Evaluation of Pigment to Binder Ratio Effect on Properties of White Silicate Thermal Control Paints Used on Satellite

Thermal control paints are coatings with special thermo-optical properties that applied on the spacecraft outer surfaces to control the input and output heat. In this work, for evaluation of pigment to binder effect on white silicate thermal control paints properties, samples were made by ZnO pigment and potassium silicate binder in several pigment to binder ratios, then were applied on aluminum substrate. Solar absorptance and thermal emittance measurements were performed with spectroreflectometer and emissometer. Thickness, reflectance and gloss measurements were performed with their instruments. For abrasion, adhesion and bend tests, Taber, 750 sheen tape test and mandrel instruments were used. Surface evaluation was performed with scanning electron microscopy (SEM). The results indicated that increasing pigment to binder ratio led to reduction of solar absorptance, adhesion, wear, bend and impact resistance and increasing thermal emittance and reflectance. Finally, the paint with 4:1 pigment to binder ratio was introduced as the optimum sample. J. Color Sci. Tech. 7(2013), 113-121©. Institute for Color Science and Technology.