Excimer Laser Surface Treatment

Guo LF, Yue TM, Man HC, (2005), Excimer laser surface treatment of magnesium alloy WE43 for corrosion resistance improvement . Journal of Materials Science, 40, 3531-3533. 

Yue TM, Wang AH, Man HC, (1997), Improvement in the corrosion resistance of magnesium ZK60/SiC composite by excimer laser surface treatment , Scripta Materialia, 38, 191-198. 

Other topics recently studied by XPS include the effects of thermal treatment on the morphology and adhesion of the interface between Au and the polymer trimethylcy-clohexane-polycarbonate [2.72] the composition of the surfaces and interfaces of plasma-modified Cu-PTFE and Au-PTFE, and the surface structure and the improvement of adhesion [2.73] the influence of excimer laser irradiation of the polymer on the adhesion of metallic overlayers [2.74] and the behavior of the Co-rich binder phase of WC-Co hard metal and diamond deposition on it [2.75]. 

In order to understand the aim of surface treatments for composite bonding, we wiU concentrate on a real composite bonding problem for aeronautical purposes. Since classical surface treatments like peel ply can be limited by a cohesive failure occurring in the material, we wiU focus on a new kind of surface treatment (excimer laser) which can completely change surface parameters. The different aspects are presented in two steps the first consists in the surface characterization of the composite material and the second is related to results of destructive single lap shear tests of composite assemblies. Finally, both steps are Hnked in order to derive general mles on phenomena governing adhesion properties of polymer composites. 

Alternatively, excimer laser treatment can be used to obtain additional improvement of adhesion. By this technique, polymer layers at the surface can be removed selectively before bonding, thus making the adhesive layer directly hnked to the fiber reinforcement itself Hence, crack propagation which occurs cohesively in the material under this polymer layer can no longer take place. Section 20.3.2 provides the results of such an approach. 

The sulfonated PC has shown improvement in both surface wettability and electroosmotic mobility. As an alternative to coating the PC surface forming the wall, UV and excimer laser (at a wavelength of 248 nm) treatment of the PC surface has also been used for surface modification. PETG is another plastic material used for the preparation of microchips. Its surface can be modified easily by NaOH treatment, resulting in ester hydrolysis and the appearance of carboxylic groups on the surface. 

The effect of other excimer lasers (ArF, KrF and XeCl with wavelengths of 193, 248 and 308 nm, respectively) has also been studied on rayon [84]. The treatment at 193 nm induced significant changes in the cloth surface, as shown by cracks detected by SEM micrographs and an increase in oxidized moieties detected by XPS. 

Wong et al. (2000) used a pulsed UV (KrF) excimer laser and an oxygen gas discharge LTP to modify the surface structure of PET fibres. Although both plasma and laser-treated fibres exhibit similar ripple/roll-like structure surfaces, the morphological modifications are not identical, as shown in Fig. 2.17. The PET fibres were firstly treated by LTP (100 W, 5 Pa, 10 min) and then by laser irradiation under different fiuence and pulses. It was found that the threshold for the formation of a ripple-like structure under laser irradiation was lower for PET with LTP pre-treatment (see Fig. 2.17). In addition,... 

The carbon dioxide laser has greater productivity than the excimer laser or the UVYAG laser when used to generate via holes larger than 60 /rni in diameter however, it cannot drill through copper foil directly. As a result, a black surface treatment is required on the thin copper foils before the laser operation. (See Fig. 63.6) Comparisons of the technical capabihties of these micro via processes of the laser systems are shown in Table 63.4. 

Sancaktar E, Lu H, Sunthonpagasit N. Effects on excimer laser treatment on self-adhesion strength of some commodity (PS, PP) and engineering (ABS) plastics. In Mittal KL, Bahn-ers T, editors. Laser surface modification and adhesion. Beverly, MA, USA Scrivener Publishing 2015. 

Surface modification techniques these can include such approaches as the laser ablation of the surface using, for example, excimer lasers. Other possibilities are to use plasma, corona and flame treatments to modify the laminate surface, chemically, to make it more amenable to adhesive bonding. As for thermoplastic matrices, it should be possible to introduce highly polar groups onto the surface to improve bonding across the interface. 

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