Plasma-surface modification (PSM) is an effective and economical surface treatment technique for many materials and of growing interests in biomedical engineering This article reviews the various common plasma techniques and experimental methods as applied to biomedical materials research, such as plasma sputtering and etching, plasma implantation, plasma deposition, plasma polymerization, laser plasma deposition, plasma spraying, and so on The unique advantage of plasma modification is that the surface properties and biocompatibility can be enhanced selectively while the bulk attributes of the materials remain unchanged Existing materials can, thus, be used and needs for new classes of materials may be obviated thereby shortening the time to develop novel and better biomedical devices Recent work has spurred a number of very interesting applications in the biomedical field This review article concentrates upon the current status of these techniques, new applications, and achievements pertaining to biomedical materials research Examples described include hard tissue replacements, blood contacting prostheses, ophthalmic devices, and other products

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Plasma-surface modification of biomaterials

On utilise une methode d'indentation dans laquelle un indenteur pyramidal est utilise pour pousser les fibres et provoquer un glissement a l'interface fibre/matrice. L'analyse des resultats permet d'obtenir une mesure de l'energie de rupture de liaison, des contraintes de frottement par glissement, de leur uniformite et de leur sensibilite a un glissement repete

Measurement of Interfacial Mechanical Properties in Fiber‐Reinforced Ceramic Composites

Corrosion and surface modification on biocompatible metals: A review.

Instrumented indentation, also known as depth-sensing indentation or nanoindentation, is increasingly being used to probe the mechanical response of materials from metals and ceramics to polymeric and biological materials. The additional levels of control, sensitivity, and data acquisition offered by instrumented indentation systems have resulted in numerous advances in materials science, particularly regarding fundamental mechanisms of mechanical behavior at micrometer and even sub-micrometer length scales. Continued improvements of instrumented indentation testing towards absolute quantification of a wide range of material properties and behavior will require advances in instrument calibration, measurement protocols, and analysis tools and techniques. In this paper, an overview of instrumented indentation is given with regard to current instrument technology and analysis methods. Research efforts at the National Institute of Standards and Technology (NIST) aimed at improving the related measurement science are discussed.

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Review of Instrumented Indentation

The hardness and Young's modulus of the successive layers across a resin-dentin bonding area were determined by nano-indentation for four commercially-available dentin adhesive systems, of which two were also applied with a different conditioning agent. With a computer-controlled nano-indentation technique, minute triangular indentations were made within a small area of a few micrometers' diameter at a load of a few milli-Newtons. The load and displacement of the indenter were continuously monitored during the loading-unloading sequence, so hardness and Young's modulus could be computed as a function of the indenter geometry and the applied load. The hardness of the resin-dentin interdiffusion zone was significantly lower than that of unaltered dentin. A gradient of moduli of elasticity was observed from the rather stiff dentin over a more elastic resin-dentin interdiffusion zone and adhesive resin layer to the restorative composite. That gradient was more substantial in those systems that produced relatively thick adhesive resin layers or supplementally provided a filled low-viscosity resin as an intermediate layer between the adhesive resin and the bulk restorative composite. Such an elastic bonding area might have a strain capacity sufficient to relieve stresses between the shrinking composite restoration and the rigid dentin substrate, thereby improving the conservation of the dentin bond and, as a consequence, the marginal integrity and retention of the restoration.

Assessment by Nano-indentation of the Hardness and Elasticity of the Resin-Dentin Bonding Area

The effect of nitrogen implantation on the wear behavior of a range of metals has been studied. Hardness measurements and pin-on-disc wear tests which characterize specifically the properties of the thin implanted layer have been carried out. It is shown that large improvements in wear resistance can be obtained by nitrogen implantation and that a loose correlation exists between reduced wear and increased surface hardness. However, it is demonstrated, on the basis of detailed examination of the wear tracks, that the best improvements in wear performance occur only when implantation produces a change in the dominant mode of wear. It is further shown that the formation of surface oxide layers during the wear process is often associated with these changes in wear behavior. The wear mechanisms, and the changes thereof, are described and discussed in detail for Ti-6Al-4V, hard chromium electroplate, and a range of ferrous alloys.

R. Hutchings

Papers

The wear behavior of nitrogen-implanted metals

Measurement of Hardness at Indentation Depths as Low as 20 Nanometres