JPH01141834A - Insulating enameled substrate - Google Patents

Abstract

PURPOSE:To prevent the occurrence of pin hole and besides, to improve the adhesibility between an enamel layer and a substrate in the insulating enameled substrate formed by the enamel layer on a ferrite stainless steel substrate, by forming a nickel electroplating layer having the surface roughness of below a fixed value, between the substrate and the enamel layer. CONSTITUTION:The nickel electroplating layer 2 having <=0.15mum surface roughness, expressed in terms of mean roughness along the center line, is formed on the metal substrate consisting of the ferrite stainless steel 1 by electroplating after removing grease from the metal substrate, washing, pickling and washing. Then, the metal substrate 1 formed the plating layer 2 is immersed in a slurry contg. SiO2-B2O3-MgO-BaO crystalline glass powder, electrodeposited, and thereafter calcined to form the insulating enamel layer 3 consisting of SiO2-B2 O3-MgO-BaO crystalline glass. The obtd. insulating enameled substrate is suitably used as a substrate for thermal head, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an insulating hollow substrate used as a substrate for a thermal head or a wear-resistant substrate.

Conventional technology So-called hollow substrates, which are made by baking two layers of gun onto a base material such as stainless steel, aluminum, or hollow steel plate, have been widely used in home appliances such as cooking utensils and heating appliances, but in recent years, crystallized glass Insulating hollow substrates using .

Next, a method for forming the insulating hollow substrate will be explained. The manufacturing process of the insulating hollow substrate is shown in FIG.

As shown in Figure 6, the glass frit made by melting and cooling is milled in a ball mill to explode a slurry for electrodeposition, a metal substrate such as stainless steel or a steel plate for hollow holes is immersed in this slurry, and a counter electrode is immersed in the slurry. Glass frit particles are electrodeposited onto the metal substrate by applying a DC voltage between the metal substrate and the metal substrate. After electrodeposition, the substrate is sufficiently dried and fired according to the firing pattern shown in FIG. 4 to form an insulating hollow substrate consisting of the metal base material 1 and the insulating hollow layer shown in FIG. 5.

The insulating hollow substrate formed by the above method has a center line average roughness Ra of 0.10 μm or less, and has small ridges. However, the insulating hollow substrate having the structure shown in FIG. 6 formed by the above-described method had poor adhesion between the insulating hollow layer and the metal base material, and moreover, had many pinholes. The cause of this pinhole is 002 from the metal base material.
This is because gas and atomic hydrogen are generated. In particular, if a conductive circuit for a thermal head is formed on an insulating hollow substrate having the above-mentioned drawbacks, the circuit will be disconnected, making it impossible to obtain a satisfactory substrate for a thermal head.

As a method to solve the above-mentioned problems, since disokel or cobalt usually has the function of absorbing hydrogen gas generated from metals, a disokel plating layer or a cobalt plating layer is formed on the metal base material by substitution plating or electrolytic plating. One possible method is to form a When nickel Im is formed using the substitution plating method used in pre-treatment of general hollow holes, the nickel layer precipitates in an island shape and cannot completely absorb hydrogen gas, resulting in pinholes and The properties and surface roughness of the hollow layer surface were also poor. Similarly, although the number of Bevin holes formed by the electrolytic plating method was smaller than that by the substitution plating method, it was not possible to completely remove them, and the surface roughness of the hollow layer was large.

Problems to be Solved by the Invention The present invention is intended to solve the above problems of adhesion between the insulating hollow layer and the metal base material and pinholes in the insulating hollow layer.

Means for Solving the Problems The present invention is based on a metal base material C ferritic stainless steel χfP3.
An electrolytic nickel plating layer is provided between the edge hollow layer and the center line average roughness of the nickel plating layer surface is 0.15.
By making the thickness smaller than μm, all of the above problems can be solved.

Function Generally, nickel has the ability to absorb hydrogen, so if a nickel layer is uniformly formed on a metal base material using electrolytic plating, it will completely absorb hydrogen gas from the metal base material and suppress pinholes. It should be possible. but,
In the conventional electrolytic plating method, the surface of the metal base material is roughened with a strong acid (HF, H2SO4, etc.) in order to improve the adhesion between the metal base material and the nickel plating layer. As a result, the adhesion between the metal base material and the nickel layer has improved, and as a result, the adhesion between the hollow layer and the metal base material has also improved, but in order to introduce an air layer between the rough surfaces on the nickel plating layer, This caused pinholes to occur. These pinholes have a large effect on the dielectric strength, and pinhole-free use is essential for applications such as insulating substrates. Therefore, by reducing the roughness of the metal surface through pickling, etc., and then providing an electrolytic nickel plating layer on top of it, the intake of air spaces is eliminated and hydrogen gas from the metal is completely absorbed. Therefore, pinholes can be completely removed.

Examples Examples of the present invention will be described below. First, each component will be explained.

(1) Metal substrate Metal substrates commonly used for hollow substrates include low carbon steel plates for hollow hollows and aluminized steel plates.

Stainless steel plates and other similar steel plates can be used. However, the SiS102-B2o3-O used in the present invention
-E a O-based crystallized glass has a thermal expansion coefficient of 11o-
130X10-'/''C, the coefficient of thermal expansion is 1
Ferritic stainless steel having a carbon content of 10 to 130×10 /C is most preferred. In this example, 5US430 was used as the ferritic stainless steel.

? ) Crystallized glass Crystallized glass must have excellent insulation and abrasion resistance, so glass normally used for hollow products cannot be used. Therefore, in the present invention, the third
Glass shown in Table a was used.

(3) Pretreatment of metal base material FIG. 1 is a cross-sectional diagram of the insulating hollow substrate of the present invention.
Electrolytic nickel plating layers 2 are provided on both sides of a metal base material 1, and insulating hollow layers 3 are further provided on both sides.

FIG. 3 shows the pretreatment process for the metal base material of this example.

The metal base material is thoroughly degreased with an alkaline degreaser and washed with water.
Dirt is completely removed. If this degreasing process is insufficient, it will have a negative effect on the subsequent nickel plating process, forming an uneven layer, and ultimately the surface condition of the hollow layer will deteriorate. Degreasing must be done with great care.

After degreasing and washing with water, pickling is performed, but the roughness Ra of the substrate surface after etching must be 0.15 μm or less. If Ra is set to 0.15 μm or more, an air layer will be easily trapped on the rough metal substrate surface, which will cause pinholes, and the surface roughness of the hollow layer will also increase, causing thermal damage. It is necessary to be very careful about the process as it will become unusable as a head substrate. Acids that can be used in the pickling process include hydrochloric acid, nitric acid, sulfuric acid aqua regia, etc.
After diluting these appropriately and using them, wash thoroughly with water.
Electrolytic plating is performed by immersing a metal base material in a mixed solution of nickel sulfate and nickel chloride boric acid to deposit a nickel layer 2 on the metal base material. The temperature of the plating liquid at this time is 6o±
6°C is preferred. Also, in this process, the thickness of the plating layer needs to be 0.4 to 5.0 μm, and the thickness is 9.0.3 μm.
Below, we will explain how to prevent pinholes from forming in the hollow layer.
On the other hand, if the thickness is 5.0 μm or more, the nickel layer will easily peel off from the metal base material, so care must be taken.

Thereafter, the pretreatment process is completed by washing with water.

(4) Method of forming an insulating hollow layer Similarly, FIG. 3 shows a process for forming an insulating hollow layer. The glass material is first melted at 1250-1360°C and a current of crystallized glass is obtained with a roller force cutter. This is pulverized using a pulverizer such as a ball mill. After this, a certain amount of large particles are removed, and the crystallized glass powder and 2-propertool, which is a dispersion medium, are added to a ball mill and milled over time to prepare a slurry.

Another dispersion medium is isobutyl alcohol.

There are ethanol, acetone, MIBK, etc., but the dispersibility is 2.
Since 2-proper tools are the most superior in terms of workability, etc., 2-proper tools were used in this embodiment.

In the slurry laminate disintegration tank prepared by the method described above, the pretreated metal base material was placed in the electrolytic tank, and the distance between the electrodes was set at 2.
Glass particles are electrophoretically electrodeposited on a metal substrate at ~4 crr1 and a DC voltage of 150 ~ eoov, and after drying the glass coating layer, it is fired in a firing pattern as shown in Figure 4 to obtain an insulating hollow layer 3. . An Au-metal organic layer was printed on this insulating hollow layer 3 and baked at 8°C and 0°C for 6 minutes.
Form a u electrode. A resistor paste made of RuO2 and glass frit is printed and fired on this electrode to form a resistor, and a glass glaze overcoat layer is further printed and fired to form the thermal head shown in FIG.

Next, specific examples of the present invention will be described.

<Example 1> Metal base material was degreased, washed with water, pickled, washed with water, nickel plated,
A pretreatment was performed by washing with water so that the center line average roughness (Ra) of the surface of the nickel plating layer was 0.04 μm.

This metal base material was immersed in a slurry prepared using the glass shown in Table 3 a, electrodeposited and fired in the firing pattern shown in FIG. 4 to form an insulating hollow substrate.

<Example 2> Similarly, pretreatment was performed so that the metal base material after pretreatment had an Ra of 0.10 μm to form an insulating hollow substrate.

<Example 3> Similarly, an insulating hollow substrate was formed using a metal base material having an Ra of 0.15 μm after pretreatment.

Comparative Example 1 Similarly, an insulating hollow substrate was formed using a metal base material having an Ra of 17 μm after pretreatment.

Comparative Example 2> Similarly, an insulating hollow substrate was formed using a metal base material having an Ra of 26 μm after pretreatment.

Comparative Example 3> An insulating hollow layer was formed on a metal base material that had only been degreased and washed with water as a pretreatment step. Ra of the metal base material at this time was 0.02 μm.

Comparative Example 4> An insulating hollow layer was formed on a metal substrate that had been subjected to all of the pretreatment steps of degreasing, water washing, pickling, and water washing.

Ra of the metal base material at this time was 0.10 μm.

Examples 1-3. The thickness of the plating layer in Comparative Examples 1 to 4 was 2.4
It is μm.

Examples 1 to 3 above. Regarding Comparative Examples 1 to 4, Japanese Industrial Standards/Industrial Glass Lining Equipment/JISR4201
The number of pinholes was determined based on the pinhole visual test method, and the average adhesion between the insulating hollow layer and the metal base material (8) was similarly determined based on the Japanese Industrial Standard Ceramic Coating Test Method ll5R4204 adhesion test. I looked into it. Furthermore, the Ra of the surface of the insulating hollow layer was also measured. The results are shown in Table 1.

As shown in Table 1, the Ra of the metal base material after pretreatment is 0.15μ.
The one with size M has no pinholes at all, and the adhesion is poor.
It can be seen that the RaO value of the a-edge hollow layer also shows an excellent value.

<Example 4> Metal base material was degreased, washed with water, pickled, washed with water, nickel plated,
Wash with water and perform pretreatment to reduce the thickness of the nickel plating layer to 0.
．． 4 μm, Ra of the plating layer surface is 0.10 μm,
Furthermore, an insulating hollow layer was formed thereon.

<Example 5> The metal base material was similarly pretreated, and the thickness of the plating layer was set to 2.
4 μm, l of the plating layer surface (a is 0.10 μm,
An insulating hollow layer was formed.

<Example 6> A metal base material was similarly pretreated to form an insulating hollow layer with a plating layer thickness of 5.0 μm and a plating layer surface Ra of 0.10 μm.

Comparative Example 5 A metal base material was similarly pretreated to form an insulating hollow layer with a plating layer thickness of 0.3 μm and a surface Ra t of the plating layer of 10 μm.

Comparative Example 6 A metal base material was similarly pretreated to form an insulating hollow layer with a plating layer thickness of 8.1 μm and a plating layer surface Ra of 0.10 μm.

Examples 4 to 5 above. Regarding Comparative Examples 5 and 6, fISH
Based on the 8504 peel test method, the adhesion between the metal substrate and the nickel plating layer was examined, and the number of pinholes in the insulating hollow layer was also examined. These results are shown in Table 2.

As shown in Table 2, the thickness of the nickel plating layer 'fI: 0.4μ
When the thickness of the plating layer is set to 5.0 μm, the adhesion between the nickel layer and the metal base material is good, and pinholes do not occur after the hollow layer is formed, but when the thickness of the plating layer is set to 0.3 μm, pinballs occur. On the contrary, it can be seen that adhesion is poor when the film thickness is 5.1 μm.

<Example> Alkaline earth metals (MqO) contained in glass.

Cab, Bad, Zn0) is at least 15% by weight or more, alkali metal (L 1 0 , i?a 20
To explain why tK2O) must be less than 21%, the glass composition shown in the table below is formed by forming an insulating hollow layer with an electrophoretic layer, and the surface roughness of the substrate and electrophoresis are Electrodeposition properties were investigated. The results are shown in Table 3. The forming method is the same as in Example 2.

According to the results in Table 3, alkaline earth metals are at least 15
It is essential that the alkali metal content be at least 2% by weight and not more than 2% by weight.

<Example 7> On the insulating hollow substrate formed in Examples 1 to 3, an electrode 2 heating resistor and an overcoat layer were formed to form a thermal head as shown in FIG.

Comparative Example 7> Similarly, a thermal head was entirely formed on the insulating hollow substrate formed in Comparative Examples 1 to 4.

Regarding cholera thermal heads, we investigated the number of disconnections within the head. The results are shown in Table 4.

As described above, the more pinholes there are, the greater the number of disconnections in the head. The reason why the number of pinholes and the number of disconnections are not equal is because pinholes smaller than the wiring width of the head (approximately 60 μm) do not cause disconnections.

As a result, it can be seen that in order to use an insulating hollow substrate as a substrate for a thermal head, it is necessary to satisfy at least the scope of the claims of the present invention.

Effects of the Invention As detailed above, the Ra of the nickel plating layer of the insulating hollow substrate consisting of ferritic stainless steel, electrolytic nickel plating layer, and Sio2-B203-MgO-BaO-based crystallized glass layer is 0.15 μm or less. What is
It has no pinholes and has excellent adhesion, so it can be used as a thermal head substrate with few defects and resistance variations.
It becomes possible to form a long-life thermal head.

Furthermore, since this insulating hollow substrate has excellent adhesion and flat surface smoothness, it can be applied as a bearing for a motor that requires wear resistance.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional diagram of an insulating hollow board according to an embodiment of the present invention, FIG. 2 is a cross-sectional diagram of a thermal head to which the same insulating hollow board is applied, and FIG. 3 is a cross-sectional diagram of the same insulating hollow board. , FIG. 6 is a process diagram showing a conventional method of forming an absolutely hollow substrate. 1... Metal base material, 2... Electrolytic nickel plating layer, 3... Insulating hollow layer. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 mouth z 2 mouth broom 3 Figure 40 Town j±su Figure 5 Figure 61

Claims (3)

[Claims] (1) The surface roughness of the electrolytic nickel plating layer of the insulating hollow substrate, which is composed of ferritic stainless steel, electrolytic nickel plating layer, and SiO_2-B_2O_3-MgO-BaO-based crystallized glass layer, is 0 in terms of center line average roughness. .15μ
An insulating hollow board characterized by having a thickness of less than m. (2) The thickness of the electrolytic nickel plating layer is 0.4 μm to 5.0 μm.
The insulating hollow substrate according to claim 1, wherein the insulating hollow substrate has a thickness of 0 μm. (3) The SiO_2-B_2O_3-MgO-BaO-based crystallized glass contains at least 15% by weight of an oxide of an alkaline earth metal, and has a composition of 2% by weight or less of an oxide of a monovalent alkali metal. An insulating hollow substrate according to claim 1, characterized in that: