JPH06305823A - Sliding member material - Google Patents

Abstract

PURPOSE:To provide a sliding member material small in pore sizes, enhanced in surface smoothness and improved in sliding characteristics so as not to give defects, abrasion, etc., to the sliding member material by specifying a CaO/Fe2O3 ratio and surface roughness in a calcium ferrite. CONSTITUTION:The characteristic of this sliding member material comprises containing CaO and Fe2O3 as main components in a CaO/Fe2O3 molar ratio of 45/55 to 67/33 and having a surface roughness Ra of <=300Angstrom . The sliding member material has a composition represented by the composition formula of Ca2Fe2-xAlxO5 wherein 0<x<=1.2, and has a surface roughness Ra of <=300Angstrom . When the CaO/Fe2O3 molar ratio is smaller than the lower limit, the lowering of the sintering property of the sliding member material, the easy generation of pores and the deterioration of sliding characteristics are caused. When the CaO/Fe2O3 molar ratio is larger than the upper limit, the generation of a small amount of a CaO phase in the material, the enlargement of the sizes of the pores, and the remarkable deterioration of the sintering property are caused. When (x) exceeds the upper limit in the composition formula of Ca2Fe2-xAlxO5, the deterioration of the sintering property, the easy generation of the pores and the deterioration of the sliding characteristics are caused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding portion material used for a strip sliding member such as a magnetic tape guide or a wire sliding member such as a fiber yarn path.

[0002]

2. Description of the Related Art Conventionally, as sliding part materials used for band material sliding members such as magnetic tape guides and wire rod sliding members such as fiber yarn paths, titania, barium titanate, calcium titanate, rutile, A sintered body containing alumina, zirconia or the like as a main component is used.

[0003]

However, a sintered body containing titania, alumina, zirconia or the like as a main component, which is used as a material for the sliding portion, has a large pore diameter generated therein and has a high sinterability. There was a problem that was bad. As a result, there is a problem that the surface roughness Ra is as large as about 0.05 μm.

That is, when a sintered body containing titania, alumina, zirconia or the like as a main component is used as the material for the sliding portion, for example, in a magnetic tape guide, the loss of stored contents due to wear of the magnetic powder becomes a problem. In addition, in the case of a fiber yarn path, there is a problem that white powder is generated or yarn breakage occurs. That is, in the case of the magnetic tape guide, there is a problem that the magnetic medium is destroyed, the data is destroyed, and the head is destroyed, so that the reliability of the magnetic recording device is significantly lowered. Particularly in recent years, magnetic tapes have become thinner, and reliability has deteriorated even with slight slippage, so that magnetic tape guides having a small pore size are required. At the same time, it is known that if the friction coefficient between the magnetic medium and the magnetic tape guide is large, the damage to the magnetic medium is large and the medium is damaged. In order to solve these problems, in recent years, there has been a demand for a material that does not cause wear on a band material such as a magnetic tape or a wire material such as a fiber and does not cause scratches, and that has a small friction coefficient. There is.

[0005]

[Means for Solving the Problems] The inventors of the present invention have conducted various studies to reduce the pore diameter generated on the surface of the sintered body and to improve the sinterability. It has been found that a sliding member having excellent sliding characteristics can be obtained by specifying the molar ratio of iron oxide to a predetermined value and limiting the surface roughness to a predetermined value or less.

Further, the present inventors set a molar ratio of iron and aluminum to a predetermined value in a solid solution in which a part of iron is replaced with aluminum in calcium ferrite, and limit the surface roughness to a predetermined value or less. It has been found that a sliding member having excellent sliding characteristics can be obtained.

That is, the material of the sliding portion of the present invention is CaO and F.
with mainly containing e ₂ O _3, CaO / F
The molar ratio represented by e ₂ O ₃ is 45/55 to 67/33 and the surface roughness Ra is 300 Å or less.
Further, in the composition formula represented by Ca ₂ Fe _{2 -X} Al _X O ₅ , 0 <X ≦ 1.2 and the surface roughness Ra is 300Å
It is the following.

The molar ratio represented by CaO / Fe ₂ O ₃ is 45/55 to 67/33 because the molar ratio is 4
If it is less than 5/55 (Fe ₂ O ₃ is excessive), the sinterability is lowered, pores are easily generated, and the sliding characteristics are deteriorated. On the other hand, when the molar ratio is larger than 67/33 (excessive amount of CaO), a small amount of CaO phase is generated in the material, the pore size is increased, and the sinterability is significantly deteriorated. The most preferable ratio of CaO and Fe ₂ O ₃ is the CaO / Fe ₂ O ₃ molar ratio of 50/50 to 66/3.
It is 4.

In the composition formula represented by Ca ₂ Fe _{2 -X} Al _X O ₅ , 0 <X ≦ 1.2 means that when X exceeds 1.2, the sinterability decreases. This is because pores are likely to occur and sliding characteristics are deteriorated.

Further, in the porcelain according to claim 1, Zr
The total content of at least one of O ₂ , TiO ₂ , MgO, and Al ₂ O ₃ is 2% by weight or less, and the porcelain according to claim 2 contains at least one of ZrO ₂ , TiO ₂ , and MgO. In order to improve the sinterability, it is preferable to contain 2% by weight or less. That is, ZrO ₂ , TiO ₂ , Mg
This is because if at least one of O and Al ₂ O ₃ is contained in a total amount of more than 2% by weight, the sinterability tends to deteriorate and the pore size tends to increase.
These oxides are added separately as a sintering aid, and Ca
It may be mixed in raw materials such as O and Fe ₂ O ₃ or by abrasion of balls such as crushing and mixing.

The sliding portion material of the present invention has, for example, a purity of 99.
% Fe ₂ O ₃ (Nb ₂ O ₅ , Ba as impurities
(Including O, SiO ₂ , SrO, etc.) and CaCl ₂ , CaCO _3, Al ₂ O _3, etc. as CaO sources, weighed a predetermined amount of them, and then wet-mixed them with a ball mill or the like. And the raw material after drying is heated at 800 to 1200 ° C. for 2 to 10 in an oxidizing atmosphere (in the air).
The material is calcined for a period of time, and the raw material after calcination is finely pulverized so that the average particle diameter becomes a predetermined value or less. Then, it is obtained by adding a binder to this, granulating, press-molding at a predetermined pressure and firing. As a firing method, firing is performed at a normal pressure of 1100 to 1350 ° C. in an oxidizing atmosphere (in the air).
In order to reduce the pore diameter of this sintered body, the sintered body was further heated to 1000 to 13 in an Ar atmosphere or an N ₂ atmosphere.
You may perform HIP processing at 00 degreeC.

[0012]

With the sliding material of the present invention, the pore size is small, the surface is smooth, and the sliding characteristics can be improved without damaging the sliding material such as scratches and abrasion. Become.

[0013]

【Example】

(Example 1) Commercially available Fe ₂ O having a purity of 99% or more
₃ (Nb ₂ O ₅ , BaO, SiO ₂ , Sr as impurities
(Including O and the like in an amount of 1% by weight or less) as a CaO source
Cl ₂ , CaCO _3, etc. were used, weighed so as to have the composition ratio shown in Table 1, and wet-mixed using a ball mill. This was dried, and the raw material after drying was calcined at 1000 ° C. for 6 hours in an oxidizing atmosphere (in the air).

Alumina balls, zirconia balls, meno balls, etc. are used as the raw material after calcination and the average particle size is 2 μm.
Finely pulverized to the following. Incidentally, zirconia, alumina, silica or the like may be mixed in an amount of 1% by weight or less by this pulverization. After adding a binder to this and granulating, it was press-molded at a pressure of 0.8 to 2.0 ton / cm ² .
Then, it is fired at a temperature shown in Table 1 in an oxidizing atmosphere (in the air), and 2000 at a temperature of 1100 ° C. by a gas species Ar.
Each sample was obtained by performing hot isostatic treatment at atmospheric pressure.

The thermal expansion coefficient, the porosity, and the sinterability of the obtained sample were investigated, and the results are shown in Table 1.

[0016]

[Table 1]

Here, the thermal expansion coefficient was determined by a thermal expansion coefficient measuring device, and the pore ratio was evaluated by measuring the pore diameter generated on the final lap surface by the diamond abrasive grains of 1 μm. Pore ratio is x when the average pore diameter is 5 μm or more, 2 to 5 μm
m is represented by Δ, 1 to 2 μm is represented by ◯, and 1 μm or less is represented by □. Sinterability is x for water absorption of 2% or more, △ for 1-2%, 0.5-1
% Is indicated by ◯, and 0.5% or less is indicated by □.

For samples Nos. 1 to 13 in Table 1,
Using a diamond abrasive grain with an abrasive grain size of 0.25 μm, it is processed into a slider shape of a magnetic head having two rails.
It was set on the disc through the mounting bracket. Then, the maximum rotation number of the disk was set to 3600 rpm, and rotation and stop (CSS) were repeated. That is, the time required to reach the maximum rotation speed was 5 seconds and the maximum rotation speed was held for 5 seconds. Further, the time from the maximum rotation speed to the stop was 4 seconds, the stop time was 5 seconds, and the 19-second cycle from the stopped state to the rotation and stop was set to one CSS number. 5000 times of CSS
The presence or absence of scratches on the disk and the sample, the maximum friction coefficient at the start of rotation, and the surface roughness Ra were examined every time, and the results are shown in Table 2.

[0019]

[Table 2]

In the results of Tables 1 and 2, sample No. 2 to
No. 6 was a sliding part material within the range of the present invention, and the porosity and sinterability were good. On the other hand, the sample No. 1 is C
Since the amount of aO is slightly large, the sinterability is poor. In addition, the sample No. 7 and No. No. 8 had a large amount of iron oxide and was inferior in sinterability. On the other hand, sample No. As for 2 to 6, it is understood from the results in Table 2 that the sliding characteristics are superior.

Sample No. 9 to 11 have a purity of 99.9.
% Fe ₂ O ₃ was used, and sample No. 9,
No. 10 is a sliding part material within the scope of the present invention, and has a good porosity and sinterability. On the other hand, the sample No. 1
No. 1 has a large amount of Fe ₂ O ₃ and is inferior in porosity and sinterability.

Further, the samples No. 2, 3, and 3 in Table 1
For compositions of 9 and 10, ZrO ₂ , TiO ₂ , Mg
O, Al ₂ O ₃ were weighed and mixed so as to have the composition shown in Table 3, molded, and then fired at the temperature shown in Table 3, and hot static at 2000 atm at a temperature of 1100 ° C. with a gas species Ar. Hydrothermal treatment was carried out, and the porcelain was examined for thermal expansion coefficient, porosity and sinterability by the same method as described above, and the results are shown in Table 3.

[0023]

[Table 3]

According to Table 3, ZrO ₂ , MgO, Ti
By adding 2% by weight or less of O ₂ and Al ₂ O ₃ ,
It can be seen that the sinterability is improved as compared with No. 2, 3, 9, and 10 without addition.

Example 2 Commercially available Fe ₂ O ₃ having a purity of 99% or more (Nb ₂ O ₅ , BaO, S as impurities)
(including 1% by weight or less of iO ₂ , SrO, etc.)
CaCl ₂ , CaCO ₃ , and Al ₂ O ₃ were used as sources, and wet mixed using a ball mill. This is dried, and the raw material after drying is subjected to 1 in an oxidizing atmosphere (in the air).
Calcination was performed at 000 ° C. for 6 hours.

Alumina balls, zirconia balls, meno balls, etc. are used as the raw material after calcination and the average particle size is 1 μm.
Finely pulverized to the following. Incidentally, zirconia, alumina, silica or the like may be mixed in an amount of 1% by weight or less by this pulverization. After adding a binder to this and granulating, it was press-molded at a pressure of 0.8 to 2.0 ton / cm ² .
Then, it is fired at a temperature shown in Table 4 in an oxidizing atmosphere (in the air), and then at 200 ° C. at 1100 ° C. with a gas species Ar.
Hot isostatic pressure treatment (HIP treatment) was performed at 0 atm, and Ca ₂
When expressed by Fe _2−x Al _x O ₅ , a sintered body having a value of X as shown in Table 4 was obtained. The obtained sample was examined for the coefficient of thermal expansion, the porosity, and the sinterability in the same manner as in Example 1,
The results are shown in Table 4. As a result of examining the crystals of the obtained sample with an X-ray diffractometer, it was confirmed that the crystals were mainly orthorhombic.

[0027]

[Table 4]

From Table 4, Sample Nos. 18 to 22 are within the scope of the present invention, and have good porosity and sinterability. On the other hand, Samples Nos. 23 and 24 contained a large amount of aluminum and had a larger pore size than Samples Nos. 18-22.

The present inventor then applied these samples to
A magnetic head having two rails was processed into a slider shape, and the magnetic head was set on a disk through a mounting bracket.
The presence or absence of scratches on the disk and the sample and the surface roughness Ra were examined in the same manner as in, and the results are shown in Table 5.

[0030]

[Table 5]

From Table 5, it can be seen that the material of the present invention hardly scratches the disk and has excellent sliding characteristics.

Example 3 Commercially available iron oxide with a purity of 99% or more (Nb ₂ O ₅ , BaO, SiO as impurities)
₂ , containing 1% by weight or less of SrO, etc., and calcium chloride (CaC) as a source of calcium oxide (CaO).
l ₂ ), calcium carbonate (CaCO ₃ ), and aluminum oxide (Al ₂ O ₃ ) are used, and the content of ZrO ₂ , MgO, and TiO ₂ in the sintered body is adjusted so that the composition ratio shown in Table 6 is obtained. Weighed and wet mixed using a ball mill. Thereafter, molding, firing, and H are performed in the same manner as in Example 2 above.
IP treatment was performed to obtain each sample. The thermal expansion coefficient, the porosity, and the sinterability of the obtained sample were examined in the same manner as in Example 1 and shown in Table 6.

[0033]

[Table 6]

According to Table 6, ZrO ₂ , MgO, TiO ₂
It can be seen that the sinterability is improved by containing 2% by weight or less.

[0035]

As described in detail above, in the sliding part material of the present invention, the pore size is small, the surface is excellent in smoothness, and the sliding member is free from damage such as scratches and abrasion. The characteristics can be greatly improved. As a result, for example, when the sliding portion material of the present invention is applied to a magnetic tape guide, wear of the magnetic powder due to this guide hardly occurs, and problems such as loss of stored contents may occur. Moreover, when the material of the present invention is applied to the fiber yarn path guide, it is possible to reliably prevent generation of white powder, yarn breakage, and the like.

Claims (2)

[Claims] 1. A composition containing CaO and Fe ₂ O ₃ as main components and having a molar ratio of CaO / Fe ₂ O ₃ of 4
5/55 to 67/33 and surface roughness Ra of 300Å
The following is a sliding part material characterized by the following. 2. In the composition formula represented by Ca ₂ Fe _{2 -X} Al _X O ₅ , 0 <X ≦ 1.2 and the surface roughness Ra is 3
Sliding part material characterized by being less than 00Å.