MnNH4P2O7-Based Coating for High Temperature Assessment on the Surfaces of Cement Composites

Abstract

This study examines the implementation of an MnNH4P2O7 (ammonium manganese III pyrophosphate)-based coating on structural elements to obtain temperature information with color changes. Based on the MnNH4P2O7 material, a coating was prepared and deposited on cement mortar surfaces. Heat experiments were then conducted to evaluate the thermochromism on the fabricated samples. The coated samples exhibited a superior irreversible thermochromic property at 400 degrees C with a color change from dark violet to light grayish blue at the heated surface. The color changes were retrieved at each temperature using a digital camera, and the change in color properties was evaluated in the RGB and L*a*b* color spaces using image processing techniques. With increasing temperature from room temperature, the RGB values were almost constant until 200 degrees C. At higher temperatures, the color changes started to accelerate until 400 degrees C. The values showed a 167%, 567%, and 49% increase in R, G, and B values, respectively, at 400 degrees C. In the L*a*b* color space, when the temperature was increased from room temperature to 400 degrees C, the L*a*b* values showed an increase of 211%, a decrease of 94%, and an increase of 78%, respectively.