 to 2.16·10–6 A cm–2. The inhibitor decreased the apparent activation energy and increased surface hydrophobicity, indicating the formation of a protective surface layer. Inhibitor adsorption obeyed the Langmuir and Freundlich isotherms, indicating additional heterogeneous surface interactions, and was characterized as spontaneous and endothermic. Electrochemical results suggested mixed-type inhibition mechanism. The results indicate that cooperative interactions between the B-, N-, and P-components promoted the formation of a stable protective layer, highlighting the potential of multicomponent inhibitor systems for corrosion protection of aluminum alloys in aggressive oilfield environments.

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Keywords
BNP inhibitor, corrosion, adsorption, aluminum, metal protection, formation water