US 9,080,235 B2Granted

Composition and method for diffusion alloying of ferrocarbon workpiece

AssigneeJamar International Corporation

InventorsLidiya Omovna Chunyayeva, Oleg Nikolayevich Chunyayev, Leonid Leonidovich Tovazhnyanskyy

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Abstract

A composition for diffusion surface alloying of ferrocarbon alloys with chromium, consisting essentially of, by weight, about 25%-40% ferrochromium; about 54%-74% aluminum oxide or mixtures of aluminum oxide, silicon oxide and magnesium oxide in a weight ratio of about 3:2:1; about 1%-3% ammonium chloride; and a reducing agent consisting essentially of about 0.1%-3% aluminum, about 0.1%-2% silicon, about 0.1%-1.5% magnesium, or about 0.1%-3% of a mixture of aluminum, silicon and magnesium in a weight ratio of about 3:2:1. A method for diffusion surface alloying of a ferrocarbon workpiece with chromium, comprising providing the above composition; exposing the workpiece to the composition; and heating the workpiece and composition for sufficient time and temperature to form a chromium containing diffusion layer on the surface of the workpiece.

A method for diffusion surface alloying of ferrocarbon workpieces with chromium, comprising:

(1) providing a composition consisting essentially of, by weight:
a) from about 25% to about 40% of ferrochromium;
b) from about 54% to about 74% of aluminum oxide or mixtures of aluminum oxide, silicon oxide and magnesium oxide in a weight ratio of about 3:2:1;
c) from about 1% to about 3% of ammonium chloride;
and
d) a reducing agent consisting essentially of from about 0.1% to about 3% of aluminum, from about 0.1% to about 2% of silicon, from about 0.1% to about 1.5% of magnesium, or from about 0.1% to about 3% of a mixture of aluminum, silicon and magnesium in a weight ratio of about 3:2:1;
(2) exposing a first workpiece to the composition;
(3) heating the first workpiece and the composition for sufficient time and temperature to form a chromium containing diffusion layer on the surface of the workpiece;
(4) cooling and removing the first workpiece from the remaining portion of the composition;
(5) providing a corrected composition consisting essentially of, by weight:
a) a chromium containing component consisting essentially of from about 1% to about 10% of ferrochromium, from about 0.5% to about 5% of chromium, or from about 1.5% to about 15% of ferrosilicochromium;
b) from about 0.2% to about 1% of ammonium chloride or chromium dichloride;
c) a reducing agent consisting essentially of from about 0.1% to about 3% of aluminum, from about 0.1% to about 2% of silicon, from about 0.1% to about 1.5% of magnesium, or from about 0.1% to about 3% of a mixture of aluminum, silicon and magnesium in a weight ratio of about 3:2:1;
and
d) the balance being the remaining portion of the composition from step (4);
(6) exposing a second workpiece to the corrected composition;
(7) heating the second workpiece and the corrected composition for sufficient time and temperature to form a chromium containing diffusion layer on the surface of the second workpiece;
and
(8) cooling and removing the second workpiece from the remaining portion of the corrected composition.

16 more elements

Abstract

Claims6