THERMOELECTRIC MATERIAL AND THERMOELECTRIC CONVERSION ELEMENT

• Main Authors: HORIO YUUMA, YAMASHITA HIROYUKI, HOSHI TOSHIHARU
• Format: Patent
• Language: English
• Published: 22.08.2000
• Edition: 7
• Subjects: ALLOYS; CHEMISTRY; ELECTRICITY; FERROUS OR NON-FERROUS ALLOYS; METALLURGY; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PROBLEM TO BE SOLVED: To enhance the performance index of a thermoelectric material by setting the aspect ratio of the mean crystal grain diameter of the major axis of crystal grains to the mean crystal grain diameter of the minor axis of the crystal grains at least at a specified value, and the mean crystal grain diameter of the minor axis and the mean crystal grain diameter of the major axis at most at a specified value, and at the same time the crystal structure of the crystal grains is constituted so that the C face is aligned in parallel to the directions of the major axis. SOLUTION: A quenching thin strip or quenching powder is crushed, and classified to make even the granularity, the powder in the range of the proper granularity is filled in a cylindrical mold 31, a pressure P is applied to the powder in the axial direction in a state where the circumferential surface of the mold is restrained in kept hot, and the powder is hot-pressed. For thin, a thermoelectric material of a crystal texture having crystal grains, which have the major axes made even in the pressing direction and the minor axes made even in the direction intersecting orthogonally the pressing direction, is solidified and can be molded. In this case, the granularity of the powder, a heat-teating condition and the like are adjusted to the mean crystal grain diameter of 30 μm or shorter of the major axes and the mean crystal grain diameter of 10 μm or less of the minor axes and at the same time, the aspect ratio of the grain diameter of the major axes to the grain diameter of the minor axes is adjusted in a ratio of 1 to 1.5 or more. Thereby, the performance index of the thermoelectric material can be raised.