The European Union has banned chromium(VI) compounds in electrical and electronic equipment (EEE), such as chromate conversion coating films. Chromium(III) compounds are not banned. Using Raman spectroscopy without any preparation, we distinguished chromium(VI) oxide from chromium(III) oxide and chromium(III) hydroxide in chromate conversion coating films. Raman bands of chromium(VI) oxide were...

nanosized tio2 particles were prepared by sol–gel method. the tio2 particles were co-deposited with chromium using electrodeposition technique. in investigating of coating surfaces by scanning electron microscope (sem), the results showed that the morphology of the coating surface was changed by adding tio2 nanoparticles to the chromium coating. the corrosion behavior of the coatings was assess...

We report on the fabrication and characterization of thick UV-patternable hybrid sol-gel films by spin coating using a modified sol-gel process. Thick coating of 25 microns with crack-free surface can be produced by one spin coating step. Thick layers of more than 100 μm can be obtained with a multi-coating process. Characterization using different techniques including optical microscope and at...

A protocol is described to assess self-healing of crack damage in a polymer coating deposited on a substrate containing a microvascular network. The bio-inspired coating/substrate design delivers healing agent to cracks in the coating via a three-dimensional microvascular network embedded in the substrate. Through capillary action, monomer flows from the network channels into the crack plane wh...

Nanosized TiO2 particles were prepared by sol–gel method. The TiO2 particles were co-deposited with chromium using electrodeposition technique. In investigating of coating surfaces by scanning electron microscope (SEM), the results showed that the morphology of the coating surface was changed by adding TiO2 nanoparticles to the chromium coating. The corrosion behavior of the coatings was assess...

A combined experimental/analytical work is carried out to elucidate the fracture resistance of a thin, hard coating bonded to a semi-infinite substrate due to indentation by a cylindrical surface. The bending of the coating under the softer substrate induces concentrated tensile stress regions at the lower and upper surfaces of the coating, from which cracks may ensue. The evolution of such dam...

Multiple healing cycles of a single crack in a brittle polymer coating are achieved by microvascular delivery of a two-part, epoxy-based self-healing chemistry. Epoxy resin and amine-based curing agents are transported to the crack plane through two sets of independent vascular networks embedded within a ductile polymer substrate beneath the coating. The two reactive components remain isolated ...

in the present study, the effects of growth defects and chromium content loss on the degradation of corrosion andpassivation of cathodic arc evaporation (cae-pvd) of stainless steel coating were investigated in 2 m sulphuricacid solution. eds analysis indicated that the micro-particles were obtained during the coating growth. in addition,it was detected that the growth defects had poor adhesion...

Chromium oxide coatings were deposited on low-carbon steel by radiofrequency reactive magnetron sputtering at different oxygen flux values. X-ray diffraction, x-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy were used to investigate the microstructure of chromium oxide coatings. Varying oxygen flux changed the coating microstructure; as with increasing oxyg...

Corrosion is the degradation or deterioration of metal components due to a reaction with the environment. Chromate conversion coating is applied to passivate metallic surface to slow down (and prevent to some extent) corrosion process. Chromate conversion process uses chromium compounds including hexavalent chromium, which is toxic, carcinogenic and hazardous to human health and environment. He...