After years of technological innovation, Earth Panda has built a core technology system for the entire production process of sintered NdFeB magnets. This includes material production, machining, surface treatment, and crape material recycling. The preceding core technologies help us improve the product's magnetic properties and of the product on the one hand, and save resources and costs on the other.
Sintered NdFeB magnetic material mainly consists of main phases and grain boundary phases among main phase grains. Although grain boundary phases account for a smaller proportion, they largely determine the material and final products' performance.
After in-depth study of the influence of grain boundary phases on the performance of sintered NdFeB permanent magnetic materials, Earth Panda independently developed innovative technologies to control the mixing of the grain boundary with multiple substances. By directly introducing different amounts of various substances directly into the grain boundaries of magnets, these substances react with the original grain boundaries during the sintering process and change the ingredients and structure of grain boundary phases, thus improving the performance of the magnets and reducing the proportion of heavy rare earths in magnets.
The grain boundary mixing control is our core technology for developing sintered NdFeB magnets with high-performance, high thermal stability or low content of heavy rare earth, as well as a core technology for recycling scrap magnets.
The performance of sintered NdFeB permanent magnetic materials is affected by the content of nitrogen, oxygen, and carbon. The high content of nitrogen, oxygen and carbon consumes the rare earth in the material, resulting in reduced coercivity, temperature resistance, corrosion resistance, etc. of the material.
Earth Panda has innovated and developed multiple technologies and equipment to control the content of nitrogen, oxygen and carbon in magnets and created a whole-process atmosphere control technology in the processes such as hydrogen decrepitation, jet milling, magnetic orientation, sintering and heat treatment. This technology effectively controls the nitrogen, oxygen and carbon content in magnets, reduces the consumption of rare earths and improves the utilization of rare earth and the comprehensive performance of products. Comparing two materials in the same production environment, this technology application increases the coercivity of the material by an average of 5-10%, and reduces the weight loss of the material by an average of 20%. The whole-process atmosphere control technology is one of our most important auxiliary technologies for the production of all of product series.
Sintered NdFeB permanent magnetic material is produced by powder metallurgy. The microscopic NdFeB alloy powder is an essential intermediate in the production process of sintered NdFeB permanent magnetic material. The properties of the powder largely determine the final performance of the magnets.
Earth Panda has innovated and developed various technologies to modify the surface of NdFeB alloy powders, including the physical vapor deposition heavy rare earth metal film technology, the powder surface diffusion modification technology, chemically synthesized membrane modification technology. The powder surface modification improves the fluidity and oxidation resistance of the powder, the anisotropy field of the powder surface, and ultimately the coercivity of the material.
As for the original NdFeB powder surface modification technology in the industry, it is mainly the addition of antioxidants, lubricants, and other chemical reagents to improve the oxidation resistance and fluidity of the powder, rarely a direct improvement of materials‘ coercivity tby changing the powderproperties.
The powder surface modification technology,developed by Earth Panda, not only improves the fluidity and oxidation resistance, but also the anisotropy field of the powder surface.This finally improves the coercivity of materials, which is one of our key technologies in preparing high-performance sintered NdFeB materials.
Magnetic field orientation and molding are the critical processes in the production of sintered NdFeB. The consistency of powder orientation and the uniformity of compact density after molding directly affect the magnets' main magnetic properties and machining yield.
Through technological innovation in the fields such as mold design, powder admixture and magnetic field orientation, Earth Panda has developed the alternating magnetic field orientation molding technology which improves the consistency of powder orientation and the powder admixture technology which improves the uniformity of powder filling and the consistency of powder orientation. Earth Panda has developed a variety of new molds which can improve the consistency of magnet orientation and reduce the fracture rate of magnets, improving the key magnetic properties and yield rate of high-performance sintered NdFeB magnets.
In industry the powder orientation consistency is mainly enhanced by improving the intensity of the orientation magnetic field and the fluidity of powder. Earth Panda improves the consistency of powder orientation through the integrated innovation of technologies and equipment, resulting in better improvement effects. Compared with the original method, the remanence of materials is increased by an average of more than 0.2kGs and the maximum magnetic energy product is increased by an average of more than 0.5MGOe. The innovative magnetic field orientation forming technology is an important auxiliary technology for the production of all of product series.
The composition and structure of grain boundary phases directly affect the properties of magnets. By introducing heavy rare earth into the grain boundary phase and the surface of the main phase grains,the grain boundary diffusion significantly improves the coercivity of the material without reducing its remanence.
Earth Panda has invented and developed multiple technologies to control the diffusion of grain boundaries of sintered NdFeB magnets. These technologies mainly include coating the surface of the magnets with heavy rare earth metals by electrolytic deposition + diffusion technology and coating the surface of the magnets with heavy rare earth metals by laser cladding technology + diffusion Technology. The development and application of these technologies have significantly improved the coercivity of magnets and reduced the content of heavy rare earth in magnets with high coercivity. They represent the company’s key technologies to produce sintered NdFeB magnets with very high performance and sintered NdFeB magnets with low heavy rare earth content.
Rare earth is a non-renewable strategic resource. The scrap produced during magnet manufacturing contains a large amount of rare earth , an important secondary resource.
Earth Panda invented and developed the technology for decontamination of magnetic surfaces and the technology for rapid removal of surface coatings. Through the extensive use of grain boundary diffusion control technology and the whole process atmosphere control technology, the waste material could be directly converted into Sintered NdFeB magnets. Compared with the original magnets, the recovery rate of all main magnetic properties is over 95%.