Effects of cooling rate on microstructures and magnetic properties of Nd–Fe–B alloys

• Published in: Journal of alloys and compounds Vol. 363; no. 1; pp. 268 - 275
• Main Authors: Ozawa, Shunpei, Saito, Tetsuji, Motegi, Tetsuichi
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.01.2004; Elsevier
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic measurements; Magnetic properties and materials; Metals. Metallurgy; Microstructure; Permanent magnets; Physics; Rapid solidification; Rare earth compounds; Studies of specific magnetic materials; Magnetic measurements; Permanent magnets; Rare earth compounds; Microstructure; Rapid solidification; Differential scanning calorimetry; Scanning electron microscopy; Magnetization; Cooling rate; Ternary alloys; Equiaxed structure; Melt spinning; XRD; Experimental study; Neodymium alloys; Boron alloys; Casting; Rare earth alloys; Dendrites; Transition element alloys; Iron base alloys; Magnetic properties
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/S0925-8388(03)00461-4

The microstructures and magnetic properties of Nd–Fe–B alloys produced by rapid solidification processing techniques were examined by X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, and in a vibrating sample magnetometer. Two rapid solidification processing techniques, metallic mold casting and melt-spinning, were used to investigate the influences of cooling rates on the microstructure and magnetic properties of the Nd–Fe–B alloys. The Nd–Fe–B alloys had equiaxed Nd 2Fe 14B grains together with α-Fe dendrites when produced by the metallic mold casting technique with moderately high cooling rates (3.3×10 2 to 1.2×10 3 K s −1). The Nd–Fe–B alloys had fine equiaxed Nd 2Fe 14B grains with or without amorphous phase when produced by the melt-spinning technique with high cooling rates (4.3×10 5 K s −1 to 1.5×10 6 K s −1). The relationships among the cooling rate, microstructure, and coercivity of the Nd–Fe–B alloys were determined.