Corrosion-resistance Cycle time

Selection of fluoropolymers is an integral part of the overall material selection process. This implies that all the available materials such metals, ceramics, and plastics are considered candidates for an application. The end user then considers these materials against established criteria such as required life, mean time between inspection (MTBI), ease of fabrication, frequency of inspection, extent of maintenance and, of course, capital cost. More often than not it is the initial capital cost, rather than the life cycle cost of equipment, that affects the decision made during the material selection step. However, the most important piece of data is the corrosion resistance of a material in the medium under consideration over the life of the equipment. This information is available in a different format for plastics than for metals. A comparison is appropriate. 

Resistant to corrosion in an environment of acidic electrolyte, hydrogen, oxygen, heat, and humidity Reasonably high stiffness, E> 25 MPa As little cost as possible Thin dimensions for maximum stack volume Light weight for minimum stack mass Effective production process with a short cycle time... 

For other coatings, aluminum vapor deposition (2-15 g/m ) was shown by Shin et al. (1992) to be more protective, thickness for thickness, on galvan-nealed substrates than on zinc-iron electroplating. At 2 g/m aluminum, salt spray corrosion resistance was five times better more meaningful tests were not conducted. The aluminum also resisted limited cycling to 500°C. 

One way to obtain enhanced heat and solvent resistance in SBR-based PSA is sulfur addition. It is difficult to obtain sufficient cure with sulfur during normal drying cycles (2-5 min at 150-180°C). Furthermore, cure via sulfur may continue after leaving the oven, thus degrading adhesion. When used in contact with copper, the sulfur may promote corrosion. The use of phenolic overcomes all of these problems despite the fact that its natural cure speed is also insufficient for the time frame available. This is overcome through addition of one of the accelerators... 

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