Thermomechanical performance enhancement of nickel-phosphorus mold by Ti-DLC coating

Abstract

Glass molding technology is an ideal method for the mass production of the glass components, and electroless nickel-phosphorus (Ni-P) plating is widely used in the glass molding process as the mold material. However, the service life of the Ni-P mold reduces due to the diffusion of Ni atoms at high temperatures. To prolong its service life and protect the mold surface, a titanium-diamond-like carbon (Ti-DLC) coating is deposited on the Ni-P mold. This research studies the crystallization and diffusion of Ni atoms in both the Ni-P mold and the Ti-DLC coated Ni-P mold under a thermomechanical field. Additionally, the influence of Ti-DLC coating on the crystallization and diffusion behavior of single crystal Ni was investigated. The results show that the Ti-DLC coating protects the mold surface by suppressing the diffusion of Ni atoms rather than preventing the crystallization of Ni-P. The number of microbumps is used to describe the extent to which Ti-DLC coating improves the thermomechanical performance of Ni-P molds. The date shows the Ti-DLC coated Ni-P mold exhibit superior stability in 80 cycles of molding for no microbumps appearing on the surface. While the microbumps appear on the Ni-P mold surface after one-time molding, thus the thermomechanical performance of the Ni-P mold is further enhanced by Ti-DLC coating.