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

ABSTRACT

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 × 10⁻³ mm year⁻¹ for pure Zn-Cu alloy to 11 × 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.

KEYWORDS:

• Nanocomposites
• electro-codeposition
• sintering
• corrosion
• micro-hardness
• in-vitro cytotoxicity assessment

Acknowledgements

We gratefully acknowledge Birla Institute of Technology and Science (BITS), Pilani Campus, Rajasthan, India, for the financial support to this research. We thank Dr Archana Singh, CSIR-Institute of Genomics & Integrative Biology (IGIB), Delhi, India, for her kind support by providing the human keratinocyte cell line (HaCaT) for cytotoxicity tests. We express our sincere thanks to Dr Surojit Pande, BITS, Pilani, for his support in corrosion testing. We are also thankful to Mr M. Dinachandra Singh and Prof. Anshuman Dalvi of BITS, Pilani, for their help and support in the X-ray diffraction studies. We thank CSIR and DST-SEED for providing fellowship to the students.

Disclosure statement

No potential conflict of interest was reported by the author(s).