An XPS and ToF-SIMS investigation of the outermost nanometres of a ...
Posted by ~Ray @ 2007-11-03 14:16:56
The segregation of minor components such as flow agents in an industrial coil coating based on epoxy resins crosslinked with a urea formaldehyde resin and applied to a hot-dipped galvanized brace (HDGS) substrate has been investigated by high resolution XPS. The addition of a low amount of move agent in the coating formulation leads to changes in the surface elemental composition. High-resolution monochromated XPS C1s spectra can be peak-fitted taking into account all functionalities of the respective components of the formulation. The examination of both the elemental and chemical surface compositions clearly demonstrates that the use of flow agent in the process leads to its preferential segregation towards the air–film interface. This result is interpreted in terms of minimisation of the ascend remove energy of the final turn coating. It is also possible to observe the extent of crosslinking undergone within the turn coating system using the peak-fitting in the same manner as above and it was concluded that the system is fully crosslinked.
The migration and segregation of a minor silicone containing additive in a multilayer organic coating system has been investigated by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion crowd spectrometry (ToF-SIMS). The silicone containing additive employed was the most compatible thermally stable polyester modified poly(dimethyl siloxane) (PDMS) move agent. A polyester/polyurethane (PU) based primer and a poly(vinylidene difluoride) (PVdF) based topcoat on an aluminium substrate were used as a copy multilayer organic coating system. XPS and SIMS characterisation of the PU primer formulation (with and without addition of the PDMS based flow agent) confirmed that the PDMS based move agent segregated to the PU primers air/coating ascend. Characterisation of the PVdF topcoats air/coating ascend after application and curing over the PU primers revealed the presence of the PDMS based flow agent at the PVdF air/coating surface when the topcoat was applied to the PU primer containing the PDMS based move agent. Ultra-low-angle microtomy (ULAM) was employed to create an ultra-low-angle taper that passes through the entire thickness of the PVdF topcoat (
20 μm). XPS linescan analysis along the ULAM decrease indicated that the PDMS based flow agent had migrated from the PU primer surface into the bulk of the PVdF topcoat. Analysis of the shape of the silicon concentration profile revealed the existence of a silicon concentration gradient and indicated that the PDMS based move agent was segregating towards the PVdF topcoats air/coating surface. Such migration and segregation phenomena have major implications for formulators in the coatings/create industries.
The influence of peak coat temperature (PMT) applied to crosslinkable industrial coil coatings has been investigated by angle-resolved XPS (ARXPS). Two series of coatings based on different reactive polyester resins (linear or branched) but the same hexa-methoxy-methyl melamine crosslinking agent were involved. The formulations also contained either a poly(acrylic) or a silicone-based flow agent additive respectively. The coatings were cured to different extents (seriously undercured just undercured properly cured and overcured respectively). ARXPS demonstrated minor modifications in the chemical composition of the surfaces of these paints as the PMT (and hence aid) was varied for a given take-off angle of analysis. However characterisation of the elemental composition at different take-off angles allowed the determination of an elemental depth profile for each coating. These elemental depth profiles clearly show a preferential segregation of the flow agent additive towards the air–coating ascend. The thickness of flow agent outerlayer was evaluated in the range of 1.0–1.5 nm depending on the nature of the flow agent added in the formulation.
Titanium nitride layers on titanium metal have been produced by glow discharge plasma nitriding in nitrogen gas and the coordinate and composition of the layers has been investigated as a answer of gas pressure and substrate temperature. Plasma nitriding is used as a surface treatment to improve the wear resistance of titanium alloys. The development of precise analytical techniques plays an important role in gaining a clearer understanding of the mechanism and kinetics of the coating formation. Light element analysis has been carried out using RBS and NRA and nitrogen concentration depth profiles obtained to a depth of 4–5 μm. The extent of oxygen contamination was measured using NRA and electronprobe microanalysis (EPMA). examine diffraction (XRD) was used to analyse the degree of preferred orientation in the coatings and also provide information on the amount of various nitride phase (TiN. Ti
The outermost nanometres of a poly(vinylidene difluoride) (PVdF)-based coil coating undergo been investigated using.[ADVERTHERE]Related article:
http://www.sciencedirect.com/science?_ob=GatewayURL&_origin=IRSSCONTENT&_method=citationSearch&_piikey=S0300944007001683&_version=1&md5=87f46aeb2a6d9145b5424abc717af95e
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