JPS62199797A - Flexible metal-ceramic composite material and its production - Google Patents

Abstract

PURPOSE:To produce a metal-ceramic composite material having superior flexibility by carrying out spark discharge on a metallic base material as the anode in an electrolytic cell contg. a silicate or a metallic salt of an oxyacid. CONSTITUTION:A metallic base material at least the surface part of which is made of a metal is placed as the anode in an electrolytic cell contg. a silicate or a metallic salt of an oxyacid, and spark discharge is carried out on the anode by two-stage electrolysis, that is, constant-current electrolysis and constant-voltage electrolysis. A ceramic layer consisting of particles of <=5mum particle size and having <=20% porosity is uniformly distributed on the surface of the metallic base material and a flexible metal-ceramic composite material is produced.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a metal-ceramic composite material consisting of a metal and a ceramic layer formed on its surface, and particularly to a metal-ceramic composite material obtained by an anodic spark discharge and It relates to its manufacturing method.

(Prior Art) Metal-ceramic composite materials, which are a combination of metal and ceramics, have been known for a long time. Thermal spraying, chemical conversion, sintering, and vapor deposition methods are known as methods for forming this composite material, but the ceramic layer formed by these methods does not adhere tightly to the surface of the metal base material. The problem is that the composite material has poor properties, and even if the composite material is slightly deformed, it will peel off from the metal base material. Furthermore, it is difficult to control the thickness of the ceramic layer formed, which disadvantageously limits the field of application of the composite material. In addition to the above methods, a method using anodic spark discharge is known as a method for forming a ceramic layer on a metal surface. For example, Special Publication No. 58-17278, No. 59-28636, No. 59-
No. 28637, No. 59-28638, No. 59-45722
No. 60-12438, etc., an electrolytic cell is constructed of an alkaline aqueous solution of silicate or various metal oxyacids, and the silicate ions and metal oxyacid ions drawn near the anode are combined with the anode metal. A method of forming a ceramic layer of silica, metal oxide, etc. on the anode metal surface by generating an anode spark discharge between the two methods is disclosed.

Compared to other methods, the ceramic layer formed by this method using anodic spark discharge has advantages such as good adhesion to the surface of the metal base material and the ability to control the thickness of the formed layer over a wide range. It is something that you have.

(Problem to be solved) Conventionally, when forming a ceramic layer on a metal base material by anodic spark discharge, the ceramic layer is formed by a so-called constant current process in which discharge is performed while keeping the applied current density constant. is normal. However, although the ceramic layer formed by this conventional anodic spark discharge method has good adhesion to the surface of the metal base material, the strength of the ceramic layer structure itself is not sufficient, and if the composite material is deformed, There has been a problem in that a part of the tissue frequently breaks down and falls off. This problem becomes more pronounced as the thickness of the ceramic layer increases.

(Means for solving the problem) The present invention was constructed in view of the above circumstances, and includes:
The ceramic layer and the metal base material have strong bonding strength, and the ceramic layer itself also has sufficient strength, so even if the composite material is deformed, the structure is unlikely to fall off. The object of the present invention is to provide a metal-ceramic composite material having the properties, ie, flexibility.

As a result of repeated research on the properties of the ceramic layer formed on the fully curved surface by anode spark discharge, the present inventors found that
It has been found that the size of the ceramic particles, the state of distribution of the particles, and the porosity have important effects on the flexibility of the ceramic layer and the adhesion to the surface of the metal base material. Based on this knowledge, we conducted further research and as a result, we arrived at the present invention. The present inventors deposited 10-20μ on the surface of the anode metal matrix by various anode spark discharge methods.
A ceramic layer with a thickness of m was formed, and its adhesion to the surface of a metal base material and flexibility were investigated. For this purpose, the present inventors have determined that the ceramic layer is
The stretching ratio specified in H8684 was measured. This elongation rate is determined by creating a specified test piece of the metal-ceramic composite material with the above-mentioned ceramic layer, fixing one end of the test piece, and bending the test piece along a curved surface to determine the boundary point at which cracks appear in the ceramic layer. It can be determined by reading the scale. This stretching ratio can be evaluated as an expression of the strength, ie, flexibility, of the ceramic layer itself. The present inventors also conducted a bending resistance test on this composite material according to the method specified in JIS K5400. This bending resistance is measured by creating a specified test piece of a composite material with a ceramic layer and using a specified test device.
It is determined based on the reciprocal of the size of the mandrel that is bent 180 degrees so that the ceramic layer is on the inside and peeling of the ceramic layer occurs. This test can be evaluated as representing both the adhesion and flexibility of the ceramic layer. As shown in FIG. 1, the stretching ratio decreases as the maximum grain size of the ceramic layer increases and as the porosity increases. When the porosity exceeds approximately 20%, the drawing rate tends to decrease significantly. FIG. 2 shows the results of the bending resistance test. According to this, the bending resistance also shows the same tendency as the stretching ratio, and decreases as the maximum particle diameter increases and as the porosity increases. When the maximum particle diameter exceeds approximately 5 μm or when the porosity exceeds 20%, the bending resistance is significantly reduced. Further, according to research by the present inventors, when the distribution of particles becomes non-uniform, the drawing rate and bending resistance decrease, and the tendency of ceramic particles to fall off becomes significant. Therefore, the flexible metal-ceramic composite material of the present invention can be applied to a metal base material in which at least the surface portion is made of metal in an electrolytic cell containing a silicate or a metal oxysate by an anodic spark discharge. A flexible metal made by electrodepositing a ceramic layer on
A ceramic composite material, wherein the ceramic layer consists of substantially uniformly distributed particles of 5 μm or less,
It is also characterized by having a porosity of approximately 20% or less.

In the conventional method using anode spark discharge, the porosity of the ceramic layer is set to about 30% or less, and the maximum particle size is set to about 10 μm.
m or less, and it is also difficult to form a structure with a uniform particle distribution state, and for this reason, it has been impossible to obtain a ceramic layer with sufficient strength.

However, the research conducted by the present inventors has confirmed that a ceramic layer with sufficient strength, that is, flexibility, can be obtained by controlling the processing current and voltage of anode spark discharge to satisfy certain conditions. Ta. The flexible metal-ceramic composite material of the present invention is produced by preparing an electrolytic cell containing a silicate or a metal oxylate, forming an anode with a metal base material with at least a surface portion made of metal, and using a pulsed power source. It is manufactured by performing anodic spark discharge through a two-step process of constant current treatment and constant voltage treatment, and electrodepositing a ceramic layer on the surface of the metal base material.

In this case, it is possible to perform constant current processing by keeping the current density constant until before and after the spark discharge starts, and then continue to perform constant voltage processing using the peak voltage at the start of the spark discharge. preferable.

The metal base material of the composite material of the present invention is 8t, Mg.

Ti or an alloy thereof can be used. In addition, the silicate used as an electrolyte has the general formula i
A 20・nSi2 (M represents an alkali metal, n is 0
．． 5 to 20), such as sodium silicate, sodium metasilicate, potassium silicate, lithium silicate, colloidal silica, etc. be able to.

It can also be prepared by dissolving a metal oxyacid in an electrolytic solution; in this case, the oxyacid includes tungstate,
stannate, molybdate, phosphate, vanadate,
Mention may be made of phosphates, chromates and permanganates. These can be used alone or in combination of two or more.Furthermore, these metal oxyacids can also be used in a mixture with silicates in an appropriate ratio. Typical power supplies that can be used for electrolytic treatment include DC power supplies that turn on and off with a switch, pulse power supplies that output pulse or triangular waveform current, and other arbitrary current waveforms. In the electrolytic treatment, the metal material to be treated is used as an anode and iron, stainless steel, nickel, etc. is used as a cathode and immersed in the above electrolytic bath.If a pulse power source is used, the components and concentration of the electrolytic bath are A constant current process is performed to maintain a constant current density until before and after spark discharge begins, by controlling the current flow and body conductance according to the current flow, and then increasing the voltage to a predetermined voltage while maintaining spark discharge to form a coating with a predetermined thickness. The voltage is maintained until .

The thickness of the film formed depends on the concentration of the electrolytic bath, the temperature of the electrolytic bath,
It is determined by the processing voltage, processing time, etc., and the electrolytic bath temperature is determined depending on the desired coating, but it is usually 5.
Performed at ~80°C.

(Effects of the Invention) The ceramic layer of the metal-ceramic composite material of the present invention has good adhesion to the surface of the metal base material, and has a strong structure that does not easily fall off even when the material is deformed. It has a structure.

That is, the composite material according to the present invention is highly flexible and bendable, and in this respect, new usefulness can be found that is not found in conventional metal-ceramic composite materials.

For example, a printed circuit board with good impact resistance can be manufactured using the metal-ceramic composite material according to the present invention. In addition, far-infrared heaters are known as combinations of gold, Akebono materials, and ceramic materials, and in order to effectively generate far-infrared rays, this heavy-duty heater requires the use of ceramic materials. In conventional far-infrared heaters, the ceramic layer that covers the metal material that serves as the heating source is extremely susceptible to brittle fracture when subjected to impact! 7: There is a tendency for peeling to occur and there is a problem in terms of durability. However, since the ceramic layer in the metal-ceramic composite material according to the present invention has good adhesion and flexibility with metal materials, the durability of the heater can be significantly improved by using the composite material of the present invention in a far-infrared heater. can be improved.

(Description of Examples) (Example 1) NaJo○4・2l-(20tOg/l and Naz
Prepare an electrolytic solution containing 2020g/] of B4O7.10H, use an A4-1100 foil with a thickness of 50μ as an anode, an Fe plate as a shank, and set the ratio of the current-carrying width of the pulse power source to the body-conducting width to 0. Set to .25”/10”, I A /dm2
The voltage was adjusted to a constant current density of , and the voltage was applied until spark discharge started. The peak voltage applied at this time is 300
(2), and the time until spark discharge started was 10 minutes. Thereafter, constant voltage electrolysis was carried out for 10 minutes while maintaining the applied peak voltage at 250 cm until the applied current value became 0. As a result, a ceramic coating with a thickness of 10.2 μm was obtained on the AI anode. The porosity of this ceramic layer was measured according to JIS C-2141 and was found to be 6.6%. Further, when this ceramic coating was observed using an electron microscope, it was found that it had a substantially uniform structure with a grain size of approximately 2 to 4 μm, as shown in the photograph of FIG.

(Example 2) An electrolytic solution of 50 g/l of K2O.5102 was prepared, and using the same electrode as in Example 1, a current-carrying width body 1r of a pulse power source was used.
lB: ratio of 0.25"/10"l: set, lΔ
The voltage was adjusted to have a constant current density of /dm2 and was applied until spark discharge started. The peak voltage applied at this time was 300μ, and the time until spark discharge started was 2
It was a minute. Thereafter, while maintaining this applied peak voltage of 300 cm, constant voltage electrolysis was performed until the applied current value became 0. The constant voltage electrolytic treatment time was 15 minutes.

As a result, a ceramic coating having a thickness of about 10.8 μm was obtained on the A1 anode. The porosity of this ceramic layer was 15.1%. Further, when this ceramic coating was observed using an electron microscope, it was found that it had a substantially uniform structure with a grain size of 2 to 4 μm, as shown in the photograph in FIG.

(Example 3) The same electrolyte solution as in Example 2 was prepared, and the same electrode was used.
The ratio of the conduction width of the pulsed power source to the body current width was set to 1.0''/9'', and the voltage was adjusted to have a constant current density of 1 A /dm2, and the voltage was applied until spark discharge started. The peak voltage applied at this time was 300 μ, and the time until spark discharge started was 3 minutes. Thereafter, while maintaining this applied peak voltage of 300 cm, constant voltage electrolysis was performed until the applied current value became 0. The constant voltage electrolytic treatment time was 12 minutes. As a result, the film thickness on the layer anode is approximately 10.
A ceramic coating of 5 μm was obtained. The porosity of this ceramic layer was 19.8%. Furthermore, when this ceramic coating was observed using an electron beam and a mirror, it was found that it had a nearly uniform structure with a grain size of 2 to 5 μm, as shown in the photograph in Figure 5. .

(Comparative Example 1) K2O・8102.100g/l and 2C,047,
An electrolytic solution containing 5 g/I was prepared, and the same electrodes as in Example 1 were used, and the ratio of the current carrying width of the pulse power supply to the body electrical width was set to 0.
The spark discharge treatment was performed for 25 minutes by setting the voltage to 5''s/3'' and adjusting the voltage to give a constant current density of 0.5 A/dm2. As a result, the film thickness on the He1 anode is approximately 15
．． A ceramic coating of 8 μm was obtained.

The porosity of this ceramic layer was 27.0%.

Furthermore, when this ceramic coating was observed using an electron microscope, it was found that it had a grain size of approximately 1 to 10 μm, and had a structure in which the grain size increased as it approached the surface, as shown in the photograph in Figure 6. It turned out that there was.

(Comparative Example 2) Using an electrolytic solution, an electrode, and a pulse power source having the same components and concentrations as in Example 3, the applied current density was set to 1. Constant current spark discharge treatment was performed at OA/dm2 for 5 minutes. As a result, a ceramic coating having a thickness of about 13.2 μm was obtained on the He1 anode. The porosity of this ceramic layer is 19.6
%Met. Furthermore, when this ceramic and wax coating was observed using an electron microscope, as shown in the photograph in Figure 7, 5.
It has a particle size of about 15 μm, and has a structure in which the particle size increases as it approaches the surface.

(Comparative Example 3) An electrolytic solution with the same components and concentration as in Examples 2 and 3, that is, an electrolytic solution of 20.S+0250 g/l, was prepared, and using the same electrode as in Example 1, the current carrying width of the pulse power source and the Constant current spark discharge treatment was carried out for 10 minutes with the ratio to the body conductance width set to 0.5''/3'''5 and the applied current density to 2.OA/dm2.As a result, a film was formed on the anode. A ceramic coating with a thickness of approximately 10.1 μm was obtained.The porosity of this ceramic layer was 15.0%.Furthermore, when this ceramic coating was observed using an electron microscope,
As shown in the photograph of FIG. 8, it has a grain size of approximately 5 to 15 μm, and has a structure in which the grain size increases as it approaches the surface.

(Comparative Example 4) An electrolytic solution with the same components and concentration as Comparative Example 3, that is, 20.
An electrolytic solution of 0.50 g/l of S was prepared, and using the same electrode as in Example 1, the ratio of the current carrying width of the pulse power source to the body electrical width was set to 0.
．． 5"/3", and the applied current density was set to 1. OA/
Constant current spark discharge treatment was performed for 7 minutes at dm2. As a result, a ceramic coating with a thickness of about 10.9 μm was obtained on the AI anode.

The porosity of this ceramic layer was 21.1%.

Furthermore, when this ceramic coating was observed using an electron microscope, it was found that it had a structure in which the grain size was approximately 5 to 15 μm, and the grain size became larger as it approached the surface, as shown in the photograph in Figure 9. There is.

(Stretching ratio and bending resistance test) The stretching ratio of the metal-ceramic composite materials of the above examples and comparative examples was measured according to JIS H8684, and a bending resistance test was conducted according to JIS K5400. The results are shown in Table 1. According to this, the composite material according to the present invention has superior properties compared to the comparative example in both stretching ratio and bending resistance.

Table 1

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between elongation and porosity of metal-ceramic composite materials, Figure 2 is a graph showing the relationship between bending resistance and porosity of metal-ceramic composite materials, and Figure 3 is a graph showing the relationship between bending resistance and porosity of metal-ceramic composite materials. FIG. 4 is a micrograph of the ceramic layer of the metal-ceramic composite material of Example 1, and FIG. 5 is a micrograph of the ceramic layer of the metal-ceramic composite material of Example 2.
The figure shows a photomicrograph of the ceramic layer of the metal-ceramic composite material of Example 30, FIG. 6 shows the photomicrograph of the ceramic layer of the metal-ceramic composite material of Comparative Example 10, and FIG. 7 shows the ceramic layer of the metal-ceramic composite material of Comparative Example 20. FIG. 8 is a photomicrograph of the ceramic layer of the metal-ceramic composite material of Comparative Example 3, and FIG. 9 is a photomicrograph of the ceramic layer of the metal-ceramic composite material of Comparative Example 4. 113 Figure 1A (X 1000) 51st Supplementary Figure 6 (X1000) Figure 7 (xlooO) Figure 8 Figure j

Claims (2)

[Claims] (1) A flexible metal made by electrodepositing a ceramic layer on the surface of a metal base material, at least the surface of which is made of metal, by an anodic spark discharge in an electrolytic bath containing a silicate or metal oxysate. - a ceramic composite material, wherein the ceramic layer has a substantially uniform distribution of substantially 5 μm;
A flexible metal-ceramic composite material comprising the following particles and having a porosity of approximately 20% or less. (2) Prepare an electrolytic cell containing silicate or metal oxysate, form an anode with a metal base material whose surface portion is made of metal, and perform two-stage treatment of constant current treatment and constant voltage treatment. 1. A method for producing a flexible metal-ceramic composite material, which comprises performing anodic spark discharge to electrodeposit a ceramic layer on the surface of the metal base material.