Solvothermal Synthesis of Acmite Conversion Coatings on Steel

Acmite (NaFeSi2O6) films were formed on steel coupons via solvothermal reaction of silica, sodium hydroxide, and 1, 4-butanediol in an autoclave under autogenous pressure. Systematic variation in processing variables led to homogenous coatings comprised of pinacoidal acmite grains with an average grain size of ~33 μm. The coatings were produced on the steel coupons from reactant conditions of 0.635 m SiO2, 2.546 m NaOH, and 3.087 m 1,4-butanediol for 72 h at 240°C.