scholarly journals Adhesion and Cohesion

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
J. Anthony von Fraunhofer
Keyword(s):  
Substrate Surface ◽  
Dissimilar Materials ◽  
Surface Wetting ◽  
Adhesive Dentistry ◽  
Adhesion Failure ◽  
Mechanical Adhesion ◽  
Adhesion Zone ◽  
Underlying Mechanisms ◽  
Adhesive Materials ◽  
Mechanisms Of Adhesion

The phenomena of adhesion and cohesion are reviewed and discussed with particular reference to dentistry. This review considers the forces involved in cohesion and adhesion together with the mechanisms of adhesion and the underlying molecular processes involved in bonding of dissimilar materials. The forces involved in surface tension, surface wetting, chemical adhesion, dispersive adhesion, diffusive adhesion, and mechanical adhesion are reviewed in detail and examples relevant to adhesive dentistry and bonding are given. Substrate surface chemistry and its influence on adhesion, together with the properties of adhesive materials, are evaluated. The underlying mechanisms involved in adhesion failure are covered. The relevance of the adhesion zone and its importance with regard to adhesive dentistry and bonding to enamel and dentin is discussed.

scholarly journals Hybrid Approaches for Selective Laser Sintering by Building on Dissimilar Materials

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5285
Author(s):  
Babette Goetzendorfer ◽  
Thomas Mohr ◽  
Ralf Hellmann
Keyword(s):  
Substrate Surface ◽  
Selective Laser Sintering ◽  
Dissimilar Materials ◽  
Polyamide 6 ◽  
Laser Sintering ◽  
New Approach ◽  
Metallic Substrates ◽  
Polyamide 12 ◽  
Melting Temperatures ◽  
Hybrid Approaches

We introduced a new approach in selective laser sintering for hybrid multicomponent systems by fabricating the sintered polyamide 12 (PA12) part directly onto a similar (PA12) or dissimilar (polyamide 6 (PA6) and tool steel 1.2709) joining partner. Thus, the need for adhesive substances or joining pressure was completely circumvented, leading to the possibility of pure hybrid lightweight bi-polymer or metal–polymer systems. By taking advantage of the heating capabilities of the sinter laser regarding the substrate surface, different exposure strategies circumvented the lack of overlapping melting temperatures of dissimilar polymers. Therefore, even sintering on non-PA12 polymers was made possible. Finally, the transfer on metallic substrates—made up by selective laser melting (SLM)—was successfully performed, closing the gap between two powder-based additive processes, selective laser sintering (SLS) and SLM.

Surface Energy and Crystallite Size Comparisons by Applying Direct Current and Pulse Direct Current on Substrate Bias in PVD Process

2013 ◽  
Vol 315 ◽  
pp. 98-102
Author(s):  
H. Hanizam ◽  
Md Nizam Abd Rahman ◽  
Noraiham Mohamad ◽  
A.R. Soufhwee
Keyword(s):  
Surface Energy ◽  
Crystallite Size ◽  
Direct Current ◽  
Substrate Surface ◽  
Film Coating ◽  
Xrd Analysis ◽  
Substrate Bias ◽  
X Ray Diffraction ◽  
Adhesion Failure

Surface morphology homogeneity and energy modifications for in situ PVD process are two critical factors to prevent unexpected adhesion failure during machining or service. Unlike during film depositing, there is still much gap to be explored on applying pulsed biasing concepts to the substrate during in situ, to ensure the substrate surface readiness prior to film coating. The purpose of this paper is to study the effects of conventional direct current (DC) and pulse direct current (PDC) applied at substrate bias to the surface energy and crystallite size. Tungsten carbide (WC) cutting tool insert and titanium nitride (TiN) were used as substrate and hard coating respectively. The runs were conducted to compare the bias at DC (-500V) and PDC (-200V, -500V, -800V). The surface energy and crystallite size were characterized through wettability test and X-ray diffraction (XRD) analysis. The applying of PDC on the substrate bias was found to further enhance the characteristics of the surface compared to the conventional DC substrate bias.

scholarly journals Adhesive materials and technology – Brazil & Japan

2018 ◽  
Vol 21 (2) ◽  
pp. 144
Author(s):  
Marcelo Giannini ◽  
Toru Nikai ◽  
Junji Tagami
Keyword(s):  
Joint Symposium ◽  
Adhesive Dentistry ◽  
Adhesive Materials

<p><strong><span style="text-decoration: underline;">BRAZIL-JAPAN JOINT SYMPOSIUM ON ADHESIVE DENTISTRY 2017</span></strong></p>

Enhanced Coercivity in BiFeO3/SrRuO3heterostructures

MRS Advances ◽  
2016 ◽  
Vol 1 (9) ◽  
pp. 597-602 ◽  
Author(s):  
Srinivasa Rao Singamaneni ◽  
J. T. Prater ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Domain Walls ◽  
Dissimilar Materials ◽  
Substrate Material ◽  
Buffer Layers ◽  
Oxide Thin Film ◽  
Magnetic Data ◽  
Piezo Force Microscopy ◽  
Underlying Mechanisms

ABSTRACTTransition metal oxide thin film heterostructures have garnered increasing research interest in the last decade due to their multifunctional properties, such as ferromagnetism and ferroelectricity, which may be utilized in next generation device applications. Many previous works reported on the deposition of such structures on oxide substrates such as SrTiO3, which are not compatible with CMOS applications where Si(100) is the mainstay substrate material. BiFeO3(BFO) is a room temperature insulating ferroelectric and antiferromagnet, a well-known multiferroic material. SrRuO3(SRO) is a ferromagnetic metal with the Curie temperature (TC) of 165K. Unexpected properties emerge when these two dissimilar materials are conjoined. However, there has been no report on exploring the magnetic properties of BFO when it is in contact with SRO, and particularly when they are integrated with Si(100) substrates, which is the subject of present study. BFO/SRO thin films have been epitaxially grown on Si (100) substrates by introducing MgO/TiN epitaxial buffer layers using pulsed laser deposition. BFO thin films show room temperature ferroelectricity as observed from piezo force microscopy (PFM) measurements. The magnetic data collected from BFO thin films show typical antiferromagnetic features as expected. The TCof SRO in all the samples studied was found be ∼ 170K, close to the reported value of 165K. Interestingly, we have noticed that the coercive field of SRO layer increased from 4 kOe to 15 kOe (nearly fourfold) by reducing its thickness from 180 to 23nm, while keeping the thickness of BFO layer constant at 100nm. Pinning of Ru ions by ferroelectric domain walls in BFO, strong interfacial exchange coupling and SRO layer thickness could cause the observed enhancement in coercivity. Our near future work will address the precise underlying mechanisms in greater detail.

scholarly journals Application of Glow Discharge Plasma for Cleaning (Activation) and Modification of Metal Surfaces while Welding, Brazing, and Coating Deposition

2021 ◽  
Vol 22 (1) ◽  
pp. 103-128
Author(s):  
M. G. Bolotov ◽  
I. O. Prybytko
Keyword(s):  
Glow Discharge ◽  
Metal Surface ◽  
Metal Surfaces ◽  
Discharge Plasma ◽  
Diffusion Processes ◽  
Substrate Surface ◽  
Dissimilar Materials ◽  
Glow Discharge Plasma ◽  
Chamber Pressure ◽  
Discharge Current Density

As known, the surface phenomena play a crucial role in the formation of strong interatomic bonds while joining dissimilar materials and the deposition of metal films. Thus, the presence of various contaminants, including oxides, on the metal surface reduces drastically the metal surface energy, thereby, preventing the diffusion processes in the contact zone and wetting them with liquid solder and adhesion of condensed films on the substrate surface. As a result, the processes of cleaning (activating) of metal surfaces before welding or coatings’ deposition begin to play a significant role. In some cases, metal surfaces have to be modified in order to give them the desired properties. Recently, for activation and modification of surfaces before welding and coatings’ deposition, gas-discharge plasma of abnormal glow discharge is widely used. The latter allows treating the surfaces of different configurations, including internal cavities, and various areas from units to tens of thousands of square centimetres. This review contains the results of research on the activation and modification of metal surfaces with low-energy ions (< 10 keV) initiated in the plasma of an abnormal glow discharge for welding, brazing, and coatings’ deposition. Particularly, we present results of studies of ion treatment with the glow discharge surface of samples, which are made of steels С45 and DC04, a number of active metals and alloys as well as chromium-containing steels 41Cr4, X20Cr13, and X6CrNiTi18-10, which possess the chemically and thermally stable Cr2O3 oxides on their surfaces. The decisive influence on the efficiency of purification and modification of metal surfaces with glow discharge by means of such regime parameters as electrode voltage, discharge current density, working chamber pressure, and ion exposure time is indicated. The optimal values of these parameters, in most cases, are determined by the technological conditions of the process and vary in the following ranges: U = 1500–3500 V, J = 0.4–1 mA/cm2, P = 3.99–7.98 Pa, t = 120–300 s, respectively.

scholarly journals Thermodynamic Modeling of Solvent-Assisted Lipid Bilayer Formation Process

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 134
Author(s):  
Hongmei Xu ◽  
Hyunhyuk Tae ◽  
Nam-Joon Cho ◽  
Changjin Huang ◽  
K. Jimmy Hsia
Keyword(s):  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Thermodynamic Modeling ◽  
Formation Process ◽  
Lipid Membrane ◽  
Substrate Surface ◽  
Experimental Conditions ◽  
Wide Range ◽  
Underlying Mechanisms ◽  
Compositional Diversity

The solvent-assisted lipid bilayer (SALB) formation method provides a simple and efficient, microfluidic-based strategy to fabricate supported lipid bilayers (SLBs) with rich compositional diversity on a wide range of solid supports. While various studies have been performed to characterize SLBs formed using the SALB method, relatively limited work has been carried out to understand the underlying mechanisms of SALB formation under various experimental conditions. Through thermodynamic modeling, we studied the experimental parameters that affect the SALB formation process, including substrate surface properties, initial lipid concentration, and temperature. It was found that all the parameters are critically important to successfully form high-quality SLBs. The model also helps to identify the range of parameter space within which conformal, homogeneous SLBs can be fabricated, and provides mechanistic guidance to optimize experimental conditions for lipid membrane-related applications.

scholarly journals Adhesion of mussel foot proteins to different substrate surfaces

2013 ◽  
Vol 10 (79) ◽  
pp. 20120759 ◽  
Author(s):  
Qingye Lu ◽  
Eric Danner ◽  
J. Herbert Waite ◽  
Jacob N. Israelachvili ◽  
Hongbo Zeng ◽  
...  
Keyword(s):  
Contact Time ◽  
Substrate Surface ◽  
Surface Forces ◽  
Recent Analysis ◽  
Surface Forces Apparatus ◽  
Substrate Surfaces ◽  
New Generation ◽  
Surface Chemistries ◽  
Adhesive Materials

Mussel foot proteins (mfps) have been investigated as a source of inspiration for the design of underwater coatings and adhesives. Recent analysis of various mfps by a surface forces apparatus (SFA) revealed that mfp-1 functions as a coating, whereas mfp-3 and mfp-5 resemble adhesive primers on mica surfaces. To further refine and elaborate the surface properties of mfps, the force–distance profiles of the interactions between thin mfp (i.e. mfp-1, mfp-3 or mfp-5) films and four different surface chemistries, namely mica, silicon dioxide, polymethylmethacrylate and polystyrene, were measured by an SFA. The results indicate that the adhesion was exquisitely dependent on the mfp tested, the substrate surface chemistry and the contact time. Such studies are essential for understanding the adhesive versatility of mfps and related/similar adhesion proteins, and for translating this versatility into a new generation of coatings and (including in vivo ) adhesive materials.

Effect of Prelube, Surface Coating and Substrate Materials on Initial Strength of Adhesive Joints Between Al Alloy and Steels

2011 ◽  
Author(s):  
Fan Zhang ◽  
Hui-Ping Wang ◽  
Christina Hicks ◽  
Blair E. Carlson ◽  
Xin Yang ◽  
...  
Keyword(s):  
Bond Strength ◽  
Substrate Surface ◽  
Dissimilar Materials ◽  
Failure Behavior ◽  
Al Alloy ◽  
Initial Strength ◽  
Automotive Body ◽  
Lap Shear ◽  
Identical Material ◽  
Automotive Production

Growing usage of lightweight materials such as Al and Mg alloys in automotive body manufacture has come to a point that bonding of dissimilar materials is a realistic problem to address. A significant issue related to the bonding of dissimilar materials is that the differences in substrate surface conditions and substrate strengths often lead the bond to fail at strength far less than the bond strength established by adhesive manufacturer for a balanced joint. This research experimentally studied several factors potentially influencing initial strengths and debonding modes of adhesively-bonded Al-steel joints using single lap-shear coupons with comparison to like-substrate joints. Three commonly-used SLS coupon fabricating processes were investigated to determine which provided consistent bond strength and was efficient in making large quantities of coupons for the subsequent study. Next, the effect of prelube on the initial bond strength and debonding mode was investigated since the amount of prelube varies from sheet to sheet in automotive production. It was observed that even a very small change in the amount of prelube being applied on Al affected the initial bond strength. The more the prelube the weaker the bond became and the more adhesive failure occurred on the bonded Al surface. On the other hand, varying amount of the mill oil on the steel surface did not make much change to the bonding strength. Finally, various combinations of Al and steel substrates were studied to observe the effect of substrate materials on the initial bond strength and failure behavior. It revealed that the strength of joints between a relatively strong substrate and a relatively weak substrate fell below the strength of identical material joint made of the relatively strong substrate, and was closer to the strength of identical material joint made of the relatively weak substrate. For bonds having a high joint efficiency, adhesive failures were observed mostly on the surfaces of relatively weak substrates in the dissimilar material bonds due to large deformation in the weak substrate resulting in higher loading on that interface.

Enhanced adhesion of coating layers by Ion Beam Mixing: An application for nuclear hydrogen production

2011 ◽  
Vol 1354 ◽  
Author(s):  
Jae-Won Park ◽  
Hyung-Jin Kim ◽  
Sunmog Yeo ◽  
Seong-Duk Hong
Keyword(s):  
Ion Beam ◽  
Substrate Surface ◽  
Dissimilar Materials ◽  
Protective Layer ◽  
Thermal Spike ◽  
Considerable Part ◽  
Hastelloy X ◽  
State Diffusion ◽  
Excellent Adhesion ◽  
Sic Film

ABSTRACTThe bonding between two dissimilar materials has been a problem, partiularly in coating metals with non-metallic protective layer. In this work, it is demonstrated that a strong bonding between ceramics/metal can be achieved by mixing the atoms at the interface by ion-beam. Specifically, SiC coating on Hastelloy X was studied for a high temperature corrosion protection. Auger elemental mapping across the interface shows a far broader mixed region than the region expected by SRIM calculation, which is thought to be due to the thermal spike liquid state diffusion. The results showed that, although the thermal expansion coefficient of Hastelloy X is about three times higher than that of SiC, the film did not peel-off at above 900 oC confirming excellent adhesion. Instead, the SiC film was cracked along the grain boundary of the substrate above 700 oC. At above 900 oC, the film was crystallized forming islands on the substrate so that a considerable part of the substrate surface could be exposed to the corrosive environment. To cover the exposed area, it is suggested that the coating/IBM process should be repeated multiply.

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