Good Adhesion Performance Research Articles

Characterization of ZrC coatings deposited on biomedical 316L stainless steel by magnetron sputtering method

ZrC coatings were fabricated on 316L stainless steel (316L SS) by radio-frequency (RF) magnetron sputtering at different substrate temperatures (Ts). The phase configuration, microstructure and mechanical properties of ZrC coatings were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), TriboIndenter hardness tester and scratch tester. The corrosion resistance in phosphate buffered saline (PBS) and the hemocompatibility of ZrC coatings were evaluated by potentiodynamic polarization and platelet adhesion test. The XRD results indicated that the microstructure of ZrC coatings was affected by Ts. The ZrC phase with (111) preferred orientation was formed when Ts was 400°C, which exhibited in the form of particulates with the crystallite sizes of about 5nm. AFM results showed that with the increase of Ts, the root-mean-square (Sq) values of the ZrC coatings decreased and the distribution of the particle size became narrower. The results of nano-indentation tests indicated that Ts has no effect on the hardness and elastic modulus of ZrC coatings. The scratch test results demonstrated that ZrC coatings deposited above 200°C exhibited good adhesion performance. The potentiodynamic polarization and platelet adhesion test results showed that the ZrC coatings deposited at Ts of 200°C and 400°C possessed better corrosion resistance and hemocompatibility than those deposited at Ts of 25°C. It is indicated that the hemocompatibility of ZrC coatings deposited on the 316L SS was influenced by the surface roughness, hydrophilicity and the surface energy of the coating.

A Novel Patternable Electrophoretic Polymer Coating for Sidewall Packaging in Microelectronic Devices

This paper presents a novel patternable electrophoretic polymer (EPP) coating technology for sidewall package in microelectronic devices. The main features of this EPP film are directly patterned via through-mask electrophoretic deposition. The proposed EPP coating has some overwhelming merits against other coating polymers, such as self-patterning via through-mask deposition, good adhesive performance, selective coating, low cost and compatible with IC process. The focus is on the process, patterning, properties characterization and application of this novel electrophoretic polymer. The main applications can be aimed for electrical/thermal isolations or sidewall packaging in semiconductor device package.

Deblocking of the water‐soluble isophorone diisocyanate blocked by sodium bisulfite and its application

AbstractA water‐soluble and low stimulation sodium bisulfite blocked isophorone diisocyanate (IPDI) has been prepared. The blocking and deblocking of the blocked IPDI is observed by hot‐stage Fourier transform infrared (FTIR) spectrophotometer. The experimental results reveal that IPDI is successfully blocked by sodium bisulfite and the blocked IPDI can regenerate isocyanate groups when the temperature is higher than 80°C. Differential scanning calorimetry analysis indicates that blocked IPDI deblocks initially at around 85°C and reaches the maximum deblocking rate at 117°C. The blocked IPDI in liquid and solid states are stable after being stored for 12 months at room temperature. The blocked IPDI is used as curing agent for waterborne hydroxyl polyurethane, which has good adhesive performance and long pot life. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Corrosion protection of aluminum 6061 in NaCl solution by silane–zeolite composite coatings

Anticorrosion properties of silane–zeolite composite coatings applied on aluminum substrates have been investigated. The composite coatings were prepared with different zeolite microparticles concentration (from 500 to 8000 ppm). Physico-chemical tests (Fourier transform infrared spectroscopy, adhesion, scanning electron microscopy, and contact angle measurements) have been carried out to evaluate the homogeneity and structural properties of the coatings. The coatings that resulted were highly hydrophobic for all zeolite contents and showed a relatively good adhesion performance. Corrosion protection performances in 3.5% NaCl solution were evaluated by means of polarization tests, evidencing good barrier characteristics of the composite layer.

A study of Ta xC 1 −x coatings deposited on biomedical 316L stainless steel by radio-frequency magnetron sputtering

In this paper, Ta x C 1 −x coatings were deposited on 316L stainless steel (316L SS) by radio-frequency (RF) magnetron sputtering at various substrate temperatures ( T s) in order to improve its corrosion resistance and hemocompatibility. XRD results indicated that T s could significantly change the microstructure of Ta x C 1 −x coatings. When T s was <150 °C, the Ta x C 1 −x coatings were in amorphous condition, whereas when T s was ≥150 °C, TaC phase was formed, exhibiting in the form of particulates with the crystallite sizes of about 15–25 nm ( T s = 300 °C). Atomic force microscope (AFM) results showed that with the increase of T s, the root-mean-square (RMS) values of the Ta x C 1 −x coatings decreased. The nano-indentation experiments indicated that the Ta x C 1 −x coating deposited at 300 °C had a higher hardness and modulus. The scratch test results demonstrated that Ta x C 1 −x coatings deposited above 150 °C exhibited good adhesion performance. Tribology tests results demonstrated that Ta x C 1 −x coatings exhibited excellent wear resistance. The results of potentiodynamic polarization showed that the corrosion resistance of the 316L SS was improved significantly because of the deposited Ta x C 1 −x coatings. The platelet adhesion test results indicated that the Ta x C 1 −x coatings deposited at T s of 150 °C and 300 °C possessed better hemocompatibility than the coating deposited at T s of 25 °C. Additionally, the hemocompatibility of the Ta x C 1 −x coating on the 316L SS was found to be influenced by its surface roughness, hydrophilicity and the surface energy.

Preparation and characterization of TaC xN 1 − x coatings on biomedical 316L stainless steel

In this paper, TaC x N 1 − x coatings deposited on 316L stainless steel (SS) by RF magnetron sputtering at various substrate temperatures ( T s), were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), scratch test and nanoindentation techniques. Then the corrosion resistance in phosphate buffered saline (PBS) and the hemocompatibility of the coating were further evaluated by potentiodynamic polarization, blood clotting test and platelet adhesion test. The substrate temperature ( T s) could significantly change the microstructure of TaC x N 1 − x coatings. When T s was less than 200 °C, the TaC x N 1 − x coatings were in amorphous condition, whereas when T s was increased to 200 °C, Ta 2CN phase was formed, exhibiting in the form of fine particulates with the crystallite sizes of about 6–9 nm. The appearance of the nanocrystalline Ta 2CN phase above 200 °C was associated with the pronounced increase in the hardness of TaC x N 1 − x coating from 10 GPa to over 30 GPa. The scratch test results demonstrated that TaC x N 1 − x coatings deposited above 200 °C exhibited good adhesion performance. The corrosion resistance of the 316L SS was improved significantly because of the deposited TaC x N 1 − x coatings. The blood clotting test and the platelet adhesion test results indicated that the TaC x N 1 − x coatings deposited at T s of 25 °C and 200 °C possessed better hemocompatibility than the coating deposited at T s of 400 °C.

Structured catalyst supports and catalysts for the methane indirect internal steam reforming in the intermediate temperature SOFC

Open cell metal foams made from Ni, Fe–Cr steel and Ni–Al intermetallic were studied as candidate catalyst supports for the internal indirect methane steam reforming. All the samples exhibited good corrosive resistance during 500–1000 h testing in H 2–H 2O–Ar environment at 600 °C. NiO/8YSZ composite based catalysts doped with fluorite-like (Pr 0.3Ce 0.35Zr 0.35O 2) or perovskite-like (La 0.8Pr 0.2Mn 0.2Cr 0.8O 3) complex oxides with high lattice oxygen mobility and promoted with Pt or Ru were prepared and deposited on the foam-structure supports. Both good catalyst adhesion and stable catalyst performance were achieved in the case of the Ni–Al foam supported catalysts. The Fe–Cr support reacted with the catalytic active components resulting in fast catalyst deactivation. The foam supported catalyst performance was compared with the same catalyst prepared in a form of 0.25 mm fraction. Porous supports with different porosities were prepared by the metal foam deformation and the catalyst performance depending on the support porosity (75–95%) was studied.

Corrosion and adhesion study of polyurethane coating on silane pretreated aluminum

In this paper, the effect of silane pretreatment pH on adhesion strength and corrosion protection of subsequent polyurethane (PU) coating on aluminum alloy substrate is evaluated. Practical adhesion of the coating on substrate was measured in dry, wet and recovered states via pull-off method for desmutted, chromated and vinyltrimethoxysilane (VTMS) pretreated aluminum alloy (AA1050). VTMS resulted in good adhesion performance in dry, wet and recovery states for VTMS treated specimens at pH < isoelectric point (IEP) which is related to the silanol groups orientation toward aluminum surface. Adhesion performance at pH > IEP is lower than desmutted specimens which can be related to presence of unreacted VTMS molecules on the surface. Vinyl groups orientate toward the aluminum surface at pH above IEP, results in prevention of VTMS reaction on the surface. Corrosion protection of PU coating was studied with electrochemical impedance spectroscopy (EIS) and salt spray in the presence of silane layer; then, compared to coated desmutted and chromated specimens. Water sensitivity of unreacted VTMS molecules leads to poor protective performance of specimens treated at pH > IEP. However, at pH < IEP protective performance is considerably higher than desmutted and comparable with chromated specimens.

Effect of colophony emulsion on the adhesive properties of vinyl acetate/n‐butyl acrylate copolymeric latex

AbstractWe prepared a novel copolymeric latex of vinyl acetate and n‐butyl acrylate (V‐B) using a semibatch emulsion polymerization process. The glass‐transition temperature (Tg), steady viscosity, flow activation energy (Ef), dynamic moduli, and amphiphilic properties of the V‐B latex in the presence of colophony were systematically investigated. The experimental results demonstrate that excellent adhesive behaviors were achieved for the V‐B latex blended with 20 wt % colophony, whereas good adhesive performance was related to the moderate Tg, viscosity, Ef, storage modulus, and low contact angle on the adherent. The debonding mechanisms for V‐B and its colophony‐modified latexes were analyzed. A possible mechanism for the V‐B latex blended with colophony emulsion was determined. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Evaluation of the effect of vinyltrimethoxysilane on corrosion resistance and adhesion strength of epoxy coated AA1050

The quality of surface treatment of aluminum alloy (AA1050) with vinyltrimethoxysilane (VTMS) was examined. Calculated surface energy with Van Oss, Chaudury and Good (VOCG) method showed higher surface energy of treated specimens. Chemical interaction between silane layer and aluminium surface was examined via FTIR-ATR. In addition, practical adhesion was measured in dry, wet and recovered states via pull-off method and compared to adhesion strength of desmutted and chromated specimens. Results showed good adhesion performance in dry state for silane treated specimens. Corrosion protective performance of epoxy coating in the presence of silane layer on aluminum was studied with Electrochemical Impedance Spectroscopy (EIS) and compared with coated desmutted and chromated specimens. Water sensitivity of silane layer resulted in poor protective performance of specimens treated at pH > isoelectric point (IEP).

Fire retardancy of polymers: challenges and new concepts

The rapidly growing polymer market increases the risk of fire. The competition for reducing the costs and the activities for increasing the recyclability are advantageous from many aspects but promote the use of cheap and flammable polymers. The relative amount of the types of fire retardants (FRs) used in polymers is changing. The halogen containing compounds initiate corrosion, furthermore, some of them proved to be harmful to the environment and human health. Therefore the new European regulations promote the substitution of some conventional flame retardants by environmental-friendly ones. Reactive processing methods bond the additives to the polymer chains thus provide solution against their release to the environment, which is critical especially for some potential pseudohormones. Beyond the increasing importance of reactive methods the nano-concept is the most widely investigated novel approach to fire retardancy. Promising is the low environmental impact of nanofillers and influence on the macromolecular arrangement owing to their high surface area (reducing the heat distortion and melt dripping at high temperature). However, their fire retardancy performance should be enhanced, which requires better understanding of the mechanism of their action. It has to be clarified what is the relative role of their catalytic and physical action. The importance of the geometric dimensions, quality of dispersion and the potential synergism between different types should be clarified as well. Furthermore, the undesirable by-effect of removing stabilizers from the polymer matrix through their high surface area has to be eliminated. Most recent concepts are the in situ formation of nanofillers (during extrusion of the polymers) and of FR-active interfaces or surfaces around inclusions. Advancement of these concepts require the development of new micro-scale fire modeling/testing methods. Based on the described research activities increasing use of reactive, halogen free solutions in combination with nanofillers of well designed interfaces are predicted. Economic approaches applying recycled polymer matrices, nanofillers and multifunctional additives will increase in the close future. A multifunctional flame retardant can be applied for example as adaptive interlayer in a multiphase systems facilitating good mechanical, transport or adhesive performance at ambient temperature and transforming to protective (heat and combustiblegas barrier) layer at the temperature of combustion.

Ostomy bag management: comparative study of a new one-piece closed bag

The aim of this study was to compare the performance of a new one-piece closed ostomy bag, SenSura, to an already established bag with a focus on minimizing problems related to use of stoma bags for individuals with a colostomy. There were 68 Danish participants with a colostomy who tested each bag for 1 week in a randomized, open, comparative, crossover study. The SenSura bag was perceived more secure than the reference bag (p=0.0006). Crucial performance and safety parameters were rated significantly better for SenSura than for the reference bag. The high preference for SenSura (85%) reflected these results (p<0.0001). Individuals with a colostomy can expect a higher sense of security with the SenSura bag than with the reference bag. This may relate to good adhesion, tack, flexibility and effective filter performance. Future studies should examine the long-term effects of SenSura on peristomal skin conditions. To our knowledge, this is the first published comparative study of one-piece closed ostomy bags.

Tribological behavior of candidate coatings for Al die casting dies

Candidate coatings on H13 steel substrates aimed at improving the tribological performance of die casting dies for the Al foundry industry have been extensively characterized. The study is part of a comprehensive research program whose objective is to design a multilayer coating system that encompasses all the requirements to provide increased surface die performance and die life. The coatings investigated were: CrC, CrN (2), ZrN, MoN x , MoZrN, TiAlN, TiN/TiC, TiB 2/TiC, NiAl, NiAlN, MoSiC/SiC, Ti–B–C–N, Cr 3Si and a control sample that was subjected to a carbonitriding thermochemical treatment. The characterization included: scratch testing, wear testing+optical profilometry, microhardness, optical microscopy and X-ray diffraction. Several wear behavior and adhesion behavior modes were identified based on the morphological characteristics of the wear and scratch marks, and the results of the tests. Wear and adhesion properties seem to be related and mainly controlled by the brittle or tough nature of the coating as well as by the nature of the substrate/coating interface, to a lesser degree by coating hardness, and only marginally by the coating coefficient of friction and roughness. Only a few of the candidate coatings had concomitant good wear and adhesion performance.

Atmospheric Pressure Plasma Deposition of Structurally Well-Defined Polyacrylic Acid Films

Ultrasonic atomization of acrylic acid monomer into an atmospheric pressure glow discharge (APGD) leads to the deposition of structurally well-defined polymeric films. High retention of the carboxylic acid group has been verified by XPS and FT-IR spectroscopy. These films are found to exhibit low water contact angle values and display good adhesive and gas barrier performance.

Joining of Single-Crystal Sapphire to Alumina Using Silicate Glasses

The joining of a sapphire single crystal plate to alumina ceramic tube is fabricated successfully using 34CaO 30Al 2 O 3 .36SiO 2 glass as an interlayer. This glass showed good adhesion performance to alumina ceramics and sapphire single crystal. The joint with no crack was obtained by heating at 1550°C for 10 min and slow cooling from 1200°C to room temperature. From the thermal shock test, the half of the specimens showed the cracks after quenching from 225°C to 0°C, but all specimens showed no cracks after quenching from 200°C to 0°C. The specimen, composed of alumina tube-sapphire plate-alumina tube showed the comparable bending strength to the specimen composed of alumina tube-alumina tube.

Aspects of the performance of PVAc adhesives in wood joints

Various modifications of polyvinyl acetate emulsion wood adhesive were made and their performance evaluated in standard tests. The results are interpreted in the context of adhesion theories and the chemical structures of the polymers and wood. The adhesion of the polymers to wood and the cohesive strength of the polymers are the two predominant factors determining the performance of the adhesives. Adhesive strength in thermosetting resins is enhanced by irreversible chemical reactions that create extensive networks within the adhesive layer and strong bonds to the wood substrate, leading to strong and durable joints that passed all of the performance evaluation tests. Most of the PVAc emulsions exhibited good adhesive performance in the dry state, but failed in water soak and boiling water immersion tests since their adhesion and cohesion are mainly based on weaker physical interactions. Emulsions with (hard) core‐(soft) shell morphology and correspondingly high glass transition temperatures gave poor performance under all conditions.

SOME PROPERTIES OF INTERFACES BETWEEN METALS AND POLYMERS

We focus on the published results of the interfaces between depositing metals and insulating and semiconducting polymers, and the interfaces between polymer films and metals. They indicated that when metal was deposited on polymer films, diffusion action occurred at the polymer surface and new interfacial states were formed during the process of deposition. Chemical reactions led to good adhesion and good performance of charge transfer between metal and polymer. When polymers were deposited on metal substrates, adsorption to the substrate occurred at the interface.

The chemistry and development of branched PRF wood adhesives of low resorcinol content

AbstractPhenol–Resorcinol–Formaldehyde (PRF) resins of good adhesive performance, and of resorcinol content much lower than in traditional PRF cold‐setting adhesives, were prepared by introducing small amounts of urea as a branching unit during preparation of the resin. Resorcinol contents as low as 10.6% were obtained by this method while still maintaining an acceptable pot‐life of the resin. Resorcinol contents as low as 8%, still with a good adhesive performance, were obtained, although the pot‐life obtained was too short. GPC, FT–IR and C13 NMR indicated that the small amount of urea branching unit used leads to the reduction of resorcinol content mostly by rapid doubling of the average linear length of the PF intermediates and of the final PF oligomers. Tridimensional branching in the liquid resin, contrary to what was previously thought, does not appear to be an important contributory factor and better adhesives are often prepared when branching is totally, or almost totally, absent. Reduction of resorcinol content is achieved simultaneously by two mechanisms: (i) the decrease of resorcinol percentage on resin solids due to the rapid lengthening (doubling) of average oligomers length and (ii) the need for these resins to operate at lower solids content, due to the increased viscosity obtained during their preparation. © 1993 John Wiley &amp; Sons, Inc.

Thin film adhesion: New possibilities for interface engineering

The good adhesion performance of a thin film on a solid substrate is now understood to depend on a variety of the attributes of the interface region, including its atomic bonding structure, its elastic moduli and state of stress, and its thickness, purity and fracture toughness. Many of these qualities can be explicitly tailored during film deposition to enhance the resulting bond. Many opportunities exist for new research in this area, and this paper is intended to review some of these possibilities. References to other more detailed publications are cited.

Wettability of selected denture base materials

D enture retention has been defined as the resistance of a denture to vertical and torsional stresses, or the resistance to removal of a denture in a direction opposite that of its insertion.‘,’ Retention of a complete denture may be influenced by a number of variables classified as physical, physiologic, mechanical, and surgical in nature.3 The physical forces operate in the salivary film between the denture and the surrounding tissues and involve factors such as adhesion, cohesion, capillarity, atmospheric pressure, surface tension, and viscosity.4-8 To produce adequate adhesion of a denture to the supporting tissues, saliva must flow easily over the entire surface to ensure wetting of the adherend surface. The fundamental requirement for good adhesive performance is intimate molecular contact between the adhesive and the adherend.’ The extent to which an adhesive will wet a surface depends on the viscosity of the adhesive, the shape of the irregularities on the surface of the adherend, and on the contact angle (e) at which the adhesive meets the adherend surface.“,” Since the tendency for the liquid to spread increases as 8 decreases, the contact angle is a useful inverse measure of spreadability or wettability.” The contact angle observed when a liquid boundary advances for the first time over a dry smooth surface is called the advancing contact angle (e,), while the contact angle observed when a liquid boundary recedes from a previously wetted surface is called the receding contact angle (0,). Contact angles are characteristic constants of liquid/solid systems.‘2 When contact angles are determined, the liquid and solid surfaces