Surface modification of nickel-phosphorus plating by Ti ion implantation for chalcogenide glass lens molding

Nickel-phosphorus (Ni-P) plating has been developed as an excellent mold material in precision glass molding (PGM) for silicate optical lenses. However, the elemental diffusion and adhesion problems hinder the application of the Ni-P mold in the molding process for infrared chalcogenide glass (ChG) optics. In this study, Ti ion implantation and annealing were proposed for the surface modification of Ni-P plating. The modification mechanism of the Ti-Ni-P plating was studied, and the Ti ion distribution was simulated using the Monte Carlo method. Several characterization methods were conducted to analyze the surface composition of Ti-Ni-P plating. The mechanical properties of the plating were tested before and after implantation, proving that ion implantation improved the surface hardness of the plating. Finally, molding experiments were carried out using the Ti implanted flat and structured molds. The molded glass does not undergo interfacial reaction, and has high structural replication accuracy and higher infrared transmittance. It is validated that Ti ion implantation has a positive effect on the inhibition of the interfacial reaction in ChG molding.