Co-deposited Zn-Cu/Gr nanocomposite: Corrosion behaviour and in-vitro cytotoxicity assessment

Zn-Cu alloys have been considered as potential candidates for bioimplant applications due to their moderate corrosion rate and admirable mechanical properties with non-toxic nature to the human body. However, with the incorporation of advanced reinforcements, such as carbon allotropes, the properties and applicability of a Zn-Cu alloy matrix can be further enhanced. In this research, graphene (Gr) nanoplatelets reinforced Zn-Cu/Gr nanocomposites were synthesised through a modified electro-codeposition method with different concentrations of Gr (25, 50 and 100 mg L-1) in the electrolyte bath. The prepared powder samples were compacted and sintered to form pellets. The pellets were tested for mechanical and in-vitro corrosion. The obtained micro-hardness, compressive yield strength (CYS) and ultimate compressive strength (UCS) of Zn-Cu/Gr (100 mg L-1) nanocomposite are 151 HV, 340 MPs and 362 MPa with increments of 84.1%, 118% and 70.7% compared to pure Zn-Cu alloy, respectively. The reduced wear rates and friction coefficients of Zn-Cu/Gr nanocomposites are attributed to crystallite size refinement and Gr content. The electrochemical corrosion rate is reduced by 66.6% from 33 x 10(-3) mm year(-1) for pure Zn-Cu alloy to 11 x 10(-3) mm year(-1) for Zn-Cu/Gr (100 mg L-1) nanocomposites, owing to Gr barrier protection. The in-vitro cytotoxicity assessment reveals that the prepared Zn-Cu/Gr nanocomposite is non-toxic for Gr concentration up to 50 mg L-1 in the electrolyte bath. The results show that a non-toxic Zn-Cu/Gr nanocomposite with outstanding tribo-mechanical and anti-corrosion properties can be synthesised by the proposed method.

Automated summary

Zn-Cu alloys are potential candidates for bioimplant applications due to their moderate corrosion rate and good mechanical properties. By incorporating graphene nanoplatelets, the properties of Zn-Cu alloy can be enhanced, resulting in improved mechanical strength, reduced wear rates and lower corrosion rate. The synthesized Zn-Cu/Gr nanocomposites demonstrate outstanding tribo-mechanical and anti-corrosion properties, showing promise for bioimplant applications.