Low-temperature case hardening of additive manufactured articles and materials and targeted application of surface modification
AssigneeSwagelok Company
InventorsCyprian Adair William Illing, Robert Bianco, Michael D. Bestic, Christina Semkow, Peter C. Williams, Todd Johns, Ronald S. Edmonson
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Abstract
A treated additive manufactured article is disclosed. The article comprises a shaped metal alloy having a treated surface layer and a core. At least one of the average hardness of the treated surface layer is greater than the average hardness of the core, and the average corrosion resistance of the treated surface layer is greater than the average corrosion resistance of the core.
Claims20
A method for chemically modifying a surface layer, the method comprising:
- placing an article in a nitrogen rich environment;
- adding, to the nitrogen rich environment, a compound comprising a guanidine [HNC(NH2)2] moiety, the guanidine [HNC(NH2)2] moiety being complexed with HCl;
- and
- altering a chemical composition of the surface layer by subjecting the article, in the nitrogen rich environment, to a heating profile, wherein:
- the heating profile comprises a single isotherm having a temperature of 550° C. or less and a duration of 30 minutes or less;
- the surface layer reacts with decomposition products of the guanidine [HNC(NH2)2] moiety during the heating profile;
- and
- upon conclusion of the heating profile, the reaction with the decomposition products of the guanidine [HNC(NH2)2] moiety renders the surface layer richer in nitrogen than a core of the article.
A method for chemically modifying an additively manufactured article, the method comprising:
- placing an additively manufactured article in a nitrogen rich environment;
- adding, to the nitrogen rich environment, a compound comprising a guanidine [HNC(NH2)2] moiety, the guanidine moiety being complexed with HCl;
- and
- chemically modifying corrosion resistance of a surface layer of the article by subjecting the article to a heating profile in the nitrogen rich environment, the heating profile comprising a single isotherm having a temperature of 550° C. or less and a duration of 30 minutes or less,
- wherein, upon conclusion of the heating profile, the surface layer is richer in nitrogen than a core of the article.
Dependencies are inferred from the claim text.