Morphology of hybrid coatings based on polyester, melamine resin, and silica and the relation with hardness and scratch resistance

The morphology of hybrid coatings based on polyester, melamine resin, and various amounts of silica has been investigated, and the hardness and scratch resistance were determined. By increasing silica content, an increase of silica particles in size and number was observed. Small silica particles were preferentially present at the surface. The influence of the silica content on the König hardness, indentation hardness, and elastic modulus was minor. The improved scratch resistance determined for a hybrid coating with 11.4 wt% silica, compared to a similar organic coating without silica, was attributed to small silica particles preferentially present at the surface