Zinc hypophosphite: a suitable additive for anticorrosive paints to promote pigments synergism

Abstract

In this investigation, the synergism promoted by zinc hypophosphite in an anticorrosive pigment mixture is reported. This paper describes the anticorrosive behavior of a commercial pigment mixture containing zinc hypophosphite, reduced levels of zinc phosphate, and zinc oxide. The anticorrosive performance of the pigment mixture was assessed by electrochemical techniques (corrosion potential and linear polarization measurements) employing pigment suspensions. The behavior of each separate component of the mixture was also studied in the same way. The nature of the protective layer was investigated by scanning electron microscopy (SEM). In a second stage, the anticorrosive properties of the pigment were assessed by incorporating it into alkyd and epoxy paints that were evaluated by accelerated (salt spray and humidity tests) and electrochemical measurements. Experimental results showed that improved anticorrosion protection is achieved in paints with reduced zinc phosphate contents as a consequence of the synergistic interaction between zinc hypophosphite and the other components of the pigment mixture.

“Smart” anti­corrosion pigment based on layered double hydroxide: construction and characterization

“…Chromates were commonly used as corrosion inhibitors, however, they are toxic and ecologically unsafe. A modern tendency is a replacement of chromates with safer anionic inhibitors: molybdates [8], dihydrophosphates [9], hypophosphates [10] and orthophosphates [7,11]. The paper [12] described the presence of synergism between corrosion inhibition of hypophosphyte and orthophopshate of zinc.…”

NaCl-NaH2PO2- Zn(H2PO2)2-H2O Dörtlü Sisteminin 333.15K’de Katı-Sıvı Faz Dengelerinin İncelenmesi

“…Fizikokimyasal özellikler kullanılarak bahsi geçen hipofosfit tuzlarının eldesi daha kolay ve ekonomiktir [6,7]. Genel olarak hipofosfit tuzları indirgen olarak kimyasal reaksiyonlarda, yangın söndürmede, mekanik ve elektriksel uygulamalarda, elektrokimyada, korozyon önlemede, hayvan besin takviyesinde, adsorbsiyon uygulamalarında, ilaç sanayide, toprak iyileştirmede yaygın olarak kullanılmaktadır [8][9][10][11][12][13][14][15].…”

Evaluation of eco-friendly anticorrosive pigments for paints in service conditions

“…Finally, a third generation arose by substituting the phosphate anion by polyphosphates (tripolyphosphate, pyrophosphate, etc.) [9][10][11][12][13][14][15][16][17]. Both pigment series are claimed to have better anticorrosive behaviour than zinc phosphate.…”