Metal pickup

For boundary lubrication, a must be on the order of 10" to account for the great reduction in metal pickup, therefore, most of the friction must be due to film-film interactions. 

Titanium IV) oxide, T1O2. See titanium dioxide. Dissolves in concentrated alkali hydroxides to give titanates. Mixed metal oxides, many of commercial importance, are formed by TiOj. CaTiOj is perovskite. BaTiOa, per-ovskite related structure, is piezoelectric and is used in transducers in ultrasonic apparatus and gramophone pickups and also as a polishing compound. Other mixed oxides have the il-menite structure (e.g. FeTiOj) and the spinel structure (e.g. MgjTiO ). 

High density tungsten alloy machine chips are recovered by oxidation at about 850°C, foUowed by reduction in hydrogen at 700—900°C. Typically, the resultant powders are about 3-p.m grain size and resinter readily. There can be some pickup of refractory materials used in furnace constmction, which must be controUed. This process is important commercially. Eor materials that may be contaminated with other metals or impurities, the preferred recovery process is the wet chemical conversion process used for recovery of tungsten from ores and process wastes. Materials can always be considered for use as additions in alloy steel melting. 

The zinc is normally melted in a gas, oU, or coal-fired reverberatory furnace with a capacity up to 100 tons or in a low frequency induction furnace with a capacity of a few tons. The more highly aUoyed compositions are more effectively melted and mixed in low frequency induction furnaces. The furnace must be refractory-lined to eliminate iron pickup by the molten metal. The metal temperature is maintained below 500°C to minimize loss by oxidation. A ladle is used to transfer the metal for casting into molds the pouring temperature is usuaUy ca 440°C. Zinc scrap is not generaUy suitable for remelting because it may contain undesirable impurities. 

Cement-Lined Steel Cement-hned steel pipe is made by lining steel pipe with special cement. Its use prevents pickup of iron by the fluid handled, corrosion of the metal by brackish water, and growth of tuberculation. Threaded pipe in sizes from to 4 in is stocked however, cement-lined pipe in sizes smaller than in is not considered practical for common use. 

Container carrier systems. Container carrier systems are being used in a limited number of cases, the most important of which are (1) the collection of wastes from only a few pickup points at which a considerable amount of waste is generated and (2) the collection of bulky items and industrial rubbish not smtable for collection with compaction vehicles, and (3) small, heavy loads such as scrap metal. 

Organic Coatings. Organic coatings or lacquers protect the steel or tin from external or internal corrosion. The can interiors are coated to prevent undesirable reactions between the interior metal surface and the product. These reactions involve (1) corrosion of the tin coating caused by oxidants in the product, (2) color or flavor loss by the product because of metal ion pickup, or (3) staining of the metal by sulfur-con-... 

FIGURE 7 Contactless coupled conductivity detection (C D) is based on two cylindrical metal electrodes, actuator, and pickup electrode, which are placed on the separation capillary. Schematically, it represents a series of a capacitor, an ohmic resistor, and a second capacitor (from Innovative Sensor Technologies GmbH). 

The acceptance of Desulco as a premium quality recarburiser in foundry application is due mainly to its rapid dissolution in molten iron. Figure 5 compares the rate of carbon pickup of various recarburiser materials and shows the Desulco rate to be the highest. Ash forming mineral matter and sulfur are known to impede carbon dissolution in molten iron (3,4,5) and, these impurities are removed to extremely low levels in the manufacture of Desulco. And because it is free of mineral matter, slag formers are not added to the molten metal system when Desulco is used. 

---