Engineering materials, main groups

There are three main groups of engineering materials. These are ... 

Historically, polyanhydrides were synthesized for engineering materials. Because of their hydrolytical instability, these polyanhydrides have never been commercialized for engineering purposes. This instability has a beneficial aspect in drug delivery systems since the implant incorporated with an active drug does not need to be retrieved. The anhydride has a labile bond in the main chain of the polymer. This labile bond then breaks down into two carboxylic acid groups. 

As a general rule ceramic materials can be grouped into three main groups traditional ceramics, refractories and castables, and advanced or engineered ceramics. 

The process engineering tasks are classified according to the product groups for which they are used. There are four main areas material mixing, material separation, reaction, and phase transformation. The common factor of all the processes in Table 2.1 is of course the high-viscosity phase and consequendy the specific difficulties of the machinery (technical design, dimensioning with respect to forces, torques, drive power, pressures). 

Processing of metallic thin films by chemical vapor deposition has been rapidly developed during the past few years, mainly due to numerous potential applications in the microelectronics industry. Research groups worldwide publish in this or allied fields. Contributions come from diverse scientific domains, such as coordination and theoretical chemistry, chemical engineering, and of course materials science. Such an interest from the scientific community reveals that CVD is an attractive route for the deposition of metallic films. However, there are numerous and complex problems to solve before optintizing it. 

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