The modification of silica coating surfaces by trimethylsilylation has contributed to enhanced hydrophobicity (θow>90°) against fluid permeation and corrosion in NaCl. These alkyl-silanized coatings were deployed to protect Mg alloy after reinforcing their intal structures with nanosilica powder. The reduced wetness of coating surfaces is attributed to their chemically-modified surface morphology, and this has been compared to the reticulate leaf structures of lotus plant. The optimum amount of silylating additive (hexamethyldisilazane) required to prepare a hydrophobic coating with minimum water adhesion has been established. Barrier per-formance of coatings were examined by electrochemical and surface analyses in 5 wt％ NaCl. The corrosion resistance of these coatings is a result of the direct contribution of their bulk stability and surface hydro-phobicity, and this is expressed in terms of the variation of electrochemical parameters with exposure time. These coatings may have emerging industrial applications, including a future in metal surface treatments and anticorrosion paints.