They deliver high-power density and offer the advantages of low weight and volume, compared with other fuel cells. 3.3 PEMFC structure Figure PEMFC- 1 Polymer ... ... middle of paper ... ...for the fuel cell. [Lister & McLean ] • Electrolyte membrane: The electrolyte membrane is usually made of Nafion because its availability, low cost, low permeability, good chemical stability and strength. However, it is expensive. [Lister & McLean ] • Catalyst: The most widely used catalyst for PEM fuel cells is Platinum.
ABSTRACT: This article is a portion of a comprehensive study on carbon fibre reinforced plastics. The thermal behaviour and dynamic and tensile mechanical properties of polypropylene carbon fibres composites are discussed. Carbon Fibre Reinforced Plastic is similar to fibre glass which is woven into a textile material and resin such as epoxy resin is applied and allowed to cure. The resulting material is very strong and has the best strength to weight ratio of all construction materials. It is an improvement on glass fibre-reinforced plastic, although much more expensive.
Keywords: sol-gel preparation; nanocomposite; alumina-silica fiber; carbon nanotube; dry-spinning 1. Introduction Alumina-based fibers have been considered very important ceramic materials because their excellent chemical stability, high temperature strength and low thermal expansion . However, the relatively low tensile strength of alumina-based fibers limited their applications. Carbon nanotubes (CNTs) possess the extremely high tensile strength, good flexibility, and low density . They have become ideal reinforcements for preparation high performance composite materials.
Carbon composite propeller blades are strong, lightweight and durable. The 200C/400C aerobatic series propeller of Whirl Wind Aviation make use of the carbon fiber blades as shown in figure 3 below Figure 3: The 200C/400C aerobatic series propeller Source: http://www.whirlwindaviation.com/props/200400series.asp Furthermore, Hartzell propeller also uses carbon fiber to manufacture propellers. The Hartzell ASC- II comprises of carbon fiber integrated into a co-molded stainless steel shank. Figure 4 below shows a 3 blade ASC - II propeller. Figure 4: 3 blade ASC - II propeller Source: http://hartzellprop.com/products/propeller-systems/composite-propellers-piston-engine-aircraft/ Natural Composites The natural composite blades are manufactured using high compressed thin laminated beech wood in the root section and a selection of lightweight laminated spruce wood is used for the remaining part of the blade.
In a relatively short period of time, carbon fiber revolutionized the manufacturing industry due to its low weight and superb structural properties. Carbon fiber is a composite material. Composite carbon fiber is composed of a woven carbon fiber which reinforces a polymer resin (usually epoxy) . The carbon fibers themselves are polymers of graphite (which has a hexagonal sheet structure) rolled into a thin filament . The tensile strength (resistance to tearing from being pulled) and Young’s Modulus (force required to stretch or compress a material) are extremely high in relation to the fiber’s weight.
The objective of gas carbonizing is to force a flow of carbonaceous gas between the two plates. The result is a penetration of carbon in less time. The plates are heated by electricity, which allows for a more uniform carbon penetration. The best-known carbon gas used for this process is carbon monoxide because of its ability to rapidly penetrate the metal. A side effect of carbon monoxide is an oxidizing effect that might harm the casehardened metal.
: Polymers can be very resistant to chemicals. Polymers can be bother thermal and electrical insulators. Generally, polymers are very light in weight with v... ... middle of paper ... ...d products. The resulting chemicals can then be used to make new plastics that can be in disguisable form the initial or virgin polymers. Feedstock recycling: the thermal depolymerisation of polyolefin's and substituted polyolefin's (large molecules made up primarily of the elements carbon and hydrogen such as polyethylene) into a variety of smaller hydrocarbon intermediates is termed as feedstock recycling.
In practice, most composites consist of a bulk material (the ‘matrix’), and a reinforcement of some kind, added primarily to increase the strength and stiffness of the matrix. This reinforcement is usually in fibre form. In addition, the manufacturing process used to combinefibre with resin leads to varying amounts of imperfections and air inclusions. Typically,with a common hand lay-up process as widely used in the boat-building industry, alimit for Fibre Volume Fraction is approximately 30-40%. With the higher quality, more sophisticatedand precise processes used in the aerospace industry, Fibre Volume Fraction’s approaching 70% canbe successfully obtained.the geometry of the fibres in a composite is alsoimportant since fibres have theirhighest mechanical properties along their lengths, rather than across their widths.This leads to the highly anisotropic properties of composites, where, unlike metals,the mechanical properties of the composite are likely to be very different when testedin different directions.
PTFE or Telfron is a common commercial organic fluoropolymer which is obtained by the polymerization of tetrafluoroethylene. It was first synthesized by Roy Plunkett accidentally in New Jersey in 1938 (Plunkett, R. J., 1987). It gradually becomes as an important industrial material for its extraordinary properties of high corrosion resistance, good electrical insulation, good heat insulation and low frictional coefficient. Due to those properties it is widely used as seals in chemical processing sector, and tubing or piping for laboratory uses. The low frictional coefficient makes it as a good lubricant as well.
Carbon in graphitic form presents many advantages for use as electrode due to its chemical inertness, good electrical conductivity, and wide potential range (Iona & et al, 2007). In addition, Carbon is electrochemically noble, corrosion resistant compared to metals used as electrodes. This makes carbon very useful for electrochemical and electro-winning electrodes (Electrodes and Electrode Materials Information, 2016). Due to its low cost, wear resistance, and good machinability, Graphite is the most commonly used electrical discharge machining (EDM) –“a process that removes metal with an electrical discharge of very short duration and high current density between the electrode and the