Evaluation of Corrosion Behavior of Galvanized Steel Treated with Conventional Conversion Coatings and a Chromate-Free Organic Inhibitor

<table class="table-group" id="tab1"><tr><td><table class="table"><tr><td class="thead-hr" colspan="4"><hr/></td></tr><tr class="thead"><td align="left">Coating</td><td align="left">Chemical composition</td><td align="left">pH</td><td align="left">Application method</td></tr><tr><td class="thead-hr" colspan="4"><hr/></td></tr><tr><td align="left">chromate</td><td align="left">200 g potassium dichromate + 6 cc sulphuric acid in 1 L of water</td><td align="left">0.8</td><td align="left">dipping for 20 sec at room temperature</td></tr><tr><td align="center" colspan="4"><hr/></td></tr><tr><td align="left">phosphate</td><td align="left">21.0 g acidic zinc phosphate + 1.2 g sodium nitrite + 1.8 g triethanolamine oleate in 1 L of water</td><td align="left">5.0</td><td align="left">dipping for 600 sec at room temperature</td></tr><tr><td align="center" colspan="4"><hr/></td></tr><tr><td align="left">inhibitor 5.0%</td><td align="left">water-soluble corrosion inhibitor containing an alkanolamine salt of a polycarboxylic acid</td><td align="left">8.0</td><td align="left">dipping for 40 sec at  75°C</td></tr><tr class="table-tr"><td colspan="4"><hr class="tbody-hr"/></td></tr></table></td></tr></table>

Some characteristics of the tested coatings.

International Journal of Corrosion

tab1

Table 1

Table 1: Evaluation of Corrosion Behavior of Galvanized Steel Treated with Conventional Conversion Coatings and a Chromate-Free Organic Inhibitor 