A significant improvement of tribological properties on Ti-6Al-4V has been achieved by developed in this study multilayer treatment method for the titanium alloys. This treatment consists of an intermediate 2 μm thick TiCxNy layer which has been deposited by the reactive arc evaporation onto a diffusion hardened material with interstitial O or N atoms by glow discharge plasma in the atmosphere ...

Pyrolytic carbon has many properties that make it suitable for use in the replacement of small joints [1]. The material has a modulus of elasticity similar to that of bone, good wear and fatigue properties, and excellent biocompatibility. Its biggest disadvantage is inadequate biological fixation. The as-deposited surface of pyrolytic carbon has a pore size of 5-10 μm and a depth of 20 μm. This...

A thermal barrier system with plasma-sprayed thermal barrier coating (TBC) has been analyzed subject to thermal cycling. The thermally grown oxide (TGO) is allowed to grow at the peak temperature in the cycle, with both thickening and lateral components of the growth strain. The stresses in the TGO are also allowed to relax at high temperature when they attain a critical level. The bond coat is...

The basic principle of liquisolid systems formulation lies in the conversion of the drug in a liquid state into an apparently dry, free-flowing and readily compressible powder by its blending (or spraying) with specific carriers and coating materials. The selection of the most suitable carrier and coating material depends especially on their values of flowable liquid retention potential (Φ), wh...

The corrosion behaviour of αand β-Ta coatings was compared to that of Cr coatings produced by cylindrical magnetron sputtering as well as electrodeposition. For Ta coatings, the corrosion process was dominated by dissolution of the steel substrate through open pores, however, at the end of 5 days, coating degradation was not observed. In contrast, while open pores were not observed with the Cr ...

and light microscopy were used to identify the changes after the heat-treatment. Microhardness and indentation modulus values were also investigated to analyse the changes in the mechanical properties after the heat-treatment. Results of this investigation indicated that the residual stress gradient within the coating material decreases after the heat-treatment, and the stress field in the subs...

Shellac is an important coating material for food products. Since the introduction of aqueous ammoniacal solutions it also regained importance for pharmaceutical applications. Because of the comparatively high dissolution pH of this material, further additives are required if shellac is used as enteric coating material. However, this dissolution behaviour of shellac may be of interest for susta...

A study of sulfur-rich sludge (71.6% pyrite) dissolution at alkaline conditions (pH ca.9) was investigated using non-stirred and stirred flow-through experiments at room temperature (26 ± 1.2oC) and O2 partial pressure of 0.20 atm. The dissolution rate of pyrite-rich sludge was calculated based on the S release (aqueous SO4) at the steady-state. Results show that: (1) in the nonstirred reactor ...

Coating of particulate solids by a thin film layer is of interest in many industrial applications such as seed and tablet coating. In seed processing, seeds are commonly coated with a protective coating layer consisting of fertilisers and crop protection products. Rotary drum batch coaters are typically used for this purpose. The coater consists of a cylindrical vessel with a rotating spray dis...

To improve the surface properties of a substrate coating plays an important role. The performance of the coating layer over the substrate can be known under different load conditions. Finite element simulation is one of the techniques to validate the result where the improvement of the coating is done by optimization. Through FEM, very complex stress strain field of thin films or bulk material ...