Other Fabrication Processes

As with any other fabrication process, masks are needed to define the features to be etched. It is common that the etch used for the semiconductor also etches the masking material. For this reason many different masks are used in etching, including photoresist, dielectric films, and metals. Masking can be a complex issue, especially when very deep etches (>5 fim) are performed with high aspect ratios (148). 

There are many heat choices available and a wide choice of temperature controls as there is with other fabricating processes. They range from simple mechanical thermostats to solid state units with PID control, to microprocessors that are proportional, programmable, and self-tuning (Chapter 3). 

Nanorongh Ti fabricated by other fabrication processes also lead to improved osteoblast functions. For instance, de Oliverira et al. reported that nanotextured Ti, which was prepared by chemical etching, enhanced metabolic activities of cultured bone cells (i.e., up-regnlations of bone sialoprotein and osteopontin) [39]. Similarly,... 

Plastics have continued to play an important role as material of construction for parts in key industries such as automotive, aerospace, medical devices, consumer, electronic, and others. Fabrication processes, such as injection molding, are capable of producing complex shape parts. In spite of this adhesion of plastic surfaces to other plastics, elastomers, metals, and ceramics are still required to produce parts with intricate design. 

Some fabrication processes, such as continuous panel processes, are mn at elevated temperatures to improve productivity. Dual-catalyst systems are commonly used to initiate a controlled rapid gel and then a fast cure to complete the cross-linking reaction. Cumene hydroperoxide initiated at 50°C with benzyl trimethyl ammonium hydroxide and copper naphthenate in combination with tert-huty octoate are preferred for panel products. Other heat-initiated catalysts, such as lauroyl peroxide and tert-huty perbenzoate, are optional systems. Eor higher temperature mol ding processes such as pultmsion or matched metal die mol ding at temperatures of 150°C, dual-catalyst systems are usually employed based on /-butyl perbenzoate and 2,5-dimethyl-2,5-di-2-ethyIhexanoylperoxy-hexane (Table 6). 

Flame Retardants. The amount of research expended to develop flame-retardant (FR) finishes for cotton and other fabrics has been extremely large in comparison to the total amount of fabrics finished to be flame retardant. The extent of this work can be seen in various reviews (146—148). In the early 1960s, a substantial market for FR children s sleepwear appeared to be developing, and substantial production of fabric occurred. In the case of cotton, the finish was based on tetrakis(hydroxymethyl)phosphonium chloride (THPC) or the corresponding sulfate (THPS). This chemical was partly neutralized to THPOH, padded on fabric, dried under controlled conditions, and ammoniated. The finish was subsequently oxidized, yielding a product that passed the test for FR performance. This process is widely preferred to the THPOH—NH process. 

One type of computer simulation which Beeler did not include (it was only just beginning when he wrote in 1970) was finite-element simulation of fabrication and other production processes, such as for instance rolling of metals. This involves exclusively continuum aspects particles , or atoms, do not play a part. 

Composite materials are not claimed to be a cure-all for every application or even necessarily competitive with other materials. However, there are many instances in which composite materials are uniquely well-suited because of their peculiar fabrication processes. Thus, this special case of a doubly tapered wing spar is not really special, but is actually a powerful example of the class of applications where composite materials offer significant advantages over conventional materials. 

Sprayed, vacuum-deposited and plated coatings can be applied to most metals and to many non-metals, e.g. vacuum deposition is applied to many substrates including plastics spray application can be used for coating fabric, plastic and paper. Hot dipping and other diffusion processes are dependent on the nature of the substrate for the properties of the coating. Most commercial applications of aluminium coatings are on iron and steel with smaller quantities applied to aluminium alloys and plastics. 

Even though this review pertains to certain fabricating processes, they can be related to other processes (1, 3, 6, 8, 9, 11, 50, 62, 64, 190). 

Chemical vapor deposition (CVD) has grown very rapidly in the last twenty years and applications of this fabrication process are now key elements in many industrial products, such as semiconductors, optoelectronics, optics, cutting tools, refractory fibers, filters and many others. CVD is no longer a laboratory curiosity but a maj or technology on par with other maj or technological disciplines such as electrodeposition, powder metallurgy, or conventional ceramic processing. 

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