Effective Surface Treatment Research Articles

A bio-inspired mineral precipitation method to improve the freeze-thaw resistance of cement concrete pavement

Mineral precipitation has been proven to be an effective surface treatment for reducing the porosity of Portland cement concrete (PCC), leading to significant improvement in its freeze-thaw (F-T) resistance. Inspired by human teeth, this study proposes to produce a protective surface layer for PCC through in-situ precipitating hydroxyapatite (HAP), the same mineral found in the tooth enamel, on the concrete surface to improve its freeze-thaw resistance. This protective layer was generated by simply treating the mortar surface with a diammonium hydrogen phosphate (DAP) solution. Experimental results reveal that the F-T resistance is significantly improved, with the DAP-treated specimens surviving three times as many cycles as the control group. The proposed treatment also enhances the compressive strength of the mortar specimens by 35% and reduces saturated water absorption by up to 50%. Analysis of mineralogy suggests that DAP reacts with calcium ions from hydrated cement, leading to HAP precipitation and calcium phosphate on the cement mortars' surface. Particularly, the nanoindentation results indicate that the mineral phase with a lower density tends to react more readily with DAP, leading to its conversion into minerals with significantly higher packing density. Quantitative backscattered scanning electrons (BSE) images and mercury intrusion porosimetry (MIP) analysis verify that the microstructure of the cement mortar surface was densified by the formation of HAP and calcium phosphate induced by the proposed treatment. The proposed method exhibits great potential in enhancing the longevity of PCC pavements in cold regions.

Improvement of Fatigue Properties of EN AW 6082 Aluminum Alloy using Different Deep Rolling Directions

Deep rolling (DR) is an effective mechanical surface treatment method to improve the fatigue properties of engineering components. In this method, the surface of the component was rolled using a roller with a predetermined force to obtain reduced roughness, hardness increases and compressive residual stresses in the surface region. These alterations allow for increasing the fatigue lives of the components in industrial applications. In the current study, DR was applied in tangential and longitudinal directions on specimens that were manufactured using EN-AW 6082-T6 aluminum. The resulting roughness, hardness and residual stresses were determined experimentally. Fatigue tests were carried out to determine the improvements in fatigue properties after DR. It was found that DR-induced compressive residual stresses depend on DR direction considerably. Due to this reason, fatigue strength improvements were found to be different for different DR direction applications. Longitudinal rolling resulted in a 23% fatigue strength increase compared to a 7% increase for tangential rolling. For both DR direction applications, fatigue cracks were shown to initiate at the sub-surface region, whereas the as-turned specimens exhibited surface crack initiation.

Study on the Influence of Pre-Oxidation Treatment on Surface Wettability and Supercapacitive Performance of Coal-Based Activated Carbon

Coal possessing high fixed carbon content can be used for the preparation of activated carbon materials, including supercapacitance electrode carbon. Taixi anthracite has less ash content and high graphitization degree, which is a good candidate as a carbon source, while its low chemical activity affects the pore growth during the activated process. In this paper, using Taixi anthracite as the raw material, the effects of H2O2 pre-oxidation on the pore structure, surface chemical structure, and electrochemical properties of prepared activated carbon were studied. The results show that H2O2 successfully reduces the hydrophobic characteristics of the coal surface, which provides the possibility for the accessibility of the activator and the electrolyte. The activated carbon with H2O2 treatment at 15% concentration (AC-15%) shows high specific surface area (2016.50 m2/g), high specific capacitance (262 F/g), and high rate performance (63%), which is much higher than AC-0% without the pre-oxidation treatment. It is due to that the stable oxygen-containing functional groups (aldehyde and anthraquinone) on coal can improve the activity of activation carbon material and increase the wettability without affecting the electrical conductivity. In addition, the material shows high energy density and cyclic stability. This study provides an effective surface treatment approach for the preparation of a high-performance coal-based supercapacitance electrode material.

Development and Optimization of Water-Soluble Double-Walled Carbon Nanotubes by Effective Surface Treatment of Inner Walls.

Carbon nanotubes are a significant class of nanomaterials with distinctive properties that have led to their application in a variety of fields, such as polymer composites, medicine, electronics, and material science. However, their nonpolar nature and insolubility in polar solvents limit their applications. To address this issue, highly functionalized and water-soluble double-walled carbon nanotubes (DWNTs) were developed by selectively oxidizing the inner walls of the DWNTs using oleum and nitric acid. The impact of reaction time on the chemical functionalization of DWNTs was investigated under two different reaction durations of 2 and 24 h. The presence of highly oxygenated functional groups resulted in high water solubility, which was confirmed by high- and low-frequency Raman spectroscopy, high-resolution transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) method, and optical spectroscopy. The conductivity of highly water-soluble W-DWNTs (24 h) was 122.65 × 102 S cm-1. After annealing for 12 h at 140 °C, the W-DWNTs retained 72% of their conductivity (88.79 × 102 S cm-1).

Experimental Study on Interfacial Shear Behavior of 3D Printed Recycled Mortar.

A novel shear test method on shear bond behavior of 3D printed interlayer interfaces and interstrip interfaces was proposed in this study. Thereafter, the effect of different replacement ratios of recycled sand, printing intervals, and surface treatments were investigated. The test results showed that under the same printing condition, the interfacial shear strengths of interlayer interface and interstrip interface were similar to each other. The interfacial shear strength slightly decreased with the increase of the replacement ratio of recycled sand, while it sharply decreased with the extension of printing interval time. The interfaces in 3D printed recycled mortar had higher time sensitivity compared with 3D printed natural mortar. Considering that discontinuous construction will introduce inferior interfaces in 3D printed concrete components, effective surface treatments should be conducted. According to the test results, the improvement effect of surface treatments was epoxy paste > cement paste > surface wetting > no treatment.

Microstructure and corrosion resistance of chromate conversion coating on cold sprayed aluminum alloy 2024

This paper examines the microstructure and corrosion resistance of chromate conversion coating (CCC) on cold sprayed (CS) aluminum alloy 2024. CCC is an effective surface treatment for aluminum aircraft alloy to improve paint adhesion as well as corrosion resistance. Although the studies of CCC on wrought aluminum alloy have been extensively conducted, understanding the interaction of CCC applied to CS deposits has not yet been addressed in the literature. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and focused ion beam (FIB) were employed for investigating the microstructure of CCC on CS2024 deposits. Potentiodynamic testing, electrochemical impedance spectroscopy (EIS), and immersion testing were performed to probe into corrosion performance of CCC on CS deposit. The results demonstrated that unique intermetallic networks inside the CS deposit formed CCC with more heterogeneous microstructure compared to CCC on wrought counterparts. Although wrought and CS 2024 presented similar corrosion resistance within a short exposure time (<48 h), CCC on CS deposits was more susceptible to corrosion damage, revealed by EIS with an extended exposure time (>48 h). Additionally, distinctive corrosion propagation of CCC on CS deposits along intermetallic networks and prior particle boundaries was seen from the immersion test.

Higher Adhesion Strength Over 10 N/mm Between Rubber and Fluoropolymer Film When Treated by Atmospheric Plasma-Graft Polymerization

An evaluation of the adhesion between rubber and fluoropolymer films treated by atmospheric plasma-graft polymerization is conducted to realize a low-permeation fuel rubber hose covered with fluoropolymer. The low-permeation fuel rubber hose is important for reducing vehicular evaporative emissions. Although fluoropolymers have extremely low permeability for fuel, it is difficult to bond them with other materials, such as rubber, because of their low adhesive properties. Plasma surface modification has been investigated to improve the adhesive properties of fluoropolymers. However, it is difficult to realize effective and permanent surface treatment using plasma alone. Based on the new and effective combined plasma surface-modification technique for fluoropolymer films, we previously proposed an atmospheric-pressure plasma method followed by graft polymerization of hydrophilic monomers such as acrylic acid (CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> = CHCOOH). In this study, three types of rubber, isobutylene isoprene rubber (IIR), ethylene acrylic elastomer (AEM), as well as white-colored ethylene acrylic elastomer (white AEM), and two types of fluoropolymer films, denatured PFA-1 and denatured PFA-2, were prepared. The treated fluoropolymer film and rubber were adhered using vulcanized adhesion, and then the 180° peeling strength test was conducted. The results show that an average peeling strength of 12.6 N/mm and a maximum peeling strength of 15.3 N/mm, which are over 10 N/mm, are attained for the sample of vulcanized bonding of the treated denatured PFA-1 and AEM.

Microshear bond strength of resin cement to a zirconia-reinforced lithium silicate glass ceramic using different surface treatments

Background: The purpose of this study was to evaluate the effect of different surface treatments on the microshear bond strength (μSBS) of resin cement to zirconia-reinforced lithium silicate ceramic and to compare it with lithium disilicate ceramic. Materials and Methods: In this in vitro study, 80 specimens containing two glass ceramics of IPS e.max press and VITA SUPRINITY were prepared and categorized into four groups according to the surface treatments (n = 10) as Group 1 (C): no treatment (control); Group 2 (HF): etching with 9% hydrofluoric acid (HF) for 90 s followed by silane application; Group 3 (SPH): sandblasting with Al2O3 particles (50 μm), etching with 35% phosphoric acid for 40 s followed by application of silane and adhesive (Clearfil liner bond F); and Group 4 (SB): sandblasting with Al2O3 followed by silanization. Then, a resin cement (Panavia F2) was applied to the prepared ceramic surfaces. All samples were subjected to thermal aging (5000 cycles, 5–55). The μSBS test was evaluated and failure modes were recorded. Data were analyzed using the Shapiro–Wilk, two-way analysis of variance and Tukey's Honest Significant Difference post hoc tests (P &lt; 0.05). Results: IPS e.max press samples revealed significantly higher μSBS values compared to VITA SUPRINITY (P &lt; 0.001), in whole surface treatments. The HF group showed the highest μSBS value, followed by the SPH and SB groups, respectively (P &lt; 0.001). Adhesive failure was recorded as a predominant failure mode. Conclusion: The adhesion performance of IPS e.max press was significantly higher than VITA SUPRINITY. The common surface treatment protocol including HF application followed by silanization was the most effective surface treatment for both glass ceramics.

Straightforward and Effective Surface Treatment of Silicon-Carbon Composite Anode Materials for Lithium Ion Battery

Straightforward and Effective Surface Treatment of Silicon-Carbon Composite Anode Materials for Lithium Ion Battery

Efficient inverted CsPbI3 inorganic perovskite solar cells achieved by facile surface treatment with ethanolamine.

The all-inorganic CsPbI3 perovskite presents promising prospects due to its suitable band gap and nonvolatile nature, while serious nonradiative recombination and unmatched energy level alignment hinder its further developments. Here, a facile and effective surface treatment strategy is proposed to modify the CsPbI3 surface with ethanolamine, leading to significantly reduced defects, and ameliorated band alignment and morphology. Consequently, a champion power conversion efficiency of 18.41% with improved stability is achieved for the inverted CsPbI3 solar cells.

An effective laser surface treatment method to reduce biofilm coverage of multiple bacterial species associated with medical device infection

Device associated infection (DAI) is recognized as a worldwide health challenge in total joint replacement (TJR). Bacteria exhibit very strong antibiotic tolerance when they attach to a device and form a biofilm and thus DAI is difficult to treat. In this study, a one-step, clean (no chemicals or additional materials involved) and effective surface engineering approach via laser surface treatment (LST) to tackle the DAI challenge is reported. Commercially pure (CP) Ti were laser-treated in open air using continuous wave (CW) fibre laser. The laser-treated CP Ti was tested against five bacterial species including Gram positive (Staphylococcus aureus and Staphylococcus epidermidis) and Gram negative (Pseudomonas aeruginosa, Escherichia coli and Proteus mirabilis). Live/Dead staining and image analysis results indicated that LST can significantly reduce biofilm coverage of the five tested bacterial species on the CP Ti surfaces. Overall biofilm coverage as a percentage of the surface reduced after laser treatment averaging from 4.24 % to 17.4 %. This meant that relative to the untreated surface, biofilm coverage was reduced after laser treatment, ranging from 84.9 % to 95.6 % across the five species. Furthermore, cytotoxicity results (using MTT assay) showed that the laser-treated CP Ti is non-toxic across both L929 fibroblast and RAW macrophage cell lines. Surface properties after LST were investigated using WLI and AFM (measuring micro-/nano-surface roughness and topography) as well as ToF-SIMS (measuring surface chemistry and oxide thickness), respectively. The cross-sectional microstructure at the surface was imaged using SEM and analysed by XRD, whilst the surface wettability was measured using sessile drop method. To summarise, the reduction of biofilm coverage can be attributed to the favourable changes in surface roughness and topography together with the increased concentration of oxides at the topmost surface after LST.

Influence of surface treatment and ageing on the bond strength of resin cement to hybrid and glass-ceramic CAD/CAM materials.

The influence of different surface treatments and ageing on the shear bond strength (SBS) of computer-aided design/computer-aided manufacturing (CAD/CAM) materials is still contentious. Therefore, this study evaluated the effect of surface treatments and ageing on the SBS of resin cement to polymer-infiltrated ceramic network (PICN) and zirconia-reinforced lithium silicate (ZLS) CAD/CAM materials. Specimens of PICN (n=10) and ZLS (n=10) were submitted to four surface treatment groups: 1) 5% hydrofluoric acid etching (HF) + silanisation (SI); 2) Air abrasion (AB)+HF+SI; 3) HF + universal adhesive (UA); 4) AB+HF+SI+UA. The treated specimens were bonded with resin cement cylinders and tested in SBS after 24 h and one year of water storage. Data were assessed by "analysis of variance" (ANOVA) and Tukey test (α=0.05) and failure modes were classified. No significant differences were observed among treatments at each evaluation time (p>0.05). SBS decreased after one year of storage, except for PICN treated with HF+UA (p=0.068). Air-abraded groups displayed a lower SBS reduction for ZLS. PICN and ZLS exhibited predominantly adhesive and mixed failures, but at one year, PICN cohesive failures increased. In conclusion, HF+UA is an effective surface treatment for PICN, while the combination AB+HF+SI+UA was more appropriate for ZLS. The water storage for one year reduced the SBS for most groups.

Single-crystal Li-rich layered cathodes with suppressed voltage decay by double-layer interface engineering

Despite lithium-rich layered oxides (LLO) are promising candidates for the next-generation cathode materials, the rapid voltage and capacity decay, caused by structural degradation, are primary challenges towards their real-world applications. Herein, via a facial and large-scale treatment method, a robust double layer (DL) cathode-electrolyte interphase (CEI), with outermost layer of amorphous Li3PO4 (LPO) and medium layer of LixNiyMn3-x-yO4 with disordered spinel structure, is uniformly introduced onto the surface of single-crystal Li1.2Ni0.2Mn0.6O2. The double-layer CEI effectively blocks the phase transition from the layered LLO structure into spinel and then rock salt, and thus relieves the voltage decay in cycling. Meanwhile, the CEI blocks the diffusion of TM-ions into the electrolyte and extra O release in cycling, since there are nearly no voids rich in defected rock-salt structure in their edges in the cycled DL-LLO. We further theoretically disclose that the defected rock-salt phase has indeed a high dissolvability of TM and the large irreversibility of O reactivity, which is an accelerator for the structural degradation in cycling. Accordingly, the problems of voltage decay and capacity fading of the modified DL-LLO are greatly relieved and with a voltage drop of only 0.83 mV per cycle and a capacity retention of 82.5 % over 300 cycles at 1 C. This work provides a guidance for effective surface treatment strategies in developing stable Li-rich layered cathodes with high capacity and cyclability.

Eco-friendly and controlled anti-pilling finishing of wool fabric by thiourea dioxide-mediated surface micro-dissolution

PurposeWool, mainly composed of keratin, is a relatively high-grade clothing material. Although woollen textile has the advantages of high wearing comfort and excellent warmth retention property as we have known, its inherent disadvantage of easy pilling has easy puzzled people for a long time. Most of the existing technologies for pilling resistance are not eco-friendly or severely damaged the internal structure of wool.Design/methodology/approachIn this work, a controlled and effective surface treatment method was proposed to controllable micro-dissolution the scale layers of wool with minor damage to its internal structure, thereby improving the anti-pilling property of wool. Thiourea dioxide (TD) is used as a dissolving agent to swell and dissolve wool surface flakes. After TD treatment, the morphology changes of wool fibers were observed by scanning electron microscope (SEM) and methylene blue staining. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to characterize the structural changes of TD wool. At the same time, the anti-pilling properties and wettability of wool fabrics were tested.FindingsThe results show that the wool scale layer is destroyed after TD treatment, which reduces the friction between fibers and improves the anti-pilling performance of wool fabrics. The methylene blue-stained images further demonstrate that low concentrations of TD can damage the superficial scale layer of wool without significant loss of strength.Originality/valueThis method is simple, eco-friendly and economical, and opens up a new direction for the surface treatment of wool fabrics.

Regeneration of interfacial bonding force of waste carbon fibers by light: Process demonstration and atomic level analysis

Although interest in recycling carbon fibers is rapidly growing, practical applications of recycled carbon fibers (rCFs) are limited owing to their poor wettability and adhesion. Surface modification of CFs was achieved through intense pulsed light (IPL) irradiation, which functionalizes surface of rCFs. Surface energy, chemical composition, morphology, and interfacial shear strength (IFSS) of rCFs before and after IPL irradiation were investigated. The rCF IPL-irradiated at 1,200V improved both polar and dispersive components of surface energy, and the IFSS significantly increased by 2.93 times in relation to that of the pristine rCF and reached 95% of that of high-grade commercial CFs. We proposed a mechanism by which oxygen functional groups on the rCF surface enhance the molecular bonding force with HDPE, and the model was validated from molecular dynamics simulations. IPL irradiation is a rapid and effective surface treatment method that can be employed for the manufacture of rCF-reinforced composites.

Covalent immobilization of VEGF on allogeneic bone through polydopamine coating to improve bone regeneration.

Objective: Promoting bone regeneration and repairing in bone defects is of great significance in clinical work. Using a simple and effective surface treatment method to enhance the osteogenic ability of existing bone scaffold is a promising method. In this article, we study the application of catecholic amino acid 3,4-dihydroxyphenylalanine (DOPA) surface coating chelated with vascular endothelial growth factor (VEGF) on allogeneic bone. Method: Allogeneic bone is immersed in DOPA solution and DOPA form polydopamine (PDA) with good adhesion. Electron microscopy is used to characterize the surface characteristics of allogeneic bone. MC3T3-E1 cells were tested for biocompatibility and osteogenic signal expression. Finally, a 12-week rabbit bone defect model was established to evaluate bone regeneration capability. Results: We found that the surface microenvironment of DOPA bonded allogeneic bone was similar to the natural allogeneic bone. VEGF loaded allografts exhibited satisfying biocompatibility and promoted the expression of osteogenic related signals in vitro. The VEGF loaded allografts healed the bone defect after 12 weeks of implantation that continuous and intact bone cortex was observed. Conclusion: The PDA coating is a simple surface modification method and has mild properties and high adhesion. Meanwhile, the PDA coating can act on the surface modification of different materials. This study provides an efficient surface modification method for enhancing bone regeneration by PDA coating, which has a high potential for translational clinical applications.

Effective cotton surface treatment using natural polymer for controlled ink droplet spreading and high-quality inkjet printing images

Digital inkjet printing is a crucial cleaner technology in cotton fabric coloration, but the problem still remains that current cotton surface treatment is inefficient in controlling the spreading of micro-scale ink droplets causing poor image quality and low dye utilization efficiency. In response to this problem, a kind of natural polymer named propylene glycol alginate (PGA) was adopted in cotton surface treatment to gain efficiency and environmental friendliness for cotton inkjet printing. Results show that PGA formed uniform film on fiber surface and in the gaps of fibers, inhibiting the fiber capillary effect. Due to the strong hydration ability of PGA, the ink droplets could be quickly held, preventing the ink spreading. Due to the numerous hydrophobic side groups on PGA molecular structure, the ink penetration was effectively decreased by the PGA film formed on cotton surface, maintaining most dyes on fabric surface with increased color strength. In comparison to polymer-free treated and sodium alginate treated samples, the apparent color depth (K/S value) increased about 1.0–1.7 times for different inks. Moreover, the electrostatic repulsion between reactive dyes and cotton fibers was weakened by the less electronegative PGA film, realizing enhanced dye fixation and desired fastness. And the mechanism of the image quality enhancement was analyzed. This work provides an efficiency method to obtain high-quality inkjet printing image on cotton fabrics and shows great potential in promoting the development of textile inkjet printing.

Investigation in Gas Carburizing of AISI 4140, EN36, and 16MnCr5 Steels Using the Grey Incidence-Based Taguchi (GIBT) Method

Gas carburizing is an effective surface treatment process for improving the hardness and wear resistance of different class of steels. The study reports an application of grey-incidence based Taguchi (GIBT) method in gas carburizing of case-hardening steels like AISI 4140, EN36, and 16MnCr5 which are widely employed in precision levers, transmission shafts, and pinions. Carburizing trials are performed using Taguchi’s L9 orthogonal array by varying the design parameters like carburizing temperature, soaking time, and tempering temperature. Surface hardness (SH), diffusion depth (DD), and wear loss (WL) are studied as process responses at the completion of various carburizing trials with replications. Optimal design variables are identified using grey incidence grade as a performance index in the GIBT method. The contribution of individual parameters is also studied using the analysis of variance (ANOVA). Microscopic examination and SEM images of the treated surface are also studied after validating the method of GIBT.

Surface treatment enabled by functional guanidinium tetrafluoroborate achieving high-performance inverted perovskite solar cells

Defects at the surface of perovskite films are considered as the main origins of efficiency loss and instability, which has severely limited the commercialization of perovskite solar cells (PSCs). Herein, a novel functional ionic compound, guanidinium tetrafluoroborate (GuaBF 4 ), is introduced into the CH 3 NH 3 PbI 3 (MAPbI 3 )/[6,6]-phenyl-C 61 -butyric acid methyl ester (PC 61 BM) interface for the surface defect passivation of perovskite films. Thanks to the synergistic effect of Gua + and BF 4 − , the GuaBF 4 surface treatment can endow the MAPbI 3 film with larger grains, smoother surface, higher crystallinity, efficiently-passivated surface defects and optimized interfacial energy level alignment. Meanwhile, systematical optical and electrical studies have demonstrated that the GuaBF 4 surface treatment can suppress trap-assisted carrier recombination loss and reduce the charge accumulation at the MAPbI 3 /PC 61 BM interface, thus promoting charge carrier transport and extraction. Based on the GuaBF 4 surface treatment, the power conversion efficiency (PCE) of devices increases from 18.09% to 20.54% for small devices (active area 0.10 cm 2 ) and from 12.35% to 15.52% for large devices (active area 1.0 cm 2 ). Moreover, PSCs undergone GuaBF 4 surface treatment display the reduced hysteresis behavior, increased moisture stability and high reproducibility. Our work provides a new surface treatment approach by functional ionic compounds for passivating surface-defects, thus achieving high-performance PSCs. A novel surface treatment enabled by guanidinium tetrafluoroborate (GuaBF 4 ) is developed to improve the efficiency and stability of inverted planar PSCs. • A novel and effective surface treatment strategy enabled by GuaBF 4 is developed. • The synergistic effect of Gua + and BF 4 − can improve the quality of CH 3 NH 3 PbI 3 films. • The surface treatment can promote the interfacial charge transport and extraction. • Device efficiency and stability are effectively improved using this strategy.

The influence of roller burnishing process parameters on surface quality and fatigue life of AA 7075‐T6 alloy

AbstractRoller burnishing method is a low‐cost and effective surface treatment method that has been frequently preferred in recent years. In this method the surface roughness is minimized by small plastic deformations, without removing chips from the surfaces, caused by the rolling element pressed against the surface with a certain force. While the surface hardness of the material increases in the process, the surface roughness decreases significantly. In this study, the effects of the process parameters of roller burnishing method (burnishing pressure and number of passes) on AA7075‐T6 aluminum alloy in terms of fatigue strength and surface roughness were investigated experimentally. Taguchi L9 experimental design method was used in the study, and the burnishing process was carried out by a specially produced disc‐shaped apparatus. As a result of the study, it was determined that the roller burnishing method increased both the fatigue strength and surface quality of AA 7075 T6 alloy. In consequence of roller burnishing, it was determined that fatigue life and surface roughness values improved by 116 % and 96 %, respectively.