Improvement of thermal plasma sprayed coating adhesion strength by laser microtexturing of aluminum

doi:10.21203/rs.3.rs-1962547/v1

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Improvement of thermal plasma sprayed coating adhesion strength by laser microtexturing of aluminum

https://doi.org/10.21203/rs.3.rs-1962547/v1

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published 24 Jan, 2023

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Surface microtexturing improves coating adhesion strength due to increased surface area and mechanical interlocking. Grit blasting and laser processing are two common methods used for surface microtexturing. Laser microtexturing offers distinct advantages over grit-blasting as it improves interface quality, provides a grit-particle-free surface, optimized processing time, and greater control over the surface roughness. This paper reports a full area method of laser microtexturing of Al 7075 alloy using a nanosecond pulsed laser to generate a large increase in surface area. This method involves a laser-induced thermo-mechanical process where tightly packed pillar-like surface features were formed due to the surface melting and re-solidification of materials combined with some ablation. The morphology of the microtexture was controlled by varying the laser processing parameters. Thereafter, the laser microtextured surface was coated with metallic coatings using thermal spray. Our method is superior to the currently used laser ablation-based microtexturing method. The surface morphology, composition, and adhesion strength results are presented. The tensile adhesive strength of the thermally sprayed metallic CoNiCrAlY coating was measured, and an improvement of over 17% in the coating adhesion strength was observed for a 5 µm deep microtexture compared to that of grit-blasted samples. This is the highest reported adhesion strength for thermally sprayed bond coating.

Laser microtexturing

Thermal spray

Adhesion strength

Coatings

Laser processing

Surface microtexturing has been known to change the physio-chemical properties of the surface to improve the surface properties of materials. Some of the widely used surface microtexturing techniques are chemical etching, electrical discharge, and sandblasting [1]. Among the different surface microtexturing techniques, grit-blasting or sandblasting is a widely used method, but one of the main disadvantages of using this technique is that it does not allow selective roughening and does not create any fixed and repeated pattern. Grit-blasting also leads to grit entrapment [2]. One of the alternative techniques for surface microtexturing is using a laser. Laser microtexturing can provide several advantages like easy automation, localized treatment, and three-dimensional profiles [3]. Surface microtexturing by laser ablation is a low-cost and scalable method, devoid of the use of hazardous chemicals [4].

The thermal spray coating/substrate adhesion has been shown to improve by laser surface microtexturing. Preparation of the substrates to be coated by the thermal spray process involves two steps: cleaning and roughening [5]. Chemicals can be used to clean (degrease) the surface [5], while the roughening process can be performed by laser. In thermal spraying, adhesion bond strength is strongly dependent on the substrate type, process temperature, and topography [6]. An increased coating contact area is favorable for increased adhesion bond strength. Laser surface microtexturing has also been shown to increase thermal spray deposition efficiency. The laser wavelength, spot size, scanning rate, pulse duration, and pulse frequency can be optimized for enhanced adhesion [3]. The process of thermal spraying uses molten particles (powder or wire feedstock) sprayed onto a surface. Specific types of coatings that are resistant to heat, wear, and erosion can be deposited using the thermal spray process [7].

However, low adhesion strength poses a serious problem to thermally sprayed coatings [7]. It is of particular interest to note that thermal spraying can be used to deposit bond coats of thermal barrier coatings (TBCs), and the quality of the TBC is strongly dependent on the adhesion between the coating and the substrate [8]. TBCs are generally used to isolate metallic turbine blades from the hot gas coming from the engine [9]. Lima et al. [8] studied the adhesion properties of thermal barrier coatings on steel substrates and reported that the general coating failure location is at the interface between the bond coat and the substrate. Laser surface microtexturing can improve the bond strength of thermal spray coatings on metals. The surface microtexture generated by the laser is responsible for creating a mechanically interlocked bond in the case of thermal spray coatings. Thermally sprayed metallic powder particles fill the pores on the surface created by laser microtexturing, and this results in a strong bond between the surface and the coating [10]. The laser surface microtexturing should be optimized in such a way that it traps more of the deposited particles due to higher surface roughness and coating builds-up [11]. For nanosecond (ns) pulsed lasers, the roughness forming mechanism is a thermo-mechanically dominated process [12]. The formation of ns laser-induced microtexture can be explained by localized surface melting and the formation of superheated droplets around the solid surface. The expelled molten materials cool down, settle back onto the surface of the metal, and resolidifies, giving rise to "pillar" like surface features [13]. The laser pulse energy density and frequency influence the shape and height of the surface features considerably. Increasing laser fluence and frequency results in the expulsion of more molten materials, which could lead to wider grooves and increased height of the resolidified surface microtexture. The laser parameters can be used to control the microtexture on the surface that influences the bonding strength of the thermal spray coatings.

The thermally sprayed coating that is adhered to the surface by a mechanical interlocking mechanism can be classified into five types – embedding, anchoring, holding-on, spreading, and a mixture of several styles [14]. Depending on the material, both mechanical and physicochemical bonds can exist, and the bonding mechanism is influenced by particle-substrate contact time, contact temperature, and contact area upon impact [15]. It should also be noted that the adhesion strength is not only dependent on the contact area ratio and the density of the features but also varies with the microtexture shape and pattern [14, 16]. The adhesion strength can be further improved by optimizing the laser parameters to create features that are even denser and taller. But this increases the time and cost associated with the laser patterning process. The thermal spray process parameters can also be optimized to enhance the adhesion strength. Adhesion strength can be significantly increased by increasing the particle velocity keeping the particle temperature constant, or by increasing the particle temperature, keeping the particle velocity at a fairly high constant value [17]. Other thermal spray process parameters like gas flow rate, spray distance, etc., may also be optimized to get a potentially superior adhesion strength.

The thermal spray coating process is widely used to coat metals. Amongst the most commonly used metals, aluminum has high-surface energy and provides strong resistance to corrosion in aggressive environments. Aluminum alloys have had a long history of usage in the construction, automotive, aviation, and astronautics industries [18, 19]. It greatly benefits from the favorable properties offered by adhesive bonding due to its excellent formidability and high strength-to-weight ratio. Apart from having environmental advantages, surface morphology by laser modification aids mechanical interlocking and might even lead to interfacial chemical bonding between the adhesive and the adherend [18]. A recent report by Maressa et al. has illustrated that laser texturing of titanium-aluminum (Ti₆Al₄V) alloy surface resulted in an eightfold increase in shear strength compared to plain surfaces and a 30% increase compared to sandblasted surfaces [20]. A study on the improvement of adhesive bonding in aluminum alloys using laser surface texturing was also done by Wong et al. [21] and Sharma et al. [22]; they demonstrated the bond strength of commercially pure aluminum coatings (CP-Al) on grit-blasted AA 2024-T351 substrates. The substrates were grit-blasted using three different grit-blasting techniques, and the coating was deposited using the cold spray process. Nitrogen and helium were used as carrier gases during the grit-blasting process. Grit-blasted samples had significantly higher adhesion strength compared to untextured samples. Kromer et al. [23] measured the tensile adhesion strength of NiAl powder coating on the Al 2017 substrates, which are widely used in aircraft structural applications. NiAl powder with a mean particle size of 67 µm was thermally sprayed onto the laser textured aluminum alloy substrates. The adhesion test results showed that a decreasing density of holes on the metal surface causes a reduction in the adhesion strength of the thermally sprayed coating. Kromer et al. [7] also measured the adhesion strength of cold sprayed coatings on grit-blasted and laser textured aluminum alloy. Several light metal alloy powders with a mean particle size of 40 µm were used for the cold-spray process. A separate study was done by Kromer et al. [6], where laser textured and grit-blasted aluminum 2017 alloy samples were coated with NiAl powder (Amdry 956) using atmospheric plasma spray. The samples were textured using a pulsed fiber laser. The laser holes were made in the X and Y directions with varying spacing between them and oriented at different angles. It was shown that the effect of changing angle had a negligible effect on the adhesion strength of the powders. Kromer et al.⁶ studied the strength of bond coats on laser textured superalloy substrate. The maximum reported adhesive bond strength was 33 MPa. In another study by CRC Lima et al. [8], it was reported that the maximum adhesion strength of Amdry 9951 coat on grit-blasted steel substrates was 52.8 MPa. Karaoglanli et al. [24] demonstrated that adhesive failure occurs at the interface of thermally sprayed CoNiCrAlY bond coat on stainless steel substrates. The adhesion strength was increased by treating the samples with heat. However, irrespective of that, adhesive failure typically occurs at around 50 MPa. A recent study done by Zhang et al. [25] used a nanosecond pulsed laser to induce microtexture on the surface of aluminum alloy. This microtexture improved the bond strength of the Al-Cu aluminum alloy coating that was cold-sprayed on the surface of the laser microtextured aluminum alloy. The maximum reported bond strength was around 48 MPa. None of the aforementioned studies [6, 7, 23] demonstrated the effect of fully microtextured metal surfaces using a laser microtexturing process based on the thermomechanical process.

In this paper, a different method of laser microtexturing is reported, and a superior coating adhesion strength of bond coats is demonstrated. Compared to traditional texturing methods like grit-blasting and some other laser microtexturing methods based primarily on the ablation process, the method reported in the paper showed much-improved bonding strength. The laser microtextured features are created by melting and the subsequent cooling down of the surface in conjunction with a small degree of ablation. Hence, a series of closely packed peaks and valleys are formed on the surface, which gives the thermally sprayed coating powder more grip and enhanced surface area. The improvement in the coating adhesion strength leads to increased longevity, robustness, and lower maintenance costs of metal parts and has potential applications in the automobile, power generation, and aerospace industries.

Material

The substrates used were aluminum alloy (Al 7075) micromachined samples (diameter = 1 inch; thickness – 0.5 inches) polished down to roughness of less than 1 µm. The chemical composition by weight of Al 7075 was Zn = 5.4%, Cu = 1.42%, Mn = 0.12%, Mg = 2.42 %, Fe = 0.42%, Cr = 0.21%, Ti = 0.11%, Si = 0.13%, and Al = 89.77%.. Al 7075 has a high strength to low weight ratio, excellent wear resistance, and provides high-temperature corrosion protection. It is widely used in the aircraft and automotive industries [26]. The full area of the aluminum samples was laser microtextured. The coating powders used for the thermal spray process were Oerlikon Metco Amdry 995C (CoNiCrAlY) and Oerlikon Metco Amdry 9951 (Co[Ni]CrAlY)). CoNiCrAlY is usually used for bond coats [8,9,24]. The mean particle sizes of the powders were 90 μm and 38 μm, respectively. The different particle sizes were chosen to demonstrate the effect of particle size on surface morphology.

Laser microtexturing

A ytterbium fiber laser (YLP-G-10, IPG Photonics) of 532 nm wavelength, 10 W average power pulse width of 1.3 ns, pulse energy of 20.2 μJ, the repetition frequency of 600 kHz, and Gaussian beam profile was used in this study. The galvanometer scan head used was a SCANcube 14, SCANLAB, with a scan pattern designed in EZCad (Beijing JCZ Technology Co. Ltd). The laser repetition rate varied from 400 kHz to 600 kHz, and a focused laser beam with a full width at a half-maximum (FWHM) size of 20 μm was used. The laser fluence used for the experiments were 0.76 J/cm², 0.92 J/cm², and 0.8 J/cm². The laser beam scan speed was maintained at 60 mm/s. For each laser fluence, the side-to-side overlap between the lines was 50%. The overlap between the laser spots along the direction of scanning was 99.25% and 99.5% at 400 kHz and 600 kHz, respectively. A galvanometer (SCANLAB SCANcube 14) controlled by a custom LabVIEW program was used to perform the raster scan of the aluminum surface. This enabled us to achieve consistent microtexture patterns on the sample. A nitrogen gas atmosphere was used during laser microtexturing to prevent oxidation. A schematic diagram of the experimental setup is shown in figure 1. The different laser parameters used in the microtexturing process are shown in Table 1.

Grit-blasting

The thermal spray coating samples were prepared on grit-blasted samples. For this process, the samples were secured to a plate using double-sided tape to ensure they remained stationary during abrasive blasting. The nozzle was manually rastered over the samples using the nominal parameters shown in Table 2. Thereafter, compressed air was used on the samples to remove any residual dust. Then, the sample surface was cleaned with ethanol.

Thermal spray process

The grit-blasted and the laser microtextured samples were coated with metal powders by atmospheric plasma spray (APS) using an Oerlikon Metco F4MB-XL plasma gun attached to a 6-axis robotic arm. The first step of this process involved cleaning the grit-blasted and laser microtextured samples with compressed air. This was followed by attaching the samples to vertical fixtures. Thereafter, the thermal spray gun was turned on and passed over the substrate in a rectangular raster pattern. Prior to applying the powder, a pre-heat was executed in order to elevate the substrate temperature to 100°C, and the powder feed was allowed to stabilize for 1-2 minutes prior to deposition. Table 3 provides the different APS parameters used in this study.

Coating adhesion testing and failure analysis

The coated samples were subjected to tensile adhesion testing, where the tensile pressure required to debond the coatings was measured. This was done following the ASTM C633 standard using an Instron C633 mechanical analyzer. As shown in figure 2, the cylindrical sample was glued between two cylindrical rods. The load was applied in the direction perpendicular to the interface between the coating and the substrate. The tensile load was gradually increased until the coating was ruptured or detached from the substrate. The glue used in the process was Polyamide-epoxy FM 1000 Adhesive Film. The adhesion strength was calculated as the load at sample failure divided by the coating area [27].

Surface morphology and chemical composition characterization

The surface morphology and elemental analysis were done using FEI Quanta 650 Field Emission SEM. 3D optical profile measurements were done using Olympus LEXT OLS4000 3D Laser Microscope to understand the variation in the microtexture heights, the peak-to-valley spacing, and the density and uniformity of the features. After deposition of the coating, the cross-sectional morphology characterization and EDS analysis were also performed using the FEI Quanta 650 Field Emission SEM.

The laser microtexturing process reported in scientific literature is performed by laser ablation of materials, and it is done by drawing orthogonal lines. Previously reported laser ablation methods [6,7,20,22,23] do not provide a full area microtexture as spacing is kept between the lines, and hence, it leads to lower coating adhesion strength. Also, the hole drilling method is selective and does not provide full area microtexture. The method presented in this paper is based on selecting the laser power in such a way that it offers melting combined with some ablation, and the laser beam is scanned over the entire surface area. The thermomechanical rearrangement of the molten material accompanied by small ablation gives dense, and uniform features across the entire surface. This approach provides a large increase in the surface area, leading to enhanced bonding strength of thermal spray coatings.

Surface morphology

As a reference, figure 3 shows the surface of a plane untextured aluminum sample. The surface of a grit-blasted sample is shown in figure 4. Figure 5 shows the variation of the surface morphology with changing laser fluences. It can be seen that at higher fluences, the ablation is much more significant than at lower ones. The fluence at which the laser starts to mark features on the surface is between 0.38 J/cm² to 0.45 J/cm². Figure 6 shows the variation of the surface morphology with changing laser repetition rate (frequency). At a lower frequency, the number of laser pulses per unit area is significantly less than that at a higher frequency. Hence, the laser rearranges the molten material differently at higher frequencies compared to lower ones. As can be seen, the surface seems much more ablated and roughened at higher frequencies.

Figure 7 shows the different laser surface microtextured patterns. It can be seen that pillar-like structures have been formed on the surface with periodic grooves. The thermally sprayed molten powders enter into the grooves and thus provide interlocking. The surface shown in figure 7(c) was obtained with the highest number of pulses per unit area compared to the other two surfaces. The three laser microtextured patterns were chosen in such a way that it provides a range of variations in feature height and spacing between the peaks. Looking at the morphology, some droplet formation appears to occur, which indicates melting and resolidification, along with ablation. Figure 8 quantifies the micropillar height variations. The average height for the laser microtextured features was around 5 μm which is less than the average surface feature height of 6.5 μm for grit-blasted surfaces. There are considerable height variations on the laser microtextured and grit-blasted samples, with maximum heights reaching up to 27 μm, 28.2 μm, 41.6 μm, and 61.48 μm for line #1, line #2, line #3, and line #4 respectively. Figure 9 shows the surface morphology variation of a grit-blasted aluminum sample. It can be observed that there is no periodicity in the features formed on the surface. Figures 10, 11, and 12 provide a detailed surface profile for the three laser microtexture patterns shown in figure 7. The 2D map shows the differences in height and density of the features across the surface, while the 3D map gives a more thorough visualization of the distribution of the features. It can also be observed that line #2 has higher peaks than that of line #1, and line #3 has higher peaks than both line #1 and line #2. This can be attributed to the fact that line #3 had the highest number of laser pulses per unit area, and line #2 had more fluence than of line #1. The average distance between the peaks in all the laser microtextured patterns was 5 μm. The cross-sectional interface morphology and the elemental composition are shown in figures 13 and 14. Figure 15 shows the cross-sectional interface morphology of the grit-blasted sample and for thermal sprayed Amdry 995C particles. It can be seen that the coating on the grit-blasted sample has much less infiltration than that on the laser microtextured surfaces. The average thickness of the coating was found to be around 275 μm. The EDS spectra in figures 13 and 14 show the oxygen concentration at the sample -Amdry 995C interface and sample-9951 interface.

Failure Analysis

Figure 16 shows the thermally sprayed surface coating on the grit-blasted aluminum sample after the tensile adhesion test has been performed. Delamination can be observed across the surface of the coating in the case of the grit-blasted sample. The grit-blasted sample displayed cohesive failure at the epoxy-coating interface as well as adhesive failure, while the laser microtextured sample displayed only cohesive failure at the epoxy-coating interface at the sample pull-off pressure.

Adhesion strength measurement results

We obtained significantly higher tensile adhesive strength for laser microtextured surfaces compared to those reported in previous laser microtexturing research studies. Our results are shown in figure 17. Four samples were tested for each of the laser microtexturing and grit-blasting to obtain the adhesion data and associated error bars. Of the three laser patterns used, line #3 gave taller surface features as the laser frequency used was relatively more than that of the other two patterns. Increasing laser frequency results in a greater number of pulses per unit area. The laser microtextured patterns in our study were also significantly denser than that reported in previous literature, as the laser was used to scan the surface area of the samples in its entirety. Thus, it can be proven that densely packed features are beneficial in increasing the bonding strength. Line #1 and line #2 had almost identical average feature height even though line #2 was scanned with a little bit more laser fluence.

The features on the surface that are formed by melting, ablation, and resolidification of the materials are affected by the different laser parameters like fluence, pulse-width, speed, and frequency. The increase in laser frequency leads to an increased number of pulses per unit of surface area. This gives rise to deeper surface features, increased surface area, and hence, increased adhesion of the coating. The depth and density of the features can be controlled by changing the fluence and frequency of the laser. Moreover, higher laser power results in the ablation of more surface materials which leads to the formation of more particles. These particles can settle down and resolidify on top of the surface "pillars," providing nanoscale roughness which can further increase the adhesion of the coating. Feature height needs to be chosen so that the microtexture is stable under APS processing conditions.

It should be noted that for all the laser microtextured and even the grit-blasted surfaces, the adhesion strength of Amdry 9951 powder is more than that of Amdry 995C powder. This is because the mean particle size of Amdry 9951 powder is much smaller compared to Amdry 995C powder. This allows for increased infiltration of the molten particles into the laser-generated microtexture, thereby providing more tensile adhesive strength, as shown in Fig. 18. Optimizing coating-substrate adhesion requires adaptation of the powder size to the surface topography in order to achieve a superior surface filling ratio [10]. The average laser-formed feature height in this work was around 5 µm compared to feature depths of 80–180 µm reported in previous laser studies [6, 7]. Hence, the throughput of the full area laser microtexturing method is higher, and the associated cost will be much lower.

Compared to grit-blasting, which only provides macroscale roughness, the fully microtextured laser method provides superior control and micro-scale roughness. The maximum adhesion strength reported in the scientific literature for thermally sprayed Amdry 9951 (CoNiCrAlY) bond coat to laser microtextured surface is around 53 MPa [24]. This value is comparable to that of the measured grit-blasted samples, which is around 55 MPa. In this paper, we have demonstrated the adhesion strength of bond coat to laser microtextured samples of 65 MPa, which is an increase of around 18%.

Some of the other potential applications of thermal spray coatings include oxidation and hot corrosion resistance of airfoils, turbine buckets, ceramic clearance control coatings, exhaust manifolds, flue gas, and fly ash systems. So, the method of surface mictrotexturing presented in this paper could have a wide range of varied applications in improving the adhesion strength of thermally sprayed coatings on other metals and alloys.

This paper demonstrates a novel method for laser microtexturing through a thermomechanical process [28] of creating dense, uniform pillar-like features for the improvement of coating adhesion strength. The entirety of the area of the surface was laser microtextured by forming densely populated micropillars, and this led to an increase of around 65% in the total surface area. The micro "pillar" like shape of the microtexture significantly increases the contact area ratio, and this led to a substantial increase in adhesion strength of thermally sprayed metallic coatings. The control of laser power and frequency allowed the variation of micropillar height to over 40 µm. The micropillars contributed to a substantial increase in the atmospheric plasma sprayed coating adhesion strength compared to untextured, grit-blasted, and other laser microtextured surfaces, as reported in the literature. The increase in bond strength was explained due to thermal spray particles filling the gap between the pillars. The results of the laser microtexturing process parameter's effect on surface morphology are reported. The cross-section of thermal spray coating of laser microtextured surfaces was studied to provide an understanding of adhesion strength improvements.

Acknowledgment – The authors would like to thank the Commonwealth Center for Advanced Manufacturing (CCAM) Innovation award for the financial support for the project and for using FEI Quanta 650 SEM (UVA NMCF). We also thank the NSF IUCRC award and the Langley Professor award for their financial support.

Funding: This work was supported by the 2020 CCAM Innovation award, NSF IUCRC, and the Langley Professor award.

Competing Interests: The authors have no relevant financial or non-financial interests to disclose.

Ethics approval: Not applicable.

Consent for publication: The authors confirm that this work is not published before and do not consider other places. The authors agree to publish the article in Springer’s corresponding English-language journal.

Data availability: The authors declare that the data and material used or analyzed in the present study can be obtained from the corresponding author at reasonable request.

Lamraoui A, Costil S, Langlade, C Coddet, C (2010) Laser surface texturing (LST) treatment before thermal spraying: A new process to improve the substrate-coating adherence. Surf Coat Tech 205:164-167. https://doi.org/10.1016/j.surfcoat.2010.07.044
Bagade VU, Duraiselvam M, Sarangi N (2022) Effect of laser surface texturing on coating adherence and tribological properties of CuNiIn and MoS₂ coating. Trans Indian Inst Met 75:239–250. https://doi.org/10.1007/s12666-021-02417-0
Kromer R, Danlos Y, Aubignat E, Verdy C, Costil S (2017) Coating deposition and adhesion enhancements by laser surface texturing – metallic particles on different classes of substrates in cold spraying process. Mater. Manuf. Process., 32:1642-1652. https://doi.org/10.1080/10426914.2017.1364750
Mulroney AT, Gupta MC (2017) Optically transparent superhydrophobic polydimethylsiloxane by periodic surface microtexture. Surf Coat Tech 325:308-317 (2017). https://doi.org/10.1016/j.surfcoat.2017.06.066
Garcia-Alonso D, Serres N, Demian C, Costil S, Langlade C, Coddet C (2011) Pre-/during-/post-laser processes to enhance the adhesion and mechanical properties of thermal-sprayed coatings with a reduced environmental impact. J Therm Spray Tech 20:719 – 735. https://doi.org/10.1007/s11666-011-9629-x
Kromer R, Costil S, Cormier J, Courapied D, Berthe L, Peyre P, Boustie M (2015) Laser surface patterning to enhance adhesion of plasma sprayed coatings. Surf Coat Tech 278:171-182. https://doi.org/10.1016/j.surfcoat.2015.07.022
Kromer R, Costil S, Verdy C, Gojon S, Liao H (2018 Laser surface texturing to enhance adhesion bond strength of spray coatings – Cold spraying, wire-arc spraying, and atmospheric plasma spraying. Surf Coat Tech 352:642-653. https://doi.org/10.1016/j.surfcoat.2017.05.007
Lima CRC, Guilemany JM (2007) Adhesion improvements of thermal barrier coatings with HVOF thermally sprayed bond coats. Surf Coat Tech 201:4694-470. https://doi.org/10.1016/j.surfcoat.2006.10.005
Crespo V, Cano IG, Dosta S, Guilemany JM (2015) The influence of feedstock powders on the CGS deposition efficiency of bond coats for TBCs. J Alloys Compd 622:394-401. https://doi.org/10.1016/j.jallcom.2014.09.216
Kromer R, Cormier J, Costil S (2016) Role of powder granulometry and substrate topography in adhesion strength of thermal spray coatings. J Therm Spray Tech 25:933-945. https://doi.org/10.1007/s11666-016-0411-y
Kromer R, Sokolowski P, Candidato RT (2019) Control of the mesostructured of suspension plasma-sprayed coating with laser surface texturing: Application to TBC. J Therm Spray Tech 28:405-416. https://doi.org/10.1007/s11666-019-00835-7
Gupta MC, L Wang, Rothenbach C, Sun K (2013) Diode pumped solid state lasers for surface microtexture. J. Laser Micro/Nanoengineering 8:124-130. http://dx.doi.org/10.2961/jlmn.2013.02.0002
Long J, Cuo Z, Lin C, Zhou C, He Z, Xie X (2019) Formation mechanism of hierarchical micro- and nanostructures on copper induced by low-cost nanosecond lasers, Appl Surf Sci 464:412-421. http://doi.org/10.1016/j.apsusc.2018.09.055
Tan N, Xing Z, Wang X, Wang H, Jin G, Xu B (2017) Effects of texturing patterns on the adhesion strength of atmosphere plasma sprayed coatings. J Mater Research 32:1682-1692. https://doi.org/10.1557/jmr.2017.164
Kromer R, Danlos Y, Costil S (2018) Cold gas-sprayed deposition of metallic coatings onto ceramic substrates using laser surface texturing pre-treatment. J Therm Spray Tech 27:809–817. https://doi.org/10.1007/s11666-018-0718-y
Zhan X, Liu Y, Yi P (2021) Effect of substrate surface texture shapes on the adhesion of plasma-sprayed Ni-based coatings. J Therm Spray Tech 30:270-284. https://doi.org/10.1007/s11666-020-01126-2
Lyphout C, Nylén P, Östergren LG (2011) Relationships between process parameters, microstructure, and adhesion strength of HVOF sprayed IN718 coatings. J Therm Tech 20:76-82. http://dx.doi.org/10.1007/s11666-010-9543-7
Spadaro C, Sunseri C, Dispenza C (2007) Laser surface treatments for adhesion improvement of aluminum alloys structural joints. Radiat Phys Chem 76:1441-1446. http://dx.doi.org/10.1016/j.radphyschem.2007.02.047
Kadleckova M, Minarik A, Smolka P, Mracek A, Wrzecionko E, Novak L, Musilova L, Gajdosik R (2018) Preparation of textured surface on aluminium-alloy substrates. Materials (Basel) 12:109-120. https://dx.doi.org/10.3390%2Fma12010109
Maressa P, Anodio L, Bernasconi A, Demir AG, Previtali B (2015) Effect of surface texture on the adhesion performance of laser treated Ti6Al4V alloy. J Adhes 91:518-537. https://doi.org/10.1080/00218464.2014.933809
Wong RCP, Houk AP, Kim JK, Yu TX (1997) Improvement of adhesive bonding in aluminum alloys using a laser surface texturing process. J Mater Process Tech 63:579-584. https://doi.org/10.1016/S0924-0136(96)02687-8
Sharma MM, Eden TJ, Golesich BT (2015) Effect of surface preparation on the microstructure, adhesion, and tensile properties of cold-sprayed aluminum coatings on AA2024 substrates. J Therm Spray Tech 24 410–422. http://dx.doi.org/10.1007/s11666-014-0175-1
Kromer R, Costil S, Cormier J, Berthe L, Peyre P, Courapied D (2016) Laser patterning pretreatment before thermal spraying: A technique to adapt and control the surface topography to thermomechanical loading and materials. J Therm Spray Tech 25:401-410. https://doi.org/10.1007/s11666-015-0352-x
Karaoglanli AC, Dikici H, Kucuk Y (2013) Effects of heat treatment on adhesion strength of thermal barrier coating systems. Eng Fail Anal 32:16-22. https://doi.org/10.1016/j.engfailanal.2013.02.029
Zhang C, Zhang D, Luo C, Peng W, Zang X (2021) Nanosecond pulse laser assisted cold spraying of Al–Cu aluminum alloy. Coatings 11:267-272. https://doi.org/10.3390/coatings11030267
Devaneyan, SP, R. Ganesh, R, Senthilvelan, T, "On the Mechanical Properties of Hybrid Aluminum 7075 Matrix Composite Material Reinforced with SiC and TiC Produced by Powder Metallurgy Method", Indian J. Mater. Sci., 2017 128-135 (2017)
ASM Thermal Spray Society (TSS), Accepted Practice to Test Bond Strength of Thermal Spray Coatings. https://www.asminternational.org/documents/17679604/17683439/AcceptedPracticeBondStrengthApprovedformatted_Intro.pdf/4bcf5903-414d-413f-ab69-7cf0cc9123bd. Accessed 24 Aug 2021
Nayak BK, Gupta MC (2010) Self-organized micro/nano structures in metal surfaces by ultrafast laser irradiation. Optics and Lasers in Engineering 48:940-949. https://doi.org/10.1016/j.optlaseng.2010.04.010

Table 1: Laser processing parameters (laser wavelength = 532 nm, scan sped = 60 mm/s, No. of scans =1); Line #1, Line #2, and Line #3 indicate the use of different process parameters

Pattern Index	Frequency (kHz)	Fluence (J/cm²)
Line #1	400	0.76
Line #2	400	0.92
Line #3	600	0.80

Table 2: Grit-blasting parameters

Blast Media	Alumina (~50 μm particle size)
Pressure	0.28 Mpa
Nozzle distance	~140 mm
Angle	70 °
Traverse speed	1000 mm/sec
Step distance	10 mm
Passes	2 orthogonal passes

Table 3: Deposition parameters for a thermal spray for Amdry 9951 and 995C powders

APS Parameters	Amdry 9951	Amdry 995C
Carrier gas flow	Argon	Argon
Carrier gas flow rate (nlpm)	4.5	3.5
Powder feeding rate (g/min)	60.5	60.1
Spray distance (mm)	120	120
Number of passes	10	10
Surface speed (mm/s)	1250	1250
Plasma temperature (°C)	2922	2612
Particle velocity (m/s)	210	166
Gun current (A)	600	600
Primary gas type	Argon	Argon
Primary gas flow rate (nlpm)	56.8	56.9
Secondary gas type	Hydrogen	Hydrogen
Secondary gas flow rate (nlpm)	8.5	57
Injector standoff distance (mm)	6	6
Water flow rate (lpm)	15.6	15.7

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Journal Publication

published 24 Jan, 2023

Read the published version in The International Journal of Advanced Manufacturing Technology →

Editorial decision: Major Revisions Needed
24 Nov, 2022
Reviewers agreed at journal
23 Aug, 2022
Reviewers invited by journal
22 Aug, 2022
Editor assigned by journal
22 Aug, 2022
First submitted to journal
17 Aug, 2022

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Improvement of thermal plasma sprayed coating adhesion strength by laser microtexturing of aluminum

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