Element symbol Pr, belonging to the periodic system IIIB group, rare earth elements, lanthanides.
Corrosion resistance in air is stronger than lanthanum, cerium, neodymium and europium, but exposure to air will produce a layer of brittle green oxide, praseodymium slowly forms a green brittle oxide layer in air; The 3 oxidation state exists and also exists in the +4 valence form.

Application field
Praseodymium can be used as catalyst in petrochemical industry.
As a rare earth element with a large amount, a large part of praseodymium is used in the form of mixed rare earth, for example, it is used as a purification modifier for metal materials, chemical catalyst, agricultural rare earth and so on. The petroleum cracking catalyst is prepared by adding the Y-type zeolite molecular sieve in the form of praseodymium neodymium enrichment, which can improve the activity, selectivity and stability of the catalyst. As a plastic modification additive, adding neodymium praseodymium enrichment to polytetrafluoroethylene (PTFE) can significantly improve the wear resistance of PTFE.
Rare earth permanent magnet material is the most popular rare earth application field today. The performance of praseodymium alone as a permanent magnet material is not outstanding, but it is an excellent synergistic element that can improve magnetic properties. Whether it is the first generation rare earth permanent magnet material samarium cobalt permanent magnet alloy, or the third generation rare earth permanent magnet material NdFeB, adding an appropriate amount of praseodymium can effectively improve and improve the performance of the permanent magnet material. For example, adding part of Pr to replace Sm in SmCo5 can improve the magnetic energy product of permanent magnet materials. The ratio of the two is generally 80%Sm-20%Pr. If praseodymium is added too much, it will reduce the coercivity and stability of the material. In the third-generation rare earth permanent magnet material NdFeB, adding praseodymium can improve the coercivity of the material. Germany, Japan and other countries all add some praseodymium when producing high coercivity NdFeB magnets. The addition amount of praseodymium is 5% to 8%, up to 10%, which can replace 1/3 of neodymium. Magnetic materials have high quality requirements for praseodymium, at least the same quality as neodymium. The addition of praseodymium can also improve the oxidation resistance (air corrosion resistance) and mechanical properties of the magnet, which has been widely used in various electronic devices and motors.
Praseodymium can also be used for grinding and polishing materials. Pure cerium-based polishing powder is usually light yellow and is a high-quality polishing material for optical glass. It has replaced the red iron oxide powder with low polishing efficiency and polluting the production environment. Neodymium oxide has little effect on polishing, but praseodymium has good polishing performance. Rare earth polishing powder containing praseodymium will be reddish-brown, also known as red powder, but this red is not iron oxide red, but the rare earth polishing powder is darkened due to the presence of praseodymium oxide. Praseodymium is also used as a new grinding material to make praseodymium-containing corundum grinding wheels. Compared with white corundum, the efficiency and durability can be increased by more than 30% when grinding carbon structural steel, stainless steel, and superalloy. In order to reduce costs, in the past, praseodymium neodymium enrichment was used as raw material, so it was called praseodymium neodymium corundum grinding wheel.
Praseodymium is also used more and more widely in the field of optical fiber. The praseodymium-doped fiber amplifier (PDFA) has been developed to amplify in the 1300~1360nm spectral region, and the technology is becoming more and more mature. With its excellent performance-price ratio, PDFA is of great practical significance to the construction, transformation and system upgrade of the 1550nm CATV system fiber-optic cable TV that is currently being laid in large numbers in China. PDFA will fundamentally change the existing 1550nm CATV network structure, making the 1310nm CATV system an ideal choice to replace the 1550nm system in the HFC system transformation.