JPS59223249A - Crystallized glass having large coefficient of thermal expansion - Google Patents

Abstract

PURPOSE:To provide crystallized glass which has a large coefft. of thermal expansion and is suitable for a base plate, etc. to be formed thereon with a thin metallic film of high expansion by subjecting glass consisting of specific weight ratios of SiO2, Al2O3, Na2O, K2O, ZnO, MgO, BaO, P2O5, etc. to a heat treatment. CONSTITUTION:Glass having the compsn. contg., by wt%, 27-50% SiO2, 7-25% Al2O3, 10-32% Na2O+K2O (where K2O is <=10%), 1.5-20% ZnO+MgO, 0- 10% BaO and 2-22% P2O5 and contg. >=90% total of these components is produced. The resultant glass is heat treated and is crystallized to obtain the intended crystallized glass of a large coefft. of thermal expansion of which the coefft. of thermal expansion at 30-500 deg.C is 110-190X10<-7>/ deg.C. The crystallized glass having desired appearance which is transparent, semitransparent or opaque is obtd. by selecting the temp. for the heat treatment for the purpose of crystallization and selecting the glass compsn. within the above-mentioned compsn. range.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel crystallized glass having an introductory coefficient of thermal expansion.

The crystallized glass of the present invention has Si0□27 to 5 in weight%.
0%, AlgOs 7-25%, Na, O-1-KI
O10-32%, however, O is 10% or less, ZnO+
MgO1, IJ-20%, Ba00-10%, p, o,
It is obtained by heat treating a glass having a composition containing 2 to 22% of these components and the total of these components being 90% or more. The main crystal phase of this crystallized glass is carnegiite and nepheline, both of which have the chemical formula Nano a A1.
o, "2SiOz), and the coefficient of thermal expansion from 30 to 500°C is a high expansion of 110 to 190XI O-7/'
It is in the range of C. Furthermore, the crystallized glass of the present invention can have a desired transparent, translucent, or opaque appearance by selecting the glass composition within the above range and selecting the heat treatment temperature for crystallization. I can do it.

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

When 5102 is less than 27%, the glass tends to devitrify, and the chemical durability of crystallized glass deteriorates,
In the above cases, crystallization due to heat treatment is difficult to occur. Al,
When O, is 7% or less, crystallization is difficult to occur, and 25%
In the above cases, the glass tends to devitrify. Nano
+KtO is less than 10% and □O is more than 10%, crystallization is difficult to occur, while Na2O+JO
is 32% or more, the chemical durability of the tempered glass deteriorates. When zno + MgO is 1.5% or less, crystallization is difficult to occur, and when it is 20% or more, the glass tends to devitrify. BaO improves the chemical durability of crystallized glass by containing 10% or less. P
2O, is a component that acts as a nucleating agent to precipitate carnegiite and nephorin as the main crystal phase, but if it is less than 2%, crystallization is difficult to occur;
In the above cases, the glass tends to devitrify. When the total of the above components is less than 90%, crystals of other types increase, making it difficult to obtain a sufficient amount of the desired high-expansion main crystal phase of carnegiite and nellaelin, and making it difficult to form a dense crystal structure.

In addition to the components described above, 10% or less of PbO and 5% or less of Ti are used to improve glass solubility, clarity, formability, etc.
e, ,ZrO,,B,Q,1. N5rO1OaO1s
b, o, As2O3, etc. can be added.

The table below shows examples of the present invention, including glass composition,
The highest heat treatment temperature for crystallizing the glass, the appearance, thermal expansion coefficient, main crystal phase, and acid resistance of the obtained crystallized glass are shown. The acid resistance was expressed as the weight loss after a 20×20×5 mm plate sample was immersed in 5% HOI at 90° C. for 24 hours.

Table - Example Table (Continued) Table (Continued) The crystallized glass samples of the above examples were manufactured as follows.

Mix the glass raw materials so that they have the composition shown in the table above. 1. Using a platinum crucible, 14. It was melted at 00 to 1550°C for 5 hours. Incidentally, tripolyphosphate fermented soda was used as the p, o, and source. This molten glass was poured into a carbon mold and shaped, and then slowly cooled. Next, heat treatment 9 for crystallization
The glass is placed in an electric furnace, heated from room temperature to 500°C at a rate of approximately 00°C/hour, and heated at a rate of 80°C/hour from 50°C to the highest heat treatment temperature shown in the table. Crystallization was achieved by heating at an increasing rate and holding at that temperature for 1 hour.

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: General Manager of Nippon Electric Glass Co., Ltd., representative of a large company: Go Uba.

Claims (1)

[Claims] In weight%, Sin, 27-50%, A1 0,7-2
5%, Na, O+ K, 0 1. O ~ 32%, however, O is 10% or less, ZnO + MgO1,5-J20
%, Ba00~10%, P! Contains 2-22% Os,
In addition, it is a crystallized glass obtained by heat treating a glass having a composition in which the sum of these components is 90% or more, and the coefficient of thermal expansion of the crystallized glass at 30 to 500°0 is 110 to 190.
Crystallized glass with a large thermal expansion coefficient of X10 10O.