Metal Finishing Technologies & Services ISO 9001:2015



Blackening Process For Iron & Steel


Dipsol BPS is a process for blackening iron and steel by simple immersion. Uniform, black coatings of ferroferric oxide, Fe(Fe02)2, are produced which are an integral part of the basis metal; they will withstand severe deformation without flaking. Beautiful, shiny, black coatings are obtained on buffed or polished surfaces, and flat, non-reflective coatings are obtained on etched or sand blasted steel. Dipsol BPS is a powdered product which is dissolved in water to make up the blackening solution. Dipsol BPS will blacken a wide range of alloys, low and high carbon steels, and low alloy steels. Dipsol BPS will even blacken some cast and malleable irons, depending upon their composition. Dipsol BPS solutions will not blacken stainless steel. Dipsol BPS contains complexing agents that eliminate the effects of copper and iron contamination in the blackening solution. In other words, red smut formation on the work, caused by copper and iron contamination of the solution, is eliminated. Dipsolt BPS also contains a surfactant that reduces surface tension thereby lowering drag out and reducing tank spray. Also, there is a greatly reduced amount of sludge formation in the operation of Dipsol BPS solutions, affording a substantial saving in the amount of heat required to maintain the operating temperature. Black oxide coatings produced by Dipsol BPS have moderate corrosion resistance and meet the requirements of Military Specification MIL-C-13924C, Class 1. In general, the lower the carbon content of the steel, the higher the corrosion resistance The dimensional changes involved in blackening are extremely small, being less than 0.01 mil. The thickness of the black oxide coatings range from 0.06 to 0.1 mil.

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