SGER: High Energy "Exchange-Spring" Permanent Magnets via Spark Erosion

SGER：通过火花腐蚀的高能“交换弹簧”永磁体

• 批准号: 0077588
• 负责人: Ami Berkowitz
• 金额: $ 8.8万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-05-15 至 2001-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0077588&HistoricalAwards=false
• 关键词: SGER; Energy; Exchange; Spring; Permanent

0077588BerkowitzThe goal of this SGER program is to determine the feasibility of using a novel technique, spark erosion, to provide the particles for a material with strong technological potential, high-energy product 'exchange-spring' permanent magnets (ESPMs). ESPMs are duplex alloys of magnetically 'hard' and 'soft' phases in which the required length scales for the two phases are in the several tens of nm range. These length scales must be well controlled for optimum performance and this has been a principal obstacle to achieving a satisfactory production method. The spark erosion approach controls the sizes of the phases by precipitating them within particles of suitable diameters and microstructure. The idea is to produce amorphous particles of the appropriate composition and diameter such that, after annealing to the equilibrium duplex crystalline state, the length scales of the two phases are constrained by the particle size and initial microstructure as optimum for ESPM. Spark erosion is an under-appreciated, but extremely versatile and economical particle production method. The particle synthesis method is on firmer ground than the control of particle size/microstructure constraining equilibrium phase dimensions, since a large variety of powders have been produced by this method. Hot pressing is the primary method for preparing the final product, high-density bulk magnets with dimensions of several cm. A second approach for preparing the bulk magnets is thermal spraying, and this technique will be pursued if warranted by the results of the hot pressing. Both of these methods should benefit from the initial amorphous state expected for the spark-eroded particles since the equilibrium crystalline duplex structure can be developed during or after consolidation. The conceptual approach, although reasonable, is currently unproven. Particle production by spark erosion without contaminants seems feasible, but must be demonstrated. In addition, the particle synthesis method is a novel and economical one, which deserves attention. It is a technique that has great potential for a wide range of applications. Finally, there is new materials science to be clarified by examining the influence of particle size on precipitate dimensions. %%%The concept for exchange-spring permanent magnets (ESPM) has been available since 1991, and it has been intensively pursued because ESPM offer the promise of permanent magnets with higher energy products than currently available, at a much-reduced cost for the rare-earth materials used. The permanent magnet market is huge, and this has inspired a great deal of very useful processing and modeling work on ESPM. However, no bulk processing technique is available at present.***

0077588 Berkowitz该SGER计划的目标是确定使用一种新技术火花腐蚀的可行性，为具有强大技术潜力的材料提供颗粒，高能量产品“交换弹簧”永磁体（ESPM）。ESPM是磁“硬”和“软”相的双相合金，其中两相所需的长度尺度在几十nm范围内。 为了获得最佳性能，必须很好地控制这些长度尺度，这是实现令人满意的生产方法的主要障碍。电火花腐蚀方法通过将相沉淀在合适直径和微观结构的颗粒内来控制相的尺寸。该想法是产生适当的组成和直径的无定形颗粒，使得在退火到平衡双晶状态之后，两相的长度尺度受到颗粒尺寸和初始微观结构的约束，作为ESPM的最佳选择。火花腐蚀是一种未得到充分重视的，但用途广泛且经济的颗粒生产方法。颗粒合成方法比控制颗粒尺寸/微结构约束平衡相尺寸更坚实，因为通过这种方法已经生产了大量的粉末。热压是制备最终产品的主要方法，具有几厘米尺寸的高密度块状磁体。 制备块状磁体的第二种方法是热喷涂，如果热压的结果证明有必要，将采用这种技术。这两种方法都应该受益于火花腐蚀颗粒预期的初始非晶态，因为在固结期间或固结之后可以形成平衡结晶双相结构。这种概念方法虽然合理，但目前尚未得到证实。无污染的电火花腐蚀颗粒生产似乎是可行的，但必须加以证明。此外，粒子合成法是一种新颖、经济的合成方法，值得关注。这是一项具有广泛应用潜力的技术。最后，通过研究颗粒尺寸对沉淀尺寸的影响，有新的材料科学需要澄清。自1991年以来，交换弹簧永磁体（ESPM）的概念已经出现，并且一直在大力推行，因为ESPM提供了比目前可用的永磁体具有更高能量积的永磁体的承诺，并且所使用的稀土材料的成本大大降低。永磁体市场是巨大的，这激发了大量非常有用的ESPM处理和建模工作。然而，目前还没有批量处理技术可用。