Material Choice

Coercivity of Thin-Film Media. The coercivity ia a magnetic material is an important parameter for appHcations but it is difficult to understand its physical background. It can be varied from nearly zero to more than 2000 kA/m ia a variety of materials. For thin-film recording media, values of more than 250 kA / m have been reported. First of all the coercivity is an extrinsic parameter and is strongly iafluenced by the microstmctural properties of the layer such as crystal size and shape, composition, and texture. These properties are directly related to the preparation conditions. Material choice and chemical inborn ogeneties are responsible for the Af of a material and this is also an influencing parameter of the final In crystalline material, the crystalline anisotropy field plays an important role. It is difficult to discriminate between all these parameters and to understand the coercivity origin ia the different thin-film materials ia detail. 

Materials play an important role ia the electronics iadustry. The effectiveness of the electrical performance of the system, its reUabiUty, and its cost aU. depend on the packagiag materials used, which are chosen for their properties and appHcations. As a result, the practicing engineer must have ready access to current information on the materials that can be used ia product development. This article gives an overview of the various material choices for the elements of an electronic product. 

Some of the most obvious examples of problems with gas and materials are frequently found in refining or petrochemical applications. One is the presence of hydrogen sulfide. Austenitic stainless steel, normally a premium material, cannot be used if chlorides are present due to intergranular corrosion and subsequent cracking problems. The material choice is influenced by hardness limitations as well as operating stresses that may limit certain perfonnance parameters. 

The demands on the PSA performance for these types of applications can be very high, especially in the areas of creep, shear resistance and long-term durability. For these reasons, crosslinked acrylics and stabilized block copolymer adhesives have become the main PSA material choices. 

The toughness of a material is a design driver in many structures subjected to impact loading. For those materials that must function under a wide range of temperatures, the temperature dependence of the various material properties is often of primary concern. Other structures are subjected to wear or corrosion, so the resistance of a material to those attacks is an important part of the material choice. Thermal and electrical conductivity can be design drivers for some applications, so materials with proper ranges of behavior for those factors must be chosen. Similarly, the acoustical and thermal insulation characteristics of materials often dictate the choice of materials. 

This space truss is seemingly an unusual example, but space is now a part of our everyday lives. Thus, there are many space examples in which you must expect to use composite materials because they are the least-expensive design solution. The raw material cost is not even close to the bottom-line cost. The raw material cost has something to do with the bottom line, but the ordering of material choices that you get based on raw material cost does not mean anything in comparison to the ordering of the actual bottom-line costs. 

Under consideration of the status quo of the technological development, the guideline series of VDI 4640 Thermal Use of the Underground presents in four different parts a proper design, a suitable material choice and a correct execution of drillings, installation and system integration of plants for the thermal use of the underground ... 

Mishnaevsky L, Freere P, Sinha R, Acharya P, Shrestha R, Manandhar P. Small wind turbines with timber blades for developing countries Materials choice, development,... 

Electrolux is the world s largest producer of powered appliances for kitchen, cleaning and outdoors. They have created comprehensive Environmental Product Declarations (EPDs) for many of their product lines. Information within the product profiles details chemicals that have been banned as well as the percentage and types of materials and how they have improved material choices. Forexample, plastic components do not contain cadmium, lead, mercury or their compounds or chlorinated or brominated flame retardants metal components are not coated with cadmium, chromium, or nickel and metal paints do not contain pigments and additives based on heavy metals. Many Electrolux products are also PVC-free. 

Limitation of pollution (good housekeeping, raw material choice, source assessment) W ... 

Staging material choice is of the highest importance to produce consistent, quality scans, and several options should be readily available to address the integrity of different specimen types. For example, if a particular specimen is fragile (e.g., E15 mouse embryos), a softer, more flexible material can be used, and conversely, if a particular sample is exceptionally robust (e.g., adult rat femur), a more rigid staging material would be more appropriate. 

In most materials selection processes, it is virtually impossible to make materials choices independent of the product shape. This includes not only the macroscopic, or bulk, shape of the object such as hammer or pressure relief valve, but also the internal or microscopic shape, such as a honeycomb structure or a continuous-fiber-reinforced composite. Shape is so important because in order to achieve it, the material must be subjected to a specific processing step. In Chapter 7, we saw how even simple objects made from a single-phase metal alloy could be formed by multiple processes such as casting or forging, and how these processing steps can affect the ultimate properties of the material. As illustrated in Figure 8.6, function dictates the choice of... 

The design of the closing section of the stem requires special attention to the material choice and shape. Usually the stem, as well as the seat, is locally heat-hardened or coated for better wear resistance. 

Much of the information represents an updating of material presented in two papers related to the ethylene area prepared by the Lum-mus Co. in 1968 (I, 2). In addition, however, particular emphasis is given to possible new developments in the United States which could dramatically affect raw material choices. We explore the effects that a potential change in the import quota system and a move to lead free gasoline could have on the U.S. ethylene industry. 

The material choice and hence the microfabrication was based on the specific needs of Fourier transform infrared (FTIR) spectroscopy, to have IR-transparent materials [110]. For this reason, CaF2 disks are an essential part of the device. The main part of the device consists of two polymer layers sandwiching one metal layer which are encased by the two disks, acting as a kind of end plates. 

The general focus of material choice for medium- to large-scale micro structured devices is on metals. Mostly stainless steels of various compositions, depending on the operation temperature, are used. 

Figure 1 Future generation MOS VLSI gate electrode and interconnect material choices.4 Reprinted by permission of the publisher, The Electrochemical Society, Inc.

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