The processes in film-forming solution based on tetraethoxysilane, phosphoric acid and calcium chloride

Abstract

Physical and chemical patterns film-forming ethanol solution based on tetraethoxysilane, orthophosphoric acid and calcium chloride have been determined. Methods of photon correlation spectrometry and electrophoresis showed that colloidal particles with size up to 25 nm are formed in the film-forming solutions. Their stability is maintained during one day, and then CaHPO[4] precipitates from the film-forming solutions. Methods of X-ray analysis, scanning electron microscopy and IR spectroscopy have shown that the dried coating solution after precipitation of CaHPO4 consists of CaClH[2]PO[4]·H[2]O and SiO[2]. The formation of these substances is due to the hydrolysis of tetraethoxysilane and interaction calciumchloride with orthophosphoric acid.