Parametric Study of the Effect of Feed Speed and Power on Laser Cut Quality of 4130 Steel
Samples of 4130 steel were cut by a CO2 laser and the effects of power and feed rate on kerf width, surface roughness, striation frequency and the size of heat affected zone (HAZ) were studied. It was observed that power had a major effect on kerf width and size of HAZ, while feed rate affects were secondary. In the other hand, surface roughness and striation frequency were affected most by feed rate. At low power levels the smallest kerf width and HAZ are obtained and the effect of feed rate is moderate. Low feed rates gave good surface roughness and low striation frequency. For optimum cut quality, kerf width, HAZ and surface roughness are kept minimum. However operating conditions that satisfy these requirements while maintaining high productivity could not be identified.
Analytical Studies On Laser Cut Surfaces
The topography of a laser cut edge shows a mixture of periodical and stochastical deviations from the ideal surface geometry /1/. Different surface profiles can lead to different functional properties of laser cut workpieces. Therefore they are of interest, especially if further production operations, e.g. forming processes are limited by surface structure.
Design and assembly of ternary Pt/Re/SnO2 NPs by controlling the zeta potential of individual Pt, Re, and SnO2 NPs
AbstractIn this study Pt, Re, and SnO2 nanoparticles (NPs) were combined in a controlled manner into binary and ternary combinations for a possible application for ethanol oxidation. For this purpose, zeta potentials as a function of the pH of the individual NPs solutions were measured. In order to successfully combine the NPs into Pt/SnO2 and Re/SnO2 NPs, the solutions were mixed together at a pH guaranteeing opposite zeta potentials of the metal and oxide NPs. The individually synthesized NPs and their binary/ternary combinations were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy (EDS) analysis. FTIR and XPS spectroscopy showed that the individually synthesized Pt and Re NPs are metallic and the Sn component was oxidized to SnO2. STEM showed that all NPs are well crystallized and the sizes of the Pt, Re, and SnO2 NPs were 2.2, 1.0, and 3.4 nm, respectively. Moreover, EDS analysis confirmed the successful formation of binary Pt/SnO2 and Re/SnO2 NP, as well as ternary Pt/Re/SnO2 NP combinations. This study shows that by controlling the zeta potential of individual metal and oxide NPs, it is possible to assemble them into binary and ternary combinations.
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