Surface Of 316L Stainless Steel Research Articles

Chemical magnetic field-assisted batch polishing method of 316L stainless steel

316L stainless steel has been extensively employed in the manufacturing of medical equipment and biomedical implants because of its good ductility, corrosion resistance and biocompatibility, etc. However, there has always been a non-neglected problem of low polishing precision and efficiency in the whole machining chain for such parts, hence, it is difficult to meet the batch demand of the market for 316L stainless steel with high-precision surface. Based on the principle of magnetic field-assisted batch polishing (MABP) proposed by our research team previously, a novel chemical magnetic field-assisted batch polishing (CMABP) method here is developed by adding chemical reagents (i.e., the mixture of oxalic acid and hydrogen peroxide) in the preparation process of regular magnetic brush, desiring and expecting to further realize the polishing of 316L stainless steel with higher precision and efficiency simultaneously. The preliminary experimental results demonstrated that the value of surface roughness Sa after CMABP became smaller and the material removal rate increased comparing to that after MABP, which did verify the potential advantage of the established CMABP approach. In detail, CMABP experiments with pH value and H2O2 concentration as variables were carried out quantitatively. The results suggested that, within the set range of pH value (from 2 to 7) and H2O2 concentration (from 0.3 wt.% to 2.0 wt.%), when pH was chosen as 4 and H2O2 concentration was adjusted as 2.0 wt.%, the value of Sa after CMABP was the minimum, which could be 38% lower than that of MABP approximately. Nonetheless, material removal rate reached to the maximum, which could be around 168% more than that after MABP, when pH and H2O2 concentration were determined as 3.0 and 2.0 wt.%, respectively. Additionally, the discrepancy between the chemical and the regular magnetic brushes were detected and analyzed comparatively both at macro and micro scales. Also, the products on the surface of 316L stainless steel, such as the weak-binding layer and the passive layer, were discovered and taken to interpret the experimental phenomena of the surface roughness and material removal rate varying with the content of chemical reagents in CMABP, thereby revealing the material removal mechanisms correspondingly and interestingly. This work is capable of providing valuable reference undoubtedly for batch precision polishing of 316L stainless steel and other significant functional materials.

Effects of Al variations on the microstructure and mechanical properties of laser-cladding AlxNbMo0.5Ti1.5Ta0.5Cr0.5 refractory high-entropy alloy coatings

Lightweight refractory high-entropy alloy coatings (RHEAcs) of AlXNbMo0.5Ti1.5Ta0.5Cr0.5 (where x = 0, 0.1, 0.2, and 0.3) were fabricated on 316L stainless steel surface by pre-placed powder laser cladding (LC) technology. The incorporation of Al element significantly enhanced the forming quality of coatings, resulting in nearly defect-free coatings with a thickness of 1.2-1.4mm. Microstructural analysis revealed that the coatings were primarily composed of body-centered cubic (BCC) solid solution and C15-Laves phase. Due to the influence of a single brittle BCC phase, the Al-free coating exhibited high strength and brittleness, leading to numerous defects caused by thermal stress. The introduction of Al element refined the microstructure and facilitated the formation of Laves phases at grain boundaries, thereby alleviating stress to a certain extent. Consequently, the microhardness of the RHEAcs was significantly higher than that of the substrate, with the Al-free coating achieving the highest microhardness of 1250 HV, which was 5.89 times that of the substrate. Wear resistance results indicated that, prior to annealing, RHEAcs with varying Al content outperformed 316L stainless steel. Post-annealing, the coatings exhibited significantly lower friction coefficients compared with the annealed 316L substrate. The Al-free coating showed significant accumulation of abrasive particles, leading to severe abrasive and oxidative wear. Conversely, post-annealing oxidation induced the formation of dense and directional oxide accumulation, resulting in a notable improvement in wear resistance. Finally, the underlying strengthening mechanisms have been proposed and analyzed.

Comparative Corrosion Inhibition Test Study in Phosphate Buffer Saline for 316L Stainless Steel with Electrospun PCL Coating with Different Additives

In this study, ten different contents of PCL-based nanofibers containing ZnO, CuO, NiO, 2F TSC, 4F TSC and graphite additives (PCL+Graphite+CuO+NiO+ZnO, PCL+ZnO+Graphite, PCL+ZnO+NiO+CuO, PCL+ZnO, PCL+Graphite, PCL+ZnO+2F TSC, PCL+ZnO+NiO+CuO+4F TSC, PCL+ZnO+NiO+CuO+2F TSC, bare PCL, PCL+ZnO+4F TSC) 316L stainless steel (SS) surface was coated. After coating with these different types of nanofibers, measurements were taken with electrochemical techniques such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) in phosphate buffer solution (PBS) for 1 hour to investigate the corrosion inhibition properties. According to the results, the PCL+Graphite+CuO+NiO+ZnO coating provided the highest corrosion inhibition with a protection efficiency value of 98.83%. The PCL+4F+ZnO coating had the lowest inhibition property with a protection efficiency value of 40.72%. At the end of the tests, Nyquist, Bode, Tafel, OCP diagrams of the coatings were obtained and equivalent circuit models were presented.

Improving the Bioactivity and Antibiofilm Properties of Metallic Implant Materials via Controlled Surface Microdeformation.

Although metallic implants provide most of the required properties for bone-related applications, especially orthopedic implants, insufficient osseointegration, which may lead to loosening of the implant or prolonged healing time, is still an issue to be resolved. Osseointegration can be improved via application of various surface treatments on the metal surface. The current study focuses on a novel surface microdeformation method, which enables the formation of controlled surface patterns of various parameters. With this purpose, a surface microdeformation procedure was applied on 316L stainless steel surfaces, forming four different patterns which affected various surface parameters such as roughness, surface energy, dislocation activities close to the surface, and wettability. Static immersion tests in a simulated body fluid (SBF) environment showed that modifying the surface parameters via controlled surface patterning promoted the formation of a stable oxide layer and calcium-phosphate (CaP) deposition on the metal surfaces, improving bioactivity. Moreover, the higher amount of CaP deposition and oxide layer formation on the modified surfaces led to reduced ion release, which contributed to improved corrosion resistance. Finally, the effect of the formed surface patterns on antibiofilm formation was investigated via incubation with C. albicans for 24 h, which exhibited that microdeformation patterns remarkably inhibited the biofilm formation. Throughout the experiments, certain patterns yielded outstanding results among the four patterns formed. Overall, it was concluded that forming controlled patterns on stainless steel surfaces via surface microdeformation significantly contributed to the metal's biocompatibility via improving bioactivity, corrosion resistance, and antibiofilm formation properties. Especially, the specific surface properties such as increased surface energy, high surface roughness, and dislocation density close to the metal surface as well as increased hydrophilicity obtained via forming the pattern with relatively deeper and narrowly spaced indents yielded the most promising outcomes. These methodologies constitute novel approaches to be used while designing new methodologies for the surface modification of metallic implant materials for improved osseointegration.

Do Wettability Measurements Define Corrosion Inhibition of Etched Surfaces? A Study on Acid‐Etched 316L Stainless Steel

Special wetting surfaces have attracted attention owing to their potential applications in the automotive, engineering, environmental, and biomedical industries. Specifically, nature‐inspired superhydrophobic surfaces are more effective in blocking moisture, thus limiting corrosion. Hence, surface wettability analysis remains the primary method for demonstrating the corrosion mitigation characteristics of rough‐engineered surfaces. Herein, the influence of wettability measurements on the corrosion inhibition of 316L stainless steel surfaces etched in HCl: HNO3 acid is systematically investigated. Interestingly, etched hydrophobic surfaces with a contact angle of ≈125° significantly improve the corrosion resistance by 50%, resulting in suppressed corrosion rates. Furthermore, the surface chemical states of the etched 316L steel are analyzed and discussed in detail.

Assessment of process parameters on modified 316L SS surfaces prepared via hybrid powders mixed EDM

This study aims to assess the influence of hybrid powders (hydroxyapatite, manganese, copper, and carbon nanotube) mixed electric discharge machining (EDM) and coating process on 316L stainless steel (SS). An efficiently machined, hydrophilic, thin, and microporous surface is produced using variable discharge energies and powders weighted percentage suspended in the dielectric medium. The research outcome indicates that the hybrid powders mixed-EDM process synthesised a coating that substitutes the base elements with foreign elements of calcium (Ca), phosphorous (P), copper (Cu), carbon (C), oxygen (O), and manganese (Mn). The surface wettability response of the coating displays a hydrophilic nature with a contact angle of 51.5° and surface energy of 52.9 mJ m−2. The coated surface exhibited a roughness value of 3.201 μm, which is expected to promote osseointegration, and the material removal rate has been enhanced to an optimal value of 100.32 mg/min. The Taguchi design demonstrated that the powder mixing ratio, current intensity, and spark time are the most influential factors in the hybrid powders mixed EDM process. This study determines a novel multiple additives-assisted EDM method to synthesise a coating on 316L SS with potential benefits for biomedical applications.

Bioinspired Self-Adhesive Multifunctional Lubricated Coating for Biomedical Implant Applications.

In the realm of clinical applications, the concern surrounding biomedical device-related infections (BDI) is paramount. To mitigate the risk associated with BDI, enhancing surface characteristics such as lubrication and antibacterial efficacy is considered as a strategic approach. This study delineated the synthesis of a multifunctional copolymer, embodying self-adhesive, lubricating, and antibacterial properties, achieved through free radical polymerization and a carbodiimide coupling reaction. The copolymer was adeptly modified on the surface of stainless steel 316L (SS316L) substrates by employing a facile dip-coating technique. Comprehensive characterizations were performed by using an array of analytical techniques including Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, optical interferometry, scanning electron microscopy, and atomic force microscopy. Nanoscale tribological assessments revealed a notable reduction in the value of the friction coefficient of the copolymer-coated SS316L substrates compared to bare SS316L samples. The coating demonstrated exceptional resistance to protein adsorption, as evidenced in protein contamination models employing bovine serum albumin and fibrinogen. The bactericidal efficacy of the copolymer-modified surfaces was significantly improved against pathogenic strains such as Staphylococcus aureus and Escherichia coli. Additionally, in vitro evaluations of blood compatibility and cellular compatibility underscored the remarkable anticoagulant performance and biocompatibility. Collectively, these findings indicated that the developed copolymer coating represented a promising candidate, with its facile modification approach, for augmenting lubrication and antifouling properties in the field of biomedical implant applications.

Coating of the Surface of 316L Stainless Steel with Hydroxyapatite Produced from Eggshell Using the Sol-Gel Method

In this study, the production of high-yield and purity calcium nitrate from eggshell, a biological waste, and the usability of the obtained calcium nitrate in the production of hydroxyapatite (HAP) by the sol-gel method were investigated. In addition, the obtained HAP was used to coat 316L steel using the dip coating method. For this purpose, calcium nitrate, which will be used as a precursor in HAP production, was produced from chicken eggshells with high calcium carbonate content. The surface of 316L stainless steel discs was coated with sol-gel obtained from a mixture of calcium nitrate and triethyl phosphite by dip-coating method. Then, the 316L discs were dried and heat treated at 500 °C to form HAP on their surfaces. XRD and SEM techniques were used for the characterization of the obtained HAP structure. Unlike previous studies, it has been shown that chicken eggshell, a biological waste, can be used to produce HAP, a biocompatible material, and the surface of 316L stainless steel can be coated with the produced HAP.

Fast reversion of hydrophility-superhydrophobicity on textured metal surface by electron beam irradiation

Reversible hydrophilic-hydrophobic transitions on metal surfaces are challenging in surface-wetting treatment. Existing preparation methods have the disadvantages of requiring a long time, producing a metal oxide layer, and being difficult to implement. In this paper, a rapid reversible transitions between hydrophilicity and superhydrophobicity was achieved on the surface of 316L stainless steel using laser etching combined with electron beam irradiation. The contents of C–C/C–H hydrophobic functional groups was found to be notably increased by low electron dose in the experiments. The contents of C-O-C, O-C = O and –OH hydrophilic functional groups decreased. The interaction of excited secondary electrons with precursor molecules generated free radical fragments that adsorbed onto surfaces and formed new chemical bonds, changing the content of the functional groups. Reversible hydrophilic and superhydrophobic transitions could be achieved by adjusting the electron dose. The contact angle continually changed from 91° to 160° with a beam current of 100 μA, to 17° with 300 μA, and back to 90° with cleaning. The entire procedure required only four minutes. Meanwhile, the superhydrophobic state with contact angle of 160° has a sliding angle of 6°, presenting excellent resistance to bacterial adhesion, UV irradiation, and delayed icing.

Evaluation of Electropolishing Characteristics of 316L Stainless Steel Tube in Contaminated Electrolyte

In the electropolishing process, the polishing quality of the metal surface varies according to the contamination of the electrolyte. In this study, the electrolyte was evaluated according to the usage time, and the effect of each factor on electropolishing was investigated. As the electrolyte is contaminated, the concentration of metal ions in the electrolyte increases and the ion conductivity decreases. In addition, the pH and specific gravity of the electrolyte increase due to the metal sludge formed as the metal ion concentration increases. When the electrolyte usage time was more than 5 days, many scratches remained on the surface of 316L stainless steel, and relatively high surface roughness was measured. The surface roughness improvement rate compared to the initial specimen was 30% for the unused electrolyte, 26% on the 3rd day, 19% on the 5th day, and 17.5% on the 13th day. Since the low current density due to electrolyte contamination causes a decrease in polishing efficiency, initial scratches on the metal surface still exist on the polished surface. Therefore, it is necessary to manage the electrolyte to maintain the quality of electropolishing.

THE EFFECT OF THE DC-SPUTTERING PROCESS ON CHANGES IN THE HARDNESS VALUE AND ELEMENTS COMPOSITION OF BIOCOMPATIBLE STAINLESS STEEL 316L MATERIAL

Titanium Dioxide (TiO2) thin films have intriguing optical, photocatalytic, and electrical properties and have been investigated for various applications, including solar cells, biomaterials, corrosion-resistant materials, and gas sensor. In this study, TiO2 thin films were deposited on the surface of 316L Stainless Steel to improve its mechanical properties as an implant material. The deposition method used was DC sputtering with variations in deposition times of 30, 60, 90, 120, and 150 minutes. Vickers hardness test and SEM-EDX characterization were carried out to determine the hardness value, elemental composition, and thickness of the TiO2 thin film formed. Based on these tests, it was discovered that the optimal hardness value of316L stainless Steel material was attained at a deposition period of 90 minutes with a hardness value of 170.10 VHN, and the average thickness of the layer formed was ± 119.02 μm.

Improved corrosion resistance and interfacial conductivity of a-C/(Ti:C)/Ti nano-thin film for 316L stainless steel bipolar plates

To enhance corrosion resistance and electrical conductivity of metallic bipolar plates for proton exchange membrane fuel cells (PEMFCs), the film containing amorphous carbon (a-C) outer layer, titanium carbon compound (Ti:C) transition layer and titanium (Ti) seed layer has been deposited on the surface of 316L stainless steel (316L SS) by multi-arc ion plating method. Dense and uniform a-C/(Ti:C)/Ti nano-thin film is relatively hydrophobic and approximately 300 nm thick, presenting a clear multilayer structure. The interfacial contact resistance of 316L SS is effectively reduced from 124.97 mΩ·cm2 to 3.97 mΩ·cm2 at 1.4 MPa after modification. Electrochemical corrosion tests are investigated in the simulated cathodic PEMFCs environment (0.5 M H2SO4 and 2 ppm HF at 70 ℃ bubbled with air). Potentiodynamic polarization results reveal that the corrosion potential of a-C/(Ti:C)/Ti film modified sample is 0.23 V (vs. Ag/AgCl) and the corrosion current density is only 0.14 μA·cm−2. The durability of the a-C/(Ti:C)/Ti film was assessed by conducting potentiostatic polarization tests at various applied potentials. After 4 h potential of 0.6 V and 0.8 V (vs. Ag/AgCl) holding tests, the current densities of the modified 316L SS have stabilized at 0.076 μA·cm−2 and 0.098 μA·cm−2, respectively.

The impact of alloying element Cu on corrosion and biofilms of 316L stainless steel exposed to seawater.

Copper-containing stainless steel (SS) has been reported to mitigate biofilms in industrial and clinical environments. However, the impact of copper released from copper-containing SS in natural seawater on biofilms and corrosion is still unclear. In this study, three kinds of 316L SS were immersed in natural seawater for 6months, and the pitting depth decreased in the order: 316L-Cu SS (annealed) > 316L SS > 316L-Cu SS (aged). The biofilm thickness and number of sessile cells on the surface of 316L-Cu SS (annealed) and 316L SS were similar but notably greater than those of 316L-Cu SS (aged). Furthermore, the results of the community analysis indicated that the addition of copper in 316L-Cu SS (aged) reduced the diversity and richness of the microbial community, resulting in a significant reduction in the number of genera constituting the biofilms. Copper ions exhibit a broad-spectrum bactericidal effect, effectively reducing the abundance of dominant populations and microbial genera in the biofilms, thereby mitigating pitting corrosion induced by microorganisms. In addition, the PCoA scatter plot showed that time also played an important role in the regulation of microbial community structure.

Chemical Species Formed on FeB-Fe2B Layers during Wet Sliding Wear Test

In the present work, X-ray photoelectron spectroscopy (XPS) survey spectra of borided AISI 316L for two different times (1 and 6 h) of exposure to simulated body fluid (SBF) were obtained after wet sliding wear. A borided layer of ~39 microns was obtained on the surface of the AISI 316L stainless steel using the thermochemical treatment of boriding. As part of the mechanical and chemical characterization of sliding wear, Berkovich nanoindentation and X-ray spectroscopy tests were used to determine the main properties of the borided layer. The results of the specific wear rate values were higher at 5 mm/s sliding speed than those recorded at 30 mm/s due to the influence of the exposure time of the sample and the complex combinations of chemical reactions with boron (e.g., B2S3, Cr2O3, and Fe2O3) on the surface during the sliding during 6 h of exposure in Hank’s solution due to the formation of the passive film. The knowledge of chemical species formed during wet sliding wear tests on borided AISI 316L is essential for understanding wear mechanisms and materials’ performance and optimizing material properties and materials’ and components’ reliability in the biomedical industry for screws and fastening plates.

Effect of Low-Temperature Plasma Carburization on Fretting Wear Behavior of AISI 316L Stainless Steel

AISI 316L stainless steel has received considerable attention as a common material for key ball valve components; however, its properties cannot be improved through traditional phase transformation, and fretting wears the contact interface between valve parts. A carburized layer was prepared on the surface of AISI 316L stainless steel by using double-glow low-temperature plasma carburization technology. This study reveals the effect of double-glow low-temperature plasma carburization technology on the fretting wear mechanism of AISI 316L steel under different normal loads and displacements. The fretting wear behavior and energy dissipation of the AISI 316L steel and the carburized layer were studied on an SRV-V fretting friction and wear machine with ball–plane contact. The wear mark morphology was analyzed by using scanning electron microscopy (SEM), the phase structure of the carburized layer was characterized with X-ray diffractometry (XRD), and the wear profile and wear volume were evaluated with laser confocal microscopy. The carburized layer contains a single Sc phase, a uniform and dense structure, and a metallurgically combined matrix. After plasma carburizing, the sample exhibited a maximum surface hardness of 897 ± 18 HV0.2, which is approximately four times higher than that of the matrix (273 ± 33 HV0.2). Moreover, the surface roughness was approximately doubled. The wear depth, wear rate, and frictional dissipation energy coefficient of the carburized layer were significantly reduced by up to approximately an order of magnitude compared with the matrix, while the wear resistance and fretting wear stability of the carburized layer were significantly improved. Under different load conditions, the wear mechanism of the AISI 316L steel changed from adhesive wear and abrasive wear to adhesive wear, fatigue delamination, and abrasive wear. Meanwhile, the wear mechanism of the carburized layer changed from adhesive wear to adhesive wear and fatigue delamination, accompanied by a furrowing effect. Under variable displacement conditions, both the AISI 316L steel and carburized layer mainly exhibited adhesive wear and fatigue peeling. Oxygen elements accumulated in the wear marks of the AISI 316L steel and carburized layer, indicating oxidative wear. The fretting wear properties of the AISI 316L steel and carburized layer were determined using the coupled competition between mechanical factors and thermochemical factors. Low-temperature plasma carburization technology improved the stability of the fretting wear process and changed the fretting regime of the AISI 316L steel and could be considered as anti-wearing coatings of ball valves.

Wear and corrosion properties of HVOF sprayed WC-Cr3C2 composite coating for application in polysilicon cyclone separator

The wear and corrosion properties of the cyclone separator play a crucial role for the preparation of high-purity trichlorosilane in the Siemens method polysilicon cold hydrogenation system. In this work, we used fluent simulation technology to determine the optimal spraying process parameters of high velocity oxy-fuel (HVOF) technology, and the Ni60-WC composite coatings with different content of Cr3C2 were prepared on 316L stainless steel surface by using HVOF technology. The microstructure, phase structure and mechanical properties of the coating were characterized, and the wear resistance and corrosion resistance of the coating were studied. By comparing the friction coefficient, wear rate, wear profile and electrochemical polarization and impedance spectrum of the coating, the effects of Cr3C2 content on the microstructure, hardness, wear resistance and corrosion resistance of HVOF sprayed WC composite coating were studied. The results show that the coating prepared by using the simulation parameters are uniform and compact, the coating is tightly bonded to the substrate. The main phases in the coating are WC, W2C and Cr3C2. With the increase of Cr3C2 hard phase, the wear resistance and corrosion resistance gradually improve. Ni60–35WC–20Cr3C2 and Ni60–35WC–30Cr3C2 volume loss rate is the lowest, the friction depth is the shiniest, compared with the substrate, the wear rate is reduced by more than 95 %. Ni60–35WC–20Cr3C2 has the highest corrosion potential, the smallest corrosion current, the smallest corrosion rate and the largest impedance spectrum radius. However, when the content of Cr3C2 reaches 30 %, the corrosion resistance is the worst. Combined with wear resistance and corrosion resistance analysis, the Ni60–35WC–20Cr3C2 coating is selected to provide support for upgrading and prolongating the service life of the cyclone separator.

Brushite/hydroxyapatite coatings on H2SO4 passivated 316LSS by electrodeposition: In vitro corrosion and anti-inflammatory activity

This study evaluated the corrosion behavior and anti-inflammatory activity of brushite (BS or DCPD, CaHPO4·H2O)/hydroxyapatite (HAp, Ca10(PO4)6(OH)2) coating on sulfuric acid (H2SO4) treated 316L stainless steel (SS). The coating was applied using the electrodeposition process on untreated and H2SO4 passivated 316L SS surface. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS) to obtain crystal and electronic structure as well as morphological and compositional information of the coated 316L SS. Electrochemical impedance spectroscopy (EIS) tests were performed in 0.9 % sodium chloride (NaCl) solution and compared with the pristine (P316L), H2SO4 treated (T316L), untreated/BS/HAp coated (BHP316L) and treated/BS/HAp coated (BHT316L) 316L SS specimens. The anti-inflammatory activity was carried out for the coated samples by the protein denaturation method. The results showed that the BS/HAp coating on H2SO4 treated 316L SS (hereafter, denoted as BHT316L) were susceptible to corrosion attack against 0.9 % NaCl solution. Additionally, the anti-inflammatory activity of the BHT316L was found to be lower compared to control (sodium diclofenac), indicating that particular concern should be given to H2SO4 treated 316L SS as the corrosion products formed by this surface modification may cause harmful effects in the human physiological environment.

Grain Orientation, Angle of Incidence, and Beam Polarization Effects on Ultraviolet 300 ps‐Laser‐Induced Nanostructures on 316L Stainless Steel

AbstractLaser‐induced periodic surface structures (LIPSS) represent a unique route for functionalizing materials through the fabrication of surface nanostructures. Commercial AISI 316L stainless steel (SS316L) surfaces are laser treated by ultraviolet 300 ps laser pulses in a laser line scanning (LLS) approach. Processing parameters are optimized (pulse energy of 2.08 µJ, pulse repetition frequency of 300 kHz, and suitable laser scan and sample displacement rates) for the generation of low spatial frequency LIPSS over a large 25 × 25 mm2 area. Different angles of incidence of the laser radiation (0°, 30°, and 45°) and different linear laser beam polarizations (s and p) produce a plethora of rippled surface morphologies at distinct grains. Scanning electron microscopy and 2D Fourier transforms, together with calculations of the optical energy deposited at the treated surfaces using Sipe's first‐principles electromagnetic scattering theory, are used to study and analyze in detail these surface morphologies. Combined with electron backscattering diffraction, analyses allow associating site‐selectively various laser‐induced‐surface morphologies with the underlying crystalline grain orientation. Resulting grain orientation maps reveal a strong impact of the grain crystallographic orientation on LIPSS formation and point toward possible strategies, like multi‐step processes, for improving the manufacturing of LIPSS and their areal coverage of polycrystalline technical materials.

Performance of electrochemically deposited hydroxyapatite on textured 316L SS for applications in biomedicine

ABSTRACT This study investigates the biocompatibility of laser-textured 316L stainless steel (SS) coated with hydroxyapatite (HA) for orthopaedic implants. Powdered HA was electrochemically deposited on the laser-textured surface of 316L SS, and various tests were conducted on its surface to assess its biocompatibility. A particle size analyser was used to determine the average HA particle size, and a 3D optical profilometer was employed to characterise the surface roughness of the laser-textured samples. Contact angle measurement results provide insights into the wettability of the substrate. Microscopy tests revealed that, compared to those without HA coating, HA coatings on spherical dimpled textures exhibited better cell adherence. Among the tested samples, a sample with 98% laser energy input, 40.45° contact angle, and 75.976 µm HA coating thickness was found to be the most suitable for bone implantation.

Experimental investigation on the superhydrophobic property of laser micromachined stainless steel 316L surface

Compared to conventional machined surfaces, superhydrophobic surfaces have advantages such as anti-corrosion, anti-bacterial, anti-biofouling, and self-cleaning qualities. In the production of biomedical, pharmaceutical, petrochemical, food processing, and marine parts that demand superhydrophobic surfaces, stainless steel 316L (SS 316L) finds use. One of the industrial procedures used to create micro-textures on the surface of a material to promote hydrophobicity is laser beam machining. The objective of this study is to use an Nd: YAG laser to create superhydrophobic surfaces through a planned set of experiments. In this work, it was analysed how the laser beam machining process parameters affected the contact angle, which is a crucial factor in determining whether a surface is hydrophobic. To find the ideal set of laser machining parameters to achieve superhydrophobicity in the shortest period, the Taguchi and ANFIS methods were used to optimise the Laser Beam Machining process parameters.