New Method For Surface Modification Research Articles

Enhanced Nanotwinned Copper Bonding through Epoxy-Induced Copper Surface Modification.

For decades, Moore's Law has neared its limits, posing significant challenges to further scaling it down. A promising avenue for extending Moore's Law lies in three-dimensional integrated circuits (3D ICs), wherein multiple interconnected device layers are vertically bonded using Cu-Cu bonding. The primary bonding mechanism involves Cu solid diffusion bonding. However, the atomic diffusion rate is notably low at temperatures below 300 °C, maintaining a clear and distinct weak bonding interface, which, in turn, gives rise to reliability issues. In this study, a new method of surface modification using epoxy resin to form fine grains on a nanotwinned Cu film was proposed. When bonded at 250 °C, the interfacial grains grew significantly into both sides of the Cu film. When bonded at 300 °C, the interfacial grains extended extensively, eventually eliminating the original bonding interface.

PMMA-Grafted Calcium Sulfate Whiskers for Applications as Fillers in PVC.

Calcium sulfate whiskers (CSWs) were hydroxylated with a sodium hydroxide (NaOH) solution and isolated for subsequent treatment with an ethanolic 3-(methacryloxy)propyltrimethoxysilane (KH570) solution to introduce C=C double bonds on the CSWs’ surfaces. Then, CSW-g-PMMA was prepared by grafting polymethyl methacrylate (PMMA) onto the surface of modified CSW using in situ dispersion polymerization. The CSW-g-PMMA was used as a filler and melt-blended with polyvinyl chloride (PVC) to prepare PVC-based composites. The surface chemical structure, PMMA grafting rate, and hydrophobic properties of CSW-g-PMMA were analyzed using X-ray diffraction, diffuse reflectance Fourier-transform infrared spectroscopy, thermogravimetric analysis, and water contact angle measurements, respectively. The effects of the CSW-g-PMMA filler on the mechanical properties of the CSW-PMMA/PVC composites were also investigated. The results showed that NaOH treatment significantly increased the number of hydroxyl groups on the surface of the CSWs, which facilitated the introduction of KH570. PMMA was successfully grafted onto the KH570 with a grafting rate of 14.48% onto the surface of the CSWs. The CSW-g-PMMA had good interfacial compatibility and adhesion properties with the PVC matrix. The tensile, flexural, and impact strengths of the CSW-g-PMMA/PVC composite reached 39.28 MPa, 45.69 MPa, and 7.05 kJ/m2, respectively, which were 38.55%, 30.99%, and 20.10% higher than those of the CSW/PVC composite and 54.52%, 40.80%, and 32.52% higher than those of pure PVC, respectively. This work provides a new method for surface modification of inorganic fillers, resource utilization, and high value-added application of CSWs from phosphogypsum.

Sulfuric acid modified magnetorheological finishing of polycrystalline magnesium aluminate spinel

Polycrystalline magnesium aluminate spinel has excellent optical, mechanical, and chemical properties; making it an ideal material for critical optical parts under extreme conditions, and it has broad application prospects in aerospace. The high hardness and polycrystalline nature of the material bring significant challenges to high-precision spinel processing, especially in magnetorheological finishing (MRF), where low processing efficiency, polishing ripples and grain effect appear during polishing, leading to degradation of processing accuracy, surface quality and optical performance. To achieve high-efficiency and high-quality MRF of spinel, a new method of surface modification of spinel with sulfuric acid followed by MRF is proposed. The effect of sulfuric acid modification on the removal efficiency and surface roughness of spinel MRF was studied. Furthermore, the material properties of the spinel surface before and after modification were analyzed by nanoindentation, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Additionally, the mechanism of sulfuric acid etching assisted MRF was investigated. The sulfuric acid modification softens the spinel surface and removes the surface damage layer, and the modified layer can be used as a sacrificial layer to suppress the grain effect. The results showed that the sulfuric acid modification improved the MRF efficiency by 2.46 times, and decreased the peak-valley values of the grain effect and the average residual stress by 69.6% and 54.5%, respectively.

Technological Features for Controlling Steel Part Quality Parameters by the Method of Electrospark Alloying Using Carburezer Containing Nitrogen-Carbon Components.

A new method of surface modification based on the method of electrospark alloying (ESA) using carburizer containing nitrogen—carbon components for producing coatings is considered. New processes have been proposed that include the step of applying saturating media in the form of paste-like nitrogenous and nitrogenous-carbon components, respectively, onto the surface without waiting for those media to dry, conducting the ESA process with the use of a steel electrode-tool, as well as with a graphite electrode-tool. Before applying the saturating media, an aluminium layer is applied onto the surface with the use of the ESA method at a discharge energy of Wp = 0.13–6.80 J. A saturating medium in the form of a paste was applied to the surfaces of specimens of steel C22 and steel C40. During nitriding, nitrocarburizing and carburization by ESA (CESA) processes, with an increase in the discharge energy (Wp), the thickness, micro hardness and continuity of the “white layer” coatings, as well as the magnitude of the surface roughness, increase due to saturation of the steel surface with nitrogen and/or carbon, high cooling rates, formation of non-equilibrium structures, formation of special phases, etc. In the course of nitriding, nitrocarburizing and CESA processing of steels C22 and C40, preliminary processing with the use of the ESA method by aluminum increases the thickness, microhardness and continuity of the “white layer”, while the roughness changes insignificantly. Analysis of the phase composition indicates that the presence of the aluminum sublayer leads to the formation of the aluminum-containing phases, resulting in a significant increase in the hardness and, in addition, in an increase in the thickness and quality of the surface layers. The proposed methods can be used to strengthen the surface layers of the critical parts and their elements for compressor and pumping equipment.

Activation of the Basal Plane in Two Dimensional Transition Metal Chalcogenide Nanostructures.

Achieving a molecular level understanding of chemical reactions on the surface of solid-state nanomaterials is important, but challenging. For example, the fully saturated basal plane is believed to be practically inert and its surface chemistry has been poorly explored, while two-dimensional (2D) layered transition-metal chalcogenides (TMCs) display unique reactivities due to their unusual anisotropic nature, where the edges consisting of unsaturated metals and chalcogens are sites for key chemical reactions. Herein, we report the use of Lewis acids/bases to elucidate the chemical reactivity of the basal plane in 2D layered TMCs. Electrophilic addition by Lewis acids (i.e., AlCl3) selectively onto sulfides in the basal plane followed by transmetalation and subsequent etching affords nanopores where such chemical activations are initiated and propagated from the localized positions of the basal plane. This new method of surface modification is generally applicable not only to various chemical compositions of TMCs, but also in crystal geometries such as 1T and 2H. Nanoporous NbS2 obtained by this method was found to have an enhanced electrochemical energy storage capacity, offering this chemical strategy to obtain functional 2D layered nanostructures.

Bonding PDMS Microfluidic Devices to PMMA and Glass Substrate Using Pulsed UV Laser Technology

This study presents a new method for surface modification of polymeric materials by using pulsed UV laser welding technology. The bonding procedures including ablation treatment, Oxygen plasma treatment, adhesive layer bonding and cured by pulsed UV laser writing system was exhibited. The investigation of various parameters for UV laser writing system was performed and discussed by using water contact angle measurement. This technique has been successfully applied to bond dissimilar polymer substrates (polydimethylsiloxane (PDMS) to polymethylmethacrylate (PMMA)). The scanning electron microscopy (SEM) image reveals clearly that there was no clogging in the microchannel or deformation observed between PDMS and PMMA. The method was straightforward and the integrity of microfluidic features was successfully preserved after bonding.

A new method for surface modification of TiO2/Al2O3 nanocomposites with enhanced anti-friction properties

In this paper, the TiO2/Al2O3 composite nanoparticles were prepared by a hydrothermal method and in situ modified with acrylic acid. It was found that the mean particle size of modified TiO2/Al2O3 composite nanoparticles was about 80nm with a uniform distribution by the particle size analysis. The modified TiO2/Al2O3 composite nanoparticles can disperse in lubricating oil homogenously for several weeks. The dispersion stabilization of modified TiO2/Al2O3 composite nanoparticles in lubricating oil was significantly improved in comparison with the as-prepared nanoparticles, which was due to the introduction of grafted polymers by surface modification. The formation of covalent bands was identified by Fourier transform infrared spectrum. Under an optimized concentration of 0.1wt%, the averaged friction coefficient was reduced by 14.75%, when the modified TiO2/Al2O3 composite nanoparticles were used as lubricating oil additivities.

A novel surface modification technique for forming porous polymer monoliths in poly(dimethylsiloxane).

A new method of surface modification is described for enabling the in situ formation of homogenous porous polymer monoliths (PPMs) within poly(dimethylsiloxane) (PDMS) microfluidic channels that uses 365 nm UV illumination for polymerization. Porous polymer monolith formation in PDMS can be challenging because PDMS readily absorbs the monomers and solvents, changing the final monolith morphology, and because PDMS absorbs oxygen, which inhibits free-radical polymerization. The new approach is based on sequentially absorbing a non-hydrogen-abstracting photoinitiator and the monomers methyl methacrylate and ethylene diacrylate within the walls of the microchannel, and then polymerizing the surface treatment polymer within the PDMS, entangled with it but not covalently bound. Four different monolith compositions were tested, all of which yielded monoliths that were securely anchored and could withstand pressures exceeding the bonding strength of PDMS (40 psi) without dislodging. One was a recipe that was optimized to give a larger average pore size, required for low back pressure. This monolith was used to concentrate and subsequently mechanical lyse B lymphocytes.

“Grafting From” Polymerization of Vinylidene Fluoride (VDF) from Silica to Achieve Original Silica–PVDF Core–Shells

A new method of surface modification based on the “grafting from” polymerization process enabled to prepare original silica nanoparticles covered with PDVF “hair”. This strategy involved two steps: (i) the radical addition of 1,4-diiodoperfluorobutane initiated by tert-butylperoxypivalate onto the double bonds of silica nanoparticles (specific area of 150 m2 g–1) led to silica that bore C4F8I end-groups on its surface, and (ii) its use as original macrochain transfer agent in the “grafting from” polymerization of vinylidene fluoride (VDF) initiated by bis(4-tert-butylcyclohexyl) peroxydicarbonate. The characterizations of both modified silica were achieved by elemental analysis, 1H and 19F magic angle spinning solid state rotational-echo double resonance NMR spectroscopy, thermogravimetry, and water contact angle (WCA) assessments. The grafting efficiency was confirmed by three features: (i) the increase of weight percentage of fluorine atom (that ranged from 0 for the starting unsaturated silica to 2.50% for silica-bearing −C4F8I end-group and to 3.32% for original silica–PVDF core–shells), (ii) a high thermostability (that reached more than 400 °C under air), and (iii) a good hydrophobicity: the WCA values were ranging from 84° to 109° and to 126° for vinyl silica, for silica coated with −C4F8I, and for PVDF-covered silica nanoparticles, respectively.

A new method for surface modification of nano-CaCO 3 and nano-Al 2O 3 at room temperature

Nano-CaCO 3 and nano-Al 2O 3 were modified using chloroform as solvent and fatty acid as modifier at room temperature. This modification process at room temperature can reduce energy consumption greatly. The results of Fourier transform infrared spectrometry (FT-IR) and transmission electron microscopy (TEM) demonstrated this modification process at room temperature was feasible. This new method for surface modification of nano-CaCO 3 and nano-Al 2O 3 at room temperature has the potential to become a general method for surface modification of more nanoparticles.

Nanocomposites of poly( l-lactide) and surface-grafted TiO 2 nanoparticles: Synthesis and characterization

A new method of surface modification of TiO 2 nanoparticles by surface-grafting l-lactic acid oligomer was developed. The surface-grafting reaction was evaluated by Fourier transformation infrared (FTIR) and thermal gravimetric analysis (TGA). The results showed that l-lactic acid oligomer could be easily grafted onto the TiO 2 nanoparticles surface in the presence of stannous octanoate and the highest amount of grafted polymer was about 8.5% in weight. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) results showed that grafted TiO 2 (g-TiO 2) in chloroform or PLLA matrix approximated to uniform, while unmodified TiO 2 nanoparticles tended to aggregate. The tensile strength of this material was greatly improved by the addition of g-TiO 2 nanoparticles in poly( l-lactide) (PLLA) matrix. The tensile strength of the g-TiO 2/PLLA nanocomposite containing 5 wt.% of g-TiO 2 was 72 MPa, which was 23.1% higher than that of pure PLLA. Even though the incorporation of the TiO 2 nanoparticles into PLLA led to the deterioration of its elongation at break, the g-TiO 2/PLLA nanocomposite also exhibited better ductility than that of TiO 2/PLLA nanocomposite.

Construction of Nonbiofouling Biofunctional Glass Surface by Self-Assembled Monolayer and Graft Hydrophilic Polymer

This paper introduces a new method of surface modification by self-assembled monolayer (SAM) and polymer monolayer grafting. Since most of the glass surfaces lack the reactive functional group, an activation process with 3-(trimethoxysilyl)propyl methacrylate(TPM) is used in our experiment to generate the vinyl reactive sites on the substrate surface for further graft polymerization. The TPM saline layer acts as the “anchor” part to link the functional part onto the surface of substrate. The paper summarizes the surface modifications by the polymerizations of PEGMA, AA(Acrylic acid) and NVP(Nitrogen-vinyl-2-pyrrolidone) respectively and their applications for protein adsorption and cell adhesion through a series of measurements. In previous research, AA and NVP had also been adopted for surface treatment and had achieved good results. The substrate can be glass, alumina, silicon, metals or stainless steel. We choose glass as our substrate during the experiment.

Laser interference metallurgy: A new method for periodic surface microstructure design on multilayered metallic thin films

Methods for micro- and nanostructuring are essential for functionalization of materials surfaces. In particular, photon-assisted methods for synthesis of functional surfaces have been intensively investigated in the last years. In this study, a new method for surface modification and production of long-range order periodical structures called “laser interference metallurgy” is explored. A metallic thin film sample consisting of three layers composed of Fe, Cu and Al (from top to bottom) on a glass substrate was irradiated with an interference pattern using a Nd:YAG laser (wavelength of 355 nm, 10 ns of pulse duration). For the interference pattern, a configuration producing a line-type energy distribution was chosen. The laser fluence was high enough to melt the aluminium and copper layers at the interference maxima but the iron layer remained in the solid state. Thus, diffusive and convective exchange occurred between aluminium and copper at the energy maxima positions leading to periodical alloy formation with a long-range order. Because it remained in solid state, the iron layer at the top acted as a protective layer effectively preventing removal of the molten layers. The interaction of the different layers was characterized using FIB, TEM and EDX in STEM mode.

Surface modification of titanium‐based alloys with bioactive molecules using electrochemically fixed nucleic acids

A new method of surface modification for titanium (alloys) with bioactive molecules was developed with the intention of providing a new basis of implant adaptation for particular requirements of certain medical indications. Nucleic acid single strands are fixed electrochemically via their termini (regiospecifically) by growing an oxide layer on Ti6Al7Nb anodically. It could be shown that they are accessible to subsequent hybridization with complementary strands at physiological pH. Amount of nucleic acids immobilized and hybridized were determined radioanalytically using 32P-labelled nucleic acids. Stable fixation was attained at and above potentials of 4 V(SCE). Up to 4 pmol/cm2 of nucleic acid single strands could be immobilized and hybridization efficiencies up to 1.0 were reached. Hybridization efficiency was found to depend on surface density of immobilized oligonucleotides, while hybridization rates increased when MgCl2 was added. A conjugate consisting of an oligonucleotide complementary to the immobilized strand and the hexapeptide GRGDSP with RGD as an integrin recognition site was synthesized. This conjugate was able to bind to integrins on osteoblasts. It was shown that this conjugate binds to the anchor strand fixed on Ti6Al7Nb to an extent comparable with the unconjugated complementary strand.

Microstructure and properties of coatings with rare earth formed by DC-plasma jet surface metallurgy

A new method of surface modification, DC-plasma jet surface metallurgy, is proposed in order to improve wear resistance of materials. This paper reports on an experiment, in which some metallurgical coatings of iron-based alloy with different contents of La 2O 3 and CeO 2 were prepared on AISI1020 steel using a homemade DC-plasma jet surface metallurgy equipment. A scanning electron microscope (SEM), energy dispersive X-ray (EDX) microanalysis and X-ray diffraction analysis (XRD) were employed to observe the microstructure and analyzed the chemical compositions of coatings. The effect of RE oxide (La 2O 3 and CeO 2) on microstructure and properties of coatings was investigated. The result shows that addition of a proper amount of RE oxide (La 2O 3 and CeO 2) can refine and purify the microstructure, significantly increase microhardness and enhance the wear resistance.

Hydroxyapatite Surface Modified by l-Lactic Acid and Its Subsequent Grafting Polymerization of l-Lactide

A new method of surface modification of hydroxyapatite nanoparticles (n-HA) by surface grafting reaction of l-lactic acid and ring-opening polymerization of l-lactide (LLA) was developed. Two modified HA nanoparticles were obtained: HA modified by l-lactic acid (l-HA) and HA grafting with poly(l-lactide) (PLLA; p-HA). The modified surface of n-HA was attested by Fourier transformation infrared, (31)P MAS NMR, and thermal gravimetric analysis. The results showed that l-lactic acid could be easily grafted onto the n-HA surface by forming a Ca carboxylate bond and initiated by the hydroxyl group of the grafted l-lactic acid and LLA could be graft-polymerized onto the n-HA surface in the presence of stannous octanoate. The highest grafting amounts of l-lactic acid and PLLA were about 33 and 22 wt %, respectively. The modified HA/PLLA composites showed good mechanical properties and uniform microstructure. The tensile strength and modulus of the p-HA/PLLA composite containing 15 wt % of p-HA were 67 MPa and 2.1 GPa, respectively, while those of the n-HA/PLLA composites were 45 MPa and 1.7 GPa, respectively. The elongation at the break of the l-HA/PLLA composite containing 15 wt % l-HA could reach 44%, in comparison with 6.5% of the n-HA/PLLA composites containing 15 wt % n-HA.

アーク表面合金化によるニオブのアルミナイド被覆

A new method for surface modification based on the arc surface alloying has been proposed and its feasibility has been investigated performing niobium aluminide coating on a niobium base metal. When tungsten arc was used to melt an aluminum plate placed on a niobium block, the niobium surface was also melted and a melt pool of an Al-Nb binary alloy was formed on the niobium block. The melt pool solidified into niobium aluminides on the surface of the niobium block, forming a thick NbAl3 layer on the top surface of the coating layer. When an Al-Si alloy plate was used instead of the aluminum plate, a niobium aluminosilicide layer was formed on the niobium block.

Cavitation Shotless Peening for Surface Modification of Alloy Tool Steel

Cavitation Shotless Peening (CSP) is a new method of surface modification. Cavitation impacts induced by the collapse of cavitation bubbles produce compressive residual stress and work hardens the material surface. In the case of CSP, shots are not required and therefore we call it Cavitation Shotless Peening. In CSP, cavitation is induced by a submerged high-speed water jet, i. e., a cavitating jet, for which the intensity and region of cavitation impact can be controlled by parameters such as the upstream pressure and nozzle size. The authors have already shown that the lifetime of forging die treated by CSP can be extended by about 50% compared with non-peened forging die. In this paper, in order to make clear the mechanism by which the lifetime of forging die is increased, an alloy tool steel (JIS SKD61) was tested both in peened and non-peened conditions. Compressive residual stress was measured by an X-ray diffraction method. It was evident from a comparison between the non-peened specimen and the cavitation shotless peened specimen that CSP improved the mechanical properties of the forging die thus giving it a longer lifetime.

Planarization of a Layer Made by Using Electrical Discharge Machining

This paper describes a new method of surface modification by EDM to create a hard surface on a workpiece and planarization of a layer. When a metallic material that makes hard carbide is used as an electrode in EDM, a hard layer can be made under certain condition. The process begins with the electrode wear by heat of the electrical discharge. Then the worn electrode material becomes hard carbide. The carbide piles up on the workpiece and becomes a layer. The layer formed by two or more electrical discharges has a problem that performance of the layer, its roughness and hardness, is not enough. Then, in order to improve the layer performance, the influence that a gap width exerts on the layer performance was studied. The increase in the gap width resulted in improving the layer performance.

Aluminide Coating on Niobium by Arc Surface Alloying

A new method for surface modification based on the arc surface alloying has been proposed and its feasibility has been investigated performing niobium aluminide coating on a niobium base metal. When tungsten arc was used to melt an aluminum plate placed on a niobium block, the niobium surface was also melted and a melt pool of an Al–Nb binary alloy was formed on the niobium block. The melt pool solidified into niobium aluminides on the surface of the niobium block, forming a thick NbAl3 layer on the top surface of the coating layer. When an Al–Si alloy plate was used instead of the aluminum plate, a niobium almino–silicide layer was formed on the niobium block.