Effect of Pretreatment Film Composition on Adhesion of Organic Film on Zinc Coated Steel Sheet

Abstract

It is known that chromate pretreatment films with dry-type silica adhere well to organic films such as paint and laminate films on a zinc coated steel sheet. The role of surface polarity in the adhesion mechanism has been investigated for a long time, but remains unclear. We examined the correlation between the composition of chromate pretreatment films with dry-type silica and their adhesion to a laminate film on a zinc coated steel sheet, for both the wet silica and without silica types of chromate pretreatment film. We also investigated the adhesion mechanism by analyzing the pretreatment films using SEM, AFM, BET, TEM and EDX.The results were as follows. Not only the type and particle size of silica, but also the silica/chromate ratio and the coexistence of chromate affected the adhesion of laminate films. The highest adhesive strength was obtained for the pretreatment films formed in a pretreatment solution with SiO 2 /Cr ratio of 4.0 and dry-type silica with a particle diameter of 7 nm. The good adhesion of chromate pretreatment films with dry-type silica is due to an anchor effect by sub-micron surface roughness and an increased number of interface bonding sites by a nano-porous structure. The formation of an insoluble Cr(III) compound layer plays an important role in binding silica particles to the zinc coating surface.

Biocompatibility Studies of Electron Beam Cured Pressure Sensitive Adhesive Tape for Medical Application

“…Composition developed for making e-beam curable PSA tape for different medical applications was homogenized by rotatory homogenizer and investigated for equal dispersion with the help of TEM analysis, presented in Figure 3. No distribution spots were observed as revealed by TEM images, while, in case of crosslinker systems it was established that ingredients added in the composition, were equally distributed in the form of tiny spots in adhesive matrix, required for the uniform film structure without any aggregation or localized accumulation ( Figure 3) 23,24 .…”

Determination of Surface Topography and Composition of Cr-Free Pretreatment Layers on Hot Dip Galvanized Steel

“…Paints mainly rely on secondary chemical bonding that is polar interactions like hydrogen bonds and van der Waals forces [3]. It has been shown by detailed AFM and transmission electron microscopy/x-ray energy dispersive spectrometry (TEM/EDX) analysis of chromate pretreatment films that a nano-porous surface increases the number of interfacial bonding sites [22]. A micro-rough pretreatment layer may thus increase the specific surface area for chemical paint adhesion.…”

“…As a result of the pH increase, the solubility product of zinc phosphate will be exceeded, followed by precipitation. The nucleation of zinc phosphate crystals will decrease the pH and eventually cease the formation of nuclei [21,22]. A further increase will result in formation of manganese phosphate.…”

Preparation of a hydrophobic cerium oxide nanoparticle coating with polymer binder via a facile solution route

“…Spray-coated thin films generally have poor adhesion with the substrate due to weak van der Waals forces between the NPs and the substrate [18]. Pretreatments that intentionally roughen the surface of the substrate to improve adhesion have been widely used, but are not appropriate for sensitive and fragile substrates where physical damage to the substrate may occur [19,20]. Alternative approaches to improving adhesion have been reported, wherein the incorporation of polymeric materials was found to improve adhesion between metal oxide powders used in the electrodes of lithium-ion batteries [21][22][23][24][25][26][27].…”