The third largest use of cerium in ce alloy products, arc carbon rods for searchlights and movie projectors. Similar to the hood of gas lamps, cerium can improve the conversion efficiency of visible light. Searchlights were once an important tool for war air defense. Arc carbon rods were also an indispensable light source for film projections.
The above three uses of cerium also represent the three early uses of rare earths. It can even be said that the early rare earth industry was completely based on the development and utilization of the properties of cerium. In the early 1950s, my country's rare earth industry also started with these three applications. These uses are all related to luminescence. It can be said that cerium, as an excellent representative of the rare earth element family, has benefited mankind as a "bright messenger" from the very beginning.