Preparation of NIR Reflective Brown Pigment โดย ผศ.ดร.ทัศนีย์ ทองก้านเหลือง
Complex inorganic brown pigments having a high near infrared solar reflectance have been synthesized. Fe2C>3 is the host component and mixtures of Sb203, Si02, A12C>3, and Ti02 were used as the guest components. Sb203, Si02, A1203, and Ti02 were mixed into 40 different compositions. It was found that a sample, denoted by ร31, with a composition of Fe203, Sb203, Si02, A1203, and Ti02 of 70, 10, 12, 2 and 6 wt% respectively, gives a maximum near infrared solar reflectance of 46.7%. Brown pigment colours were measured in CIE L*a*b* colour index. The ร31 pigment powder was then prepared as a reflective coating material with different amounts of pigment powder from 48 g in 100 g of ceramic glaze. The prepared materials were sprayed on the biscuit clay tiles for reflectance measurements. It was found that 5 g of ร31 pigment powder mixed with 100 g of ceramic glaze gives the highest near-infrared reflectance value of 41.3 %. The newly synthesized pigment is a suitable ceramic roof coating for its high reflectance performance and the durability performing once the ceramic roof installed on house.