Grain　boundary　diffusion　(GBD)　Nd-Fe-B　sintered　magnets　were　prepared　using　a　newly　developed　solid　-liquid　phase　separation　diffusion　(SepD)　technique,　as　well　as　a　currently　popular　solid-liquid　phase　si-multaneous　diffusion　(SimD)　technique.　The　magnetic　properties,　microstructures,　and　magnetic　domain　morphologies　of　the　magnets　with　different　Tb　contents　diffused　using　the　two　techniques　were　then　in-vestigated.　A　SepD　magnet　using　0.25　wt%　Tb　exhibited　a　similar　coercivity　and　a　stronger　maximum　energy　product　compared　to　a　SimD　magnet　with　0.50　wt%　Tb,　demonstrating　high　Tb　availability.　Moreover,　by　using　the　new　diffusion　technique,　Tb　could　diffuse　deeper　into　the　magnet　and　distribute　more　homo-geneously　around　the　surface　region　of　the　Nd2Fe14B　crystal　grains,　forming　the　crucial　core-shell　structure　without　undesirable　enrichment　in　the　surface　area　of　the　magnet.　As　a　result,　the　squareness　factor　in-creased　noticeably　from　0.842　for　the　current　technique　diffused　magnet　to　0.925　for　the　new　technique　diffused　magnet　with　a　thickness　of　8　mm.(c)　2023　Elsevier　B.V.　All　rights　reserved.