Optimization of Flow Rate for Uniform Zinc Phosphate Coating on Steel Cylinders: A Study on Coating Uniformity and Elemental Composition Using Scanning Electron Microscopy (SEM)

Materials (Basel). 2025 May 23;18(11):2442. doi: 10.3390/ma18112442.

Abstract

Uniformity in material coating is not only essential for ensuring durability and long-term reliability but also for reducing costs, optimizing resources, and maintaining high-quality standards in industrial applications. Zinc phosphate is notable for coating steel surfaces due to its excellent corrosion resistance and adhesion properties in various industries. This study investigates the optimal flow rate of a diaphragm pump for achieving the effective and uniform coating of a steel cylinder. The coating uniformity was assessed using Scanning Electron Microscopy (SEM), focusing on layer thickness and elemental composition. A range of flow rates was analyzed to determine their influence on coating quality and regularity, with Energy-Dispersive Spectroscopy (EDS) revealing the distribution and homogeneity of the applied layer. The results identified a flow rate of 30 L/min as optimal with a thickness of 3.6 µm of coating on both sample sides, as it minimized surface defects and ensured consistent thickness across the cylinder. This study provides valuable insights for optimizing industrial coating processes, contributing to improved efficiency and reduced resource waste.

Keywords: energy-dispersive spectroscopy; flow rate; phosphating; scanning electron microscopy; uniformity; zinc phosphate.