Study on mechanical and tribological properties of electroformed nickel composite mould co-deposited with nano-sized PTFE particles
Tianyu Guan, Michael D. Gilchrist, Fengzhou Fang, Nan Zhang
Abstract
To improve the lubrication and wear resistance of nickel composite moulds, nano-sized polytetrafluoroethylene (PTFE) particles were co-deposited with nickel. This work reports the effect of using micro-sized and nano-sized PTFE particles on the surface, mechanical and tribological properties of Ni composite moulds. The experimental results indicate that using nano-sized PTFE particles is significantly more effective than micro-sized PTFE particles in improving the lubrication, mechanical and tribological properties of the composite moulds. The microhardness of the composite mould increases by 2.5 times to 483 Hv for a Ni-PTFE nanocomposite mould, along with the COF against polymethyl methacrylate (PMMA) decreasing by 52.2% to 0.22. Using micro-sized PTFE particles serves to roughen the mould surface, which results in faster adhesive wear. In comparison, the Ni-PTFE nanocomposite mould has a low surface roughness and enhanced wear resistance against PMMA, while the tool lifetime increases by 11.5 times. Finally, a Ni/PTFE nanocomposite mould was successfully fabricated via UV-LIGA, and its lubricating properties were validated by producing high-quality PMMA replicas via micro hot embossing.