Special Issue "Laser Surface Treatment"

A special issue of Coatings (ISSN 2079-6412).

Deadline for manuscript submissions: closed (31 March 2018)

Special Issue Editor

Guest Editor
Dr. Frank L. Palmieri

NASA Langley Research Center, Hampton, VA, USA
Website | E-Mail
Interests: laser surface preparation of composites and aerospace alloys for secondary bonding operations; laser surface modification to prepare hydrophobic and superhydrophic surfaces

Special Issue Information

Dear Colleagues,

You are invited to submit your manuscript for a Special Issue of Coatings on "Laser Surface Treatment". Laser ablation is useful to modify the surface roughness and chemistry of essentially any absorbing material. The controlled development of micro/nano-structures and the activation of chemical species by ablation is an active area of research to prepare surfaces with disparate applications. The surface may have low energy for easy/self-cleaning, superhydrophobicity, ice phobicity and bio-antifouling properties. Conversely, high energy surfaces are often prepared to enhance bonding for structural applications where bond performance is critical. Laser-induced deposition adds yet another dimension to the surface treatment processing window. Finally, laser treated surfaces combined with functional coatings can greatly enhance as-ablated surface properties. Ablation can activate a surface for chemical bonding to covalently link coatings to a substrate and enhance durability and resist corrosion. This Special Issue of Coatings is devoted to advances in the processing of surfaces by laser ablation with an emphasis on ablation science and demonstrations of new processes and materials. Submissions of original research and review articles are welcome.

In particular, topics of interest include without being limited to:

  • Physics of laser ablation and surface modification
  • Surface modification of polymers, ceramics and metals
  • Development of hierarchical surface roughness
  • Chemical characterization of ablated surfaces
  • Laser treatments to prepare ice-phobic surfaces
  • Laser treatments to reduce adhesion with solids or liquids
  • Laser treatment for enhanced bonding
  • Surfaces with corrosion-resistant properties
  • Chemical/mechanical treatments for peened metals with enhanced chemical properties

 Dr. Frank L. Palmieri
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Coatings is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (8 papers)

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Research

Open AccessArticle ANN Laser Hardening Quality Modeling Using Geometrical and Punctual Characterizing Approaches
Coatings 2018, 8(6), 226; https://doi.org/10.3390/coatings8060226
Received: 25 April 2018 / Revised: 5 June 2018 / Accepted: 18 June 2018 / Published: 20 June 2018
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Abstract
Maximum hardness and hardened depth are the responses of interest in relation to the laser hardening process. These values define heat treatment quality and have a direct impact on mechanical performance. This paper aims to develop models capable of predicting the shape of [...] Read more.
Maximum hardness and hardened depth are the responses of interest in relation to the laser hardening process. These values define heat treatment quality and have a direct impact on mechanical performance. This paper aims to develop models capable of predicting the shape of the hardness profile depending on laser process parameters for controlling laser hardening quality (LHQ), or rather the response values. An experimental study was conducted to highlight hardened profile sensitivity to process input parameters such as laser power (PL), beam scanning speed (VS) and initial hardness in the core (HC). LHQ modeling was conducted by modeling attributes extracted from the hardness profile curve using two effective techniques based on the punctual and geometrical approaches. The process parameters with the most influence on the responses were laser power, beam scanning speed and initial hardness in the core. The obtained results demonstrate that the geometrical approach is more accurate and credible than the punctual approach according to performance assessment criteria. Full article
(This article belongs to the Special Issue Laser Surface Treatment)
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Open AccessArticle Thermo-Mechanical Finite Element Modeling of the Laser Treatment of Titanium Cold-Sprayed Coatings
Coatings 2018, 8(6), 219; https://doi.org/10.3390/coatings8060219
Received: 11 May 2018 / Revised: 3 June 2018 / Accepted: 8 June 2018 / Published: 12 June 2018
Cited by 1 | PDF Full-text (3585 KB) | HTML Full-text | XML Full-text
Abstract
This paper implements a thermo-mechanical model to simulate the laser treatment effects on a cold-sprayed titanium coating and aluminum substrate. The thermo-mechanical finite element model considers the transient temperature field due to the laser source and applied boundary conditions, using them as input [...] Read more.
This paper implements a thermo-mechanical model to simulate the laser treatment effects on a cold-sprayed titanium coating and aluminum substrate. The thermo-mechanical finite element model considers the transient temperature field due to the laser source and applied boundary conditions, using them as input loads for the subsequent stress-strain analysis. Numerical outcomes highlighted the relevance of thermal gradients and the presence of thermally-induced stress-strain fields responsible for promoting damage in the coating. Full article
(This article belongs to the Special Issue Laser Surface Treatment)
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Open AccessShort Note An Analysis of Effect of CO2 Laser Treatment on Carbon Fibre Fabric
Coatings 2018, 8(5), 178; https://doi.org/10.3390/coatings8050178
Received: 14 March 2018 / Revised: 30 April 2018 / Accepted: 2 May 2018 / Published: 6 May 2018
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Abstract
The colour of carbon fibre fabric is black which limits its aesthetic properties. CO2 laser has been used for cutting carbon fibres. The impact of CO2 laser treatment to modify the surface of carbon fibre fabric is investigated in this work. [...] Read more.
The colour of carbon fibre fabric is black which limits its aesthetic properties. CO2 laser has been used for cutting carbon fibres. The impact of CO2 laser treatment to modify the surface of carbon fibre fabric is investigated in this work. Different combinations of laser process parameters, i.e., pixel time (110, 120, 130, 140, 150, 160, 170, 180, 190 and 200 µs, with 10 µs intervals) and resolution (70, 80, 90 and 100 dpi (dots per inch), with 10 dpi intervals), were used for treating carbon fibre fabric surface. Since the laser process is a surface treatment, contact angle measurement was used for evaluating the wetting property imparted after laser processing. The resistivity of the laser-treated carbon fibre fabric was measured to evaluate any effect on the original electrical property of the carbon fibre fabric. Moreover, surface morphology and functionality of laser-treated carbon fibre fabric were assessed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy-attenuated total internal reflectance (FTIR-ATR), respectively. SEM assessment was to examine the physical change in the carbon fibre surface after laser processing. On the other hand, the FTIR-ATR measurement can help to evaluate the chemical change in the carbon fibre surface after laser processing. Full article
(This article belongs to the Special Issue Laser Surface Treatment)
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Open AccessArticle Effects of Laser Microtexturing on the Wetting Behavior of Ti6Al4V Alloy
Coatings 2018, 8(4), 145; https://doi.org/10.3390/coatings8040145
Received: 20 March 2018 / Revised: 5 April 2018 / Accepted: 14 April 2018 / Published: 17 April 2018
Cited by 3 | PDF Full-text (61489 KB) | HTML Full-text | XML Full-text
Abstract
Surface modification procedures by laser techniques allow the generation of specific topographies and microstructures that enable the adaptation of the external layers of materials for specific applications. In laser texturing processes, it is possible to maintain control over the microgeometry and dimensions of [...] Read more.
Surface modification procedures by laser techniques allow the generation of specific topographies and microstructures that enable the adaptation of the external layers of materials for specific applications. In laser texturing processes, it is possible to maintain control over the microgeometry and dimensions of the surface pattern through varying the processing parameters. One of the main areas of interest in the field of surface modification treatments is the ability to generate topographies that are associated with specific surface finishes, in terms of roughness, that can improve the manufactured part’s functional capabilities. In this aspect, several types of phenomena have been detected, such as the friction and sliding wear behavior or wetting capacity, which maintain a high dependence on surface roughness. In this research, surface texturing treatments have been developed by laser techniques through using the scanning speed of the beam (Vs) as a control parameter in order to generate samples that have topographies with different natures. Through assessments of surface finish using specialized techniques, the dimensional and geometrical features of the texturized tracks have been characterized, analyzing their influence on the wetting behavior of the irradiated layer. In this way, more defined texturing grooves has been developed by increasing the Vs, which also improves the hydrophobic characteristics of the treated surface. However, due to the lack of uniformity in the solidification process of the irradiated area, some deviations from the expected trends and singular points can be observed. Using the contact angle method to evaluate the wetting behavior of the applied treatments found increases in the contact angle values for high texturing speeds, finding a maximum value of 65.59° for Vs = 200 mm/s. Full article
(This article belongs to the Special Issue Laser Surface Treatment)
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Open AccessArticle Effects of V and Cr on Laser Cladded Fe-Based Coatings
Coatings 2018, 8(3), 107; https://doi.org/10.3390/coatings8030107
Received: 7 February 2018 / Revised: 4 March 2018 / Accepted: 13 March 2018 / Published: 15 March 2018
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Abstract
Fe-based coatings with high V and Cr content were obtained by laser cladding using Fe-based powder with different Cr3C2 and FeV50 content. The results showed that Fe-based coatings were uniform and dense. The constituent phases were mainly composed of [...] Read more.
Fe-based coatings with high V and Cr content were obtained by laser cladding using Fe-based powder with different Cr3C2 and FeV50 content. The results showed that Fe-based coatings were uniform and dense. The constituent phases were mainly composed of α-Fe solid solution with the increase of Cr3C2 and FeV50, γ-Fe and V8C7 phases were achieved. The microstructure of the coatings exhibited a typical dendrite structure. The concentration of C, V and Cr were saturated in dendritic areas, and the other alloying elements were mainly dissolved in the interdendritic areas. The hardness and wear resistance of Fe-based coatings were enhanced with the Cr3C2 and FeV50 addition. The specimen with 15% Cr3C2 and 16% FeV50 had the highest hardness of 66.1 ± 0.6 HRC, which was 1.05 times higher than the sample with 4.5% Cr3C2 and 5% FeV50, and the wear resistance of the former was three times greater than the latter. Full article
(This article belongs to the Special Issue Laser Surface Treatment)
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Open AccessArticle Effect of Laser Remelting Power on Immersion Corrosion of Amorphous Al–Ti–Ni Coatings
Received: 19 November 2017 / Revised: 18 January 2018 / Accepted: 22 January 2018 / Published: 25 January 2018
Cited by 3 | PDF Full-text (19940 KB) | HTML Full-text | XML Full-text
Abstract
An arc-sprayed amorphous Al–Ti–Ni coating on S355 structural steel was processed by laser remelting (LR) at powers of 600, 800, and 1000 W. The surface-cross-sectional morphologies, chemical element distributions, and phase compositions of the as-obtained Al–Ti–Ni coatings were analyzed using a scanning electron [...] Read more.
An arc-sprayed amorphous Al–Ti–Ni coating on S355 structural steel was processed by laser remelting (LR) at powers of 600, 800, and 1000 W. The surface-cross-sectional morphologies, chemical element distributions, and phase compositions of the as-obtained Al–Ti–Ni coatings were analyzed using a scanning electron microscope (SEM), energy-dispersive spectrometer (EDS), and X-ray diffractometer (XRD), respectively. The immersion corrosion tests of Al–Ti–Ni coatings in 3.5% NaCl solution for 720 h were performed to investigate the effects of LR power on their immersion corrosion behaviors. The test results show that the amorphous Al–Ti–Ni coatings form good metallurgical bonding with the substrate after LR. The AlNi, Al3Ti, Al3Ni2, Ti3O5, and Al2O3 amorphous phases are detected in the Al–Ti–Ni coatings after LR. The corrosion potentials of Al–Ti–Ni coatings after LR show a positive shift relative to that of S355 steel, implying that the corrosion resistance of Al–Ti–Ni coatings was superior to that of S355 steel. A dense protective Al2O3 film is formed on the Al–Ti–Ni coating surface at an LR power of 1000 W, at which power the highest corrosion potential of −0.233 V is observed. The corrosion mechanisms of Al–Ti–Ni coating at the LR power of 1000 W are uniform corrosion and pitting corrosion, while those of Al–Ti–Ni coatings at the LR powers of 600 and 800 W are localized corrosion and pitting corrosion. The corrosion resistance of Al–Ti–Ni coating with the LR power of 1000 W is better than those at the LR powers of 600 and 800 W, effectively improving the corrosion resistance of S355 steel. Full article
(This article belongs to the Special Issue Laser Surface Treatment)
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Open AccessArticle A Study of CO2 Laser Treatment on Colour Properties of Cotton-Based Fabrics
Coatings 2017, 7(8), 131; https://doi.org/10.3390/coatings7080131
Received: 18 July 2017 / Revised: 16 August 2017 / Accepted: 18 August 2017 / Published: 20 August 2017
Cited by 2 | PDF Full-text (3638 KB) | HTML Full-text | XML Full-text
Abstract
In this study, laser was applied to two types of cotton-based woven fabrics in order to study the effect of CO2 laser technology on colour and fabric strength properties. The woven fabrics had different fibre compositions, i.e., one was 100% cotton while [...] Read more.
In this study, laser was applied to two types of cotton-based woven fabrics in order to study the effect of CO2 laser technology on colour and fabric strength properties. The woven fabrics had different fibre compositions, i.e., one was 100% cotton while the other had 60% cotton blended with 40% polyester. They were treated with different combinations of laser processing parameters, i.e., resolution (52, 60, and 68 dpi) and pixel time (110, 120, 130, and 140 μs). There were two approaches adopted: (1) laser treated and then dyed (LD); and (2) first dyed and then laser treated (DL), in order to study the effects of the two different sequences on the resultant colour. Colour properties include reflectance value, colour yield, CIE L*a*b* values and levelness measured by spectrophotometer; pH value and tensile strength were also measured. It was discovered that laser treatment had no influence on chromaticity of cotton fabrics. Moreover, fabrics treated with laser had a lighter shade than the control samples. This confirmed that both approaches, i.e., laser treatment conducted before and after dyeing, can provide a colour fading effect. The tensile strength of fabrics was affected differently in relation to the dyeing and laser process. According to results obtained from the pH measurement, it is confirmed that laser treatment can provide a colour fading effect without affecting the pH value, and the fabrics can be used instantly right after the laser treatment. Full article
(This article belongs to the Special Issue Laser Surface Treatment)
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Open AccessArticle Optimization of the Laser Hardening Process by Adapting the Intensity Distribution to Generate a Top-hat Temperature Distribution Using Freeform Optics
Received: 29 March 2017 / Revised: 22 May 2017 / Accepted: 2 June 2017 / Published: 7 June 2017
Cited by 6 | PDF Full-text (6340 KB) | HTML Full-text | XML Full-text
Abstract
Laser hardening is a surface hardening process which enables high quality results due to the controllability of the energy input. The hardened area is determined by the heat distribution caused by the intensity profile of the laser beam. However, commonly used top-hat laser [...] Read more.
Laser hardening is a surface hardening process which enables high quality results due to the controllability of the energy input. The hardened area is determined by the heat distribution caused by the intensity profile of the laser beam. However, commonly used top-hat laser beams do not provide an ideal temperature profile. Therefore, in this paper the beam profile, and thus the temperature profile, is optimized using freeform optics. The intensity distribution is modified to generate a top-hat temperature profile on the surface. The results of laser hardening with the optimized distribution are thereupon compared with results using a top-hat intensity distribution. Full article
(This article belongs to the Special Issue Laser Surface Treatment)
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