Fugitive ceramic mold, formulations and method for investment casting

1. A method of producing a cast-metal part, the method comprising:

three-dimensionally (3D) printing a preceramic resin in a shape of a fugitive mold, the fugitive mold comprising a solid portion comprising a supportive solid surface around the outer and lower perimeter of a fillable portion;

curing the preceramic resin to form a preceramic polymer;

pyrolyzing the fugitive mold to convert the preceramic polymer to a metastable ceramic material comprising an amorphous silicon oxycarbide ceramic;

filling the fillable portion of the fugitive mold with a liquid metal or alloy;

allowing the liquid metal or alloy to solidify over a first length of time to form the cast-metal part embedded in the fugitive mold; and

heating the fugitive mold at a temperature lower than the melting point of the cast-metal part for a second length of time longer than the first length of time to disintegrate the metastable ceramic material by a heat-induced phase change and remove the cast-metal part from the metastable ceramic material.

2. The method of claim 1 , wherein the 3D printing is achieved by stereolithography.

3. The method of claim 1 , wherein the 3D printing is achieved by direct ink write (DIW).

4. The method of claim 1 , wherein the pyrolyzing is carried out at about 800° C. to about 1100° C. under an inert atmosphere.

5. The method of claim 1 , wherein the allowing the liquid metal or alloy to solidify further comprises actively cooling the liquid metal or alloy.

6. The method of claim 1 , wherein the heating of the fugitive mold is carried out for about 4 hours to about 12 hours at a temperature about 10% to about 50% lower than the melting point of the cast-metal part.

7. The method of claim 1 , wherein the heating of the fugitive mold is carried out under an atmospheric pressure of less than about 0.25 bar.

8. The method of claim 1 , wherein the amorphous silicon oxycarbide ceramic comprises silicon in an amount of about 10 to 60 atom %, carbon in an amount of about 10 to 60 atom %, and oxygen in an amount of about 10 to 60 atom %.

9. The method of claim 1 , wherein the amorphous silicon oxycarbide ceramic comprises silicon in an amount of about 10 to 30 atom %, carbon in an amount of about 20 to 40 atom %, and oxygen in an amount of about 30 to 50 atom %.

10. The method of claim 1 , wherein the amorphous silicon oxycarbide ceramic further comprises nitrogen in an amount of about 1 to 20 atom %.

11. The method of claim 1 , wherein the amorphous silicon oxycarbide ceramic further comprises boron in an amount of about 1 to 20 atom %.

12. The method of claim 1 , wherein the amorphous silicon oxycarbide ceramic further comprises a metal in an amount of about 1 to 20 atom %.

13. The method of claim 1 , wherein the amorphous silicon oxycarbide ceramic further comprises sulfur in an amount of about 1 to 20 atom %.

14. The method of claim 1 , wherein the amorphous silicon oxycarbide ceramic further comprises hydrogen in an amount of about 1 to 20 atom %.

15. A fugitive mold for producing a cast-metal part, the fugitive mold comprising a three-dimensionally (3D) printed solid portion comprising a supportive solid surface around the outer and lower perimeter of a fillable portion,

the fillable portion corresponding to the cast-metal part;

the solid portion comprising a metastable ceramic material;

the metastable ceramic material being removable from the cast-metal part by a heat-induced phase change; and

the metastable ceramic material comprising an amorphous silicon oxycarbide ceramic.

16. The fugitive mold of claim 15 , wherein the solid portion comprises the metastable ceramic material in an amount of greater than about 50% by volume, and the remaining volume of the solid portion comprises particles of a non-metastable ceramic material.

17. The fugitive mold of claim 15 , wherein the amorphous silicon oxycarbide ceramic comprises silicon in an amount of about 10 to 60 atom %, carbon in an amount of about 10 to 60 atom %, and oxygen in an amount of about 10 to 60 atom %.

18. The fugitive mold of claim 15 , wherein the solid portion further comprises a core extending into the fillable portion to define an interior feature of the cast-metal part.

19. The fugitive mold of claim 15 , wherein the solid portion further comprises one or more cooling channels to be formed in the cast-metal part.