High-temperature properties of Fe-Pt film-magnets prepared by electroplating method

We prepared L10 ordered Fe50Pt50 thick-films on Cu substrates using the electroplating method and evaluated their high-temperature properties in the temperature range of 25-200°C. The Hc and the (BH)max at 150°C for the Fe50Pt50 films annealed by ordinary annealing method (700°C, 60 min) were 500 kA/m and 50 kJ/m3, respectively, and the thermal coefficient of Hc was -0.3%/°C. To improve the high-temperature properties, we employed a flash annealing method using an infrared furnace (8 kW). The flash annealing method improved the high-temperature properties (Hc = 700 kA/m, (BH)max = 70 kJ/m3 at 150°C) and the thermal coefficient (-0.21%/°C). The thermal stability of the films is comparable to those for Sm-Co-system magnets and better than for Nd-Fe-B-system ones. We, therefore, found the L10 ordered Fe50Pt50 films prepared by the electroplating and the flash annealing are one of the hopeful small magnets in the wide temperature range.We prepared L10 ordered Fe50Pt50 thick-films on Cu substrates using the electroplating method and evaluated their high-temperature properties in the temperature range of 25-200°C. The Hc and the (BH)max at 150°C for the Fe50Pt50 films annealed by ordinary annealing method (700°C, 60 min) were 500 kA/m and 50 kJ/m3, respectively, and the thermal coefficient of Hc was -0.3%/°C. To improve the high-temperature properties, we employed a flash annealing method using an infrared furnace (8 kW). The flash annealing method improved the high-temperature properties (Hc = 700 kA/m, (BH)max = 70 kJ/m3 at 150°C) and the thermal coefficient (-0.21%/°C). The thermal stability of the films is comparable to those for Sm-Co-system magnets and better than for Nd-Fe-B-system ones. We, therefore, found the L10 ordered Fe50Pt50 films prepared by the electroplating and the flash annealing are one of the hopeful small magnets in the wide temperature range.