Magnetic coatings

Thickness of coat This can be checked by a magnetic coating thickness tester gauge (Figure A13.5)... 

Perhaps the most important polyester is polyethylene terephthalate), commonly known as PET (or PETE 1 on plastic beverage bottles). The annual production of PET in the United States is of the order of 108 kg (105 metric tons). Much of this is converted into fabric (trade name, Dacron) or magnetically coated film (Mylar). 

If y-Fe203 could be selectively synthesized, this could be a method of obtaining magnetic coatings. 

Figure 7-1 Typical setup for a titration. The analyte is contained in the flask, and the titrant is in the buret. The stirring bar is a magnet coated with Teflon, which is inert to most solutions. The bar is spun by a rotating magnet inside the stirring motor. 

Iron oxide— Tiny, needle-shaped particles that can be easily magnetized, coating one side of the plastic cassette tape. 

More than 2 million tons of this polymer is produced annually in the United States. Dacron, the fiber produced from this polyester, accounts for approximately 50% of all synthetic fibers. It absorbs very little moisture, and its properties are nearly the same whether it is wet or dry. Additionally, it possesses exceptional elastic recovery properties so it is used to make permanent-press fabrics. This polyester can also be made into films of great strength (e.g.. Mylar), which can be rolled into sheets 1/30 the thickness of a human hair. Such films can be magnetically coated to make audio- and videotapes. 

Prakash, S. et al.. The recovery of fine iron minerals from quartz and corundum mixtures using selective magnetic coating, Int. J. Miner. Process., 57, 87, 1999. 

More than 2 million tons of poly(ethylene terephthalate), commonly referred to as PET or PETE, are produced in the United States each year for use in beverage bottles, apparel, tire cord, film for photography, food packi ing, coatings for microwave and conventional ovens, and home furnishings. Polyester textile fibers are marketed under such names as Dacron and Terylene. Films of the same polyester, when magnetically coated, are used to make audiotapes and videotapes. This film. Mylar, has unusual strength and can be rolled into sheets 1/30 the thickness of a human hair. 

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