Composite plating

The air-coupled ultrasonic probes are essentially built up by the piezo-composite plate and a front side matching layer, made of air bubbles filled plastic materials. By using a thermoplastic material as matrix material of the composite, the transducer can easily be shaped by heating up, forming and cooling down to realize focusing transducers. Because of the low... 

Composite Plating. An electroless nickel matrix can be used to securely bond diamonds to cutting tools, and electroless nickel—diamond composites are also used (see Tool materials). The NYE-CARB process gives a siUcon carbide—electroless nickel composite that has extremely high abrasion resistance (49). Electroless nickel—Teflon composites are being promoted as low friction materials. 

Composite Plate—an electrodeposit that consists of two or more layers of metals deposited separately. 

Laminated composite plates under in-plane tensile loading exhibit deformation response that is both like a ductile metal plate under tension and iike a metai plate that buckles. That is, a composite plate exhibits progressive faiiure on a layer-by-layer basis as in Figure 4-34. Of course, a composite plate in compression buckles in a manner similar to that of a metal plate except that the various failures in the compressive loading version of Figure 4-34 could be lamina failures or the various plate buckling events (more than one buckling load occurs). 

M. S. Ewing, R. J. Hinger, and A. W. Leissa, On the Validity of the Reduced Bending Stiffness Method for Laminated Composite Plate Analysis, Composite Structures, Volume 9, 1988, pp. 301-317. 

Pagano studied cylindrical bending of symmetric cross-ply laminated composite plates [6-21]. Each layer is orthotropic and has principal material directions aligned with the plate axes. The plate is infinitely long in the y-direction (see Figure 6-16). When subjected to a transverse load, p(x), that is, p is independent of y, the plate deforms into a cylinder ... 

DavkJ Ford Sims, Viscoelastic Creep and Relaxation Behavior of Laminated Composite Plates, Ph.O. dissertation. Department of Mechanical Engineering and Solid Mechanics Center, Institute of Technology, Southern Methodist University, Dallas, Texas, 1972. (Also available from Xerox University Microfilms as Order 72-27,298.)... 

For more general laminated fiber-reinforced composite plates, the relations between forces, moments, middle-surface strains, and middle-surface curvatures. 

An analogous line of reasoning shows that at a strain of 1.25% the stress intensity in the glass is 125,000 psi (862 MPa) and in plastic B and C at 12,600 and 4,500 psi (87 and 31 MPa), respectively. The corresponding loads on rods made with plastics B and C are 34,400 lb (15,600 kg) and 32,375 lb (14,700 MPa), respectively. Additional detailed information is available concerning this analysis as well as developing data for plain RP plates, composite plates, bending of beams and plates, etc. (10). 

The elastic modulus of laminated composite plate in which an ER silicone gel of carbonaceous particles is sandwiched between two PVC sheets also changed under the influence of an electric field. It was found that an electric field of 1.17 kV/mm caused a gain in the elastic modulus of the gel of 13% [57]. 

SOFC electrodes are commonly produced in two layers an anode or cathode functional layer (AFL or CFL), and a current collector layer that can also serve as a mechanical or structural support layer or gas diffusion layer. The support layer is often an anode composite plate for planar SOFCs and a cathode composite tube for tubular SOFCs. Typically the functional layers are produced with a higher surface area and finer microstructure to maximize the electrochemical activity of the layer nearest the electrolyte where the reaction takes place. A coarser structure is generally used near the electrode surface in contact with the current collector or interconnect to allow more rapid diffusion of reactant gases to, and product gases from, the reaction sites. A typical microstructure of an SOFC cross-section showing both an anode support layer and an AFL is shown in Figure 6.4 [24],... 

Section 5.2.2 include composites and metals. From a cost reduction point of view, it is estimated, according to the cost model, that the cost percentage of the plate in a stack can be reduced from -60 to 15-29% if the graphite plate were replaced by the composite plate or metal plate [15]. However, many uncertain factors are involved in the estimation. The progress and major challenges in development of bipolar plates fabricated by these candidate materials will be introduced in the following parf of this section. 

The composite as a unique material normally refers to hybrid or mixed materials between dispersed filler or reinforcemenf in fhe form of fiber, powder, flake, etc. and the continuous matrix. The composite applied to manufacture the plate mainly belongs to the type of nonmefallic composite with both nonmetallic filler and mafrix, alfhough research work on composite plates with metal filler has been carried ouf. This research will not be specifically introduced here because no promising results have been reported so far. The other sandwiched composite plate consists of layered metals and thermal expanded graphite and was developed by Russian scientists [11] however, no technical details were released. 

In all composite plates, a certain percentage of the graphite in the traditional graphite plate is replaced by the cheaper nongraphite matrix material so that... 

In addition to the advantages of the composite plate over the traditional graphite plate mentioned before, the carbon/carbon composite plates have the advantage of lower densify (about 30% lower than the thermoset- or thermoplastic-based composite plates [16]) and higher manufacturing efficiency. This offers the potential of continuous production in comparison with the machining process for graphife plates. 

One typical example of carbon/carbon composite plates is that made by Oak Ridge National Laboratory (ORNL) in the United States [12]. The composite preform was fabricafed by a slurry-molding process from fhe mixed slurry befween short carbon fibers (graphite fibers were also added in some sample plates) and fhe phenolic resin. The mass rafio between fiber reinforcement and phenolic matrix is 4 3. The phenolic matrix improves the mechanical properties and dimensional stability of the plate. A subsequent vacuum molding process was utilized to fabricate composite plates and fluid fields with relatively high resolution (Figure 5.3, [11]). 

In addition to graphite, carbon filler has also been added in composite plates. The major difference between graphite and carbon fillers in the composite plate is that the latter is less electrically conductive but is cheaper than... 

GRAFCELL plates (thermoset-based graphite composite plates) made by GrafTech ALT. (GrafTech International. 2008. http //www.graftechaet.com/GRAFCELL/GRAFCELL-Products/ Flow-Field-Plates-(FFP).aspx (accessed Dec. 20, 2008).)... 

Thermoplastic-based composite plate is another major type of composite plate with the thermoplastic matrix. The major advantage of this type of plafe is fhaf fhe well-developed injection molding processing in the thermoplastic industry can be used to manufacture the plates for saving cosf and improving production efficiency. 

Normal plastics, such as polypropylene (PP), with low prices and good ability of fhe injection molding process can be used as matrix materials in composite plates. However, the lower working temperature (around 70-80°C), lower... 

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