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Fe-ni-cr Alloys for Coatings and Electroforms.
MISSING :13 pages
As part of a Bureau of Mines research program to conserve critical and strategic metals, an aqueous electrodeposition method for preparing stainless-steel-type coatings was studied. Chromium powder (averaging 3-um diam) was suspended in a ferrous-nickelous sulfate electroplating bath and occluded in the electrodeposited fe- ni alloy matrix. Subsequent heat treatment of the resulting composite coating formed the ternary alloy. The occlusion process was affected by the quantity of cr powder suspended in the electrolyte and by the microstructure and composition of the electrodeposited matrix. Coatings containing up to 21 wt pct cr were deposited from an electrolyte containing 20 vol pct suspended cr powder. Heat treatment at 1,100 deg. C for 8 h homogenized the composite coating. Deposition of 44fe36ni20cr alloy coatings (250 um thick) on aisi 1020 carbon steel rods, followed by heat treatment, provided complete protection of the carbon steel during exposure to a boiling 65-pct-hno3 solution. Corrosion rates of 0.6+/-0.4 Mm/yr for the coating in the boiling hno3 approximate that of 304 stainless steel. Practically shaped electroforms have been prepared by the coating method.
IH; Report of Investigations;
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division