JPS5836948A - Alumina substrate - Google Patents

Abstract

PURPOSE:To give superior resistance to heat and pulses to an alumina substrate, by coatong the alumina substrate with a glass layer containing specified proportions of SiO2, Al2O3, BaO, CaO, SrO, B2O3, and ZrO2. CONSTITUTION:The surface of an alumina substrate is coated with a glass layer contg. by weight 48-55% SiO2, 8-15% Al2O3, 8-25% BaO, 5-15% CaO, 0- 15% SrO, 2-6% B2O3, and 1-5% ZrO2, and the total of these oxides amounting to >=95%, and the sum of SiO2 and Al2O3 amounting to 58-65%, and besides, the total of BaO, CaO, and SrO amounting to 20-35%. To coat this layer, this mixture is melted at 1,500-1,600 deg.C, crushed with a water-cooled roller, etc., further finely pulverized to 1-10mum average particle diameter, coated on the alumina substrate by screen printing, and heat treated at 1,200-1,300 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a substrate coated with a glass layer),
In particular, the present invention relates to improvements in ID glass layers for heat-insulating heat-generating resistors on substrates used in thermal heads and the like.

A thermal head is a device in which thermal paper t' is run over a fine heating resistor element, and electricity is applied to the heating resistor element corresponding to the pattern to be written to generate heat, thereby recording on the thermal paper. The heating resistor part has a three-layer structure consisting of a glass layer covering the glass substrate, a heating resistor layer on top of the glass layer, and a protective layer on top of the glass layer. ζO Al construction board 0
The f-las layer acts as a barrier for heat transfer from the heating resistor to the board), and plays an important role in determining the O peak temperature and cooling rate of the heating resistor in response to the applied electric power. I am accomplishing it. Therefore, the ζOy tus layer is 10 to 10
The thickness must be controllable within the range of 0μ, and it must be homogeneous and smooth. The properties of the surface of the glass layer are particularly important because foreign substances such as crystals, bubbles, pinholes, clutter, etc. can hinder the formation of the heating resistor formed on the warp. Furthermore, since this OfTs layer is in direct contact with the heating resistor, it is subjected to a large heat Δx exceeding the peak temperature s o o c', so it must be able to withstand this. This is a major factor that affects the characteristics of head printers. Printers are becoming faster, have larger capacities, and have longer lifespans, and the development of glass layers that can accommodate these trends is at an all-time high.

Furthermore, when the heating resistor is energized, an electric field is also applied to the heated glass layer, which causes electrolysis and deterioration if alkali ions are present, so alkali-free glass is required.

The conventional glass for alumina substrates is 810. -B, Os
-PbO-muL, 0. system, 8102-muz2os-pb
o-RO system (R: alkaline earth), StO,-mu1,0
s-R'20 (R': alkali) system, 819. -Mut, O, -B, O, -RO systems are known, but none have sufficient characteristics from the viewpoint of glass for a substrate for a thermal head.

It is an object of the present invention to provide a substrate having a glass layer of t%, which has a homogeneous and smooth surface, is heat resistant, and has excellent pulse resistance when used for a thermal head.

The glass layer in the present invention is 81O□-mu! ,O,-RO
-B, 0. belongs to the system. Although this system itself is well known, in general, an attempt to increase heat resistance results in a decrease in the coefficient of thermal expansion and devitrification, so it has not been known that t has sufficient characteristics from the standpoint of pulse resistance characteristics.

Therefore, we reviewed this system from the above viewpoint and found a composition range that would be excellent as a glass layer for an aluminum substrate for a thermal head. That is, the glass layer of the aluminum substrate according to the present invention has a weight ratio of 810.48 to 55-1 Aj, 0.8 to 1511 G,
BaO8~25 lll5 CaO3~151G, Br
OO~15%, 1120B! ! ~6 *%Zr
containing 021 to 5, and the sum of these oxides is 95 or more), and 810. The sum of t and 0□ is 58 to 455
*s BaO* CaO and 8rO (D sum is 20
The reason for the composition limitation will be explained below.In order to provide good characteristics for thermal heads, the first K%810
．． and 0.0 concentration is important.

The figure is on the vertical axis. The sum of the concentration tubes of the horizontal axis KSiO indicates 5.8-. Compositions in the lower part of the diagram below laK have poor pulse resistance.

This is probably due to the insufficient heat resistance of glass. Also, the mu B line is w, o, 15%, and the mu F line is 81
It represents 0.48%. Outside this range,
The glass tends to devitrify), making it impossible to obtain a smooth glass surface. Next: BC line is 810° and m, osO sum is 65-
1CDI#1810. #551g is shown. If it is out of this range, the flow and properties of the glass will be poor, and pinholes and uneven film thickness will likely occur.

The proportion of alkaline earth oxides (RO) in the total is also important. If the total exceeds 35-, the f-las-O heat resistance will decrease and the pulse resistance will deteriorate. On the other hand, to obtain good compatibility with the alumina substrate, the coefficient of thermal expansion of the glass should be 52 to 65 x 1
It is in the range of 0-'/'C.

However, if the sum of RO is less than 20, the coefficient of expansion will fall below this range, and the glass layer will have fuzz. Among the components as RO, the concentrations of CaO and BaO are particularly important. CaO is essential for increasing the coefficient of thermal expansion and adjusting it within the above range, and the glass becomes devitrified if the force exceeds the minimum force of 111511), but it is necessary to If the ratio of RO to the entire total exceeds 2511t, the pulse resistance characteristics will deteriorate and the thermal expansion coefficient cannot be adjusted within the above range. 8rO shows an intermediate surface effect between the two, and if added within a range not exceeding 18gIIt-! The lath O fluidity is improved.

Glasses limited to the above composition range can provide -t pulse resistance, thermal compatibility with the substrate, and fluidity, but
In order to improve these drawbacks [B20. and Z rOB are essential @ B, O, are necessary to improve the wettability of the substrate and glass, lower the melting temperature, and homogenize the glass, and their effect becomes obvious at 2ts or more, but 6-" If the ZrO2
is a component that lowers the melting temperature of the glass, improves the homogeneity of the columnar tube, and also improves the pulse resistance properties, and its effect becomes noticeable at 19b or higher, but it is preferable that the glass becomes devitrified when it exceeds 5-. do not have.

Ag2O3 within the range of less than 5 to the above basic composition
Antifoaming agents such as , sb, o, etc. p Coo p NIOeM
Colorants such as nO g La201 e pbo #k
A flux such as hlotTi205sv205 can be added.

To make such glass, first, each component raw material,
For example, silica sand, aluminum hydroxide, boric acid, barium carbonate, calcium carbonate, zircon, etc. are mixed according to the required composition, and platinum is used at 1500 to 160%.
0 which melts at 0℃, then this is good for turning the lath into powder using a water-cooled roller. The end of the glass is mixed with ethyl cell ■-x etc. as a binder, and mixed with an O solvent such as α-terewinol to form a paste), and printed on the target Δ turn at a temperature at which the glass softens and flows. , usually 1200 to 1300 tons.

〔Example〕

810, etc. in the composition ratio (weight -) flc shown in the table below, tune each component raw material to create a patch, and platinum Lutsu (
SOO・・・・capacity) using a Sunso gas furnace 1!
It can be melted for 3 hours at a temperature of $00 to 1600'C, homogenized, and the molten gas is cooled and sliced in a water-cooled bag-tube, and crushed for one day in a glass powder. The average coefficient of thermal expansion of the resulting glasses between 190°C and 800°C is shown in the table below. All of these glasses have a layer temperature of 7.
The temperature was 50°C or higher.

For these glass powders (325 mesh 1 passage) 7°,
Mix 30 parts of α-Televisionaire 3-Ethyl Loose solution, and then add ? - A glass paste was obtained by pulverizing for 2 days in Runlu.

A 25 x 25 x 2 inch aluminum substrate was prepared, the glass paste was printed in a line shape with a width of 10 square meters, and baked at 1300°C for 15 minutes. The thickness of the f lath layer was adjusted to about 30μ. Visual inspection using the inner eye showed that all the pieces were good, and the smoothness was within ±22μ. Next, threatening tantalum was deposited on top of this to a thickness of 1μ using Suba and Talinda.
Width 10 using caustic soda hydrogen peroxide etching solution.
A resistor/4 turns with a length of 600μ and 0 voice was formed. Next, a conductive/electrical paint was applied by screen printing and baked to form wiring, and then 81021-81021 was vapor-deposited on the resistance element. It was used as a test membrane. A power pulse k 10 was applied to this test device, which was adjusted so that the peak temperature of the device was 500°C.
Current was applied 10 times at a rate of 1 time for ms', and the fluctuation in resistance value thereafter was measured. Although the target was a resistance variation rate of 5- or less, all samples had a resistance variation rate of 0 within 3vI at most.

In addition, the same power ΔRus'' was applied to a commercially available glazed glass (lead borosilicate glass) substrate.
The resistance fluctuation rate exceeded 10- after X10' pulses.

[Brief explanation of the drawing]

The figure shows 810. of glass in the present invention. Tomu1,0. shows the concentration relationship of

Claims (3)

[Claims] (1) In an aluminum substrate whose surface is coated with a glass layer, the glass layer has a weight ratio of 1110°48 to
551L At, 0.8~IS 91G, l1m08
~25chi, CaO3~1! SIs% 8rOO-15
%, B, 0°2 to 611% Zr0t 1 to 5-', the sum of these oxides is 95- or more, and 8
10 and AA20. The sum is 58~65-1B20 +
A substrate on which the sum of CaOe and BrO is in the range of 20 to 35% KTo or t-%. (2) The alumina substrate according to claim 1, wherein the glass layer is for keeping a heating resistor formed thereon warm. (3) The aluminum substrate according to claim 1, wherein the glass layer is formed by a printing method so as to cover a predetermined area of the surface of the glass substrate.