http://sciforum.net/conference/ecm-1 Original Article Sodium Silicate Free Geopolymer As Coating Material: Adhesion To Steel M.Irfan Khan 1a, *, Khairun Azizli 1b , Suriati Sufian 1c , Ahmer Ali Siyal 1d , Zakaria Man 1e , Hafeez Ullah 1f 1 Dept. of Chemical Engineering, University Teknologi PETRONAS, Tronoh, 31750, Perak, Malaysia * a mirfanwazir@gmail.com Tel.+60146974803; b khairun_azizli@petronas.com.my, c suriati@petronas.com.my, d ahmersiyal@gmail.com, e zakaman@petronas.com.my, f hafeez_wazir@yahoo.com Abstract: Geopolymer is a green and sustainable material synthesized by alkali activation of raw aluminosilicate rich materials. In this study class F-fly ash based sodium silicate free geopolymers were synthesized and used for coating application at 60 o C. Setting time and adhesion strength analysis were performed using Vicat needle and Elcometer 108 according to ASTM C 807-08 and D 4541 respectively. Infra Red spectroscopy was used to understand the degree of geopolymerisation by observing the vibration frequency of -Si-O-T bonds around 1000 cm -1 . A gradual increase in adhesion strength was observed with alteration of Na/Al ratio from 0.6 to 1.0. A maximum of 3.8 MPa adhesion strength was produced by geopolymer with Na/Al=1. Final setting time shows variation with varying Na/Al at a constant water content. It was found that geopolymers gained maximum strength within first 3 days and only partial changes has been noticed in terms of adhesion strength. Scanning electron microscopy of the final product revealed that the formation of geopolymer has occurred without addition of sodium silicate. It can be concluded that sodium silicate free geopolymer has the potential to be used as a sustainable and green coating material for metals protection. Keywords: Geopolymer; Fly ash; Coating, Adhesion; Elcometer; FTIR; Microstructure 1. Introduction Treatment and removal of fly ash as a waste from coal based power plants is going to be an uneconomical and environment unfriendly task. Reutilization is mostly focused as pozzolanic material and about 10-15% of fly ash is used by cement sector. Dumping in lowlands is the most common practice used for discarding of fly ash causing water, land and aerial contamination [1]. Geopolymer, an amorphous alumino silicate, is synthesized from fly ash in an environment friendly and green process compared to OPEN ACCESS