Evaluation of enamel coatings general corrosion in sulphuric acid solution at different temperatures

Abstract EN

The aim of this study is to evaluate the general corrosion resistance for different ground and cover enamel coated specimen in 20 % (by volume) of sulphuric acid solution for 48 hrs.

Duration time.

Groups of enameled specimen were tested, was of low carbon steel base metal (0.14 % ˚C) that was covered two layer coating and the outer layer having different wt % of titanium oxide Ti02 content (15.5, 20, and 24.5 %) each tested at solution temperature (65°C, 96°C, 150°C, and 200°C) separately in apparatus specified by DIN 51.157.

General corrosion rate is calculated for each specimen in mil per year MPY.

ResuIts revealed that as the Ti02 content increased in the outer ground coated cover, MPY values also increased (higher corrosion and for all the test temperatures.

The highest MPY value was recorded at 200 "C, at 24.5 % of Ti02 content (MPY= 0.59).

This result was attributed to the formation of the Ti-ion bonding in the glassy network of the enamel this bond enhance the chemical resistance.

Glossiness test and restitution hardness tests were performed to investigate the results obtained previously for the enameled tested specimens.

Both tests confirm the results showing that higher Ti02 cover content yields higher glossiness percent (low corrosion).

Also restitution hardness tests show an increase in the hardness values recorded as the weight content of Ti02 in the cover coat increases, whatever the solution temperature was