The influence of sodium silicate water glass content on the structure and properties of silicate thermal insulation coating

Thermal insulation slurry was fabricated using sodium silicate water glass (SSWG) as the film-forming material and hollow glass microspheres (HGM) as thermal insulation fillers. The thermal insulation slurry was coated on 316L stainless steel to fabricate a silicate thermal insulation coating. The results show that SiO2 phase is formed by SSWG in the thermal insulation coating after sintering at 680 ℃. Through polymerization and dehydration reactions between Si-OH groups, the Si-O three-dimensional network structure develops at 680 ℃. The optimal value of SSWG to aggregate mass ratios is 2.00. Under this condition, the silicate thermal insulation coating exhibits smooth surface, continuous and dense microstructure, high Shore hardness of 50.1 HSD, remarkable thermal insulation efficiency of 21 % at 260 ℃, and excellent resistance to drop and thermal shock tests without any noticeable cracks or detachment.