Thermal Durability Improvement of Nanosized Iron Oxide Yellow

α-FeOOH particle has a yellowish color and is called iron oxide yellow. It is harmless and it has been used from ancient age just the same as iron oxide red. Nanosized iron oxide yellow can be used as transpigment with a function of UV absorbent, same as iron oxide red particles. Iron oxide yellow is one of hydrate oxide. α-FeOOH particles would be dehydrated to α-Fe2O3 particles by heating at 180–200°C, and its yellowish color easily changes to a reddish one. Nanosized iron oxide yellow particles have such a high specific surface area that they are dehydrated at lower temperatures such as below 160°C. In the case of usage at room temperature, nanosized iron oxide yellow particles would still maintain the yellowish color; however, they have a problem of changing color in the case of high-temperature applications such as baking paint and thermal resin kneading. Thermal durability of nanosized iron oxide yellow particles should be improved for many practical applications. The aluminum hydrate surface coating onto nanosized iron oxide particles has been suggested to improve thermal durability. α-FeOOH particles with a particle diameter of 80 nm were suspended in water with stirring. The pH value of slurry was adjusted at 4.0 by adding diluted sulfuric acid. A certain amount of aluminum sulfate solution was added to the slurry with enough stirring. Next, a diluted sodium hydrate solution was added to the slurry to adjust pH of 6.0 with continuous stirring. The obtained aluminum hydrate–coated α-FeOOH was washed, filtered, dried, and finished to derive the final surface-modified trans-iron oxide yellow particles. TEM photograph of aluminum hydrate–coated trans-iron oxide yellow particles are described in Fig. 38.6. The typical characteristics and thermal durability of trans-iron oxide yellow particles. If you are looking for high quality, high purity and cost-effective Iron oxide, or if you require the latest price of Iron oxide, please feel free to email contact mis-asia.

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