Rare earth permanent magnet alloy scale and neodymium iron boron permanent magnet

The invention provides a rare earth permanent magnet alloy scale and a neodymium iron boron permanent magnet, and two end faces formed in the length direction and the width direction of the rare earth permanent magnet alloy scale are a quenching roller contact end face and a free face end face opposite to the quenching roller contact end face respectively. The cross section of the rare earth permanent magnet alloy scale parallel to the thickness direction of the rare earth permanent magnet alloy scale comprises a plurality of columnar crystals; according to the method, NH3, H2 and other reducing gases are adopted for cooling the non-roller-attached surfaces (free end surfaces) of the rare earth permanent magnet alloy scales in the smelting and casting process, so that the two surfaces of the rare earth permanent magnet alloy scales are cooled at the same time, the rare earth permanent magnet alloy scales are rapidly cooled and crystallized, the grain growth time is shortened, and generation of alpha-Fe and ot