Papers by Keyword: Bonding Strength

Abstract: T2 red copper plate and DT4C electrical pure iron plate were cladded by explosive welding. Microcosmic analysis and bonding strength of the bonding interface were also studied. Results indicate that the welded zone appears periodical wavy metallurgical interface and obvious element diffusion occurs in the interfacial zone. In addition, no separation happens after the bonding strength test and tension-shear test and the broken zone takes place in the T2 red copper part of the samples, indicating that the bonding strength of the welded interface can get no less than the strength of T2 red copper.

Abstract: Majority of engineered wood product such as glulam, laminated veneer lumber and parallel strand lumber relies greatly on wood adhesive bonding and adhesive penetration. Determination of bonding strength and adhesive penetration of adhesive-wood could enhance effective utilization of wood as construction material. Kapur (Dryobalanops aromatica) and Kelat (Syzygium spp.) were two commercial Malaysian medium hardwoods were used in the study. Since pressure is essential during wood bonding, the purpose of the study is to determine the effect of different pressure on bonding strength and adhesive penetration. Kapur and Kelat samples were bonded using Phenol resorcinol formaldehyde (PRF) and press at three different pressures (100 psi, 200 psi and 300 psi). Shear stress of bond line and Adhesive penetration were measured. The result shows that Kapur has lower bonding strength compares to Kelat and both samples pressed with 200 psi pressure shows higher shear strength then 100 psi and 300 psi. The result of adhesive penetration shows that higher pressure applied during bonding assembly resulting in the higher adhesive penetration into the wood porous structure.

Abstract: In this study, alfalfa protein modified by sodium hydroxide was used to prepare adhesive. The effect on the bonding property by adding different amount of sodium hydroxide was discussed. The upper limit using temperature of alfalfa protein-based adhesive was increased and its bonding property was improved after the protein modified by sodium hydroxide. The adhesive prepared by alfalfa protein modified by 6% sodium hydroxide had the best bonding strength of 2.5MPa.

Abstract: Effect of Supersonic Particles Deposition processing parameters on porosity and bonding strength of Al-Si coating on the surface of ZM5 Magnesium alloy was studied. The result shows that the porosity rates of Al-Si coating are all below 0.6% and the bonding strength is all above 35MPa. With air pressure increasing, the porosity of Al-Si coating reduces to below 0.3% and the bonding strength increases to above 40MPa. With spray distance increasing, the average percent voids of Al-Si coating tends to increase and the bonding strength is better between 160mm and 200mm. The minimum porosity and the maximal bonding strength of the coating can be reached when the speed of feeding powders is at 6r/s.

Abstract: Nanocrystalline cellulose (NCC) was used for improving the formaldehyde (HCHO) emission and bonding strength of urea formaldehyde (UF) resin adhesive in fiberboard and plywood. The original NCC was modified by 3-aminopropyltriethoxysilane (APTES) and the wetting property with UF resin adhesive was improved by 26.4%. The UF resin adhesive with modified NCC was characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TG) and Fourier transform infrared (FT-IR). The crystal region of UF resin adhesive was influenced by NCC and the diffraction intensity of the peak at 2θ = 22.82° was enhanced significantly. The thermal stability of UF resin adhesive with 1.0% modified NCC increased by 4.9%. And modified NCC led hydroxyl groups into the UF resin adhesive. HCHO emission and bonding strength of the UF resin adhesive with modified NCC were tested according to Chinese National Standards GB/T 17657-1999 and GB/T 9846-2004. The HCHO emission of fiberboard and plywood with 1.5% modified NCC decreased by 13.0% and 53.2%, respectively. The bonding strength of fiberboard increased by 158.3% (from 0.12 MPa of control group to 0.31 MPa of fiberboard with 1.5% modified NCC), while 1.5% modified NCC led to a 23.6% increase in the plywood.

Abstract: Plasma sprayed hydroxyapatite (HA) coatings on titanium alloy substrates have been used extensively due to their excellent biocompatibility and osteoconductivity. However, the low bonding strength between HA and Ti substrates is still problematic in the long-term implantation lifespan. In this paper, HA/Ta composite coatings with various Ta contents (20% and 60%) were fabricated by vacuum plasma spraying (VPS). The microstructure, phase composition of the coatings was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The results revealed that the coatings had a rough surface and lamellar structure including some pores. ASTM C-633 standard was used for the measurement of bonding strength, which was found increasing with the increase of Ta contents in the composite coatings. The bonding strength of the composite coating containing 60% Ta (H4T6) reached to 37.2 MPa, which is about 1.9 times that of HA coating. In vitro bioactivity evaluated in simulated body fluids (SBF) showed that bonelike apatite layer was formed on the composite coatings surface, which indicated the good bioactivity of the HA/Ta composite coatings.

Abstract: Cement based materials are brittle in nature. Fibers have been used to improve flexural/tensile behaviors of the cementitious materials from one hundred years ago. Recently, a new generation of high performance fiber reinforced cementitious composites (HPFRCCs) has been introduced by Professor V.C. Li which was called Engineered Cementitious Composite (ECC). ECC showed incredible flexural and tensile strengths as it was called as flexible concrete by some researchers. Usually, high modulus fibers have been used in ECCs as reinforcement. In this research, homemade low modulus fibers (acrylic, nylon 66 and polypropylene) were used as reinforcement in ECC. Flexural strength test were performed on the ECC sheets. Also, Pull out test was performed to determine adhesion energy and toughness between the fibers and the matrix. It was found that low modulus fibers caused lower flexural strength and bonding to matrix than PVA fibers. However, they were found as suitable fibers for products with good cost-quality balance especially for construction purposes.

Abstract: In order to achieve the composite of the AZ91 magnesium alloy and pure aluminum sheet, Zn-Sn-Al solder as compound agent, electric arc plating was employed to spray the brazing solder on the surface of AZ91 and pure Al sheets. The sheets were then subjected to heat treatment at 420 for 10min before rolling lamination at a reduction of 10%. The as-rolled sheets were annealed at 390 for 4hours. The microstructure, phase constitution and bonding strength of the composite interface were tested and analyzed by using SEM and energy dispersive scope (EDS), x-ray diffraction and tensile test. Experimental results showed that, under the atmospheric environment, AZ91/Al composite can be successfully fabricated with Zn-Sn-Al solder by brazing and hot-rolling, and the shearing strength can reach 22.46MPa. After annealing for 4 hours, a diffusion layer composed mainly of Al and Zn elements was formed near Al matrix, and the intermetallic phases were MgZn₂ and Mg₂Sn which was the same to the phases at the interface of AZ91/Al composite without annealing, but the amount was relatively higher. The interfacial fracture of composite was mainly due to the existence of intermetallic phases.

Abstract: In order to protect magnesium alloy structure used in equipments, Al-based alloy coating on ZM5 magnesium alloy surface was prepared by Supersonic-Particles-Deposition(SPD). Microstructure,bonding strength,hardness, anti-scratch property of the deposited Al-based alloy coating were analyzed and tested using scanning electron microscope(SEM),energy dispersive spectrmomter(EDS), dualization stretching method and scratch testing machine. The results indicated that the coating was compacted with 1.19% porosity on superficial layer and 0.08% porosity on cross-section, respectively. The bonding strength value was 42.37MPa, moreover the interface was distinct and continuous,without defects such as ablation and impurity. Microhardness of the coating was about 1.3 times to that of uncoated substrate. The anti-scratch property of the processed coating improved obviously compared to Mg-substrate.

Abstract: The application of geopolymer has been expand in many areas where before this it only used for the production of cement and concrete. One of the new applications of geopolymer is for coating. Metakaolin, fly ash and granulated blast furnace slag has been used as source for the production of geopolymer coating. The result for the geopolymer coating showed that it can prevent corrosion in seawater structure, high bonding strength between existing structures (OPC concrete), lower water permeability and also stable during high temperature exposure.