KR930002640B1 - Production of tio2-cao-based sliding materal - Google Patents

Abstract

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Description

Method for preparing titanium dioxide-calcium oxide perturbation material

The present invention relates to a method for producing a titanium dioxide (TiO ₂ ) -calcium oxide (CaO) -based perturbation material that is used as a slider or spacer for a magnetic head of a storage device, in particular a hard disk device, and also moves as a tape guide of various tape devices. It is about.

Perturbation materials used for magnetic head sliders and the like are required to be dense in order to exhibit sufficient perturbation characteristics and to have high electrical resistance in order to improve insulation. TiO ₂ -CaO-based ceramic materials are known as one of the perturbation materials that satisfy these conditions.

When such a TiO ₂ -CaO ceramic material is used as the slider for the magnetic head, the slider for the magnetic head is bonded so that the ferrite magnetic head and the perturbation surface are the same, so that the discrimination with the black ferrite magnetic head can be improved. There is a need. Therefore, the TiO ₂ -CaO-based ceramic material is preferably its original white / beige, and moreover, the uniform index is required.

Conventionally, a TiO ₂ -CaO-based ceramic material has been produced by calcining a raw material containing titanium dioxide and calcium oxide in the air, followed by HIP treatment (hot hydrostatic press treatment—Hot Isostatic Press).

However, in the conventional manufacturing method, since a pressure medium composed of only inert gas such as argon is used in the HIP treatment, a catalyst defect occurs in the CaTiO ₃ phase in the TiO ₂ -CaO fired body during HIP treatment, resulting in blackening of the whole. In addition, the electrical resistance is low.

Therefore, reheating of the material after HIP treatment in the air is performed, thereby eliminating oxygen defects, thereby returning the color of the material to the original white / beige and increasing the electrical resistance.

However, when this refiring is performed, pores are generated in the material and this densification is damaged. In order to solve this problem, Japanese Patent Application Laid-Open No. 63-l34560 proposes to obtain a material having excellent perturbation properties by calcining a material containing titanium dioxide and calcium oxide in the air and then HIP treatment in the presence of oxygen concentration.

However, the present inventors performed a test bar, HlP treatment under a mixed gas atmosphere of oxygen and 5% or more bunam coral and the inert gas is in the above publication to a desired range, his original cause is unknown one, TiO ₂ -CaO Ceramics It was found that the reproducibility of the index white / beige was poor and blackened, and it was difficult to confirm the presence or absence of contamination when cleaning the material.

It is an object of the present invention to provide a method for producing a TiO ₂ -CaO-based perturbation material having good perturbation characteristics and high electrical resistance and having good reproducibility in the original color.

According to the present invention, a raw material containing titanium dioxide and calcium oxide is calcined in an atmospheric atmosphere, and then hot hydrostatic press treatment is carried out in an atmosphere of a mixed gas of oxygen and an inert gas having an oxygen partial pressure greater than 0% and 4% or less.

By using a mixture of oxygen and an inert gas as a pressure catalyst in the HIP treatment, generation of oxygen defects in the CaTiO ₃ phase is suppressed, and a dense perturbation material having sufficient electrical resistance is obtained. In addition, when the oxygen partial pressure is greater than 0% and less than 4%, the reproducibility of the color of the obtained perturbation material is good, and blackening can be prevented.

These and other objects, details, and advantages of the present invention will become apparent from the following examples.

First, a composition of TiO ₂ and CaO were weighed the CaTiO ₃ powder and TiO ₂ powder so that the TiO ₂ 54 mol%, CaO 46 mol%, and wet-mixed at a cylinder Water was added to the raw material thereof. Subsequently, the mixed raw materials are calcined at a temperature of 1,000 ° C to 1,400 ° C, water is added again, and wet mixing is performed in a cylinder. After shaking these, a binder, such as polyvinyl alcohol, is added and granulated.

This powder is press-molded at the pressure of 1 ton / cm <^3> or more, and it bakes at 1,150 to 1,300 degreeC in air | atmosphere. The fired body is subjected to HIP treatment at a temperature of 1,200 ° C to 1,250 ° C and a pressure of 900atm to 1,100atm in an atmosphere of mixed gas of oxygen and argon gas having an oxygen partial pressure greater than 0% and 4% or less. The fired body subjected to the HIP treatment is ground and wrapped to prepare a desired slide material.

In addition, trace amounts of CaO, SrO, Al ₂ O ₃ , SiO ₂ , ZrO _2, etc. mixed in the raw materials or in the manufacturing process have no effect on the effects of the present invention.

Table 1 shows the physical properties (color, hardness, electrical resistance, pore) of the perturbation material obtained as described above together with the HlP treatment conditions, and the physical properties of the comparative example.

In Table 1, sample numbers 1-5 are examples of this invention, and sample numbers 6-11 are comparative examples. Sample Nos. 6 to 9 were subjected to HIP treatment in an atmosphere where the oxygen partial pressure was larger than the range according to the present invention. Sample No. 10 was HIP treatment under the condition that oxygen partial pressure was not present, and Sample No. 11 was not HIP treatment. It was refired in the atmosphere without.

In Table 1, the measurement method and indication method of each property value are as follows.

Color: Measured by the method specified in JIS Z 8722, and indicated in accordance with the method specified in JIS Z8730. In the table, L is lightness, a is red-green direction, b is chromaticity in yellow-blue direction, and the color tone by the neck side is also indicated.

Hardness: Vickers hardness, unit is Hv.

Resistance: Volume specific resistance and unit is Ω.cm.

Pore: by observation under an electron microscope.

TABLE 1

Table 1 shows the following.

(1) As shown in Sample Nos. 6 to 9, when the oxygen partial pressure is greater than 4%, there is no problem with hardness, electrical resistance, and pore, but blackening (less L).

(2) If the material is refired in the atmosphere as in sample number 11, there is no problem with respect to color and electrical resistance, but the pore is large. Therefore, in order to obtain a perturbation material having sufficient performance against color, electrical resistance and pore, HIP treatment is carried out in an atmosphere of a mixed gas of oxygen and an inert gas having an oxygen partial pressure greater than 0% and not more than 4% as in Sample Nos. 1 to 5. I found it effective.

While the preferred embodiments of the invention have been described above, it should be understood that they may be modified into other specific forms without departing from the essential features of the invention. Accordingly, the foregoing embodiments are illustrative of the present invention and not intended to limit the invention. The scope of the invention should be construed by the appended claims rather than the foregoing description.

Claims (7)

Titanium dioxide-oxidation consisting of calcining a mixed raw material containing titanium dioxide and calcium oxide in an atmospheric atmosphere, and hot-pressurizing the calcined body under a mixed gas atmosphere of oxygen and inert gas having an oxygen partial pressure greater than 0% and less than 4%. Method for preparing calcium perturbation material. The method of producing a titanium dioxide-calcium oxide perturbation material according to claim 1, wherein the hot hydrostatic press treatment is performed at a temperature in the range of 1,200 to 1,250 ° C. The method for producing a titanium dioxide-calcium oxide perturbation material according to claim 1, wherein the hot hydrostatic press treatment is performed at a pressure in the range of 900 to 1,100 atm. The method for producing a titanium dioxide-calculated oxide perturbation material according to claim 1, wherein the composition of the raw material containing titanium dioxide and calcium oxide is 54 mol% titanium dioxide and 46 mol% calcium oxide. The method for producing a titanium dioxide-calcium oxide perturbation material according to claim 1, wherein the inert gas is argon. The method for producing a titanium dioxide-calcium oxide perturbation material according to claim 1, wherein firing is performed at a temperature in the range of 1,150 to 1,300 ° C. The method for producing a titanium dioxide-calculated oxide perturbation material according to claim 1, wherein before firing of the mixed raw material containing titanium dioxide and calcium oxide, plasticity of the mixed raw material and a binder are added to perform granulation and press molding.