Development of Fire Protective Coatings for Grp Composites Using PlasmaDeposition Technology, Phase 2

摘要

Plasma spray technology was developed for applying ceramic based coatings(alumina and zirconia) onto glass reinforced polymeric materials (GRP's). The effect of surface preparation on the adhesion of the coating was examined, and the failure of coating adhesion was evaluated qualitatively. Surface preparation by grit blasting as normally used for plasma spraying of metal and ceramic substrates was found to be unsuitable for obtaining adherent coatings on GRP's. Chemical etching just prior to grit blasting at moderate to low pressure was found to give the desired results. The failure of coating bonding initiated either from glass fiber/coating interface or due to the presence of significant carbon buildup. The adhesive strength of the coating decreases with increasing thickness, most probably due to buildup of thermal stresses in the coating. Phenolic based GRP's were found to be most suitable for developing plasma sprayed coating. The fire protective properties of the coatings were also studied; in most cases the coated materials showed significant improvement in fire protection.