In this study, we have demonstrated
an innovative single-step,
low-cost approach for producing a hybrid layered steel surface with
superior properties using waste as the resource. This promising method
of transforming an industrial grade steel surface into a multilayered
multiphase ceramic/diffused subsurface structure using only the waste
source could replace technically challenging and expensive high-performance
materials. Strong chemical bonds can be achieved between metal and
ceramic structures if a suitable structure can be generated by the
judicious choice of materials and processes. We recovered various
ceramic materials (Ti, Al, Si/nitrides, oxides, etc.) from a complex
mixture of wastes, such as automated shredder residue and metalized
plastics from food packaging, through a controlled selective reaction
to generate a chemically bonded multiphase ceramic and diffused subsurface
on high-carbon steel surface as an ultrahard ceramic surface. The
diffused subsurface contains submicrometer-sized carbides (Cr/Mn/SiC)
which formed by diffusion of carbon into the base metal. Our result
reveals that by turning the normal high-carbon steel surface into
a multiphase ceramic/diffused subsurface structure, a seamless gradient
of hardness from 14.5 GPa in the nanoceramic layer to 6.5 GPa in the
base material can be achieved.