Metal Finishing Guide Book

2011-2012 Surface Finishing Guidebook

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Turbulence, such as that sup- plied by slosh washers or turbo washers, in which cleaning solu- tion is turbulently flowed over the surfaces to be cleaned. Cavitation supplied by ultrason- ics. Abrasive brushing in solution. Abrasive slurry. Chemical Processes Solubilization is the cleaning method in which surface contami- nants become soluble in the cleaning solution. Examples are the dissolu- tion of iron oxide in acids or acrylic coatings in alkaline aqueous solu- tions. Emulsification is the process by which a normally insoluble soil becomes uniformly dispersed in an incompatible solvent. The most com- mon emulsion encountered by peo- ple is milk, in which insoluble fats and proteins are dispersed in water. Emulsification is accomplished by a combination of proper surfactants, cosolvents, and coupling agents. Saponification is the reaction of oils containing reactive fatty acids with alkali to yield soluble soaps. An example of this mechanism would be the cleaning of a lard oil lubri- cant from stamped steel by the use of an aqueous cleaning solution con- taining significant amounts of sodi- um or potassium hydroxide. Wetting is the method by which a soil is displaced from the substrate surface by the use of wetting agents that have a greater affinity for the substrate surface than for the soils present. The wetting agent can work by having the same action on the soil particles present. In both cases the attraction between soil and sub- strate surface is eliminated and soils are removed. Complexing is accomplished by the use of chelators, sequesterants, or complexors. The soils—typically met- X Superior Technology • Reduced Costs • Consistent Quality X Product Innovation • Low Temperature Phosphates • Phosphate Free Conversion Coatings X Superior Service • Solving Complex Finishing Problems • Rapid In Plant Service stay ahead of the game With STEELCOTE, A Brite's superior line of Phosphate/ Pre-Treatment Chemistry TOLL FREE: 1.888.8A BRITE www.abrite.com www.metalfinishing.com/advertisers 69 Line up aSTRIKE with...

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