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Systematic microstructural studies of hot pressed HDDR, fully dense Nd 16 Fe 76 B 8 magnets have been carried out. A fine grained, hard magnetic phase structure with a grain size of a few hundreds of nanometres is the most outstanding microstructural characteristic of these magnets. Apart from the compact fine grained microstructure with hardly any Nd-rich phase, partially isolated, fine hard magnetic grains with a Nd-rich surrounding were also found. Abnormal grains were observed, arising from the early stages of growth. These grains had a close contact to small neighbouring grains as well as larger abnormal grains of up to 10 µm with straight borders. Other phases identified were the Nd 1+ε Fe 4 B 4 and Nd 5 Fe 2 B 6 intergranular platelets.