Resist materials important characteristics

Besides the material based characteristics, the difference of density of the used particle/substrate combination is a very important criterion. The difference of density influences the contrast of the radiographic tests. Tungsten carbides were used as mechanically resistant particles and titanium based alloys as substrate. The substrate material is marked by an advantageous relation of strength to density. This material is often used in aeronautics, astronautics, and for modification of boundary layers. The density of tungsten carbide (15.7 g/cm ) is about 3.5 times higher than the density of titanium (4.45-4.6 g/cm ). 

Nickel-iron alloys have a number of important applications that are derived from such special physical properties as their unique magnetic characteristics in the regions of 35, 50 and 80% nickel and from their abnormally low thermal expansion in the region of 36-50% nickel. Although not specifically used as corrosion-resistant materials, their high resistance to attack from many common environments is of benefit in their specialised applications. 

Include plastics with coefficient of friction, chemical resistance, and others. Many plastic materials inherently have a low coefficient of friction. Other plastic materials can incorporate this property by compounding a suitable ingredient such as graphite powder into the base material. It is an important feature for moving products, which provides for selflubrication. Chemical resistance is another characteristic that is inherent in most plastic materials the range of this resistance varies among materials. 

Preliminary Examination of PATE Imaging Characteristics. The data herein have shown that PATE resins are easily photolyzed in the deep UV region to form crosslinked films which are of sufficient integrity for photoresists. However, in addition to these film performance properties, a potential resist material must meet other equally important criteria. For example, the masked (unphotolyzed) portion of the resist film must be removed prior to etching, without damage to the cured film. Also, the cured films must withstand an etchant bath. Therefore, since PATE resins seem to meet the necessary requirements of solubility and solvent resistance, investigation of performance under crude simulated processing conditions was undertaken. 

Polymers were never intended to be bearing- or wear-resistant materials and in fact are usually unsuitable for tribological purposes. Hence, the number of polymers with valuable tribological properties is limited. Table 2 shows the most important polymers used for tribological applications along with their tribological characteristics [35]. 

Plastic selection ultimately depends upon the performance criteria of the product that usually includes aesthetics and cost effectiveness. Analyzing how a material is expected to perform with respect to requirements such as mechanical space, electrical, and chemical requirements combined with time and temperature can be essential to the selection process. The design engineer translates product requirements into material properties. Characteristics and properties of materials that correlate with known performances are referred to as engineering properties. They include such properties as tensile strength and modulus of elasticity, impact, hardness, chemical resistance, flammability, stress crack resistance, and temperature tolerance. Other important considerations encompass such factors as optical clarity, gloss, UV stability, and weatherability.1 248>482... 

Most UF membranes are made from polymeric materials, such as, polysulfone, polypropylene, nylon 6, PTFE, polyvinyl chloride, and acryhc copolymer. Inorganic materials such as ceramics, carbon-based membranes, and zirconia, have been commercialized by several vendors. The important characteristics for membrane materials are porosity, morphology, surface properties, mechanical strength, and chemical resistance. The membrane is tested with dilute solutions of well-characterized macromolecules, such as proteins, polysaccharides, and surfactants of known molecular weight and size, to determine the MWCO. 

Aromatic polycarbonates are transparent and highly impact resistant materials, and these characteristics make them important engineering plastics with an annual production of about 2 million tons this market is steadily increasing.22 In addition, the... 

Young s Modulus (sometimes referred to as Modulus of Elasticity, meaning "measure" of elasticity) is an extremely important characteristic of a material. It is the numerical evaluation of Hooke s Law, namely the ratio of stress to strain (the measure of resistance to elastic deformation). To calculate Young s Modulus, stress (at any point) below the proportional limit is divided by corresponding strain. It can also be calculated as the slope of the straight-line portion of the stress-strain curve. (The positioning on a stress-strain curve will be discussed later.)... 

One of the most important characteristics of aluminium and its alloys is the thin oxide film which forms on their surfaces when exposed to the atmosphere. If the oxide film is broken it will reform quickly, and this gives these materials excellent corrosion-resistance. This oxide film can be artificially thickened to give added protection - a process known as anodising - and can be easily coloured to provide a highly decorative appearance. 

The most important characteristics of ceramic materials are high hardness, resistance to high compressive force, resistance to high temperature, brittleness, chemical inertness, electrical insulator properties, superior electrical properties, high magnetic permeability, special optic and conductive properties, and so forth. 

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