Development history of aluminum powder industry for metal coatings in China

Aluminum powder is one of the most widely used metal pigments because of its wide use, large demand and variety. The aluminum particles used in pigment are flake like, and it is precisely because of this flake like particle state that aluminum powder has metal color and shielding function. The industrial production of aluminum powder has existed for a long time. The early production method was the ramming method. The aluminum chips were placed in the groove of the ramming machine, and the aluminum chips in the groove were continuously rammed by the ramming pestle driven by the machine. The malleable aluminum gradually became thin and broken under the impact. After the aluminum became very thin and small, the aluminum powder was screened to take out the qualified aluminum powder as the product. The production efficiency of tamping method is very low, the product quality is not easy to grasp, and there is a lot of dust in the production process, which is very easy to fire and explosion. In 1894, hamtag, Germany, used a ball mill to produce aluminum powder. Steel balls, aluminum scraps and lubricants were put into the ball mill, and the flying steel balls were used to smash the aluminum scraps to form flake aluminum powder. Inert gas was filled in the ball mill and pipes. This method is still used, which is called "dry production". In 1910, American J. hall invented adding petroleum solvent instead of inert gas into the ball mill to produce aluminum powder pigment. This method is simple in equipment, safe in process, and very convenient in use. It was quickly adopted by countries all over the world. Most of the modern aluminum pigments use this method, which is also called "wet method".