Inhibitory Action of 1–phenyl–3–methylpyrazol–5–one (HPMP) and 1–phenyl–3–methyl–4–(p–nitrobenzoyl)– pyrazol–5–one (HPMNP) on the Corrosion of Alpha and Beta Brass in HCl Solution

Abstract

The inhibition of corrosion of Alpha - Brass (70% Cu, 30% Zn) coupons and Beta - Brass (60% Cu, 40% Zn) coupons in different concentrations of Hydrochloric acid solution (HCl) at room temperature by 1-phenyl-3- methylpyrazol- 5- one (HPMP) and 1-phenyl-3-methyl-4-(p-Nitrobenzoyl)-pyrazol-5-one (HPMNP) was investigated, using weight loss technique. Generally, inhibition was found to increase with increasing inhibitor concentration. HPMNP inhibited the two Brasses better than HPMP, and Beta - Brass (60% Cu, 40% Zn) corroded faster than Alpha - Brass ( 70% Cu, 30% Zn ). The inhibition was assumed to occur via adsorption of the inhibitor molecules on the metal surface. The effect of immersion time was also carefully followed to study the corrosion and inhibition phenomenon.