A SINTERED R-T-B BASED PERMANENT MAGNET

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The present invention provides a sintered R-T-B based permanent magnet characterized by : - a crystal structure with a first-type grain boundary in the direction of the easy-orientation axis of the magnet and a second-type grain boundary perpendicular to the easy-orientation axis of the magnet, both being a face-centered cubic structure (fcc); and - a first triple junction area phase including an Al and Ga element rich rare-earth phase with an amorphous crystal structure, whose composition satisfies the condition (atomic percentage) : 65%≤Pr+Nd≤88%, 10%≤Al+Ga≤25%, O≤10%, and other elements, Fe+Cu+Co≤2%; and/or a second triple junction area phase including a Cu and Ga rich rare-earth phase with a densely packed hexagonal crystal structure (dhcp), whose composition satisfies the condition (atomic percentage) : 50%≤Pr+Nd≤70%, 10%≤Cu+Ga≤20%, 10%≤Fe+Co≤20%, and O≤10%.