Surface defect elimination in microgrooving of electroless nickel phosphide plating layer by brittleness enhancement

Electroless nickel phosphide (Ni–P) plating is used to fabricate microgrooves for precision glass molding (PGM) due to its excellent mechanical properties as a mold material. To achieve a high-quality microgroove fabrication, the causes of the machining defect, like burrs on the mold surface during the microgrooving of amorphous nickel phosphide (a-Ni–P) by single-point diamond cutting, are investigated. We find that the burrs can be eliminated by increasing the brittleness of a-Ni–P, so the brittleness enhancement of the material is conducted by crystallization. Then, the machined surface and the chip morphology during cutting crystalline nickel phosphide (c-Ni–P) are analyzed and compared with that during a-Ni–P microgrooving. Through this innovation, the surface quality of the microgroove is improved with minimized burrs.