Particulates and methods of making particulates
A method of making an article using an additive manufacturing technique includes depositing a powder. The powder includes particles formed from an article material and having particle surfaces. A coating formed from a sacrificial coating is deposited over the particle surface. The sacrificial material has a composition that is different from the composition of the article material and is separated from the article material during fusing of the article material into a layer of an additively manufactured article.
1. A method of making an article, comprising:
depositing a powder, the powder comprising:
particles comprising an article material and having particle surfaces; and
particle coatings comprising a sacrificial material deposited over the particle surfaces, wherein the sacrificial material has a composition different from a composition of the article material, wherein depositing the coating includes (a) depositing a polymer over at least a portion of the particles surfaces, (b) disposing the coating particles in a build chamber, (c) converting the deposited precursor to form a carbonaceous, oxide, or nitride coating, and (d) separating the coating from the particulate in the build chamber;
separating the sacrificial material from the article material; and
fusing the article material to form a layer of an article.
2. The method as recited in claim 1 , wherein separating the sacrificial material comprises:
melting the article material; and
floating the sacrificial material in the molten article material or vaporizing the sacrificial material.
3. The method as recited in claim 1 , wherein fusing the article material comprises heating the sacrificial material and conducting heat from the sacrificial material into the article material.
4. The method as recited in claim 1 , further comprising:
depositing additional powder over the separated sacrificial material;
separating sacrificial material from the additional powder; and
aggregating the sacrificial material underlying the additional powder with the sacrificial material separated from the additional powder.
5. The method as recited in claim 4 , wherein the article layer is a first article layer, and further comprising fusing the additional article material to form a second article layer, wherein fusing the second article layer requires less incident energy than fusing the first article layer per unit mass of article material.
6. A powder for use in an additive manufacturing technique, comprising:
a plurality of particles comprising an article material and having particle surfaces; and
particle coatings comprising a sacrificial material deposited over the particle surfaces, wherein the sacrificial material has a composition different from a composition of the article material, wherein depositing the coating includes (a) depositing a polymer over at least a portion of the particles surfaces, (b) disposing the coating particles in a build chamber, (c) converting the deposited precursor to form a carbonaceous, oxide, or nitride coating, and (d) separating the coating from the particulate in the build chamber.
7. The powder as recited in claim 6 , wherein the sacrificial material is insoluble in the article material.
8. The powder as recited in claim 6 , wherein the sacrificial material is less dense than the article material.
9. The powder as recited in claim 6 , wherein the sacrificial material has a reflectance that is less than a reflectance of the article material.
10. The powder as recited in claim 6 , wherein the sacrificial material has affinity for a contaminant that is lower than affinity for the contaminant of the article material.
11. The powder as recited in claim 6 , wherein the sacrificial material is less flammable than the article material.
12. The powder as recited in claim 6 , wherein the sacrificial material comprises one or more of a carbonaceous material, an oxide, and a nitride.
13. The powder as recited in claim 6 , wherein the article material comprises one or more of an oxide, a nitride, a carbide ceramic, glass, aluminum, titanium, copper, iron, nickel, cobalt, titanium, and alloys thereof.
14. A method of making a powder for an additive manufacturing technique, comprising:
receiving particles comprising an article material and having particle surfaces;
receiving a sacrificial material; and
depositing a coating comprising the sacrificial material over at least a portion of the particle surfaces, wherein depositing the coating includes (a) depositing a polymer over at least a portion of the particles surfaces, (b) disposing the coating particles in a build chamber, (c) converting the deposited precursor to form a carbonaceous, oxide, or nitride coating, and (d) separating the coating from the particulate in the build chamber.
15. The method of making a powder as recited in claim 14 , wherein depositing the coating comprises depositing the coating using a line of sight coating technique.