JPS5988337A - Glaze composition for ceramic substrate - Google Patents

Abstract

PURPOSE:To obtain a composition having high surface smoothness, >=750 deg.C yield point and high heat resistance without adding alkali and Pb by using a specified mol% each of SiO2, Al2O3, >=1 kind among CaO, SrO and BaO, and B2O3 as principal components. CONSTITUTION:This glaze composition for a ceramic substrate consists essentially of, by mole, 58-63% SiO2, 6-12% Al2O3, 20-28% >=1 kind among CaO, SrO and BaO, and 3-8% B2O3. Starting materials for the composition are well mixed, melted at 1,280-1,450 deg.C for 20-40min in a refractory crucible, and charged into water to form frit glass by rapid cooling. The frit glass is suspended in water, sprayed on a ceramic substrate, and calcined at 1,170-1,260 deg.C. The frit glass may be mixed with an org. binder and printed on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glaze composition for glazing a ceramic substrate.

With the recent development of electronic devices such as facsimiles,
For example, there is an increasing demand for glazed ceramic substrates used in multi-heads and the like. Such glazed ceramic substrates are desired to have good surface smoothness on the glazed surface due to requirements such as obtaining good circuit wiring and uniformly glazing the heating element, and of course also having high electrical insulation properties. desired. In particular, facsimile thermal heads have come to be exposed to severe conditions such as rapid temperature drops and rapid temperature drops as facsimile printing speeds have become increasingly faster.
In addition to the above characteristics, high heat resistance is also required.

By the way, the conventional glazed ceramic substrate J3 contains alkali and lead in order to maintain the smoothness of the glazed surface. As a result, the yield point was approximately 550 to 610°C, and due to repeated use many times, alkali and lead were concentrated, resulting in a decrease in electrical insulation. A glaze containing alkali and lead can also have a yield point of 700'C or higher, but in that case, the smoothness deteriorates.

In order to improve the above-mentioned conventional drawbacks, the present inventors first developed a product that is lead-free, alkali-free, has good surface smoothness, and has a yield point of 740°C.
In the present invention, we have developed a glaze composition that has a relatively low temperature, but in the present invention, it has been further improved to have a good surface smoothness without containing alkali and lead, and a heat-resistant glaze composition with a yield point of 150°C or higher. The object of the present invention is to provide a glaze composition for a Hiramic substrate which has good properties and whose electrical insulation properties do not deteriorate due to repeated use. The gist of the present invention is S! 0258~
63 mol%, AI 2036-12 mol%, at least one weight of CaO, SrO and eao to 20/28 mol%
, 82033 to 8 t% as a main component.

In the present invention, Si 02 is the main component constituting the glass, and if its white content is less than 58 mol % and other oxides increase, volatilization and pinholes are likely to occur simultaneously on the glaze surface. Moreover, if it exceeds 63 mol%, it becomes a hard glaze, making it difficult for the bubbles generated therein to come out.

Al2O3 improves the yield point and, when coexisting with alkaline earth metals, acts as a flux to help melt the glaze. If the amount is less than 6 mol%, not only will the yield point be 7506C or lower, but the pinball will become difficult to control. 1
If it exceeds 2 mol %, the glaze surface will deteriorate at the required firing temperature of 1170 to 1260°C.

In the present invention, CaO is used as the alkaline earth element.

It has been found that a glaze with good surface smoothness can be obtained using either Sr 2 O or Ba 2 O. If the total amount of these oxides exceeds 28 mol %, the yield point will be 750° C. or lower, and the thermal expansion coefficient will increase. In the case of J, the coefficient of thermal expansion is higher than that of the alumina substrate, and cracks (penetration) do not occur during firing. Also, 20 mol%
If it is less than that, it becomes difficult to melt and takes on a milky white color or remains unmelted, failing to produce the desired effect.

B203 is a strong solvent, but if it is less than 3 mol %, its effect is lost and it becomes difficult to melt. If it exceeds 8 mol%, the melting power will be large and the yield point will be significantly lowered from 150°C.

In the present invention, ZnO and MgO1ri02 do not affect the properties of the glaze at all even when added up to 6 mol%.

Further, various oxides inevitably mixed in from the raw materials used may be mixed as unavoidable impurities up to 0.2 mol %.

In the present invention, due to the above-mentioned composition, each property is combined to provide a flat surface W that is good even without containing alkali or lead.
＃The degree is right, and there is no deterioration of electrical insulation properties due to repeated use.
A highly heat-resistant glaze with a yield point of 750° C. or higher can be obtained.

In order to make the glaze of the present invention, each component raw material may be used in the form of an oxide, hydroxide or carbonate, but it is better to use finely pulverized raw materials or compounds so that they can be easily melted. . These raw materials are thoroughly mixed, melted in a fireproof crucible at 1280 to 1450°C for 20 to 40 minutes, and then poured into water to be rapidly cooled to obtain Fritz I glass.

To apply this to a ceramic substrate, it can be suspended in water and applied to a ceramic substrate by spraying.
Mixed with a winding machine binder such as ethyl cellulose and printed on a ceramic substrate by a printing method, the 1170
It is sufficient to perform firing at ~1260°C.

As a ceramic substrate that is the subject of the present invention, an alumina substrate with an expansion coefficient as high as this (70 to 90X
1O-7) is preferred.

Next, examples will be described.

The table below shows examples N011 to N009 of the present invention and comparative examples (
The composition of conventional product) and its test results are shown below.

Composition
(mol%) ZnO 618265 61813135 61813135 63625E1 58 12 2
7 361 10 24
562 6
23 5
MTIO626101351"10z (j 62 6 13 1
0 Ei ZnO62,69,54,
63,211,95,3 Properties NazOK2O ℃ Smoothness 108 times 800 Good No cracks 790 〃 780 JI 760 I/ 780 〃 810! ! 780 〃 770 l! 760,.

2.1 0.7 670 As is clear from the table above, the product of the present invention does not contain alkali or lead and is a prescribed glaze composition /C, with a yield point of 760-800
The temperature is 90 to 140°C, which is higher than that of conventional glazes, and the heat resistance is improved. Further, a continuous pulse test was carried out using the product of the present invention as a 71 comb glue head, and no cracks were generated in the glaze even after 10 B pulses or more, and there was no deterioration in electrical insulation. Furthermore, the surface smoothness of the product of the present invention is good;
It does not cause any waviness and can be satisfactorily installed even in multi-ttt and fine circuit wiring.

Patent applicant: Narumi Seito Co., Ltd. Agent: Patent attorney: Hidetake Komatsu

Claims (1)

[Claims] l, 5i0258~63 mol%, △120!16~
12 mol% of at least one of CaO, SrO and BaO as main components, 20 to 28 mol% of at least one of CaO, SrO and BaO, and 3 to 8 mol% of B20s as main components.