ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Electrodeposition of Ni–ZnO nano-composite for protecting the agricultural mower steel knives

Mohamed Refai, Z. Abdel Hamid, Roshdy M. El-kilani, and Gamal E. M. Nasr

Agricultural Engineering Department, Faculty of Agriculture, Cairo University, Giza, Egypt

E-mail: mohamed.refay@agr.cu.edu.eg

Received: 6 April 2020  Accepted: 14 July 2020

Abstract:

There is little information about the improvement of agricultural reciprocating mower knives against wear and corrosion using nanotechnology. Therefore, in the present study, the electrodeposition of pure Ni and Ni–ZnO nano-composite coatings has been used. The influence of pH values and the applied current density on the surface morphology, corrosion resistance, and mechanical properties as abrasion resistance, scratch, and fretting tests of Ni and Ni–ZnO nano-composite coatings using nanoindentation machine have been investigated. The results demonstrated that Ni deposited on steel from the alkaline bath displayed fine grain sizes than that deposited from the acidic bath. EDX analysis proved that the maximum incorporation of ZnO (2.7 wt%) into the Ni matrix was achieved with an alkaline bath at 5A/dm². High-performance properties were obtained with the steel coated by Ni–ZnO nano-composite coating from an alkaline bath. The surface is harder (4.8 Gpa) than the steel coated by pure Ni (2.8 Gpa) and consequently exhibited a higher ratio of the hardness, the resistance to the plastic indentation, elastic recovery, scratching, fretting, abrasion, and corrosion resistance (in 3.5% NaCl solution). The highest corrosion resistance (0.0047 mm/year) compared with uncoated steel (0.094 mm/year) was obtained with the steel coated by Ni–ZnO nano-composite from the alkaline bath containing 1 g/L ZnO operated at 5 A/dm² and pH 10. The testing results concluded that the steel coated by Ni–ZnO nano-composite coating from an alkaline bath appears promising to protect mower knives.

Keywords: Electrodeposition; Nano-composite coatings; Nano-indentation; Nano-scratch; Crop harvester; Agricultural mower knives

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-020-01291-2

Chemical Papers 75 (1) 139–152 (2021)