Compacted graphite

One of the outstanding properties of the austenitic irons is their resistance to graphitic corrosion or graphitisation . In some environments ferritic cast irons corrode in such a manner that the surface becomes covered with a layer of graphite. This compact graphite layer, being more noble than the matrix, markedly increases the rate of attack. The austenitic irons rarely form this... 

Figure 12. Typical microstructure of compacted graphite iron (200x)...

Use In-mold filtration of gray, malleable, or white, compacted graphite, and ductile cast irons, as well as nonferrous aluminum- and copper-based alloys. 

Compacted graphite iron is midway between gray and ductile or malleable iron in properties. It is primarily used in automotive applications. 

SEM studies on the cathode deposit reveal multiple features. Curved and compact graphite layers are deposited on the outer shell. Inner core deposits contain bundle-like structures, which contain randomly distributed nanotubes and polyhedral particles (Fig. 9). It is possible that, as a result of carbon vapour... 

Depending on the concentration and form of the carbon (lamellar, spheroidal or compact), various types of cast iron may be defined lamellar iron carbon in the form of flakes nodular iron carbon in spheroidal form compact graphite iron carbon in bonded form. 

Grey iron cast iron with grey-coloured fracture may be found with lamellar, nodular and compact graphite but the term is most often used for lamellar iron... 

Abele R, Sahm A, Schultz H (2002) Wear mechanism when machining compacted graphite iron. Ann CIRP 51(l) 53-56... 

Fuel compact Diameter 1.25 cm (0.492 in.) Length 5.3 cm (2.087 in.) Standard fuel element 1.60 g U per compact Number of compacts per fuel hole 15 Fuel compact graphite matrix 1.74 g/cm ... 

Compacted graphite iron Compacted (vermicular) graphite F.P Gray SoUdification... 

This fuel form has been successfully operated in reactors to very high bumups. The plutonium density limit, which is about an order of magnitude below that of the Pu-Al system, is driven by the fact that a quantity of carbon is needed inside a TRISO particle to chemically stabilize the Pu02, in addition to all the other materials needed to make the fission product container parts of the particle and the compact graphite. 

This fuel form could be further contained in cladding materials such as stainless steel or aluminum for low temperature operation in a water-cooled reactor. A water corrosion resistant cladding is necessary because the compact graphite is quite porous and cannot be expected to keep water from directly contacting and corroding the fuel particle surfaces. 

Anode Metal anodes consisting of noncorrosive stainless steel mesh can be utilized [76], but copper is not useful due to the toxicity of even trace copper ions to bacteria. The most versatile electrode material is carbon, available as compact graphite plates, rods, or granules, as fibrous material (felt, cloth, paper, fibers, and... 

Table 11.5 Designations, Minimum Mechanical Properties, Approximate Compositions, and Typical Applications for Various Gray, Nodular, Malleable, and Compacted Graphite Cast Irons... 

Compacted graphite irons are now being nsed in a nmnber of important applications, including diesel engine blocks, exhanst manifolds, gearbox housings, brake discs for high-speed trains, and flywheels. 

Gray, ductile (or nodular), malleable, and compacted graphite irons are the four most widely used cast irons the last three are reasonably ductile. 

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