Development of coatings containing rice husk and coal ash addition

Full text: Annually are produced about 5.137 million tons of rice per year only in the state of Rio Grande do Sul, the shells represent about 20% of this value. The shells can be exploited in different ways, one of which is the generation of energy by direct combustion. However, in this case, the ash formed is a potential pollution of the environment. The reuse of ash for any commercial purpose complete the cycle industrialization of rice, being possible the utilization of raw materials. A similar phenomenon occurs in the generation of thermal energy from the combustion of mineral coal, the large amount of ash generated, makes them seek alternatives to reduce these emissions, as well as for the rational use of this ash. In this study we evaluate the possibility of use of rice husk ash and coal ash add in an alkyd resin, applied as anticorrosion coating in order to improve the barrier property conferred by the coating. The barrier characteristics can be attributed to the fact that addition increased the path of diffusion of O₂ and H₂O to the interface polymer/metal. Oxides of Si, Al and Fe, chemical constituents of ashes show inhibitory properties of corrosion reactions. Analyzing the dispersion of size and morphology of the particles by size distribution curves by light scattering and optical microscopy (OM). The images were analyzed in software Image J. The characterization of the coatings was carried out by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The coatings develop with different concentrations of ash (0, 1, 5 and 10% by weight) were applied on 304 stainless steel samples. The performance of the resin with and without addition of ash was evaluated by exposure in climatic chamber with relative humidity (RH) and temperature controlled. (author)