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Fiber metal laminates as one of new hybrid materials with the bonded structure of thin metal sheets and fiber/epoxy layers have been developed for the last three decades. These kinds of materials can provide the characteristics of the excellent fatigue, impact and damage tolerance with a relatively low density. Because metal sheets and fiber/epoxy layers are bonded each other, the bonding between two materials is critical. In this study, the bonding strength is investigated experimentally with respect to surface roughness of metal sheets. The equivalent material properties of carbon reinforced aluminum laminates as the input data in the numerical simulation are also investigated and compared with the experimental result. The application of the equivalent material property to the numerical simulation can provide the high degree of efficiency in the build-up of the finite element model and the numerical simulation.

High-performance poly-ether-ketone-ketone (PEKK) thermoplastic (TP) composites, which are beginning to gain interest in the aerospace industry, require a joining procedure to integrate the individual parts. Amorphous TP bonding has been recently proposed to address the limitations of commonly used joining techniques for composites, such as mechanical fastening and adhesive bonding. In this study, we investigated the adhesive properties of a polyetherimide (PEI) film applied by hot press welding as an amorphous polymer interlayer of PEKK laminate. The temperature range of the bonding process was determined via differential scanning calorimetry analysis. The bonding strength was evaluated through single-lap shear tests. The effect of process temperature on the bonding strength was qualitatively analyzed via fracture surface morphology analysis. The interface between PEKK and PEI was analyzed via optical microscopy. The adhesive strength was as low as about 5 MPa up to the bonding temperature of 280${}^{\circ }$C but then started to improve as the temperature increased, which is attributed to the interdiffusion of the PEKK matrix and PEI adhesive film. The maximum bonding strength of 23 MPa was confirmed at a bonding temperature of 340${}^{\circ }$C. A mixed failure mode consisting of a relatively high ratio of fiber-tear failure to light-fiber-tear failure is observed at this process temperature. This failure mode can be attributed to the bonding temperature condition at which PEKK begins to melt.

In order to improve the bonding strength of hydroxyapatite coating on carbon/carbon composites, a surface hydrophilic modification was performed on carbon/carbon composites using a combination of H₂O₂ and FeSO₄ ⋅ 7H₂O under ultraviolet irradiation. The hydroxyapatite coating was prepared by an ultrasound-assisted electrochemical deposition method. The results showed that the surface hydrophilic modification introduced a large number of oxygen-containing functional groups (C=O, C–O and COOH group) onto the surface of carbon/carbon composites. The surface hydrophily of the modified carbon/carbon composites was significantly improved with the water contact angle decreasing from 85.7 ± 4.1° to 11.9 ± 1.5°. The modified carbon/carbon composites had strong induction ability for the deposition of hydroxyapatite crystals. The hydroxyapatite showed a wavy-shaped crystal at initial deposition process and subsequently formed a compact and uniform coating. The bonding strength of hydroxyapatite coating on modified carbon/carbon composites (9.58 ± 0.40 MPa) was significantly higher than that of the coating on unmodified carbon/carbon composites (3.04 ± 0.20 MPa).

Al_xO_y films coated on both Ni-based superalloy and silica substrates were prepared by DC reactive magnetron sputtering. Post-deposition annealing was carried out on those as-deposited films. And then 1 h heat treatments were done on the annealed films at constant temperatures ranging from 600–900°C to simulate the high-temperature application. The Al_xO_y film heated at 600°C exhibited good film property. Bonding strength between the 600°C-heated Al_xO_y film and the Ni-based substrate was about 11.6 MPa.

Due to the biocompatibility, mechanical strength and esthetics properties, titanium–porcelain prosthetic plays an important role in prosthodontics. However, weak bonding strength and considerable thickness of the porcelain restrict its application. Whether we can find a method to increase the bonding strength and reduce the thickness of the porcelain is an acute problem. In this study, ceramic coatings with similar color of nature teeth are fabricated on the surface of pure titanium by micro-arc oxidation (MAO). The colors, thickness and bonding strength of the coatings can be controlled by adding ferrous sulfate into the electrolytes. These new coatings can be used in titanium–porcelain prosthetic to substitute the opaque and dentin porcelain which can enhance the bonding strength and decrease the thickness of the porcelain compared with the conventional technique.

AlCrTiSiN coatings were deposited on YT14 cemented carbide using cathodic arc ion plating (CAIP) method. The surface and cross-section morphologies, chemical composition, phases, surface roughness, and binding energies of chemical elements of obtained coatings were analyzed using a field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray diffractometer (XRD), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), respectively, and its mechanical properties were characterized using a scratch tester and nanoindentation tester. The friction-wear behaviors of AlCrTiSiN coatings at 700^∘C, 800^∘C and 900^∘C were investigated using a high temperature wear test, the distributions of chemical elements on the worn tracks were analyzed using a plane scan analysis of EDS, and the high temperature wear mechanisms were also discussed. The results show that the chemical elements are uniformly distributed on the AlCrTiSiN coating with the surface roughness of 105nm, which is composed of faced centered cubic (FCC)–(Cr, Al)N, body-centered cubic (HCP)–AlN and Si₃N₄ amorphous phases. The interfacial bonding strength, microhardness and elastic modulus of AlCrTiSiN coating is 26.15N, 25.789GPa, and 251.364GPa, respectively. The average coefficient of friction (COF) of AlCrTiSiN coatings at 600^∘C, 700^∘C and 800^∘C is 1.06, 0.73, and 0.97, respectively, of which friction performance is the best at 700^∘C. The wear mechanism of AlCrTiSiN coating at 600^∘C, 700^∘C and 800^∘C is adhesive wear $+$ fatigue wear, abrasive wear $+$ oxidation reaction, and adhesive wear $+$ fatigue wear, respectively.

In order to improve the interfacial bonding at coating-substrate, a graphene oxide-hydroxyapatite (GH) coating was designed and constructed. The microstructure, bonding strength and in vitro bioactivity of the coating were analyzed. The results showed that GH coating presented uniform and crack-free structure with a flake morphology. The bonding strength of GH coating was 7.81MPa, which is about 1.2 times that of pure hydroxyapatite coating. In vitro bioactivity test using simulated body fluid exhibited that GH coating processes the ability to induce apatite formation. The GH coating should have potential application in surface modification for biomedical materials.

Vanadium carbide (VC) coating is prepared with Thermal Diffusion (TD) method in the salt bath, and its surface-interface microstructures and energy spectrums were observed with Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS), respectively, and the distributions of C, V, Cr, Si, Fe, and Mo in VC coating interface are analyzed. Its interfacial and bonding methods are discussed, and the bonding micromechanism of VC coating in its bonding interface by TD process is analyzed. The experimental results show that the structure of coating surface by TD is single-phase, that is composed of V and C elements, and no other elements, the chemical elements such as V, Cr, CSi, Fe, Mo are the grade distributed in its bonding interface; its bonding method is metallurgical status; microhardness of coating-substrate is the grade distribution, which is direct ratio with the V distribution, microhardness of the coating surface is 3050–3200 HV, and the effect of TD process on roughness of cold-working die surface is little.

A measurement system based on crack-opening method has been developed to measure the fracture toughness of silicon direct bonding wafers. The theory of crack-opening method was introduced and amended according to the shape of the specimen. The parameters and function required in the measurement of bond energy were mentioned, and the selection principle of thickness of the razor was given. A new experimental device based on IR vision and image processing in the measurement was developed. Finally, a contrast experiment was carried out successfully and the error of the method was analyzed which validated the feasibility and the localization of the method.

To evaluate the effect of silica coating with Sol-Gel processing on the bonding strength between dental high-strength ceramic and composite resin. Method: 80 zirconia ceramic discs were randomly divided into four groups (n=20 in each group), and received different surface treatments, then the shear bonding strength of the ceramics and composite resin were calculated. Results: The three groups with silica coating had a higher bonding strength than the un-coated group with a significant difference (P<0.05); group C had the highest bonding strength (P<0.05). There were no significant differences between group B and group D (P>0.05). Conclusion: Silica coating followed by silane coupling agent treatment can significantly increase bonding strength between dental ceramic and composite resin; 30% silica sol may be more effective.

Fiber metal laminates as one of new hybrid materials with the bonded structure of thin metal sheets and fiber/epoxy layers have been developed for the last three decades. These kinds of materials can provide the characteristics of the excellent fatigue, impact and damage tolerance with a relatively low density. Because metal sheets and fiber/epoxy layers are bonded each other, the bonding between two materials is critical. In this study, the bonding strength is investigated experimentally with respect to surface roughness of metal sheets. The equivalent material properties of carbon reinforced aluminum laminates as the input data in the numerical simulation are also investigated and compared with the experimental result. The application of the equivalent material property to the numerical simulation can provide the high degree of efficiency in the build-up of the finite element model and the numerical simulation.

As a candidate for highly loaded bone substitute, tantalum metal has attractive features such as biocompatibility, high malleability and ductility. The present authors previously showed that NaOH and heat treatments make tantalum metal to form a bonelike apatite layer on its surface in a short period, although even the untreated tantalum metal forms the apatite in a long period. In the present study, bonding strength of the apatite layer, which was formed on the NaOH- and heat-treated tantalum metal, to the substrate was measured under tensile stress and compared with that of the apatite formed on the untreated substrate. The former showed much higher bonding strength than the latter. The higher bonding strength of the former was attributed to a graded structure at the apatite-substrate interface where the apatite gradually changes into the interior metal substrate.

The effect of different surface energies of substrate on adhesive bonding at room temperature is investigated in this paper. Comparing to the RCA cleaning procedure, the improved cleaning procedure increases surface energies of wafers which were detected by water contact angle (WCA) measured with JY-82 contact angle goniometer. This higher surface energy leads to stronger bonding properties between Si and glass with epoxy (TS814) at room temperature. The bonding strength was detected by Series IX Automated Materials Testing System. Compared with the RCA cleaning simples, the one with high surface energy of wafers reached 8.56Mpa, more than seven times stronger than the others.

In order to find out the relationship between the bonding current and the bonding strength, four sets of experiments, each contains 200 samples, were done with the bonding current limited to 0.05mA, 0.25mA, 0.45mA and 0.65mA respectively. The qualified rate, mean value and standard deviation of the bonding strength measured subsequently were chosen to judge the influence of the bonding current on the bonding strength. The results show that the bonding strength under lower limiting current is determined by the interfacial region, while under higher limiting current, the bonding strength is determined by the glass. With the increase of the limiting current, the qualified rate and mean value of the bonding strength increase first and then decrease, while the standard deviation of the bonding strength first decreases and then increases. Limiting the bonding current is beneficial to improve the qualified rate and stabilize the bonding strength.