Oxidation　kinetics　of　Nd-Fe-B　permanent　magnets　prepared　by　both　spark　plasma　sintering　(SPS)　and　conventional　sintering　techniques　has　been　studied　at　elevated　temperature　in　dry　air　environment.　Compared　with　the　conventional　sintered　magnet,　the　SPS　magnet　possesses　much　lower　oxidation　rate,　which　leads　to　less　reduction　of　magnetic　properties　of　the　SPS　magnet　than　that　of　the　conventional　sintered　magnet.　Microstructure　observation　shows　that　the　SPS　magnet　possesses　unique　microstructure　due　to　the　special　sintering　mechanism　of　SPS　technique.　In　detail,　the　grain　size　of　the　Nd2Fe14B　main　phase　is　fine　and　uniform,　only　a　few　Nd-rich　phases　form　along　the　grain　boundaries　of　Nd2Fe14B　phase,　while　most　of　them　agglomerate　into　triple　junctions　as　small　particles.　Such　microstructure　modification　restrains　effectively　the　intergranular　corrosion　along　Nd-rich　phase　in　the　SPS　magnet.　As　a　result,　the　SPS　magnet　possesses　excellent　corrosion　resistance　at　elevated　temperature.　(C)　2008　American　Institute　of　Physics.