Over the years, the production technology and equipment level of rare earth permanent magnet materials in China have been rapidly improved and improved, and the quality and magnetic properties of Permanent magnets have been improved rapidly, which has promoted the development of industrial applications. For example, the Sc furnace is continuously improved, the thickness of the Sc sheet is controlled at 0.3-0.4 mm, the precipitation of Q-Fe is suppressed, the photo-crystal refinement of 2:14:1, and the capacity of the Sc furnace is gradually expanded from 50 kg to 600 kg to 1000 kg, thereby reducing energy consumption. Reducing operators can help reduce costs.
In addition, from the disclosure of patent technology in rare earth permanent magnet materials industry in China in recent years, China's rare earth permanent magnet materials technology has also developed rapidly. The number of patented technologies published each year has increased from 64 in 2005 to 303 in 2017. .
The Strip Casting process (referred to as the SC process) is a dissolution casting method that controls the precipitation of primary iron, that is, strip casting. It is well known that to obtain good magnetic properties, the main corresponding in the magnet should be as much as possible, and the amount of both the main phase and the Nd-rich phase should be optimally matched in order to obtain high magnetic properties. However, in the solidification process, the alloy firstly precipitates the highest melting point α-Fe. The precipitation of α-Fe not only “recaptures” the iron which should form the main phase, but the main phase is greatly reduced, and the soft magnetic α- The presence of Fe is detrimental to the performance of the magnet.
The appearance of the Strip Casting process (referred to as SC process) effectively avoids this problem. The SC process suppresses the precipitation of α-Fe, greatly improves the microstructure of the master alloy, and prepares the high-performance sintered NdFeB. Technology points to new directions and has attracted the attention of the majority of magnet researchers. At present, Sumitomo, Shin-Etsu and other companies representing the world's advanced production level began to adopt SC technology in the late 1990s. The SC scales were produced by Showa Denko and Sande Metal Co., and their magnet products were stable around N48M.
Since the beginning of 2000, the development and research of SC technology has been carried out in China. In this respect, we have made gratifying progress and developed processes and equipment with independent intellectual property rights. Some Chinese equipment manufacturers including Antai Technology Co., Ltd. have also begun to manufacture SC. Scale flake alloy quenching furnace, SC flake alloy has begun to be commercialized.