Influence Of Energy Distribution Research Articles

Synthesis and mechanism of quaternary ammonium salts based on porphyrin as high-performance copper levelers

The molecular structure and energy distribution of organic compounds have a great influence on their adsorption capacity on the metal surface. However, there are still insufficient researches on the influence of energy distribution on adsorption properties of organic molecules. Herein, a family of porphyrin derivatives (TPyP-Et, TPyP-Oct, TPyP-Bn and TPyP-Al) bearing quaternary ammonium groups were synthesized for the first time as promising levelers for through-hole copper electrodeposition. Electrochemical tests revealed that all four TPyP derivatives displayed enhanced electrochemical properties. Theoretical calculations and molecular dynamics simulations were carried out to investigate the physisorption capacity and chemical reaction activity of the TPyP molecules, as well as the adsorption capacity on the surface of the copper layer. Through optical and scanning electron microscopy as well as X-ray diffractometry, it was demonstrated that TPyP molecules are effective electroplating levelers. TPyP-Oct, with its longer carbon chain substituent, exhibited superior hole-filling performance in practical PCB experiments among the four compounds. This study expandes the application range of porphyrin compounds, analyzes the influence of organic molecular adsorption properties in copper electrodeposition, and provides theoretical guidance for the future study of organic compounds adsorbed on metal surfaces.

Numerical modelling of the impact of energy distribution and Marangoni surface tension on track shape in selective laser melting of ceramic material

The present study is based on a formerly developed 3D finite element modelling of the selective laser melting process (SLM) at the track scale. This numerical model is used to assess the impact of two phenomena on the shape of the elementary track resulting from SLM processing: laser interaction on one hand, and Marangoni effect on the other hand. As regards laser interaction, it is modelled by a Beer-Lambert type heat source, in which lateral scattering and material absorption are considered through two characteristic parameters. The impact of these parameters is shown in terms of width and depth of melted zone. The Marangoni effect caused by tangential gradients of surface tension is modelled to simulate the fluid dynamics in the melt pool. The resulting convection flow is demonstrated with surface tension values either increasing or decreasing with temperature. The influence of energy distribution, surface tension effects, as well as laser scanning speed on temperature distribution and melt pool geometry is investigated. The stability and regularity of the solidified track are a direct output of the simulations, and their variations with material and process conditions are discussed.