X-ray photoelectron spectroscopy analysis of oxide formation on 8150 aluminium foils

It is known that an enrichment of metallic elements in the oxide layer of aluminium foils may significantly affect their surface properties. Elemental compositions at various depths of the newly developed 8150 aluminium foil were determined by x-ray photoelectron spectroscopy for selected heat treatment conditions. © Institute of Materials Engineering Australasia Ltd

Innovative bioceramics

Overall, the benefits of advanced ceramic materials in biomedical applications have been universally appreciated, specifically, in terms of their strength, biocompatibility and wear resistance. However, the amount of supporting data is not large and the continuous development of new methods is pertinent for better understanding of the microstructure-properties relationship and, in general, for obtaining new directives for their further improvement. This paper gives an overview of some of the more innovative applications of bioceramics in medicine. © Institute of Materials Engineering Australasia Ltd - Materials Forum Volume 27 - Published 2004

The effect of surface treatment on delamination for a nylon interleaving material

One method of controlling delamination and increasing the inter-lamina toughness in composite laminates is the use of thermoplastic interleaving films, primarily to absorb energy. In this study the effect of controlling the surface energy of a nylon interleaving film on the interlaminar fracture toughness was investigated. It was found that as the surface energy of the nylon increased so did the Mode I delamination resistance. Surface energy was measured via dynamic contact angle measurements and delamination resistance via double cantilever beam specimens. It was concluded that control of the surface energy of the interleaving material is paramount in controlling delamination. © Institute of Materials Engineering Australasia Ltd

Fracture Toughness Of Nanoscale Zirconia Coatings On Titanium Substrates

In the biomedical field, the surface modification of titanium aims to inhibit wear, reduce corrosion and ion release, and promote biocompatibility. Sol-gel-derived ceramic nanoscale coatings show promise due to their relative ease of production, ability to form a physically and chemically uniform coating over complex geometric shapes, and their potential to deliver exceptional mechanical properties due to their nanocrystalline structure. In this study zirconia coatings on titanium were investigated for their fracture toughness

A solution for estimating the tensile yield strength from small specimens

The small punch test is an innovative test that utilises small disc-shaped specimens to assess the mechanical behaviour of materials. The main advantage is the relatively small specimen size. In this article, a modified analytical solution for the small punch maximum bend strength is proposed that is based on classical plate theory. A clear linear relationship is observed between the tensile yield strength σYS and the small punch maximum bend strength σy for both alloys and metal matrix composites. Copyright by ASTM Int'l (all rights reserved)

Comparative study of conversion of coral with ammonium dihydrogen phosphate and orthophosphoric acid to produce calcium phosphates

© 2014, Australasian Ceramic Society. All rights reserved. Biogenic materials like corals, which are readily available, could be used to produce bioceramic materials and address significant advantages due to their unique structures and chemical compositions that contain Mg and Sr. Many conversion processes has been in the past proposed. In this work, a comparison study between the conversion of coral with orthophosphoric acid and ammonium dihydrogen phosphate was conducted. The resultant structures and compositions were studied using XRD, ICP-MS, SEM and FTIR. The results show that with phosphoric acid the coral was converted into mainly monetite (92%). The ammonium dihydrogen phosphate converted approximately 76% of the coral to hydroxyapatite through solid state reactions. The two routes proved to be effective in producing bioceramic materials from corals under moderate conditions of temperature with a basic condition favouring the yield of hydroxyapatite

Characterisation of Bioglass based foams developed via replication of natural marine sponges

A comparative characterisation of Bioglass based scaffolds for bone tissue engineering applications developed via a replication technique of natural marine sponges as sacrificial template is presented, focusing on their architecture and mechanical properties. The use of these sponges presents several advantages, including the possibility of attaining higher mechanical properties than those scaffolds made by foam replica method (up to 4 MPa) due to a decrease in porosity (68-76%) without affecting the pore interconnectivity (higher than 99%). The obtained pore structure possesses not only pores with a diameter in the range 150-500 mm, necessary to induce bone ingrowth, but also pores in the range of 0-200 mm, which are requested for complete integration of the scaffold and for neovascularisation. In this way, it is possible to combine the main properties that a three-dimensional scaffold should have for bone regeneration: interconnected and high porosity, adequate mechanical properties and bioactivity

Metal-polymer nanocomposites

Polymers have low strength and stiffness, high dielectric strength and poor thermal properties. They are poor conductors of electricity and heat and are non-magnetic. Attempts have been made to change and improve some of these to increase the range of applications. Recently, researchers have shown interest in using nanoparticles. This chapter looks at metal nanoparticles, which exhibit uniquely different electronic and optical properties from their bulk counterparts. It is these interesting new properties that are one of the driving forces for their incorporation in polymer matrices. Methods of incorporation of metal nanoparticles into a polymer, the resultant properties, applications and future trends will be discussed. © 2012 Woodhead Publishing Limited All rights reserved