Experimental Investigation and Optimization for the Effective Parameters in the Laser Direct Structuring Process

Abstract

Nanostructure formation on bulk metals (copper, gold, and silver) by picosecond (FWHM = 10 ps) Nd:YAG laser irradiation was studied aiming at the production of low-reflectivity surfaces. The experiments were performed at two distinct wavelengths (λ = 355 and 1064 nm) using 20 kHz repetition frequency. The fluence was varied in the 1-11 J/cm 2 range, while the samples were shot by an average pulse number from 0 to 50 depending on the scanning speed of the applied galvanometric scanner. The reflectivity of the treated surfaces was recorded with a visible near-infrared microspectrometer in the 450-800 nm range. Morphological investigations of the irradiated metal surfaces were performed with scanning electron microscope, which showed that mainly two types of nanostructures can be responsible for the reflectivity decrease depending on the type of the illuminated metal. Finite element modeling was performed to simulate the laser absorption-induced heating of the illuminated samples, which helps in the understanding of the structure formation process. It was found that two main processes take place in the production of micro-and nanostructures on the surface; the ejection and falling back of molten metal droplets, and the back scattering and aggregation of nanoparticles.

The Effect of Antimony (III) Oxide on the Necessary Amount of Precursors Used in Laser-Activated Coatings Intended for Electroless Metallization

“…The use of lasers makes it possible to eliminate the use of several baths for surface activation, and thus the use of concentrated and hazardous chemicals. However, to successfully activate the surface of polymeric materials by laser irradiation, a suitable catalyst should be incorporated into the matrix of the polymeric material or a coating with this catalyst (precursor) should be applied [ 9 , 10 ]. A whole group of compounds is known that can act as a precursor for electroless metallization.…”

Comparative Evaluation of Cu(acac)2 and {[Cu(μ-O,O′-NO3) (L-arg) (2,2′-bpy)]·NO3}n as Potential Precursors of Electroless Metallization of Laser-Activated Polymer Materials

“…In the direct method of surface activation, the material can be simultaneously modified and metallized. However, this requires the use of appropriate compounds named metallization precursors, added at the processing stage to the polymer material [ 10 , 11 ]. The precursors may be added to the total volume of the material (e.g., during the extrusion and injection molding) or be present in polymeric coatings which cover the substrate.…”

Copper Filled Poly(Acrylonitrile-co-Butadiene-co-Styrene) Composites for Laser-Assisted Selective Metallization

“…Laser irradiation can be used to activate the surface of the polymer material immersed in special solutions containing compounds of seeded metal as a catalyzer or to preactivate the surface which, in the next step, can be activated selectively by means of chemical treatment [12][13][14]. However, the most commonly used manufacturing method for 3D-MIDs is the laser direct structuring (LDS) method, in which special metal-organic compounds are co-compounded with the polymer material intended to be injection molded [15,16]. As a result of laser irradiation, organic ligands of the metalorganic compounds along with polymer matrix are ablated while heavier metallic atoms left on the surface, thus constituting active sites for reduction of metal ions from metallization bath.…”