Patent ID: 7800271
Filing Date: 2010-09-21
Classification: H01F

Abstract:
1. A rotating machine comprising a sintered magnet, wherein the sintered magnet includes crystal grains of a ferromagnetic material consisting mainly of iron, and a layer of a fluoride compound or a layer of an oxyfluoride compound, containing at least one element selected from the group consisting of an alkali metal element, an alkali earth metal element, and a rare earth element, the layer of the fluoride compound or the layer of the oxyfluoride compound being formed inside some of the crystal grains or in a part of a grain boundary part, a fluoride compound or oxyfluoride compound containing carbon in a stratified form is formed on an outermost surface of the sintered magnet, the layer of fluoride compound or the layer of oxyfluoride compound formed inside some of the crystal grains or in the part of the grain boundary contains at least one light rare earth element and at least one heavy rare earth element, and the at least one heavy rare earth element has a concentration lower than that of the light rare earth element, and the layer of the fluoride compound or the layer of the oxyfluoride compound formed in some of the crystal grains or in the part of the grain boundary has a difference in continuity thereof between a direction parallel to a direction of anisotropy and a direction perpendicular to the direction of anisotropy.