Porous Interface Coatings

Sol-gel processing has been used to prepare beta-alumina [113] and coatings could be prepared by this method. Such coatings likely would not possess the desired crystalline orientation. 

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Eig. 2. Microstmctural design approaches for composite interfaces (a) mechanically weak coating (b) porous interface and (c) ductile interface. 

While there are abundant reasons for academic consideration of porous-matrix oxide-oxide composites, much of the practical interest, and opportunity to pursue them, is owed to two factors the economical availability of numerous types of fibers, and the absence of the necessity to coat fibers. Both of these factors significantly affect the ease and cost of experimentation, and, more importantly, the ultimate cost of the materials. An additional significant advantage is that in many cases fabrication can be very similar to that employed for polymeric composites.The majority of this section is therefore focused on porous matrix composites, since these materials are the most mature. Research on composites containing interface coatings is also addressed in this section (4.3). 

Walpole A, Briggs E, Karlsson M, Palsgard E, Wilshaw P. Nano-porous alumina coatings for improved bone implant interfaces. Mater Werkst 2003 34 1064-8. 

The ingress of corrosive ions into an anodized coating through its pores is not a slow process for a porous anodized coating. After corrosive ions reach a critical concentration threshold at the film/substrate interface and trigger the corrosion of the substrate Mg alloy, the corrosion of the anodized magnesium starts. Mg is dissolved into the solution in the pores, which gradually makes... 

The second series of results that we present have been obtained by small-angle neutron scattering (SANS). Contrary to the EWIF method and to the neutron-reflectivity technique, SANS does not deal with a single, flat, well oriented, small surface but need a large amount of interface coated by polymer. The polymer substrate is therefore a porous medium or a colloidal suspension. For such samples, the scattered intensity i(q) per unit volume (in cm" ) is the sum of three terms resulting from the interferences between the amplitudes scattered by the solid and by the polymer. 

Current ceramic femoral components used in knee prostheses generally require bone cement to connect the implant to living bone. However, metal femoral components are available in cementless varieties which incorporate a plasma-spray hydroxyapatite (HA) coating or a porous bead coating on the fixation side to promote bone growth and avoid the potential adverse effects of bone cement, such as the hypersensitivity [6]. In addition, it is generally considered that hard bone cement particles released from the bone-prosthesis interface can increase the polyethylene wear significantly if they flow into the conjunction. Therefore, the lack of cementless fixation in ceramic knee prostheses has limited their use. 

This study has shown that typical coating biocides can be encapsulated within modified silica frameworks. These porous frameworks offer a means to inhibit the aqueous extraction of the biocide. In such combinations the biocides retain their anti-microbial properties, while controlled delivery facilitates a dynamic equilibrium to maintain a minimum inhibitory concentration at the coating interface, over an extended time period. There is evidence that biocide housed in such frameworks has a longer effective activity for a given initial concentration, since it is to some extent protected from the usual environmental degradation processes. 

Perhaps more important than cost is the solution to the crucial problem of interfacial contacts that always plagues homogeneous GPE films prepared from traditional approaches. Since both cathode and anode composite materials are coated on their substrates with the same PVdF—HEP copolymer as the binder, the in situ gellification following the electrolyte activation effectively fuses the three cell components into an integrated multilayer wafer without physical boundaries, so that the interfaces between anode and electrolyte or cathode and electrolyte are well extended into the porous structures of these electrodes, with close similarity to the interfaces that a liquid electrolyte would access. 

In the sheathless interface, the electrical contact is obtained by coating with either a metal [85, 88-90] or a conductive polymer [91] the separation capillary outlet, which is shaped as sharp tip. Also employed are sheathless interfaces in which the electrical contact is established using a metal electrode or a conductive wire inserted into the outlet of the separation capillary [92], A small gap between the separation capillary and the needle of the ionization device filled by a liquid is the approach made to establish the electrical contact in the liquid junction interface [86,87], This arrangement is also realized by making porous through chemical etching the tip [93] or a small section of the wall [94] of the separation capillary at its outlet. 

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