Nozzle geometry for planar flow casting of metal ribbon

An apparatus for planar flow casting of metal ribbon comprising a movable chill surface, a reservoir for holding molten metal and a nozzle in communication at its top with the reservoir and having at its bottom two lips adjacent to the chill surface, a first lip and a second lip numbered in the direction of movement of the chill surface, wherein

• (a) the lips are separated by and define a slot for depositing molten metal on the chill surface;
• (b) the leading and trailing edges of the slot are substantially parallel, to each other and are generally perpendicular to the direction of movement of the chill surface;
• (c) the bottom of the lips comprises at least two now-coplanar surfaces, including a substantially planar first surface substantially parallel to the chill surface, said first surface including the leading edge of the first lip and the side edges at the bottom of the lips but not including the trailing edge of the slot;
• (d) the first surface is separated from the chill surface by at least about 0.20 mm;
• and
• (e) all points on the bottom of the lips are at least as far from the chill surface as is the first surface, but are no further from the chill surface than about 1 mm.