Molds that include a ceramic material surface, and related methods for making and using the molds

1. A mold comprising a graphite mold body having one or more mold features having a surface comprising:

ceramic material having formula (I):

M 2 A 1 X 1   (I)

wherein

M is at least one transition metal,

A is selected from Si, Al, Ge, Pb, Sn, Ga, P, S, In, As, Tl and Cd, and

combinations thereof, and

X is carbon, nitrogen, or a combination thereof;

ceramic material having formula (II):

M 3 A 1 X 2   (II)

wherein

M is at least one transition metal,

A is selected from one of Al, Ge, and Si, and combinations thereof, and

X is carbon, nitrogen, or a combination thereof; or

ceramic material that includes a combination of ceramic material having formula (I) and ceramic material having formula (II),

wherein the ceramic material has a coefficient of thermal expansion that differs from a coefficient of thermal expansion of the graphite mold body by 1 part per million/° C. or less.

2. The mold of claim 1 , wherein the ceramic material includes at least 95 atomic percent of the elements M, A, and X.

3. The mold of claim 1 , wherein A is selected from silicon, aluminum, and a combination thereof.

4. The mold of claim 1 , wherein the ceramic material is Ti 3 SiC 2 , Ti 2 SiC, Ti 3 AlC 2 , Ti 2 AlC, Ti 3 SiN 2 , Ti 2 SiN, Ti 3 AlN 2 , Ti 2 AlN, or a combination thereof.

5. The mold of claim 1 , wherein the one or more mold features are adapted to form a precision shaped glass item.

6. The mold of claim 5 , wherein the one or more mold features include a surface having a surface roughness that does not exceed about 25 microns in deviation from an average surface plane of the surface of the mold feature.

7. The mold of claim 6 , wherein the precision shaped glass item is a cover glass of an electronic device, and the surface having the surface roughness is a flat surface.

8. The mold of claim 1 with aluminosilicate glass in contact with the one or more mold features.

9. A method of forming a shaped glass item, the method comprising:

softening aluminosilicate glass, and

placing the softened aluminosilicate glass in contact with one or more mold features of a mold to form the shaped glass item,

wherein the mold comprises a graphite mold body having the one or more mold features and having a surface comprising:

ceramic material having formula (I):

M 2 A 1 X 1   (I)

wherein

M is at least one transition metal,

A is selected from Si, Al, Ge, Pb, Sn, Ga, P, S, In, As, Tl and Cd, and combinations thereof, and

X is carbon, nitrogen, or a combination thereof;

ceramic material having formula (II):

M 3 A 1 X 2   (II)

wherein

M is at least one transition metal,

A is selected from one of Al, Ge, and Si, and combinations thereof, and

X is carbon, nitrogen, or a combination thereof; or

ceramic material that includes a combination of ceramic material having formula (I) and ceramic material having formula (II),

wherein the ceramic material has a coefficient of thermal expansion that differs from a coefficient of thermal expansion of the graphite mold body by 1 part per million/° C. or less.

10. The method of claim 9 further comprising removing the shaped glass item from the mold and contacting the shaped glass item with molten salt.

11. The method of claim 9 , wherein the shaped glass item has a flat surface formed by contact with a flat mold feature, the flat surface having a surface roughness that does not exceed about 25 microns in deviation from an average surface plane of the flat surface.

12. The method of claim 9 , wherein the softened aluminosilicate glass is placed in contact with the one or more mold features of the graphite mold body while the graphite mold body and the softened aluminosilicate glass are in a concentrated nitrogen atmosphere.

13. A method of forming a mold comprising a graphite mold body and a ceramic material surface, the method comprising:

depositing onto the graphite mold body:

ceramic material having formula (I):

M 2 A 1 X 1   (I)

wherein

M is at least one transition metal,

A is selected from Si, Al, Ge, Pb, Sn, Ga, P, S, In, As, Tl and Cd, and

combinations thereof, and

X is carbon, nitrogen, or a combination thereof;

ceramic material having formula (II):

M 3 A 1 X 2   (II)

wherein

M is at least one transition metal,

A is selected from one of Al, Ge, and Si, and combinations thereof, and

X is carbon, nitrogen, or a combination thereof; or

ceramic material that includes a combination of ceramic material having formula (I) and ceramic material having formula (II),

wherein the ceramic material has a coefficient of thermal expansion that differs from a coefficient of thermal expansion of the graphite mold body by 1 part per million/° C. or less.

14. The method of claim 13 , wherein the ceramic material includes at least 95 atomic percent of the elements M, A, and X.

15. The method of claim 13 , wherein A is selected from silicon, aluminum, and a combination thereof.

16. The method of claim 13 , wherein the ceramic material is Ti 3 SiC 2 , Ti 2 SiC, Ti 3 AlC 2 , Ti 2 AlC, Ti 3 SiN 2 , Ti 2 SiN, Ti 3 AlN 2 , Ti 2 AlN, or a combination thereof.

17. The method of claim 13 comprising:

forming the graphite mold body by machining a piece of bulk graphite into the graphite mold body containing one or more mold features at a surface of the graphite mold body, and

depositing the ceramic material onto the one or more mold features by: chemical vapor deposition, atomic layer deposition, physical vapor deposition, reactive physical vapor deposition, spray coating, or aerosol deposition.

18. The method of claim 13 , wherein the deposited ceramic material encapsulates the graphite mold body.

19. The method of claim 18 , wherein the one or more mold features deposited with ceramic material include a flat surface that has a surface roughness that does not exceed about 25 microns in deviation from an average surface plane of the flat surface.