Comparing the environmental and economic performances of different substrate pre-treatment processes for diamond coating deposition

Abstract

The deposition of diamond coatings on hard metals substrates is a common strategy to improve mechanical characteristics of parts (e.g. cutting tools), but requires the pre-treatment of substrates. The study aims to investigate the environmental and economic sustainability of two different substrate pre-treatment processes: (i) two-step chemical etching process, and (ii) high-power continuous wave diode laser method. The cradle to gate study considers the superficial treatment of a WC-Co specimen as functional unit. The Life Cycle Assessment results highlight that for most of the ReCiPe impact categories, the environmental impact of laser treatment is greater than that of the chemical process (+38% in case of Climate Change, +45% in case of ReCiPe endpoint Single score), mainly due to the high energy consumption of the laser. The cost estimation, instead, highlights relevant savings for the laser process (about -98%), due to higher cost of chemicals than for electricity.