Adhesion Strength Of Coatings Research Articles

Effect of non-contact induction heating on HA coatings and bone cement, an ex vivo study

Background Prosthetic joint infection is a serious complication that can arise after total joint replacement surgery. When bacteria colonise an orthopaedic implant, they form biofilms that protect them from their environment, making them difficult to remove. Treatment is further complicated by a global rise of antimicrobial resistance. These protective mechanisms make treatment of prosthetic joint infection increasingly complex. Non-contact induction heating is an upcoming technology that uses heat to eradicate bacteria that are present on the surface of metallic implants. This study aims to provide insight into the feasibility of using non-contact induction heating on metallic implants that are in direct contact with other biomaterials, such as coatings composed of hydroxyapatite and bone cement composed of poly (methyl methacrylate) (PMMA). Methods Characterisation of hydroxyapatite coatings and adhesion strength tests were conducted according to standards set by the International Organisation for Standardisation (ISO 13779-2). The fixation strength of acrylic bone cement was tested according to an adapted method from ISO. Results It was found that non-contact induction heating did not significantly affect the adhesion strength of hydroxyapatite coatings (p=0.697). In contrast to hydroxyapatite coatings, acrylic bone cement softened temporarily as the temperature exceeded the glass transition temperature (83.38 ± 10.88°C). However, the induction heating temperature had no significant effect on the fixation strength after the cement was allowed to cool down (p=0.535). Conclusion This study shows the feasibility of using non-contact induction heating up to 80°C when bone cement or ceramic coatings are present in contact with infected metallic implants.

Thermal insulation capability and adhesion strength of unpyrolyzed thick thermal barrier coatings

Thermal insulation capability and adhesion strength of thick thermal barrier coatings (TBC) produced by unpyrolyzed powder (UPTTBC) were compared with those of the conventional TBC, thick TBC (TTBC), and dense vertically cracked (DVC) TTBC. Thermal insulation capability was evaluated using temperature drop. The adhesion strengths of the coatings were also measured by pull-off test method according to ASTM C633. The results indicated that the adhesion strength of UPTTBC and DVC TTBC was 35% and 25% higher than that of the TTBC, respectively. This could imply that the non-melted areas with sub-micron dimensions in UPTTBC structure, act as a trap and prevent the cracks propagation. In addition, the results of thermal insulation tests showed that DVC TTBC coatings had the lowest thermal insulation capability with temperature drop rate of 0.28 °C/µm and UPTTBC coatings had the highest insulation capability with temperature drop rate of 0.40 °C/µm. Due to the presence of sub-micron zones in the microstructure of UPTTBCs, the coatings exhibited superior thermal insulation capability. In contrary, the DVC TTBC showed the lowest thermal insulation capability because of its dense structure.

Wire-arc spray directed energy deposition: Correlation of chamber kits refurbishing and particle defects reduction in Ta/TaN thin-film physical deposition processes

Physical Vapor Deposition (PVD) of Tantalum/Tantalum Nitride (Ta/TaN) liner and barrier plays a crucial role in the copper-interconnecting part of semiconductor manufacturing, and this is used for the 130 nm–5nm technology node and beyond. This study focuses on the surface preparation and characterization of wire-arc spray directed energy deposition (DED) coating in the refurbishment process of PVD chamber kits. Spray coating adhesion strength is enhanced due to the pretreatment of the substrate with grit blasting, which creates a suitable surface texture, and the replacement of aluminum alloy as wire-arc spray DED coating material from pure aluminum (99.8%). However, it was experimentally found that using high adhesion strength coating chamber kits increases the probability of out-of-control (OOC) occurrences in the mid-stage of the kit lifetime, and the fundamental reasons may be attributed to the spiky surface morphology of wire-arc spray DED coating layers. Finite element analysis simulates stress distribution and identifies stress concentration regions within the multilayer Ta/TaN thin film using two surface morphologies with significantly different curvature radii of spray coatings. Differences in wire-arc spray DED processing parameters include a slower travel speed, a longer spray time, and a lower feed rate. It is numerically simulated and experimentally observed that coating surface morphology dramatically affects thin film delamination, which is the primary cause of particle defects. This study emphasizes the potential mechanisms for forming particle defects, improved uniformity in spray coatings, and increased surface curvature radius to minimize stress concentration.

To be or not to be a hydrophobic matrix? the role of coating hydrophobicity on anti-icing behavior and ions mobility of ionic liquids

The demand for anti-icing coatings to endure extremely low temperatures is substantial. Despite the innovative pioneering research on the anti-icing potential of ionic liquids (ILs), the development of such coatings is still in its infancy. Our study investigates how matrix hydrophobicity influences mobility of ILs at subzero temperatures and, consequently, their anti-icing behavior. Wettability results highlight the key role of IL anion hydrophobicity. Dielectric spectroscopy distinguishes ion mobility in the coatings at low temperatures. We also investigate how varying crosslink density affects ion mobility by measuring the water absorbency. Higher mobility of released ILs from the coatings at subzero was confirmed by their presence in water solutions, validated with UV–vis spectroscopy, and resulted in increased ionic conductivity. Differential scanning calorimetry and experimental setups were employed to assess ice formation temperature, time, and ice adhesion strength. Notably, surfaces containing IL exhibited a remarkable reduction in ice formation temperature to –23.5 ℃ and achieved an exceptionally low ice adhesion strength (∼15 kPa), attributed to the formation of a quasi-liquid layer (QLL). Solid-state NMR spectroscopy provided confirmation of the existence of QLL at the interface. Ice adhesion strength of coatings was examined against accelerated weathering, icing/de-icing cycles, as well as endurance against frost formation under freeze–thaw. Our findings underscore the significance of selecting the right matrix with regards to hydrophobicity and ILs when designing coatings for subfreezing applications.

Analyzing the corrosion and tribocorrosion performances of monolayer TiO2 and bilayer TiO2-SiO2 coatings at different SBF temperatures

In this study, monolayer TiO2 coating was formed by the anodization method and bilayer TiO2-SiO2 coating was formed by the spin-coating method on commercially pure titanium (Cp-Ti) samples. The aim of this work compare the effects of monolayer and bilayer coatings at 37 °C and 60 °C in simulated body fluid (SBF) on the corrosion and tribocorrosion behaviors of Cp-Ti material. XRD and SEM were used for structural characterization of the coatings. Afterward, the adhesion strength of monolayer and bilayer coatings was investigated. The bilayer film began to separate from the Cp-Ti surface at higher forces, which was associated with energy dissipation between the layers, increased load-carrying capacity, and increased surface hardness. The best resistance was achieved from the bilayer film in tribocorrosion experiment at both 37 °C and 60 °C SBF temperatures; the result was attributed to higher surface hardness and film thickness. Consequently, untreated, monolayer, and bilayer Cp-Ti samples were tested for adhesion strength, corrosion, and tribocorrosion and bilayer samples exhibited the highest performance.

ЭКСПЕРИМЕНТАЛЬНЫЕ ИССЛЕДОВАНИЯ ПРОЧНОСТИ СЦЕПЛЕНИЯ ТВЕРДОГО АНТИФРИКЦИОННОГО ПОКРЫТИЯ С ОСНОВОЙ

The article presents a detailed study of individual samples of MODENGY solid antifriction coatings. The selected solid antifriction coatings are described, the roughness of the applied coatings is analyzed, and measurements of the thickness of the antifriction layer on the surface of steel samples are given. The methodology for determining the quantitative assessment of the adhe-sion strength of a solid antifriction coating based on GOST 32299-2013 was analyzed and a set of experiments using a bursting machine with a built-in electronic force meter IR 5047-50 was con-ducted. As a result, a quantitative assessment of the adhesion strength of solid antifriction coatings with a steel base was obtained. Conclusions are drawn about the adhesion strength of solid antifriction coatings. Recommendations on their use for automotive equipment are given.

Preparation and anticorrosion performance of graphene-reinforced epoxy powder coating

Existing studies have reported that graphene can enhance the corrosion resistance of solvent-based organic coatings. However, the role of graphene in organic powder coatings remains to be obscure. In the present study, the graphene powder was prepared through liquid-phase exfoliation of graphite followed by freeze drying and the effects of graphene on structures, anticorrosion performance and adhesion strength of epoxy powder coatings were investigated. Scanning electron microscopy (SEM) demonstrated that graphene reduced surface micropores and enhanced structural compactness of the epoxy powder coatings. Electrochemical impedance spectra, Tafel polarization measurement and salt spray test indicated that a small amount (0.0125, 0.025 and 0.05 wt%) of well-dispersed graphene powder would be sufficient to effectively reinforce the anticorrosion performance of the epoxy powder coatings, especially for the coating with 0.025 wt% graphene, of which the impedance modulus maintained the highest values of nearly 107 and 105.8 Ω cm2 after immersion in 3.5 % NaCl solution for 21 and 30 days. Pull-off test confirmed that graphene enhanced the adhesion strength of coatings after salt spray test for 240 h, while the coating with 0.025 wt% graphene exhibited the highest adhesion strength up to 3.88 MPa. In addition, differential scanning calorimetry (DSC) indicated that graphene sheets could improve the thermal conductivity and promote curing reactions of epoxy powder. The mechanism for the reinforcement of epoxy powder coating by graphene has also been proposed.

Investigating the effect of the degree of cross‐linking in styrene butadiene rubber on the performance of graphite anodes for the use in lithium‐ion batteries

AbstractCarboxymethyl cellulose/styrene butadiene rubber (CMC/SBR) has been proven to be an effective binder system for the use of graphite anodes within the lithium‐ion battery industry. However, often when this system is employed, there is no acknowledgement regarding the specific chemistry of the SBR used. This is an important omission because properties such as glass transition temperatures and tensile strengths are heavily dependent on the ratio of styrene to butadiene content and the degree of cross‐linking within the SBR. In this study, we investigate the impact of using styrene butadiene rubbers (SBRs) with different degrees of cross‐linking on the performance of graphite anodes. We demonstrate that SBRs with a higher degree of cross‐linking provide longer and more stable capacity retentions, than SBRs with a lower degree of cross‐linking. This was found to correlate with the adhesion and cohesion strengths of the electrode coatings, and the degree of electrolyte swelling the SBRs systems undertook. Overall, the findings from this study indicate that the degree of cross‐linking within the SBR impacts the overall performance of the battery.

Effects of TiO2 nanoparticles and silane coupling agents on the adhesion strength and weathering properties of silicone rubber coatings

Environmental contamination on high voltage outdoor insulators can cause leakage currents and electrical flashover and finally reduce the reliability of electric distribution systems. To prevent energy losses and enormous damages, the in-service life of insulators has to be extended. For this purpose, room-temperature-vulcanizing (RTV) silicone rubber coatings are used due to their hydrophobicity. The objective of the current paper is to enhance the weathering resistance and proper adhesion of these coatings to the insulator. In the present study, adhesion improvement was achieved by adding titanium dioxide (TiO2) nanoparticles and silane coupling agents to the silicone rubber. The mechanical properties of nanocomposite coatings were characterized using the pull-off test method. Also, the water immersion method was employed to investigate the weathering resistance. The results revealed that adding TiO2 nanoparticles and silane coupling improved nanoparticle dispersion, adhesion strength, hydrophobicity, and weathering properties of RTV coatings.

Chemical reaction and strength of tricalcium phosphate nano-coating application on dental implants by atomistic calculations

The success of dental titanium implants depends on the interaction of the implant with the surrounding bone, including the type of coating that promotes osseointegration. The most popular are calcium phosphate coatings, in particular tricalcium phosphate (TCP). Since cases of delamination of coatings from titanium have been observed in practice, it is important to be able to evaluate and predict the adhesion strength of coatings of different compositions to titanium.The work involves ab initio quantum chemical modeling of the interaction of TCP with titanium oxide and calculation of their binding energy. Considering that titanium instantly oxidizes in air, calculations were carried out with titanium dioxide. The Gaussian09 DFT B3LYP package with the 6-31G basis set was used. We synthesized tricalcium phosphate stepwise by assessing the binding energies between its constituents and titanium dioxide, as well as other structural characteristics including bond lengths, bond angles, dihedral angles, and charges. A method for assessing adhesion strength at the macro level using binding energy values calculated at the nano level is proposed. The values obtained are in reasonable agreement with experimental data and other numerical calculations. Using the methods of micromechanics of inhomogeneous media for the polycrystalline/amorphous structures of hydroxyapatite (HA) and β-TCP coatings, their anisotropic elastic characteristics were averaged and the degree of their closeness to the characteristics of the Ti substrate was compared.A comparison of two CFs showed that HA has an advantage over TCP both in terms of greater chemical affinity with the titanium substrate (higher adhesive bond energy) and in terms of proximity to the substrate in terms of mechanical characteristics (lower stress concentration at the bond boundary).

Efficient reduction of photopolymerization shrinkage stress through microporous particles templated from Pickering emulsion droplets

Photopolymerization of acrylate based resin is a rapid, efficient and low-energy curing process that is achieving wide applications in many industrial fields. However, the volumetric shrinkage and the shrinkage stress of the cured resin have long been the major factor reduces adhesion strength of UV curable coatings onto the substrate. In this paper, the Pickering emulsion template method is employed to prepare elastic microporous particles with well-defined surface and internal structures and these microporous particles are thus added into the UV curable resin formulation to verify their capability to reduce polymerization stress through the microporous structure. The gel point time of UV-curable materials is delayed by 11 s with 1.5 wt% addition of the microporous particles and the double bond conversion at the gel point is subsequently increased. By real time MIR-photo-rheology and 3D line scanning laser confocal measurement, it is found that addition of microporous particles into the resin formulation can reduce the volume shrinkage of the resin by 61.2 % with only 1.5 wt% microporous particles, while the excellent mechanical and thermal properties of the cured resin is basically maintained.

Improving abrasion resistance of low temperature enamel (LTE) coating by alumina addition

Low temperature enamel (LTE) coating has advantages in material durability, hardness, corrosion resistance, and high-temperature tolerance, but shows unsatisfying abrasion resistance due to its brittle nature. Here, alumina was added to the LTE coating with contents of 0, 5, and 10 wt%. The thermal stability of alumina in the LTE matrix and the microstructure, phase composition, microhardness, impact resistance, adhesion strength, abrasion resistance, and corrosion protection properties of different LTE coatings were investigated. Results indicated that alumina had high thermal and chemical stabilities in the LTE matrix without affecting the pore structure of the coating. As an abrasion-resistant filler, alumina increased the hardness and impact resistance of LTE coatings while reducing adhesion strength. In the abrasion test, alumina showed an advantage in delaying the formation and expansion of cracks, and the alumina-enhanced LTE coating demonstrated a 70 % reduction in mass and thickness losses when compared to pure LTE coating. In particular, all LTE coatings survived 8000 cycles of abrasion without significant degradation in corrosion protection. The findings of this study confirmed the feasibility of alumina as an abrasion-resistant filler and provided a modified LTE coating for coupled corrosion and abrasion conditions.

Influence of anodization in electrophoretic deposition of strontium substituted hydroxyapatite coatings

The anodization of the titanium surface is believed to assist in good adhesion strength for electrophoretic deposition (EPD) of hydroxyapatite (HAp) coatings. Different time durations are employed to attain the varying thicknesses of anodized TiO2 nanotube (ATNT) arrays. Strontium was substituted in HAp (SrHAp) to elevate the bioactivity and mechanical properties of the HAp. The surface roughness (Ra) of the coatings was increased with the increase of ATNT thickness. The HAp and SrHAp coatings exhibited average Ra values of 2.861 ± 0.418 μm and 2.668 ± 0.458 μm respectively, at 3 h anodization. Conversely, the adhesion strength of the EPD coatings decreased at 3 h of ATNT. Hence, the tailored ATNT thickness and optimized EPD parameters provide bioactive and mechanically stable coatings for efficient osseointegration.

Adhesion Strength and Anti-Corrosion Performance of Ceramic Coating on Laser-Textured Aluminum Alloy

Laser surface texturing and micro-arc oxidation provide excellent approaches to enhance the adhesion strength and anti-corrosion performance of adhesive bonding interfaces in aluminum alloys, which can be applied in the field of automotive light weighting. Herein, micro-arc oxidation coatings were fabricated on the laser-textured aluminum surface under the voltage of 500 V for various treatment times (5 min, 15 min, 30 min, 60 min). The anti-corrosion performance of ceramic coatings on the laser-textured surface was analyzed using electrochemical measurements. The results of electrochemical measurement indicate that the coating on the sample surface presents two time constants corresponding to a dual-layer structure. The sample grown under 500 V for 60 min exhibits excellent protective performance with a value of 1.3 × 107 ohm·cm2. The adhesion strength of laser-textured ceramic coating is improved compared with the as-received substrate. The sample treated with 500 V for 30 min exhibits the highest bonding strength with a value of 52 MPa. The wider pores and bulges for the sample grown in 60 min would introduce microcracks and consequently reduce the adhesion strength.

Adhesion Strength of TiN Coatings Deposited on VT1-0 Titanium with Different Surface Conditions

Adhesion Strength of TiN Coatings Deposited on VT1-0 Titanium with Different Surface Conditions

Mechanical integrity of PVD TiAlN-coated PcBN: Influence of substrate bias voltage and microstructural assemblage

Polycrystalline cubic boron nitrides (PcBN) have been increasingly used together with PVD coatings, mainly for hard turning operations. Within this context, effectiveness of coated PcBN as cutting tool is usually addressed by evaluation of its machining performance. Meanwhile, studies aiming to assess and understand the correlation between microstructural features and mechanical behaviour of the coating-substrate system are rather limited. Aiming to overcome such lack of information, in this study the influence of substrate bias voltage (−35 V as compared to −60 V) and microstructural assemblage (as a function of cBN content and binder chemical nature) on the mechanical integrity of TiAlN-coated PcBN systems is investigated. In doing so, contact damage response and coating adhesion strength of different coated-PcBNs are evaluated by means of indentation testing using distinct loading conditions (static and sliding) and tip geometries (spherical and conical). Such testing program is complemented by detailed FESEM inspection of the involved failure micromechanisms, as well as microstructural and micromechanical characterization of the deposited films. Results indicate that resistance against crack nucleation and propagation of coated PcBN, induced by either spherical or conical indentation, is enhanced by using harder (high content of cBN particles) and tougher (metallic binder) substrates (H-PcBN). Regarding bias voltage, systems with coatings deposited using a higher value (−60 V as compared to −35 V) show improved adhesive strength, this being particularly true for combinations involving low cBN content and ceramic binder substrate (L-PcBN). Similar beneficial effect was found, but exclusively in coated L-PcBN systems, regarding resistance to radial cracking emergence and to material removal through cohesive-failure chipping induced in Rockwell C tests. Although these findings are linked to the higher compressive residual stresses exhibited by coatings deposited under −60 V bias voltage, the latter does not translate in significant changes in microstructural and intrinsic mechanical properties of the TiAlN coating itself.

Synthesis of Silanated Coconut Oil-Based Waterborne Polyurethane Coating for Corrosion Protection

In this study, an eco-friendly coconut oil-based polyol blend was synthesized for bio-based waterborne polyurethane (WBPU) and WBPU-silane composite coatings. It was demonstrated that an increase in silane content incorporated into the WBPU matrix significantly enhanced the corrosion protection of WBPU coatings. Results also show a fourfold increase in the adhesion strength of WBPU-silane composite coatings as compared to that of bare WBPU coatings. Further, the water contact angle revealed that hydrophobic properties increase as the silane content incorporated into the WBPU matrix increases. This work provides a novel route for enhanced corrosion protection utilizing a bio-based polyol blend.

Corrosion behavior and mechanical properties of plasma sprayed Al2O3-aluminum bronze and Ca2SiO4-aluminum bronze coatings

NiCr–Al2O3-aluminum bronze (NAC) and NiCr–Ca2SiO4-aluminum bronze (NDC) coatings were prepared by atmospheric plasma spraying. Corrosion experiments were performed on coatings including immersion in simulated seawater and dry-wet composite salt spray test. Phase composition and microstructure of the coatings were investigated by X-ray diffraction, energy dispersive spectrometry and scanning electron microscopy, before and after the corrosion tests. The adhesion strength and hardness of coatings were also evaluated. As observed, Ca2SiO4 had much lower hardness than Al2O3 layer. Due to the rougher surface and higher thermal expansion of Ca2SiO4 layer, NDC coatings possessed better adhesion. Further, NDC coatings exhibited relatively superior corrosion resistance. According to the microstructure and phase analysis, this finding was attributed to the hydration reaction of Ca2SiO4 during the tests.

ИССЛЕДОВАНИЯ АДГЕЗИОННОЙ ПРОЧНОСТИ ВИБРАЦИОННЫХ МЕХАНОХИМИЧЕСКИХ ПОКРЫТИЙ И ИХ ВЛИЯНИЕ НА КОРРОЗИОННУЮ СТОЙКОСТЬ ДЕТАЛЕЙ

The results of experimental studies of the adhesive strength of vibrational mechanochemical coatings and their effect on the corrosion resistance of parts are presented. The relationship between the corrosion resistance of the estimated permeability index and the adhesive strength of the coating is established and an empirical dependence is proposed that allows evaluating the operational characteristics of the product at the stage of technological preparation of production.

Surface Characterization, Mechanical Properties, and Corrosion Behavior of Zn-Ni Alloy Coated Steel Using Electroplating-Hot-Dip Galvanizing

In this study, the processing of zinc-nickel alloys with an electroplated nickel layer as the first layer followed by hot-dip galvanizing on plain carbon steel (St37) is investigated. The effect of the nickel layer and the effect of the immersion time on the alloy layers of the coating obtained by this method are studied. In addition, some properties of the obtained coating, such as the overall thickness, hardness, surface uniformity, coating adhesion strength, and corrosion resistance, were investigated using the optical microscope, scanning electron microscopy, energy dispersive x-ray spectrometer analysis, and potentiostat. The results show that the 16-min immersion time is the optimum galvanizing time at which an alloy with a nickel content of 0.11 wt% is formed and that the overall thickness of the galvanized sheet, especially the alloy layers, decreases compared to the pure zinc sheet. In addition, a more ductile, corrosion-resistant, and smoother surface is obtained.