Negative thermal expansion glass ceramic

• US 6,521,556 B2
• Filed: 10/11/2001
• Issued: 02/18/2003
• Est. Priority Date: 10/23/1998
• Status: Expired

• Current Assignee: Kabushiki Kaisha Ohara
• Original Assignee: Kabushiki Kaisha Ohara
• Inventors: Goto, Naoyuki, Shindo, Ayako
• Primary Examiner(s): GROUP, KARL E
• Application Number:
  US09/973,785
• Publication Number:
  US 20020045527A1
• Time in Patent Office: 495 Days
• Field of Search: 501/4, 501/7
• US Class Current: 501/4
• CPC Class Codes: C03C 10/0027 containing SiO2, Al2O3, Li2O as main constituents
• CPC Class Codes: G02B 6/0218 using mounting means, e.g. by using a combination of materials having different thermal expansion coefficients
• CPC Class Codes: G02B 6/3854 Ferrules characterised by materials

Abstract

A negative thermal expansion glass ceramic having a negative coefficient of thermal expansion, which is a sufficiently large absolute value in a temperature range of −40° C. to +160° C. and a method for producing the same are provided. The negative thermal expansion glass ceramic has a coefficient of thermal expansion of −25 to −100×10⁻⁷/° C. in the temperature range of −40° C. to +160° C., and comprises main crystalline phases which are one or more types selected from a group consisting of β-eucryptite solid solution (β-Li₂O·Al₂O₃·2SiO₂ solid solution), β-eucryptite (β-Li₂O·Al₂O₃·2SiO₂), β-quartz solid solution (β-SiO₂ solid solution), and β-quartz (β-SiO₂), wherein a total amount of crystals of the main crystalline phases can be 70 to 100% in mass percent.

Claims

1. A negative thermal expansion glass ceramic, comprising:

5.5-15 mass percent of Li₂O; and

0.5-4 mass percent of BaO;

wherein the negative thermal expansion glass ceramic has a coefficient of thermal expansion of −

25 to −

100×

10<sup>−

7</sup>/°

C. in a temperature range of −

40°

C. to +160°

C.

2. The negative thermal expansion glass ceramic of claim 1, comprising 40-65 mass percent of SiO₂.

3. The negative thermal expansion glass ceramic of claim 1, comprising 25-45 mass percent of Al₂O₃.

4. The negative thermal expansion glass ceramic of claim 1, comprising a main crystalline phase which is at least one crystalline phase selected from the group consisting of β

-eucryptite solid solution, β

-eucryptite, β

-quartz solid solution, and β

-quartz.

5. The negative thermal expansion glass ceramic of claim 4, wherein a total amount of crystals of the main crystalline phase is 70 to 100% in mass percent.

6. The negative thermal expansion glass ceramic of claim 1, wherein the glass ceramic is a material that is essentially free of anisotropy.

7. The negative thermal expansion glass ceramic of claim 1, wherein the glass ceramic is applied to a temperature compensating member, the glass ceramic being combined with a material having a positive coefficient of thermal expansion.

8. The negative thermal expansion glass ceramic of claim 1, wherein the glass ceramic is applied to a device securing an optical fiber.

9. A negative thermal expansion glass ceramic, comprising:

40-65 mass percent Of SiO₂;

25-45 mass percent of Al₂O₃;

5.5-15 mass percent of Li₂O; and

0.5-4 mass percent of BaO;

wherein the negative thermal expansion glass ceramic has a coefficient of thermal expansion of −

25 to −

100×

10<sup>−

7</sup>/°

C. in a temperature range of −

40°

C. to +160°

C.

10. A negative thermal expansion glass ceramic, comprising:

34-45 mass percent of Al₂O₃; and

0.5-4 mass percent of BaO;

wherein the negative thermal expansion glass ceramic has a coefficient of thermal expansion of −

25 to −

100×

10<sup>−

7</sup>/°

C. in a temperature range of −

40°

C. to +160°

C.