Hydrophilic protective layers bonded on hydrophobic substrates for use at elevated temperature

摘要

Disclosed is a method of coating a hydrophobic substrate (5,15,16) with a hydrophilic protective layer free of organic carbon (20A,20B,20C,20D) to protect the substrate (5,15,16) when used at high temperature. The method comprises: applying one or more layers of a slurry comprising hydrophilic colloidal particles and/or hydrophilic inorganic polymeric particles onto the hydrophobic substrate followed by drying to form a heat stable intermediate bonding layer on the hydrophobic substrate. One or more layers of a slurry forming the hydrophilic protective layer are applied onto the intermediate bonding layer followed by drying and/or heat treating to form the hydrophilic protective layer on the intermediate bonding layer. The slurry forming the intermediate bonding layer contains at least one carbon compound selected from hydrophobic carbon monomers and hydrophobic carbon polymers and comprising hydrophilic substituents in an amount sufficient to bond the hydrophilic colloidal/inorganic polymeric particles to the carbon compound(s).