Method of making in-situ whisker reinforced glass ceramic

• US 5,186,729 A
• Filed: 04/26/1991
• Issued: 02/16/1993
• Est. Priority Date: 04/26/1991
• Status: Expired due to Fees

• Current Assignee: Virginia Tech Intellectual Properties, Inc.
• Original Assignee: The Center For Innovative Technology, VPI & SU
• Inventors: Hirschfeld, Deidre A., Brown, Jesse J., Lee, K. H.
• Primary Examiner(s): LINDSAY JR, ROBERT
• Application Number:
  US07/692,214
• Time in Patent Office: 662 Days
• Field of Search: 65/33, 501/7
• US Class Current: 65/442
• CPC Class Codes: C03C 10/0027 containing SiO2, Al2O3, Li2O as main constituents
• CPC Class Codes: C03C 10/0045 containing SiO2, Al2O3 and MgO as main constituents
• CPC Class Codes: C03C 14/00 Glass compositions containing a non-glass component, e.g. compositions containing fibres, filaments, whiskers, platelets, or the like, dispersed in a glass matrix devitrified glass ceramics C03C10/00
• CPC Class Codes: C03C 2214/06 Whiskers ss
• CPC Class Codes: C03C 2214/20 Glass-ceramics matrix
• CPC Class Codes: C03C 2214/30 Methods of making the composites

Abstract

A heat processing procedure is used to create reinforcing whiskers of TiO₂ in glass-ceramic materials in the LAS and MAS family. The heat processing procedure has particular application in creating TiO₂ in-situ in a modified β-eucryptite system.

Claims

1. A method for the in-situ formation of TiO₂ whiskers with a glass-ceramic matrix material, comprising the steps of:

combining six to twelve weight percent of TiO₂ with a ceramic material selected from the group consisting of Li₂ O·

Al₂ O₃ ·

nSiO₂ where n ranges between 1 and 4, MgO·

Al₂ O₃ ·

nSiO₂ where n ranges between 1 and 4, Li_1-x AlP_x Si_1-x O₄ where x ranges between 0.05 and 0.65, and Li_x Mg_x AlP_x Si_1-x O₄ where x ranges between 0.05 and 0.65;

forming a glass of the mixture of said TiO₂ and said ceramic material;

creating exposed surfaces in said glass; and

heating said glass with said exposed surfaces to a temperature and for a period of time sufficient to cause in-situ formation of TiO₂ whiskers within a glass-ceramic matrix material of a size sufficient to reinforce said glass-ceramic matrix material.

2. A method as recited in claim 1 wherein said temperature and said period of time sufficient to cause in-situ formation of whiskers within said glass-ceramic matrix material are greater than 1000°

C. and greater than fifty hours, respectively.

3. A method as recited in claim 1 wherein said step of creating said exposed surfaces in said glass is accomplished by quenching said glass after said forming step such that microfractures are created in said glass.

4. A method as recited in claim 1 wherein said step of creating said exposed surfaces in said glass is accomplished by powderizing said glass after said forming step.

9. A method as recited in claim 1 wherein said ceramic material is Li₀.41 Mg₀.35 AlP₀.52 Si₀.48 O₄.

5. A method for the in-situ formation of whiskers with a glass-ceramic matrix material, comprising the steps of:

combining an amount of a nucleating agent selected from the group consisting of TiO₂ and ZrO₂ with a ceramic material selected from the group consisting of Li₂ O·

Al₂ O₃ ·

nSiO₂ where n ranges between 1 and 4, MgO·

Al₂ O₃ ·

nSiO₂ where n ranges between 1 and 4, Li_1-x AlP_x Si_1-x O₄ where x ranges between 0.05 and 0.65, and Li_x Mg_x AlP_x Si_1-x O₄, said amount of said nucleating agent being sufficient to form nuclei for ceramic and whisker growth but not to devitrify a glass made from said ceramic material;

forming said glass of said ceramic material;

creating exposed surfaces in said glass; and

heating said glass with said exposed surfaces to a temperature and for a period of time sufficient to cause in-situ formation of whiskers of said nucleating agent within a glass-ceramic matrix material of a size sufficient to reinforce said glass-ceramic matrix material.

6. A method as recited in claim 5 wherein said temperature and said period of time sufficient to cause in-situ formation of whiskers within said glass-ceramic matrix material are greater than 1000°

C. and greater than fifty hours, respectively.

7. A method as recited in claim 5 wherein said step of creating said exposed surfaces in said glass is accomplished by quenching said glass after said forming step such that microfractures are created in said glass.

8. A method as recited in claim 5 wherein said step of creating said exposed surfaces in said glass is accomplished by pulverizing said glass after said forming step.

10. A method as recited in claim 5 wherein said ceramic material is Li₀.41 Mg₀.35 AlP₀.52 Si₀.48 O₄.