Articles you may be interested inEffect of target-substrate distance on properties of flexible InZnSnO films grown by linear facing target sputtering J. Vac. Sci. Technol. A 30, 031510 (2012); 10.1116/1.4705520Influence of the film properties on the plasma etching dynamics of rf-sputtered indium zinc oxide layers Influence of the target-substrate distance on the properties of indium tin oxide films prepared by radio frequency reactive magnetron sputtering Electrical, optical, and structural properties of indium-tin-oxide thin films deposited on polyethylene terephthalate substrates by rf sputtering

Southern pine and spotted gum are two of Australia’s most important locally produced commercial timbers. However, internationally, they are amongst the most problematic species to glue cost-effectively, especially for sawn-laminate-based structural engineered wood products, such as glulam and cross-laminated timber. This study investigated the efficacy of different pre-gluing wood surface machining preparations on the tensile shear strength of lap shear samples prepared from both species. Surface machining methods tested included planing, face milling, and sanding post-planing with 40 and 80 grit sandpaper. Wood face milling is not currently used commercially in Australia and has not previously been adequately tested on Australian commercial timbers to improve wood adhesion. Planing is currently the most common method used internationally for preparing wood surfaces for gluing. For both species, face milling with fast feed speed (45 m/min), slow cutter speed (57 m/s), and sanding treatments post-planing resulted in significantly higher tensile shear strength compared to planing for lap shear samples that had been subjected to an accelerated weathering process. Performance differences in tensile shear strength between surface machining methods are likely to be related to the effects of these machining methods on surface roughness, fibrillation, and sub-surface cell damage.

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A rapid thermal annealing (RTA) technique has been employed to process lead zirconate titanate (PZT) films prepared by reactive magnetron sputtering. The films were fabricated by dc sputtering a multielement metal target in an oxygen ambient at a substrate temperature of 200 °C. A subsequent postdeposition RTA at 600 °C for 5 s crystallizes the films into a perovskite-type structure through various intermediate phases. Due to the short postdeposition processing times inherent in the RTA method, the initial nature of the as-grown films has a critical influence on the crystallization kinetics. The reaction sequence in the formation of perovskite PZT from the films deposited at low substrate temperatures by the sputtering technique has been evaluated, and various key factors influencing the crystallization of PZT have been identified. As-grown films are constituted of polycrystalline orthorhombic lead oxide in an amorphous matrix of titania and zirconia. During annealing lead oxide transforms into a cubic phase, and the lead oxide stoichiometry determines the processing route to PZT. In the case of lead-rich films, intermediate compounds of lead with titania and zirconia are observed, which react during the final stage of annealing at 600 °C to form PZT. In lead-deficient films, the formation of a pyrochlore phase has been observed, which crystallizes into perovskite at 750 °C. The Zr/Ti ratio also influences the crystallization sequence. In the case of Ti-rich PZT, the intermediate compounds initially involve a zirconium-rich rhombohedral PZT, with which residual titanium reacts to form tetragonal PZT. The films showed good ferroelectric and other electrical properties with a remanent polarization of 24 μC/cm2, coercive field of 32 kV/cm, ε′=950, tan δ=0.02, and σdc (300 K)=10−12 Ω−1 cm−1 with an activation energy between 0.9 and 1.4 eV.

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Natural plant fiber-reinforced polymer composites have been in the limelight in the field of materials science for their mechanical properties, economy, and eco-friendliness. Properties of such novel composites depend on the adhesion and interaction between the fibers and the polymer matrix. Consequently, poor interaction can lead to declined mechanical properties, particularly strength. Surface modifications of fibers are carried out to enhance the bonding with the matrix by certain chemical treatments that remove hydroxyl groups in the amorphous cellulose region, making them hydrophobic and hence compatible with the matrix. Doing so also strengthens the composites, widening their scope of application. This review article provides comprehensive information about various surface modification techniques that include alkali, silane, acetylation, permanganate, peroxide, benzoylation, acrylation, acrylonitrile grafting, isocyanate, addition of maleated coupling agents, and fungal treatments. The working mechanisms and the effects of such treatments on mechanical strength are also elucidated. Furthermore, this review provides an overview of nanoclay inclusion in polymers, their addition techniques, and the augmentation of the mechanical properties of polymer matrix composites. The article concludes along with the field of applications, summary of pertinent challenges, and directions for future work.

Darwin stringybark (Eucalyptus tetrodonta) is one of Northern Australia’s most important commercial forest resources. The wood exhibits desirable wood properties including high strength, natural durability, and visual appeal. The production of engineered wood products (EWPs) such as glulam from this resource represents a significant commercial opportunity for the timber industry in northern Australia. However, a major challenge to overcome is the achievement of satisfactory glue bond performance. This study evaluated the effects of different surface machining preparations, adhesive types, and curing temperatures on the bonding characteristics of Darwin stringybark. The pre-gluing surface machining method significantly influenced the timber wettability, roughness, permeability and tensile shear strength of adhesive bonds. Planing resulted in the lowest wettability, roughness, and permeability, while bonded planed samples produced the poorest tensile shear strength. Alternative surface machining methods including face milling and sanding post-planing were shown to significantly improve the timber wettability, roughness, and permeability, and also to increase the tensile shear strength of bonded samples. The resorcinol formaldehyde adhesive resulted in slightly improved tensile shear strength in most cases compared to the polyurethane adhesive. There was no significant improvement in tensile shear strength with the use of elevated temperature curing.

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