졸-겔법에 의해 실리카 코팅된 아연분말 제조 및 특성

Abstract

Zinc has enhanced the longevity and performance of steel. zinc coating method provide the most effective and economical way of protecting steel against corrosion. Therefore zinc powder is widely used to protect steel and increase safety in the automobile, shipping, railway and air travel industries, etc. However zinc powder has poor dispersability because of the high specific gravity. Addition of zinc powder has tendency to settle and cause re-stirrable sedimentation. In case of ultra fine zinc powder, with an average particle size of smaller than 3, reduce durability in corrosion environment. This study was performed to manufacture the silica coated zinc powder from the ultra fine zinc powder by sol-gel method. The reaction was carried out with the variation of following reaction parameters(the amount of NH3 as a catalyst, NaCl as a salt, the reaction time and the number of coating process). The silica coated zinc powder were identified by the SEM-EDX, TEM, PSA and ELS analysis. As a result, silica coating layer and finer particle size could be controlled by the reaction time and the number of coating process. The particle size was decreased with the decrement of molar ratio of NH3 and the increment of concentration. Also dispersability and acid resistance tests were performed to compare the performance between zinc powder and silica coated zinc powder. Consequently, dispersability of silica coated zinc powder has improved nearly quadruple than raw zinc powder. Besides, its acid resistance has advanced, too. The silica coated zinc powder will be used as a pigment for high durability anticorrosive coatings.