Enhancing Corrosion Resistance of Stainless Steel 304 Using Laser Surface Treatment

2008 ◽  
Vol 384 ◽  
pp. 157-183 ◽  
Author(s):  
Ibrahim M. Ghayad ◽  
Madiha Shoeib ◽  
Taha Mattar ◽  
Huda M. Hussain
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Surface Treatment ◽  
Laser Irradiation ◽  
Laser Treatment ◽  
Surface Composition ◽  
Specific Treatment ◽  
Laser Surface ◽  
Laser Surface Treatment ◽  
Aisi 304

Stainless steel AISI 304 was laser treated to enhance corrosion resistance and improve surface properties. . This alloy has many applications in auto industry (car body,) as well as oil and gas industry. Different conditions were applied in the laser surface treatment, namely: laser power density, scan speed, distance between paths, medium gas (air, argon and nitrogen). After laser treatment, the samples microstructures were investigated using optical microscope to examine micro structural changes due to laser irradiation. Specimen surfaces were investigated using XRD, SEM and EDAX before and after laser treatment to examine the surface composition changes brought by laser irradiation. Results showed that laser irradiation enhances the corrosion resistance of AISI 304 Stainless steel to a large extent. Corrosion rates as low as 0.011 mpy for laser treated samples were obtained in comparison to 0.952 mpy obtained for the untreated samples. Superior pitting corrosion resistance was obtained under specific treatment conditions. The enhancement of corrosion resistance depends on the laser irradiation conditions. The corrosion protection afforded by laser treatment is attributed mainly to the grain refinement of the top surface layer. This layer is found to consist of nano-scale grains.

Wetting properties of Nd:YAG laser treated copper by SAC solders

2017 ◽  
Vol 29 (2) ◽  
pp. 69-74 ◽  
Author(s):  
József Hlinka ◽  
Miklós Berczeli ◽  
Gábor Buza ◽  
Zoltán Weltsch
Keyword(s):  
Surface Treatment ◽  
Laser Treatment ◽  
Contact Angles ◽  
Laser Surface ◽  
Lead Free Solder ◽  
Solder Paste ◽  
Laser Surface Treatment ◽  
Content Type ◽  
Wetting Properties ◽  
Free Solder

Purpose This paper aims to discuss the effect of surface treatment on the wettability between copper and a lead-free solder paste. The industrial applications of laser technologies are increasing constantly. A specific laser treatment can modify the surface energy of copper and affect the wetting properties. Design/methodology/approach The surfaces of copper plates were treated using an Nd:YAG laser with varying laser powers. After laser surface treatment, wetting experiments were performed between the copper plates and SAC305 lead-free solder paste. The effect of laser treatment on copper surface was analysed using optical microscopy and scanning electron microscopy (SEM). Findings The experimental results showed that the wetting contact angles changed with the variation in laser power. Furthermore, it means that the surface energy of copper plates was changed by the laser treatment. The results demonstrated that the contact angles also changed when a different soldering paste was used. Originality/value Previous laser surface treatment can be a possible way to optimize the wettability between solders and substrates and to increase the quality of the soldered joints.

scholarly journals Fibre Laser Treatment of Beta TNZT Titanium Alloys for Load-Bearing Implant Applications: Effects of Surface Physical and Chemical Features on Mesenchymal Stem Cell Response and Staphylococcus aureus Bacterial Attachment

Coatings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 186 ◽  
Author(s):  
Clare Donaghy ◽  
Ryan McFadden ◽  
Graham Smith ◽  
Sophia Kelaini ◽  
Louise Carson ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Surface Treatment ◽  
Laser Treatment ◽  
Bulk Composition ◽  
Bacterial Attachment ◽  
Laser Surface ◽  
Fibre Laser ◽  
Elemental Distribution ◽  
Laser Surface Treatment ◽  
Load Bearing

A mismatch in bone and implant elastic modulus can lead to aseptic loosening and ultimately implant failure. Selective elemental composition of titanium (Ti) alloys coupled with surface treatment can be used to improve osseointegration and reduce bacterial adhesion. The biocompatibility and antibacterial properties of Ti-35Nb-7Zr-6Ta (TNZT) using fibre laser surface treatment were assessed in this work, due to its excellent material properties (low Young’s modulus and non-toxicity) and the promising attributes of fibre laser treatment (very fast, non-contact, clean and only causes changes in surface without altering the bulk composition/microstructure). The TNZT surfaces in this study were treated in a high speed regime, specifically 100 and 200 mm/s, (or 6 and 12 m/min). Surface roughness and topography (WLI and SEM), chemical composition (SEM-EDX), microstructure (XRD) and chemistry (XPS) were investigated. The biocompatibility of the laser treated surfaces was evaluated using mesenchymal stem cells (MSCs) cultured in vitro at various time points to assess cell attachment (6, 24 and 48 h), proliferation (3, 7 and 14 days) and differentiation (7, 14 and 21 days). Antibacterial performance was also evaluated using Staphylococcus aureus (S. aureus) and Live/Dead staining. Sample groups included untreated base metal (BM), laser treated at 100 mm/s (LT100) and 200 mm/s (LT200). The results demonstrated that laser surface treatment creates a rougher (Ra value of BM is 199 nm, LT100 is 256 nm and LT200 is 232 nm), spiky surface (Rsk > 0 and Rku > 3) with homogenous elemental distribution and decreasing peak-to-peak distance between ripples (0.63 to 0.315 µm) as the scanning speed increases (p < 0.05), generating a surface with distinct micron and nano scale features. The improvement in cell spreading, formation of bone-like nodules (only seen on the laser treated samples) and subsequent four-fold reduction in bacterial attachment (p < 0.001) can be attributed to the features created through fibre laser treatment, making it an excellent choice for load bearing implant applications. Last but not least, the presence of TiN in the outermost surface oxide might also account for the improved biocompatibility and antibacterial performances of TNZT.

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