JP2823626B2 - Method for producing Mn-Zn ferrite joined body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a magnetic recording / reproducing apparatus, in particular, a bonded body of a Mn-Zn ferrite single crystal and a Mn-Zn ferrite polycrystal used for a magnetic head of a VTR. It relates to a manufacturing method.

(Prior art) Mn-Zn ferrite single crystal is widely used as a material for magnetic heads for VTRs, because it is a chemically stable substance and has a high electric resistance, so that it can be used in the high frequency range. This is because it has advantages such as high magnetic permeability, excellent wear resistance, and good workability. However, the Mn-Zn ferrite single crystal has a drawback that S / N is deteriorated due to large sliding noise. On the other hand, Mn-Zn ferrite polycrystal
It is used as a magnetic head for HDDs and FDDs and has the advantage of low sliding noise. However, it has disadvantages such as easy removal of crystal grains, difficulty in narrow gap processing, and short life.

In order to solve these problems, a magnetic head using a joined body of a Mn-Zn ferrite single crystal and a Mn-Zn ferrite polycrystal has been used. These magnetic heads have a structure in which a single crystal is arranged near a gap where a medium slides, and a polycrystal is arranged in other parts, and a glass welding method and a bonding method using an adhesive have been adopted. Was. However, these methods have a disadvantage that a nonmagnetic layer is formed between the two ferrites, which increases the magnetic resistance of the magnetic head and significantly lowers the magnetic permeability.

(Problem to be Solved by the Invention) As an improved method of such a disadvantageous bonding method, Japanese Patent Publication No. 60-26076 discloses a method in which a liquid is interposed between the bonding surfaces of a single crystal and a polycrystal of Mn-Zn ferrite. Japanese Patent Publication No. 53-32692 discloses a method of heat treatment to promote a solid phase reaction, and a method of causing a solid phase reaction by heating and pressurizing to directly join. However, in the former, it is difficult to allow the liquid to intervene over the entire surface of the bonding surface, and the liquid collects in the center of the bonding surface. When trying to obtain a joined body, a single crystal and a polycrystal having a considerably larger shape than that must be joined, resulting in poor yield and difficulty in obtaining a large joined body.

On the other hand, according to the latter, the surface roughness Rmax of both joint surfaces is about 0.
After finishing to 1μm mirror surface, butted joint surfaces
It is set in a heat treatment furnace without any intervening between the joining surfaces, and heated and pressed. In that case, to prevent the occurrence of cracks,
The atmosphere in the furnace must be controlled to have an equilibrium oxygen partial pressure. For this reason, an atmosphere control device is required,
The cost is high.

In addition, as a method of easily creating an equilibrium oxygen partial pressure without the need for such a special device, the joining surface between a single crystal and a polycrystal of Mn-Zn ferrite is buried in a Mn-Zn ferrite powder by abutting the joining surfaces. Then, there is a method of applying heat and pressure. In this case, when the joining is completed, the Mn-Zn ferrite powder becomes Mn-
Due to sticking to the Zn ferrite joined body and poor workability, an inert ceramic powder such as alumina or zirconia may be mixed with the Mn-Zn ferrite powder. However, even with this method, when the two mirror surfaces are buried in the powder by abutting each other, the powder enters the bonding surface and the bonding becomes impossible, or the bonding surface is shifted and the bonding area is reduced. There are drawbacks.

An object of the present invention is to solve the above-mentioned problems and to provide a method for manufacturing a complete joined body by a joining method that has a good yield and does not adversely affect magnetic properties.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present inventors have applied a specific bonding agent to both bonding surfaces, dried and applied the Mn-Zn ferrite powder and / or ceramic powder. The inventors have found that a complete bonded body can be obtained by applying heat and pressure in the body, and have studied the composition of the bonding agent and the bonding conditions in detail to complete the present invention.

That is, the present invention relates to a single crystal of Mn-Zn ferrite and Nn-
Fe, Mn, as a bonding agent on the bonding surface of Zn ferrite polycrystal
Applying an aqueous solution and / or slurry containing at least one compound selected from oxides, inorganic acid salts, ammonium metal complex salts and organic acid salts of a metal element of Zn or a metal element capable of forming a solid solution in Mn-Zn ferrite Mn-Zn ferrite, characterized in that the bonding surfaces are pressed together, dried, buried in Mn-Zn ferrite powder and / or inert ceramic powder, and heated and pressed to bond. The gist of the invention is a method of manufacturing a joined body.

 Hereinafter, the present invention will be described in detail.

The bonding agent of the present invention is a constituent element of Mn-Zn ferrite.
An aqueous solution containing at least one compound selected from the group consisting of oxides, inorganic acid salts, ammonium metal complex salts and organic acid salts composed of a metal element of Fe, Mn, Zn or a metal element capable of forming a solid solution with Mn-Zn ferrite; Or, it is composed of slurry (also called slurry).
₂ O ₃ , Fe ₃ O ₄ , MnO, ZnO, FeCl ₃ , MnCl ₂ , ZnCl ₂ , Fe ₂ (SO ₄ ) ₃ , Mn
SO ₄ , ZnSO ₄ , Fe (NO ₃ ) ₃ , Mn (NO ₃ ) ₂ , Zn (NO ₃ ) _{2 and the} like are exemplified. Of these compounds, water-soluble ones may be adjusted to a concentration of several weight% in pure water, and insoluble ones are finely pulverized to several μm order and used as a slurry of several weight% order.

In addition, these compounds include oxides, inorganic acid salts, ammonium metal complex salts and organic acid salts made of a metal element that can be dissolved in Mn-Zn ferrite without changing the spinel structure of Mn-Zn ferrite. At least one compound is also effective as a bonding agent, and is composed of elements such as Sn, Ti, In, and Ge, such as SnO ₂ , TiO ₂ , InO ₂ , GeO ₂ , SnCl ₂ , Ti (SO ₄ ) ₂ , and In (N
O ₃ ) _{2 and the} like. Further, these compounds are
You may use together with the compound which consists of a Mn-Zn ferrite constituent element. This mixing ratio can be arbitrarily set, and the concentration of the aqueous solution or the slurry may be adjusted to the order of several weight%.

According to the present invention, the bonding agent interposed between the bonding surfaces becomes solid by drying and fixes the Mn-Nn ferrite single crystal and the polycrystal. Further, the solid existing between the bonding surfaces is diffused into the Mn-Zn ferrite by heating and pressing. Therefore, the bonding agent to be interposed between the bonding surfaces must be a compound containing at least one of the elements constituting the Mn-Zn ferrite, that is, Fe, Mn, and Zn.
In addition, since the solid existing between the bonding surfaces before heating and pressing is extremely small, an element that does not change the spinel structure of the Mn-Zn ferrite, that is, Mn-Zn ferrite such as Sn, Ti, In, and Ge is used. A compound containing at least one of the elements capable of forming a solid solution in a mixture of a compound containing at least one of Fe, Mn, and Zn with an element that does not change the spinel structure It may be. Even if a slurry (slurry) -like substance composed of fine particles containing at least one of the above elements is interposed between the bonding surfaces instead of the aqueous solution of these compounds, the dried state is the case where the aqueous solution is interposed. Is the same as Therefore,
The inclusion of a sludge is optional.

 Next, the joining method of the present invention will be described in the order of steps.

First, an Mn-Zn ferrite single crystal prepared by the Bridgman method and a polycrystal having substantially the same composition as the single crystal are cut into a shape of a predetermined size, and the joining surface is polished to obtain a surface roughness Rmax.
Finish to a mirror surface of 0.1 μm or less. Next, the bonding agent is applied, the bonding surfaces are overlapped, set on a jig, pressed, and dried in a dryer at 100 ° C. The two crystals temporarily fixed by drying are removed from the jig and buried in a ceramic powder such as Mn-Zn ferrite powder or alumina or zirconia inert to Mn-Zn ferrite set in a pressure-resistant firing furnace. Then, they are joined by heating under pressure. The heating temperature is in the range of 950 to 1,500 ° C., preferably 1,150 to 1,350 ° C., and the pressure is 2 kg / cm ² or more.

Hereinafter, specific embodiments of the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 53 mol% of Fe ₂ O ₃ , 30 mol% of MnO, and 17 mol% of ZnO were mixed using a ball mill and calcined at 1200 ° C., which was melted at 1,700 ° C. in a platinum crucible. The Mn-Zn ferrite single crystal was prepared by lowering the crucible and gradually crystallizing it from the tip of the crucible. A plate of 20 × 20 × 1 mm was cut out from the Mn—Zn ferrite single crystal ingot, and was processed into a mirror surface having a surface roughness Rmax of 0.08 μm using a 20 × 20 mm surface as a bonding surface.

A polycrystal having almost the same composition as this single crystal was prepared by calcining at 1300 ° C for 5 hours under an equilibrium oxygen partial pressure, and a
Cut out a 20 × 2mm plate, same as a single crystal 20 × 20m
m surface was finished into a mirror surface with a surface roughness Rmax of 0.08 μm. Next, the bonding agents described in Table 1 were applied to the two mirror surfaces as bonding surfaces, the bonding surfaces were overlapped, set in a jig, and dried in a dryer at 100 ° C.

The Mn-Zn ferrite single crystal and polycrystal temporarily fixed by drying are embedded in Mn-Zn ferrite powder, and 5 kg / cm ²
Under a pressure of 1250 ° C. for 1 hour.

During the production of the joined body, there was no powder that penetrated between the joining surfaces and could not be joined, or a single crystal and a polycrystal were shifted. 20x20x3mm Mn obtained in this way
From the joined body of -Zn ferrite, 18 pieces of 18 × 1 × 3 mm pieces were cut out, and how many of them were completely joined was examined. The results are also shown in Table 1.

(Comparative Example 1) A bonded body was prepared in the same manner as in Example 1 except that no pressure was applied in the heating / pressurizing step and the bonding agents used were Nos. 4 and 12, and the bonding state was evaluated. The results are shown in Table 2. During the production of the joined body, there was no powder that penetrated between the joining surfaces and could not be joined, or a single crystal and a polycrystal were shifted. Table 1 No. Bonding agent Number of pieces that could be joined 1. Aqueous iron nitrate solution 17 2. Aqueous manganese nitrate solution 16 3. Aqueous zinc nitrate solution 16 4.1 + 2 + 3 18 5. Aqueous iron sulfate solution 17 6. Aqueous iron chloride solution 16 7.5 + Titanium sulfate Aqueous solution 138.6 + tin chloride aqueous solution 13 9. iron oxide slurry 15 10. manganese oxide slurry 14 11. zinc oxide slurry 14 12.9 + 10 + 11 15 13.12 + tin oxide slurry 14 14.13 + germanium oxide slurry 13 (Comparative Example 2) Ten bonded bodies were produced under the same conditions as in Example 1 except that no bonding agent was used. As a result, three pieces could not be joined due to the intrusion of powder between the joining surfaces, four pieces were displaced between the single crystal and the polycrystal, and only three pieces could be joined without defects. Was. Table 2 No. Bonding agent Number of bonded pieces 4 (= 1 + 2 + 3) 5 12 (= 9 + 10 + 11) 3 (Effect of the Invention) The present invention provides a solid-state reaction between a Mn-Zn ferrite single crystal and a Mn-Zn ferrite polycrystal. In the method for producing a Mn-Zn ferrite bonded body directly bonded by the method, the bonding surface of Mn-Zn ferrite single crystal and polycrystal, Fe, Mn, Zn as a bonding agent
An aqueous solution and / or slurry containing at least one compound selected from the group consisting of oxides, inorganic acid salts, ammonium metal complex salts and organic acid salts composed of a metal element or a metal element soluble in Mn-Zn ferrite. The bonding method is characterized in that the bonding surfaces are pressed together, dried, buried in Mn-Zn ferrite powder and / or inert ceramic powder, and heated and pressed to bond. Compared with the method, the yield of a joined body that is completely joined is extremely high, and its practical value is extremely large without adversely affecting its magnetic properties.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C04B 37/00

Claims (3)

(57) [Claims] An oxidation method comprising the steps of: bonding a metal element of Fe, Mn, or Zn as a bonding agent or a metal element capable of forming a solid solution with Mn-Zn ferrite on a bonding surface of a single crystal of Mn-Zn ferrite and a polycrystal of Mn-Zn ferrite; An aqueous solution and / or slurry containing at least one compound of at least one of a compound, an inorganic acid salt, an ammonium metal complex salt and an organic acid salt, and crimping the joint surfaces together,
A method for producing a joined body of Mn-Zn ferrite, comprising drying, drying, embedding in Mn-Zn ferrite powder and / or inert ceramic powder, and joining by heating and pressing. 2. An oxide, an inorganic acid salt, an ammonium metal complex salt and an organic acid salt comprising a metal element capable of forming a solid solution in Mn-Zn ferrite without changing the spinel structure of the Mn-Zn ferrite. The method for producing a Mn-Zn ferrite joined body according to claim 1, comprising an aqueous solution and / or a slurry containing at least one or more compounds. 3. An oxide, an inorganic acid salt or an ammonium metal complex comprising a metal element capable of forming a solid solution in the Mn-Zn ferrite without changing the spinel structure of the Mn-Zn ferrite in the bonding agent according to claim 1. And a method for producing an Mn-Zn ferrite joined body, wherein the joining is performed with a joining agent obtained by adding at least one compound among organic acid salts.