Effect Of Laser Surface Treatment Research Articles

Effect of Laser Surface Treatment on the Corrosion Resistance of Zircaloy-4 at High Temperature

Effect of Laser Surface Treatment on the Corrosion Resistance of Zircaloy-4 at High Temperature

Effect of laser surface treatment on shear bond strength between polyetheretherketone and heat-activated polymethylmethacrylate resin.

To compare the shear bond strength between polyetheretherketone (PEEK) and heat activated polymethylmethacrylate (PMMA) resin after laser treatment. A total of 128 PEEK discs were fabricated (10mm diameter and 2mm thickness) and allocated into two groups. Group 1 was subjected to surface treatment followed by thermal cycling for 5000 cycles and group 2 was subjected to surface treatment followed by thermal cycling for 10,000 cycles. Each group was further subdivided into four subgroups (n = 16) which were: no surface treatment; primer treatment; acid etching; and laser surface treatment. PEEK was then bonded with PMMA resin using the conventional flasking technique. The shear bond strength was evaluated using a universal testing machine with a crosshead speed of 1mm/min. Statistical analysis was done using one-way ANOVA for comparing within groups, followed by Tukey HSD test. Student's T-test was done to evaluate between the two groups. In group 1, the highest shear bond strength was exhibited by the laser group (19.08 ±0.16MPa) followed by the acid etch group (14.84 ±0.23MPa), and the primer group (6.43 ±0.20MPa), while the least shear bond strength was observed in the no surface treatment group (4.98 ±0.34MPa) which was found to be significant (p<0.05). In group 2, the highest shear bond strength was observed in the laser group (18.21±0.23MPa) followed by the acid etch group (13.77±0.48MPa), and the primer group (6.04±0.11MPa), while the least shear bond strength was observed in no surface treatment group (4.35±0.21MPa) which was found to be significant (p<0.05). The shear bond strength between PEEK and PMMA resin was highest for specimens that were surface treated with laser and followed by specimens treated with acid etching, primer application, and without surface treatment, respectively. Increasing thermal cycling from 5000 cycles to 10,000 cycles also reduced the bond strength.

A comparative analysis of the effect of laser surface treatment on the dry sliding wear behavior of ductile cast irons with different microstructures

In this study, the wear behavior of ferritic (GJS 400) and pearlitic (GJS 700) ductile cast iron (DCI) specimens after laser surface hardening were investigated comparatively. In general, multi-pass laser applications are inevitable in a laser surface treatment (LST) applied for surface hardening because the laser spot diameter is quite small compared to the applied surface area. This situation may cause a decrease in wear resistance due to residual stress formation because of the thermal gradient and softening effect due to the overlap ratio. In this study, a single-pass laser surface hardening (LSH) process with a laser pulse area of 20 × 5 mm2 compatible with the laser energy density (6.28 J/mm3) used in the literature, was applied to overcome these limitations. Thus, it is aimed to make it possible to evaluate the comparative analysis more reliably. After LSH processes, hardness values of DCI samples increased approximately 4.3 times compared to untreated ones due to the transformation hardening effect. In the microstructure of the laser-treated pearlitic DCI samples, martensite was present as the dominant phase in addition to a small amount of residual austenite. As for the ferritic DCI samples, the ledeburite and martensite phases were detected. Dry sliding wear tests were performed using different loads (5 N, 10 N) and sliding speeds (10 mm/s, 20 mm/s, 30 mm/s). As a result, the wear volume loss values of laser-treated ferritic and pearlitic DCI samples could be reduced by approximately 26.6% and 30.7%, respectively, compared to untreated ones. The COF values of the untreated samples increased with increasing load, while those of LSHed decreased. Severe plastic deformation and delamination were observed for untreated samples, while mild plastic deformation and micro-grooves were observed for samples with LSHed.

Effect of laser surface treatment of glass fiber posts on their bond strength to intra-radicular dentin at different root levels: An in-vitro study

Statement of the problem: Despite the fact that adhesive luting is recommended for teeth rehabilitation with glass fiber posts, the most common failure of these restorations is debonding of the glass fiber posts.Aim: To evaluate the effect of laser surface treatment of glass fiber posts on their bond strength to intra-radicular dentin at different root levels.Materials and Methods: Twenty extracted single-rooted permanent human teeth were decoronated and endodontically treated. Post space of 10 mm length was prepared to receive glass fiber post. Teeth were randomly divided into 2 groups based on the surface treatment applied to the post surface as follows; Group A (Control): post surface received conventional silane treatment, Group B: Er:YAG laser was applied to the post surface followed by silane application. Prepared post spaces of all teeth were irrigated using standard irrigation protocol then dried and self-adhesive resin cement was used for posts cementation. For push-out bond strength evaluation, three slices for each sample were prepared, and the test was performed using a universal testing machine at a crosshead speed of 1 mm/min.Results: Statistical analysis showed that group B provided significantly higher bond strength values compared to group A. When different root sections were compared in each group: group A showed a significantly higher bond strength values in the middle and apical sections compared to cervical (p0.05). In addition, the Comparison between both groups in each section revealed that: group B showed significantly higher bond strength values in cervical and apical sections than group A. While in the middle section, group B recorded a non-significant increase in the bond strength compared to group A. Conclusion: Er: YAG laser treatment for the post surface can be used as an alternative to conventional silane treatment to enhance its bonding to intra-radicular dentin.

Enhancement of Mechanical Properties and Corrosion Resistance of Cast Iron Alloy Using CO2 Laser Surface Treatment

This work aimed to study the effect of laser surface treatment on the mechanical characteristics and corrosion behaviour of grey cast iron type A159. Many technical applications used conventional surface treatment, but laser surface hardening has recently been used to enhance the surface properties of many alloys. The mechanical characteristics, including microstructure, microhardness, and wear resistance of A159 grey cast iron, were studied, in addition to corrosion behaviour. The experimental laser parameters in this work were 0.9, 1.2, and 1.5 KW power with continuous wave carbon dioxide lasers with scanning speeds of 10 and 12 mm/s were used. The results found that phase-transitional alterations in microstructure were influenced by laser therapy. Also, the microhardness increased with increasing power, with the maximum reaching approximately 950 HV while the base metal has an average of approximately 260 HV. Also, we found the power laser increased corrosion resistance by lowering the corrosion rate (CR) from 21.10 for the untreated sample to 1.02 (m.p.y.), additionally, corrosion protection efficiency (CPE) increased to 95.27 percent. On the other hand, the wear test revealed that mass loss decreased as laser surface treatment power increased; it reached 0.19 g for the laser-treated samples, compared to 1.25 g for the base metal after the 50th minute of the wear experiment.

Effect of Laser Surface Treatment on the Initiation of Corrosion Defects near Nonmetallic Inclusions

Effect of Laser Surface Treatment on the Initiation of Corrosion Defects near Nonmetallic Inclusions

The effect of laser surface treatment of titanium samples on the adhesive strength of adhesive joints

The article considers the strength of adhesive joints of specimens made of OT-4 titanium alloys, the surface of which has been treated with laser radiation. The paper presents the results of the dependence of the macro- and microgeometry of the obtained surface, chemical composition, wetting angle and adhesion strength of adhesive joints under shear on laser processing modes. The purpose of this work is to determine the optimal parameters of laser processing for obtaining high strength adhesive joints. The results obtained can be used for gluing spacecraft structural elements. The studies were carried out on the adhesive pair «Titan – Titan». Depending on the processing mode, characteristic surface textures were identified, which were combined into groups «B», «K» and «C». High-energy modes of laser surface treatment of samples before gluing lead to a significant increase in the strength characteristics of the adhesive joint (up to 70 %) due to an increase in the area of the gluing surface and mechanical locking of the adhesive in the microrelief of the texture of the samples. In addition, the use of this method, in comparison with mechanical and chemical methods, significantly increases the productivity of surface treatment.

The Use of Laser Surface Modification Technologies for Obtaining Parts of Roller-Screw Mechanism

A number of parts of roller-screw mechanisms (RSM), which work in aggressive environments, are made of corrosion-resistant stainless steel 40Cr13 (AISI420 analogue). These elements include a screw and rollers. For these parts, it is necessary to have hard surface layers and a soft core. A promising method for obtaining the necessary requirements is surface laser modification. The article investigated the effect of laser surface treatment on the value of the coefficient of elasticity, hardness, coefficient of friction and the amount of wear of products made of stainless alloy steel 40Cr13. For laser processing, the SVAROG-1-5DR laser complex (Russia) was used. Various modes of surface laser modification were set. For this purpose, the power of the laser power, the speed of movement of the laser beam relative to the treated surface, and the focal length were varied. The Vickers hardness and tribological characteristics were measured using a microcombitester and tribometer manufactured by SSM Instruments SA (Switzerland). The Rockwell hardness was measured using a TN 301 hardness tester manufactured by Time Group (China). The structure of the alloy was studied by metallography and X-ray diffractometry. It was found that the indicators of hardness and wear resistance of the surface layers of sctructural 40Cr13 steel strongly depend on the laser treatment modes. These dependencies are extreme, with highs and lows. The paper presents the quantitative values of the hardness and wear resistance indicators before and after laser treatment of the surface of this steel in various modes. The reasons for the change in the hardness and wear of the surface layers of 40Cr13 steel after laser treatment under different modes are established. The results of the work were used to optimize the modes of laser treatment of the surface of 40Cr13 steel in order to obtain the maximum values of hardness and wear resistance.

Effects of ytterbium laser surface treatment on the bonding of two resin cements to zirconia

Monolithic zirconia crowns bonded to zirconia abutments have become more commonly used in the construction of cement-retained implant superstructures. The present study aimed to examine the effects of laser surface treatments on the bond strength of two resin cements to zirconia. Three types of surfaces were examined: untreated, alumina blasted, and ytterbium laser treated; and two types of resin cements: 4-META/MMA-TBB resin cement and composite resin cement. Half of the specimens were subjected to a thermocycling process. Subsequently, a shear bond test was carried out. In addition, surface roughness was measured for each surface type. The results showed that laser treatment increased zirconia surface roughness and that laser treatment significantly increased shear bond strength after the thermocycling of both cement types compared to no treatment. Our experimental results suggested that ytterbium laser surface treatment of zirconia increased the bond strength of resin cements.

Effect of the Laser Surface Treatment on Properties of the Alloy (Ni-Cu-V) Nanoparticles Prepared by Powder Metallurgy Method

In this research, an alloy with a nanostructure was prepared using a metallurgical technique. To prepare an ideal alloy, three nanoscale powders were used (70 percent Ni, 25 percent Cu, and 5 percent V). The dried alloy was stored under 8 Tons of cold pressing at 80°C for 30 minutes. After that, a surface treatment of the prepared alloys with different laser energies (0, 200, 260, 300) mJ was carried out with a pulse time (10 seconds) at a distance of (100 cm). and hardness (Rockwell method) is studied. By immersing samples in a solution (3.5 percent NaCl) for different periods (3, 5, 7, 9, 11) days, the effect of laser surface treatment on the corrosion resistance of the alloy was investigated. Results show that porosity, water absorption ratio decreases after laser surface treatment with rising hardness values. Additionally, the wear resistance decreases as laser energy increases. Atomic force microscope images show that grain sizes increase as laser energy increases, and by increasing the laser energy, the surface of the nanoparticles is more homogeneous. Easy architecture and high nanostructure alloy consistency play a key role in improving the mechanical and physical properties.

Effect of Laser Surface Treatment on Transition Temperature of Ni/Ti SMAS

It is well established that SMAs have a great important as: engineering and biomaterial applications, because of unique properties that had as well as, good biocompatibility. however, duo to its possible corrosion in physiological solution, dissolution of toxic Ni might be happening. Several studies have been carried out to improve the stability of the passive protective film of Tio2 and prevent the Ni ion relies out of NiTi. Surface treatment is one of these methods or techniques such as, ion implantation, plasma electro polishing, passivation, ultra-sonic treatment and laser treatment, most of these treatments are effects on transition temperatures (As,Af,Ms,Mf). Change of these temps. will affected the normal use especially in human body, so keeping these temps. within the range of the human body is of main requirements to Evaluation the efficiency of any treatment. In this study (55 wt% Ni, 45 wt % Ti) SMAs has been prepared by (PM), compacted at 850 MPa and sintered. Laser pulses deposition technique at (1064, 532) nm at different energy (2, 2.3, 2.7) J. At power (200) wat in constant duration time (2 ns) has been used to modify surface by continuous stricks (side by side) to study mechanical, corrosion properties and how laser pulses effects on transition temp. All results confirmed that there is a positive effect on properties, % improving in hardness with respect to reference sample are (145, 132.8, 123.8) and (180.9, 169.5, 152.3) at 1064, 532 wave length respectively. Improvement in Ni relies are equal to (52, 38) % with respect to reference sample. On the other hand, there are slight positive change on transition martensitic transformation, thermal hysteries ( As−Ms) there are reduction in degress from 50°C (untreated sample) to (36.9, 33.6)°C, while for martensitic transformation ( Af−Mf) the degress are decrease from (65)°C for untreated sample to (57.5, 51.7)°C wave length respectively.

New approach for the high electrochemical performance of silicon anode in lithium-ion battery: A rapid and large surface treatment using a high-energy pulsed laser

Silicon nanoparticle based anode is effective to extend cycle life by reducing pulverization of silicon particles during lithiation and de-lithiation. However, it is hard to handle nano-scale materials during a series of manufacturing processes in the industry. Particularly, during the drying process, inhomogeneous material distribution within electrode is prone to form a dense surface region by agglomeration of the nanoparticles, causing degradation of electrochemical performances. In this work, we report the effects of laser surface treatment on the dense surface region formed by heterogeneous distribution of materials within the silicon anode based on nanoparticles during the drying process. Laser surface treatment enhanced the cycle life (laser-treated, 1000 mAh g−1 vs. original, 250 mAh g−1 at 200 cycles), rate capability and columbic efficiency considerably. From mechanism study on physicochemical changes at the surface region during laser surface treatment, it is revealed that the characteristics of the laser-treated surface contributes to the reduction of internal resistances and thickness of the solid electrolyte interphase layer, and improves diffusion characteristics.

Laser Treatment of Fiber Post and Final Push-Out Bond Strength: A Systematic Review and Meta-Analysis.

Purpose: This review article tries to answer this question: "What are the effects of laser surface treatment of fiber posts (FPs), compared with other surface roughening methods, on bond strength of cemented FPs?" Methods: Search was carried out in six electronic databases by focusing on defined key words. Related titles and abstracts, up to March 2019, were collected, read, and selected for quality assessments. A total of 2408 articles were included in the study at the initial stage of the searching phase. Results: Finally, seven studies were recognized to be reliable to be reviewed and meta data analysis in the study. All the studies were in vitro with a total of 340 samples. None of the Er:YAG (-0.27, 95% CI: -2.29 to 1.76; p = 0.79) and Er,Cr:YSGG (-0.04, 95% CI: -1.43 to 1.35; p = 0.95) treated samples showed any significant overall mean differences in final push-out bond strength (PBS) compared with the control groups. Conclusions: Laser pretreatment of FP surfaces might not be effective in providing high PBS. FP surface are susceptible to damage of high-level laser irradiation and might show decreased bond strength.

Laser modification of the microstructure and mechanical properties of (Cr3C2-25(Ni20Cr))-5(Ni25C) cermet coatings containing a solid lubricant

This paper presents a study on the effect of laser surface treatment on the microstructure and mechanical characteristics of cold sprayed Cr3C2-25(Ni20Cr)-(Ni-graphite) cermet coatings. The as-sprayed deposits retained the initial powder phase composition. The Cr3C2 particles were homogeneously distributed within the deformed nickel-chromium matrix phase. Moreover, the carbide particles were heavily fragmented due to a high-velocity impact on the substrate or particles already embedded. The solid lubricant (graphite) was mostly distributed between crushed Cr3C2 particles or deformed nickel-chromium matrix. The surface of the as-deposited coatings was laser-treated using a CO2 laser. With the higher applied power of the laser beam, the changes in the coating microstructure and surface topography were more significant. The refinement of the deposit structure and formation of new phases such as Cr7C3 and Cr2O3 were observed. All coatings, both those cold sprayed and those laser-treated, revealed compressive residual stresses, which increased with higher laser power. The post-deposition laser modification of the coating surfaces improved their mechanical properties by almost half.

The effect of laser surface treatment on the adhesive bonding performance of aluminum alloy

For the purpose of convenient treatment before gluing and improving the adhesive bonding performance, we compared the tensile shear strengths of epoxy adhesive bonding to 2A12 aluminum with preferred pre-treatments. Taking advantages on both convenience and pre-treatment quality, we investigated the influences of duration of laser treatment on the adhesive bonding strength to obtain the optimized extents of laser treatment. With the analysis of scanning electron microscopy, laser confocal scanning microscopy and contact angle measurements adopted to characterize the surface morphology, roughness and wettability, respectively, we discussed the effects of pre-treatments on the surface status and adhesive bonding. As a result, we proposed a pre-treatment with laser treatment on aluminum to improve adhesive bonding performance, by which the removal of oxide layer, surface roughening and cleaning were easily accomplished before gluing.

Effect of laser surface treatments on a thermoplastic PA 6/carbon composite to enhance the bonding strength

Adhesive bonding is an appropriate method to assemble structural composite components without a machining process. Compared with the properties of the carbon fiber reinforced thermoset polymer (CFRP), the carbon fiber reinforced thermoplastic polymer (CFRTP) have advantages, such as recyclability and superb impact, corrosion and temperature resistance. However, CFRTP have a low bonding strength with structural adhesives. In this study, a laser treatment was applied to an epoxy based CFRP and polyamide 6 (PA 6) based CFRTP surfaces to improve the adhesive bonding strength. Shear and tensile adhesive bonding tests were performed, and the mechanism of the laser treatment was investigated by the failure mode, surface free energy and Fourier transform infrared spectroscopy (FTIR) analyses. The adhesive bonding strengths of the CFRP and CFRTP were significantly improved by the laser treatment, and each wettability and functional groups is increased.

Effect of laser surface treatment on surface and bonding properties of carbon fiber reinforced composites

Carbon fiber reinforced plastics (CFRP) is widely used in the aerospace and automotive industries due to their light weight and high strength. The effective joining method of CFRP is bonding, and the surface state of CFRP is the main reason that affects the shear strength of the bonded joints. In order to improve the surface state of CFRP and shear strength, this paper systematically studied the effects of different power (80 W, 120 W, 180 W) laser treatment on the surface characteristics and bonding performance of CFRP and compared with the mechanical treatment (alcohol ultrasonic cleaned, sandpaper sanding). Four different adhesives were used in the adhesive joints, which were performed lap-shear tests. The SEM, XPS and contact angle measuring instrument were used to analyze the changes of physicochemical properties of CFRP after different surface treatment. The results showed that compared with alcohol cleaned and sandpaper sanding, 120 W laser treatment greatly improved the surface roughness of CFRP and formed micron-sized gaps. The water contact angle was reduced from 85° to 59.5°, and the surface energy increased from 25.6 mJ/m2 to 62.7 mJ/m2. The lap-shear results showed that the shear strength of the epoxy joints was improved after laser treatment, and the failure type was changed from interface failure to substrate failure. The polyurethane joint shear strength was not obviously improved and the combination failure of interface and cohesion was transformed into a pure interface failure after surface treatment.

Effect of laser irradiation on push-out bond strength of dental fiber posts to composite resin core buildups: A systematic review and meta-analysis.

The bonding of fiber posts (FPs) to composite resin core buildups is a challenge due to limited penetration of resin to the polymeric matrix of FPs. This review article tries to answer this question: "What are the effects of laser surface treatment of FPs, compared to other surface roughening methods, on push-out bond strength (PBS) of FPs bonded to composite resin core buildups?" Searches were run in seven electronic databases with a focus on proper key words. Related titles and abstracts, up to February 2019, were screened, selected, read and subjected to quality assessments. After the initial search, a total of 2635 articles were included in the study. Finally, 6 studies were reliable enough in methodology to be included. All the studies were in vitro with a total of 359 samples. Er:YAG (-0.05, 95% CI: -2.96 to 2.86; P = 0.97) and Er,Cr:YSGG (0.84, 95% CI: -0.12 to 1.81; P = 0.08) treated samples showed no significant overall mean differences in final PBS compared to the control groups. Moreover, pretreatment with Er,Cr:YSGG laser and sandblasting with 50 μm alumina showed an overall mean difference of -0.42 for PBS (95% CI: -1.23 to 0.39) with no significant differences. Laser irradiation of FPs seems to provide no significant increase in PBS values of FPs bonded to composite resin core buildups. Effects of surface treatment of FPs with laser irradiation and sandblasting with 50 μm alumina might be similar in increasing the final PBS, either.

The effect of laser surface treatment on the thermal shock behavior of plasma sprayed Al2O3/YSZ multilayer thermal barrier coatings

The aim of the present research was to investigate the effect of laser surface treatment on the thermal shock behavior of plasma sprayed Al2O3/YSZ multilayer thermal barrier coatings. In this regard, specimens of Inconel 718 were sprayed with Ni–22Cr–10Al–Y bond coat and Al2O3/YSZ top coat using an atmospheric plasma spraying approach. Then, top surfaces of specimens were under exposed to Nd-YAG laser radiation and thereby were glazed. Thermal stabilities of both coatings were evaluated by rising the environment temperature up to 1000 °C, keeping at this temperature for 15 min, and also rapid cooling of specimens in cold water. Using FESEM with EDS and XRD, the microstructure and morphology observations, elemental investigations and also phase identification were carried out. Findings displayed that both sprayed and glazed coatings were damaged as a spallation of top coats. Furthermore, by checking the life-time of coatings, the number of thermal cycles led to 20% destruction of top surfaces of coatings, increased from 232 cycles in sprayed coating to 325 cycles in laser glazed Al2O3/YSZ multilayer coating which displayed 40% improvement of thermal shock resistance after laser glazing process. This enhancement in resistance to thermal shock was due to strain adaptability improvement via a network of segmented cracks on the top surface produced by laser glazing process.

Laser Treatments for Improving Electrical Conductivity and Piezoresistive Behavior of Polymer⁻Carbon Nanofiller Composites.

The effect of carbon nanotubes, graphene-like platelets, and another carbonaceous fillers of natural origin on the electrical conductivity of polymeric materials was studied. With the aim of keeping the filler content and the material cost as low as possible, the effect of laser surface treatments on the conductivity of polymer composites with filler load below the percolation threshold was also investigated. These treatments allowed processing in situ conductive tracks on the surface of insulating polymer-based materials. The importance of the kinds of fillers and matrices, and of the laser process parameters was studied. Carbon nanotubes were also used to obtain piezoresistive composites. The electrical response of these materials to a mechanical load was investigated in view of their exploitation for the production of pressure sensors and switches based on the piezoresistive effect. It was found that the piezoresistive behavior of composites with very low filler concentration can be improved with proper laser treatments.