Dip Coating From Density Mismatching Mixture

Abstract

Solid transfer technology from mixtures is gaining ever-increasing attention from materials scientists and production engineers due to their high potential in near-net-shaped production of cost-effective engineering components. Dip coating, a wet deposition method, is an effective and straightforward way of thin-film/layers formation. The dipping mixtures are often embedded with inorganic fillers, nanoparticles, or clusters (d < 30 nm) that produce a thin film ranging from nm to couple microns. An increase in the volume of solid transfer by the dipping process can open-up a novel three-dimensional near-net-shape production. However, adding a larger inorganic particle size (>1 μm) or adding a higher solid fraction will increase the solid transfer but may result in a multiphase heterogeneous mixture. In this work, the physical mechanism of an increased volume of solid transfer with a larger spherical particle size (>5 μm) is investigated. Polymer-based glue and evaporating solvent are mixed to construct the liquid carrier system (LCS) for large inorganic hard particles. Moderate volume fraction of inorganic particles (20% < ϕp < 50%) are added into the LCS solution as solid loading. Three levels of binder volume fraction are considered simultaneously to investigate the effect of the solid transfer. Cylindrical AISI 304 steel wire with dia 0.81 mm is used as the substrate for dipping and coating. The coating thickness, weight, and surface packing coverage by the particles are measured in our lab. The results presented the influence of volume fraction of inorganic particle and glue composition on the solid transfer from the heterogeneous mixture.