JPS59203736A - Crystallized glass - Google Patents

Abstract

PURPOSE:To obtain the titled glass for forming a metallic thin film on its surface and useful for a substrate material for electric machines and instruments comprising a primary crystalline phase consisting of alpha-quartz and alpha-cristobalite, and having a large coefft. of thermal expansion and being superior in mechanical strength and chemical durability due to its dense crystalline compsn. CONSTITUTION:Crystallized glass obtd. by the heat treatment of glass having a compsn. consisting of 50-65wt% SiO2, 10-22wt% Al2O3, 15-30wt% ZnO, 0- 3wt% MgO, 0-3wt% BaO, 2-4wt% ZrO2, and 1-5wt% TiO2 wherein the total of the above described components is >=95wt%. The primary crystalline phase of the above described crystallized glass consists of alpha-quartz and alpha-cristobalite and coefft. of thermal expansion of the crystallized glass is (130-180)X10<-7>/ deg.C at 30-500 deg.C. When the starting material glass having the above described compsn. is heated in an electric furnace from room temp. to 700 deg.C at 300 deg.C/hr, held for 1hr at the temp., heated at 40-80 deg.C/hr upto the max. crystallization temp., and held for 1-5hr at the temp. and then cooled to room temp. by allowing to stand, white and opaque crystallized glass as described above is obtd.

Description

[Detailed description of the invention] The present invention relates to crystallized glass having a large coefficient of thermal expansion.

11 The crystallized glass of the present invention has a weight percent Sin of 50 to 6
5%, A110B 10-22%, 29015-30%
, Mg00~3%, BaOo ~3%, zrO! 2-4
%, Tie, 1 to 5%, and the total of these components is 95% or more, and the main crystal phases are α-quartz and α-cristobalite, 13 with high thermal expansion coefficient at 500℃
It is characterized by being 0 to 180×10/”C.

The reason why the range of the glass composition to be crystallized in the present invention is limited as described above will be described below.

S10. If it is less than 50%, it will be difficult to obtain a sufficient amount of the desired dense crystals, and the chemical durability of the crystallized glass will deteriorate, and if it is more than 65%, the viscosity of the glass will increase, resulting in poor solubility and formability. becomes worse. A1. O.

If it is less than 10%, the glass tends to undergo phase separation, and the chemical durability of the crystallized glass deteriorates.
% or more, the amount of high-expansion α-quartz and α-cristobalite precipitated decreases, making it impossible to obtain the desired high-expansion crystallized glass. When ZnO is less than 15%, it becomes difficult to melt, and when it is more than 30%, phase separation or devitrification tends to occur, and the chemical durability of the crystallized glass deteriorates. Ea
The O content of 3% or less has the effect of suppressing the occurrence of phase separation of the glass, lowering the liquidus temperature, and preventing the occurrence of devitrification during melting. When MgO is 3% or more, crystals grow coarsely in the crystallization heat treatment and the degree of crystallinity is lowered. ZrQ
l and T10. is a component that acts as a well-forming agent to precipitate high-expansion d-quartz and α-cristobalite as the main crystal phase, but when Zr is 0.2% or less,
Moreover, when Ti is less than 0.1%, its effect is not exerted,
On the other hand, when Zr01 is 4% or more, the liquidus temperature increases and the glass tends to devitrify during melting, and when Tie is 5 or more, phase separation or devitrification tends to occur in the glass, and the desired high Only a small amount of expansion crystals precipitate. This Zr01 and Ti
, O, is a more preferable relationship is zro, 10Tio, λ4
and Zr01 /Ti01 ) is 0.7. When the total of the above components is less than 95%, coarse crystals of other types increase, making it difficult to obtain a sufficient amount of the desired high-expansion main crystal phase of α-quartz or α-cristobalite. In addition to the components described in section 2, Na, 01L1,0, B, 08, As! O,, K, O
1P! 06sOaO, 5rO1PbO1SnO1, sb
, o, etc. may be contained within 5%.

The table below shows examples of the present invention, and the table shows the glass composition, the highest crystallization temperature at which the glass is heat-treated, the thermal expansion coefficient at 80 to 500"C of the obtained crystallized glass, and the main crystal phase. shows.

Table - Example 5 - Table (Continued) Table (Continued) The crystallized glass of the above example is manufactured as follows.

As per the composition in Table 1, glass raw materials were prepared and melted using a platinum crucible at 1550~1600''C for 7~16 hours, and then the molten glass was poured into a carbon mold.
The molded product was placed in an electric furnace kept at 700 to 750°C to slowly cool it, and then left to cool to obtain a glass. Next, heat treatment for crystallization was performed using a two-stage treatment method. That is, the glass is heated in an electric furnace from room temperature to 750°C at a heating rate of 300°C/hour, held at that temperature for 1 hour, and then heated at 40°C to 750°C to the highest crystallization temperature listed in the same table. After heating at a high speed and maintaining the humidity for 1 to 5 hours, the mixture was allowed to cool to room temperature to obtain a crystallized glass having a white and opaque appearance and having a coefficient of thermal expansion and a main crystalline phase as shown in the table. In addition to the main crystal phases of α-quartz and α-cristobalite, there are also gahnite (ZnO・A1□03) and willemai (2zno
A small amount of crystals such as -sto, ) are precipitated.

The crystallized glass of the present invention described above has a large coefficient of thermal expansion, a dense crystal structure, excellent mechanical strength, and excellent chemical durability. Particularly useful applications are expected as substrate materials on which high-expansion metal thin films are formed.

Patent applicant: Nippon Electric Glass Co., Ltd. Representative Jun Nagasaki -

Claims (2)

[Claims] (1) In weight%, Sin, 50-65%, A1to
310~22%, Zn015~30%, MgO0
-3%, BaQO -3%, Zr0.2-4%, Ti0.
A crystallized glass obtained by heat treating a glass containing 1 to 5% of these components and a total of 95% or more of these components, the crystallized glass has main crystal phases of α-quartz, α-quartz, and α-quartz.
- A crystallized glass which is cristobalite and has a thermal expansion coefficient of 130 to 18o x 10/''C at 30 to 500C. (2) The glass composition further includes ZrO, +T1. O,l
4. The crystallized glass according to claim 1, wherein zro*, "1"i0* > 0.7.