JP5745771B2 - Anisotropic sliding member - Google Patents

Description

The present invention relates to a method for producing an anisotropic sliding material and an anisotropic sliding material, and more specifically, a method for producing an anisotropic sliding material starting from a weak magnetic material that transforms into a magnetic material by reaction, and The present invention relates to an anisotropic sliding material.
Note that weak magnetism is a term for ferromagnetism, which means weak magnetism when the interaction between electron spins responsible for magnetism is weak and there is no spontaneous orientation of spins. Specifically, it refers to paramagnetism or diamagnetism.

  A thin film type magnetic recording medium, which is a typical example of a high recording density magnetic recording medium used in the information industry, is usually formed by laminating a magnetic metal or an alloy thereof on a nonmagnetic substrate by plating, vapor deposition or sputtering. Manufactured. In actual use, the magnetic head and the magnetic recording medium slide in contact with each other at a high speed, which may cause wear damage or deterioration of magnetic characteristics.

  As a means for solving the problem of wear damage and deterioration of magnetic characteristics caused by high-speed contact sliding between the magnetic head and the magnetic recording medium, a magnetic element having a magnetoresistive element and a guard member embedded with the magnetoresistive element is provided. A technique using a head is known. In this case, a smooth sliding surface on which the magnetic tape slides is formed by the surface of the magnetoresistive element and the surface of the guard member. The role of the guard member is to prevent the deterioration of the S / N ratio of the reproduction signal and the recording signal without damaging the magnetic tape.

For this reason, a material having high hardness and wear resistance is used as the guard member. Specifically, for example, alumina / titanium carbide (Al ₂ O ₃ —TiC) which is a composite material is often used. However, since Al ₂ O ₃ —TiC wears more alumina part than titanium carbide part, a step is generated between Al ₂ O ₃ / TiC and unevenness occurs on the sliding surface. For this reason, the magnetic tape may be damaged, the recording signal may be lost, or the S / N ratio may be deteriorated, and proposals have been made to make the wear resistance of the guard member uniform.

For example, Patent Document 1 describes a magnetic head using Ni—Zn ferrite or α-hematite (α-Fe ₂ O ₃ ) as a guard member. And although it describes that this Ni-Zn ferrite or alpha hematite is a single crystal material or a polycrystalline material, it is not described about the anisotropic material.
On the other hand, as an anisotropic material, Patent Document 2 describes an anisotropic magnetic material obtained by a reaction process in which a weak magnetic material is used as a starting material, an external field is applied and oriented, and transformed into a magnetic material. And although α-Fe ₂ O ₃ is described as this magnetic material, the wear resistance of this anisotropic magnetic material is not described.

JP 2003-59009 A JP 2009-188044 A

However, generally, Ni—Zn ferrite and hematite, which are iron oxide-based materials, have lower wear resistance than Al ₂ O ₃ —TiC, which is a high-hardness ceramic material, and need to be improved. On the other hand, in the industry, it is required to provide a material that uses an element with a high level of extractability on the earth (an element with a large number of Clarkes) as a metal or at least reduces the amount of a metal element with a small number of Clarkes. It has been.
Therefore, the object of the present invention is to use an element having a high level of extractability on the earth as a metal (an element having a large number of Clarkes) or at least reducing the amount of a metal element having a small number of Clarkes so that the material itself is wear resistant. It is an object to provide a method for manufacturing a sliding material that can improve wear resistance by a specific treatment even if the material is considered to have low properties.
In addition, another object of the present invention is to use an element having a high level of extractability on the earth (an element having a large number of Clarkes) as a metal, or at least reducing the amount of a metal element having a small number of Clarkes, thereby making the material itself Is to provide a sliding material that can be improved in wear resistance by a specific treatment even if the material is considered to have low wear resistance.

The present invention comprises a step of preparing a slurry containing α-FeOOH rod-like particles as a weak magnetic material that transforms into a magnetic material by reaction as a starting material, and applying an external magnetic field to the material and solidifying and molding the constituent material. The obtained orientation includes a step of obtaining an oriented molded body and a reaction step of firing a material in the orientation state to produce a metal oxide to obtain an anisotropic sliding member that is an orientation control structure. From the wear scar cross-sectional area after the wear test in three directions of the sample cut into a cube in the control structure, the formula: S2 / S1 [S1 = shows the minimum wear scar cross-sectional area on the Side surface (ab surface) of the measurement sample wear sectional area in the direction S1 of the surface, the side surface wear degree of anisotropy determined from the wear cross-sectional area] in terms of maximum wear scar direction S2 showing the cross-sectional area at (ab plane) of S2 = sample 1 4 Ru der above, obtained by the production method of the anisotropic sliding member, the Side surfaces have a high hardness and Young's modulus than the unoriented structure having the same composition in (ab plane), in the direction S1 The present invention relates to an anisotropic sliding member for wear-resistant mechanical parts having wear resistance at least 87 times that of non-oriented hematite which is a sliding member.

The anisotropy in the anisotropic sliding member in the present invention means the wear scar cross-sectional area after the frictional wear test indicating the wear resistance of the molded article measured by the method described in detail in the column of the examples below. It means that the degree of anisotropy obtained from the trace is 10 or more.
Further, in the present invention, the topotactic (transformation) reaction is a reaction for changing to a product (substance to be obtained) while maintaining the properties of the starting material (for example, particle orientation). This topotactic (transformation) reaction itself is a well-known reaction, and examples of use for imparting orientation of ceramics and the like are known.

According to the present invention, the material itself has wear resistance by using an element having a high level of extractability on the earth (an element having a large number of Clarkes) as a metal or reducing the amount of a metal element having a small number of Clarkes at least. Even if the material is considered to be low, a sliding member having improved wear resistance can be easily obtained.
Moreover, according to this invention, the sliding material which improved wear resistance can be obtained using a metal with a large Clark number as a metal component.

FIG. 1 is a graph comparing the wear resistance of hematite. FIG. 2 is a schematic diagram showing the surface direction of oriented hematite. FIG. 3 is a model diagram of orientation-controlled bulking of a material. FIG. 4 is a model diagram showing transformation from a goethite oriented body to a hematite oriented body in one embodiment of the reaction step of transforming the material into a magnetic body. FIG. 5 is a schematic diagram showing a sampling profile measurement location of a sample. FIG. 6 is a graph comparing the friction coefficient average values of the samples. FIG. 7 is a graph comparing changes over time in the coefficient of friction of the samples. FIG. 8 is a copy of a wear mark photograph of the mating ball material when measuring the wear resistance in the S2 direction on the Side surface of the oriented sample. FIG. 9 is a graph showing a copy of a disc material wear scar analysis photograph and a wear scar cross-sectional area measurement result when measuring the wear resistance in the S2 direction at a position of +0.25 mm from the center of the Side surface of the oriented sample. FIG. 10 is a graph showing a copy of a disc material wear scar analysis photograph and a wear scar cross-sectional area measurement result when measuring the wear resistance in the S2 direction at the center position of the Side surface of the oriented sample.

FIG. 11 is a graph showing a copy of a disc material wear scar analysis photograph and a wear scar cross-sectional area measurement result when measuring the wear resistance in the S2 direction at a position of −0.25 mm from the center of the Side surface of the oriented sample. FIG. 12 is a copy of a wear mark photograph of the mating ball material at the time of measuring the wear resistance in the S1 direction on the Side surface of the oriented sample. FIG. 13 is a graph showing a copy of a disc material wear scar analysis photograph and a wear scar cross-sectional area measurement result at the time of measuring the wear resistance in the S1 direction at a position of +0.25 mm from the center of the Side surface of the oriented sample. FIG. 14 is a graph showing a copy of a disk material wear scar analysis photograph and a wear scar cross-sectional area measurement result when measuring the wear resistance in the S1 direction at the center position of the Side surface of the oriented sample. FIG. 15 is a graph showing a copy of a disk material wear scar analysis photograph and a wear scar cross-sectional area measurement result when measuring the wear resistance in the S1 direction at a position of −0.25 mm from the center of the Side surface of the oriented sample. FIG. 16 is a copy of a wear mark photograph of the mating ball material at the time of measuring the wear resistance on the top surface of the oriented sample. FIG. 17 is a graph showing a copy of a disk material wear scar analysis photograph and a wear scar cross-sectional area measurement result at the time of wear resistance measurement at a position of +0.25 mm from the center of the top surface of the oriented sample. FIG. 18 is a graph showing a copy of a disc material wear scar analysis photograph and a wear scar cross-sectional area measurement result at the time of wear resistance measurement at the center position of the top surface of the oriented sample. FIG. 19 is a graph showing a copy of a disk material wear scar analysis photograph and a wear scar cross-sectional area measurement result at the time of wear resistance measurement at a position of −0.25 mm from the center of the top surface of the oriented sample. FIG. 20 is a copy of a wear mark photograph of the mating ball material when measuring the wear resistance of the non-oriented sample.

FIG. 21 is a graph showing a copy of a disc material wear scar analysis photograph and a wear scar cross-sectional area measurement result when measuring the wear resistance at a position of +0.25 mm from the center of the surface of the non-oriented sample. FIG. 22 is a graph showing a copy of a disc material wear scar analysis photograph and a wear scar cross-sectional area measurement result at the time of wear resistance measurement at the center position of the surface of the non-oriented sample. FIG. 23 is a graph showing a copy of a disc material wear scar analysis photograph and a wear scar cross-sectional area measurement result at the time of wear resistance measurement at a position of −0.25 mm from the center of the surface of the non-oriented sample. FIG. 24 is a graph showing the result of measuring the friction coefficient in the S2 direction of the Side surface of the oriented sample. FIG. 25 is a graph showing the measurement results of the friction coefficient in the S1 direction of the Side surface of the oriented sample. FIG. 26 is a graph showing the measurement results of the friction coefficient of the top surface of the oriented sample. FIG. 27 is a graph showing the measurement results of the friction coefficient of the surface of the non-oriented sample. FIG. 28 is a graph showing a comparison of nanoindentation hardness measurement results of samples. FIG. 29 is a graph showing a comparison of Vickers hardness measurement results of samples. FIG. 30 is a graph showing a comparison of Young's modulus measurement results of samples.

In an embodiment of the present invention, a weak magnetic material that transforms into a magnetic material by reaction, for example, a step of preparing α-FeOOH as a starting material, and applying an external field to the material and solidifying and molding the orientation of the constituent materials And a topotactic (transformation) reaction step in which the material in the oriented state is transformed into a magnetic material, for example, α-Fe ₂ O ₃ by the above reaction. An anisotropic sliding member that can be used in a sliding direction according to the anisotropy of dynamic characteristics can be obtained.

Hereinafter, the present invention will be described with reference to FIGS.
Referring to FIG. 1, oriented hematite, which is an anisotropic sliding member according to an embodiment of the present invention, includes S1 out of the S1 direction surface, S2 direction surface, and T direction surface (Top surface) shown in FIG. Wear cross-sectional area on the surface in the direction (eg 9 μm ² ) is compared with wear cross-sectional area on the surface in the S2 direction (eg 1565 μm ² ) and wear cross-sectional area on the surface in the T direction (eg 762 μm ² ) It is small and is 1/174 or less and 1/85 or less, respectively, and has specific anisotropy with respect to wear resistance on the surface in the S1 direction. The wear cross-sectional area (for example, 9 μm ² ) on the surface in the S1 direction is smaller than that of the non-oriented product (for example, 786 μm ² ), and is 1/87 or less.

  According to the embodiment of the present invention, even a material that is considered to have low wear resistance using α-FeOOH as a starting material has a particularly good wear resistance on the surface in the S1 direction shown in FIG. By using as a sliding member by paying attention to the above, it is possible to provide a sliding member that can easily improve the wear resistance.

Hereinafter, each step of the present invention will be described with reference to FIG. 3 which is a model diagram of bulking by orientation / arrangement control of the nanomaterial of one embodiment of the present invention.
As shown in FIG. 3, the process A is a process of preparing a weak magnetic material that transforms into a magnetic body by a reaction as a starting material, and the orientation process of aligning the constituent materials of the material by applying an external field to the material. According to a certain step B, a bulk body of weakly magnetic material whose sequence is controlled is obtained.

The sliding member may include a single metal or may include two or more kinds of metals, but as a substance in the case of including a single metal, Fe ₂ O ₃ , For example, Fe ₂ O ₃ may contain MnO, ZnO, NiO, MgO, CuO, Li ₂ O as a material in the case of containing two or more types of metals, such as Fe ₃ O ₄ , iron oxide such as Fe ₃ O ₄ , cobalt oxide such as CoO and CoO _2. Etc., for example, spinel ferrite such as NiO—MnO—ZnO—Fe ₂ O ₃ , MnO—ZnO—Fe ₂ O ₃ , NiO—ZnO—Fe ₂ O ₃ , garnet type ferrite, spinel type (cubic crystal) ) of _γ-Fe 2 _{O 3,} it may be mentioned _γ-Fe 3 _{O 4} or the like. Among these, α-Fe ₂ O ₃ , Fe ₃ O ₄ , γ-Fe ₂ O _{3 and the} like, particularly α-Fe ₂ O ₃ are preferable. Further, the sliding member may have a single shape, but may have two or more shapes.

Examples of the starting material include FeOOH, Fe (OH) ₃ , and Co (OH) ₂ when the sliding member is iron oxide or cobalt oxide, and preferably FeOOH. When the sliding member is ferrite, examples of starting materials that give metal oxides other than the iron component include metal hydroxides and hydroxy carbonates. Since the material can be oriented by an external magnetic field, it needs to have magnetocrystalline anisotropy. The shape may be any shape.

When the starting material is an iron-based compound, hematite: α-Fe ₂ O ₃ can be obtained by a dehydration step using the weak magnetic material goethite: α-FeOOH as a starting material.
As an example of the transformation from the material to the magnetic material, a transformation from goethite: α-FeOOH as a material to hematite: α-Fe ₂ O ₃ which is a weak ferromagnetic material can be preferably exemplified.

In the above step, it is necessary to combine the alignment step of aligning the constituent materials of the material by applying an external field to the material and the reaction step of transforming the material in the alignment state into a magnetic material by the reaction. It is necessary to select conditions that allow the material to be easily rotated and oriented by an external magnetic field.
In order to satisfy the above conditions, an alignment control step in the liquid phase can be prepared by a slurry which is a solvent mixture in which nanoparticles as a material are dispersed.

The solvent of the solvent mixture is not particularly limited as long as it is a solvent that does not react with particles, and is usually water or a non-aqueous solvent. Usually, water, methanol, ethanol, and a water / methanol mixed solution are used because of the ease of preparing a stable slurry. A water / ethanol mixture, preferably water.
The solvent mixture slurry in which the above materials are dispersed preferably contains a surfactant in order to prevent aggregation between particles.
As the surfactant, various types of nonionic surfactants, cationic surfactants and anionic surfactants can be applied.
It is preferable to form a uniform slurry by the solvent mixture containing the above-mentioned material, solvent and surfactant.

In the above method, the constituent material of the material is oriented by applying an external magnetic field to the material, preferably the material in the slurry, as shown in Step B of FIG.
In this orientation step, for example, a goethite molded body can be formed by slip casting in a magnetic field in which the application direction of the external magnetic field is the gravitational direction (direction parallel to gravity).
Said material is provided in a container. The container is not particularly limited as long as it is formed from a substance that is not affected by an external magnetic field, and examples thereof include a resin container, a ceramic container, and a glass container.

In the above-mentioned method, it is necessary to orient the constituent materials of the material by applying an external magnetic field to the material.For this reason, for example, a material obtained by applying an external magnetic field to the solvent mixture containing the material in the container is oriented. It is necessary to obtain an oriented molded body by depositing and bulking.
As a method for obtaining an oriented molded body in which the constituent materials of the material are oriented, a method in which orientation, deposition, and bulking of the material are simultaneously performed while applying an external field is preferable. For example, a method of depositing and bulking by slip casting or electrophoresis while applying an external magnetic field can be mentioned.

In the above method, when the orientation, deposition, and bulking of the material are performed simultaneously while applying an external magnetic field, a combination of the magnetic field, deposition, and slip casting as the bulking means is simple and preferable.
For this reason, for example, it is preferable to obtain an oriented molded body of a material by using a container capable of separating a solvent and achieving deposition and bulking of the material from a solvent mixture containing the material oriented by a magnetic field.
The oriented molded body of the above material is a bulky body that is shapeless and retains shape unless an external force is applied, and can be easily cut into a bulk molded body of a desired shape by cutting with a knife or a cutter. can do.

  In a preferred embodiment of the above method, the solvent in the slurry, which is a solvent mixture containing the material, is absorbed by a container capable of separating the solvent in which the slurry is installed. If the absorption rate at this time is too high, the degree of orientation of the non-magnetic material particles is reduced, and if the absorption rate is too low, it takes too much time for solidification molding. It is preferable to adjust the density. For this reason, it is preferable to use a porous container, for example, a container such as gypsum or alumina porous body, as the container. It is preferable to use a porous container and appropriately select and use a filter having a determined pore size. Moreover, it can also be set as the form which puts a filter on a porous substrate and installs a glass or resin cylindrical container on it.

  In addition, if the magnetic field strength of the magnetic field is too strong, the magnetic interaction between the material particles or the particles and the magnet that gives the magnetic field becomes large, making it difficult to obtain a uniform molded body, and therefore, it is difficult to form a bulk molded body. become. If the magnetic field strength is too weak, the material particles cannot be oriented. The magnetic field strength may be constant while the magnetic field is applied, or may be gradually increased. As a preferable magnetic field condition, a uniform molded body can be obtained, and therefore, a bulk molded body can be molded. The standard of the magnetic field strength is preferably 1T or more and less than 10T, particularly preferably 1.5T or more and 8T or less. In addition, when a magnetic field is applied, the direction of the magnetic field is not particularly limited and may be any direction. For example, the direction may be opposite to the direction of gravity (perpendicular to the ground) or the direction of gravity. It may be perpendicular to the direction (parallel to the ground).

A driving force (magnetization energy) for rotating and orienting the material particles using a magnetic field as an external field is expressed by the following equation.
ΔE = ΔχVB ² / 2μ ₀
However, Δχ: Anisotropy of magnetic susceptibility V: Volume B: Magnetic field strength μ ₀ : Vacuum permeability The orientation conditions for orienting the particles are as follows.
ΔE> kT
kT: Thermal vibration energy

  It is preferable to use a magnetic field as the external field in combination with slip casting as a method of deposition and bulking, and further to use FeOOH particles as the material, and the strength of the magnetic field is 1T (Tesla) or more and 7T. It is preferable that it is less than 1.5, especially 6.5-6.5T or less.

Next, the material of the oriented molded body in the oriented state is transformed into a magnetic body by reaction.
The reaction step for transforming to a magnetic body will be described with reference to FIG. 4 which is a model diagram showing the transformation from a goethite oriented body to a hematite oriented body in one embodiment of the reaction process for transforming from a material to a magnetic body.
In the left figure of FIG. 4, the acicular goethite particles are in a lying state. On the other hand, in the right diagram of FIG. 4, the fired hematite has a plate shape.
Due to the transformation from the goethite oriented body to the hematite oriented body after firing, the shape of the particles is lost as shown in FIG. 4, but the anisotropy indicated by the orientation of the particles is obtained.

An example of the reaction that transforms the material in this orientation state into a magnetic material is a dehydration reaction by heating.
As described above, this topotactic (transformation) reaction itself is a known reaction, but is different from the conventionally known technique in that it is applied to a pre-oriented material and the applied material is a magnetic substance after transformation. By doing so, a member having anisotropy in sliding characteristics is obtained.

A reaction for transforming the material into a magnetic material, for example, a dehydration reaction by heating, can be appropriately selected depending on the weak magnetic material used. For example, when the material is diamagnetic α-FeOOH as a starting material, 250 to It is preferable to heat at a temperature of 300 ° C. or higher, preferably 900 to 1500 ° C. at which a sintered body is obtained, particularly 1100 to 1200 ° C. in which the degree of orientation is improved by grain growth.
In the dehydration reaction, an oriented molded body made of a weak magnetic material in an oriented state is directly or after being formed into an arbitrary shape such as a plate material or a cube by an arbitrary processing method such as cutting or laminating, and then a heat resistant container such as alumina. It is possible to obtain an anisotropic sliding member that is an orientation-controlled bulk molded body by performing a reaction in a container made of an arbitrary heat-resistant material at a temperature and time at which dehydration is completed in the presence of air and transforming it into a magnetic body. it can. Alternatively, after the reaction, it is also possible to form an anisotropic sliding member as an orientation controlled bulk molded body by further molding the magnetic body into an arbitrary shape by an arbitrary processing method.

The anisotropic sliding member obtained by the present invention is a novel material, and a bulk structure with high mechanical strength and controlled orientation can be obtained.
According to the present invention, it is possible to obtain an orientation control structure composed of a sliding member exhibiting anisotropy in two directions of the Side surface shown in FIG.

The anisotropic sliding member according to the present invention is anisotropically determined by the following of the wear scar cross-sectional area according to the wear resistance test showing the wear resistance of the molded body, as will be described in detail in the section of the examples below. The case where the nature is 10 or more, particularly 50 or more.
Anisotropy = Wear mark cross-sectional area ( S2 ) / Wear mark cross-sectional area ( S1 )
Wear scar cross-sectional area ( S2 ): the largest wear scar cross-sectional area in the wear resistance test for the oriented sample Wear scar cross-sectional area ( S1 ): the smallest wear scar cross-sectional area in the wear resistance test for the oriented sample

  Since the orientation member obtained by the present invention is oriented, the tribological characteristics differ depending on the direction. For this reason, for example, it is preferable to apply to the field where the guide member of the magnetic head slides in a certain direction.

Examples of the present invention will be described below.
In each of the following examples, the physical properties of the materials were evaluated by the following measurement methods. In addition, the method shown below is an illustration and it cannot be overemphasized that other equivalent measuring methods can be employ | adopted.
1. Tribological characteristics evaluation method a. Abrasion resistance 1) Test method A friction and abrasion test was conducted using a tribometer (product number S / N: 12-170) manufactured by CSM Instruments. The measuring method is as follows. FIG. 5 shows the profile measurement points of the sample.
Start ⇒ Slide for a certain distance with a tribometer ⇒ Measure the wear scar profile of the sample at three locations ⇒ Measure the length of the ball wear scar ⇒ End 2) Test conditions Measurement conditions Round trip distance: 2.0 mm, speed: 5 .0cm / sec, load: 5.0N
Number of reciprocations: 4000 cycles Mating material: Al ₂ O ₃ , Shape: Ball, Diameter: 6.35 mm, Supplier: Nanotech Corporation 3) Test environment Temperature: 22-24 ° C., Humidity: 40-50%
4) Measurement content
i. Optical micrograph of the ball wear scar
ii. Optical micrograph and cross-sectional analysis of sample wear trace The sample wear trace shows the measurement results in three lines at the center and at a position of ± 0.25 mm from the center.

B. Hardness and Young's modulus Hardness (indentation hardness, Vickers hardness) and Young's modulus were evaluated by the nanoindentation method.
1) Test method A hardness test was performed using Nano Indentation Testers (product number S / N: 02-02877) manufactured by CSM Instruments. As the indenter, a Belkovic indenter (B-J81) was used. The measurement conditions are shown below.
Approach speed: 1000nm / min
Delta slope contact: 50%
Maximum load: 50mN
Loading speed: 100 mN / min
Unloading speed: 100 mN / min
Pause: 20 sec
Indentation hardness (Oliver & Pharr calculation method) of ISO14577 standard was used for calculation of hardness. The Vickers hardness is a value converted from indentation hardness.
2) Test conditions Temperature: 22-24 ° C, Humidity: 40-50%

C. Regarding the structure of the magnetic goethite molded body and the hematite fired body, TOP is a surface perpendicular to gravity, and thus parallel to the ground, and the SIDE surface is a surface parallel to gravity.
About hematite fired body, confirmation of VSM measurement (vibrating sample magnetometer system) on TOP surface and SIDE surface of molded body using VSM measuring device manufactured by Lake Shorc as a magnetic body Went.

Example 1
1. Step of preparing a weak magnetic material as a starting material 16 g, Toagogi manufactured by Titanium Industry Co., Ltd. (trade name: LEMON, shape: rod, average length 800 nm, aspect ratio within a range of 1: 5 to 1:10) A surfactant (trade name: Aron A6114) 0.2 g and ion-exchanged water 36 g manufactured by Synthetic Co., Ltd. were weighed, mixed and dispersed by an ultrasonic homogenizer to prepare a stable slurry.

2. Orientation process for orienting the constituent material of the weak magnetic material A filter (membrane sheet) is laid on the alumina porous body, a glass cylinder is placed on this, and the slurry in which the goethite particles are dispersed is poured into the cylinder. It is. This is installed in a superconducting magnet and left standing overnight at room temperature (20-25 ° C) and solidified while applying a magnetic field with a magnetic field strength of 6T in the magnetic field (B) direction from the bottom to the top of the cylinder. Thus, a gate-site oriented molded body was obtained.
The molded body itself can be cut and processed into an arbitrary shape. When a strong force is applied, the molded body collapses.

3. Reaction Step for Transformation to Magnetic Material The solidified oriented molded body obtained in the previous step was fired in air. The firing temperature was 1200 ° C. and the firing time was 2 hours. This heat treatment caused a structural change from goethite to hematite. The resulting hematite was silver.

4). Evaluation of Oriented Structure From this hematite oriented fired body, a sample for measuring physical properties, for example, a cube having a final shape of 2 mm × 2 mm × 2 mm was cut out for VSM measurement. The magnetic properties of the obtained hematite alignment fired body (alignment structure) were evaluated by VSM and confirmed to be a magnetic body.
Moreover, the abrasion resistance test was done about the molded object by the above-mentioned measuring method. The results are shown in FIGS. The results of Comparative Example 1 are shown together in FIG.
Further, the obtained molded product was measured for a friction coefficient, nanoindentation hardness, Vickers hardness and Young's modulus. The results are collectively shown in FIGS. 24 to 26 and FIGS. 28 to 30.

From FIG. 1, the anisotropy of the aforementioned sliding member is 174 when calculated from the following equation.
Anisotropy = Wear mark cross-sectional area ( S2 ) / Wear mark cross-sectional area ( S1 ) = 174
Wear scar cross-sectional area ( S2 ): The largest wear scar cross-sectional area in the wear resistance test for the oriented sample Wear scar cross-sectional area ( S1 ): The smallest wear scar cross-sectional area in the wear resistance test for the oriented sample The amount of wear in the S1 direction is 1/174 of the amount of wear in the S2 direction.

Comparative Example 1
A goethite molded body was obtained in the same manner as in Example 1 except that no magnetic field was applied (indicated by 0T in the figure).
A hematite fired body was obtained by firing at 1200 ° C. for 2 hours in the same manner as in Example 1 except that this goethite shaped body was used.
Since the obtained hematite fired body is molded without a magnetic field, no orientation is observed in the fired body.
Moreover, the abrasion resistance test was done about the molded object by the above-mentioned measuring method. The results are shown in FIGS. The results of Example 1 are shown together in FIG.
Further, the obtained molded product was measured for a friction coefficient, nanoindentation hardness, Vickers hardness and Young's modulus. The results are collectively shown in FIG. 27 and FIGS.

  From the above results, the member obtained in Example 1 is oriented hematite having anisotropic tribological characteristics, and a large anisotropy is observed in the friction and wear characteristics on the Side surface (ab surface). The wear resistance is 174 times the wear resistance in the S2 direction, and the wear resistance reaches 87 times that of the non-oriented hematite which is a conventionally known sliding member, and the friction coefficient is also the friction in the S1 direction. The coefficient (0.477) is 20% lower than the friction coefficient (0.598) in the S2 direction and 34% lower than the friction coefficient (0.718) of the non-oriented product that is a conventional sliding member. . Further, oriented hematite also has a hardness and Young's modulus, the S-plane (ab-plane) of oriented hematite is about 5% higher than the T-plane (c-plane) and about 10% higher than the non-oriented product. As described above, oriented hematite (especially S-plane, particularly S1 direction) is extremely superior tribological characteristics compared to conventional materials, that is, as an oriented anisotropic sliding member that is hard, low friction, and difficult to wear. It has characteristics.

  According to the present invention, it has tribological characteristics that greatly surpass a conventionally known magnetic head by using a large amount of metal material, and can be applied to a guard member of a magnetic head. It can be applied to mechanical parts such as CVT materials (pulleys / belts) that require anisotropic tribological characteristics in the vertical direction thereof, and all tribological materials such as MES.

Claims (1)

A step of preparing a slurry containing α-FeOOH rod-like particles as a weak magnetic material that transforms into a magnetic body by reaction as a starting material, and a molded body in which constituent materials are oriented by applying an external magnetic field to the material and solidifying and molding And a reaction step of obtaining an anisotropic sliding member that is an orientation control structure by firing a material in the orientation state to produce a metal oxide, and in the obtained orientation control structure From the wear scar cross-sectional area after the wear test in the three directions of the sample cut into a cube, the formula: S2 / S1 [S1 = surface in the S1 direction indicating the minimum wear scar cross-sectional area on the Side surface (ab surface) for the sample to be measured wear cross-sectional area of, in S2 = side surface wear degree of anisotropy determined from the wear cross-sectional area] at maximum wear scar direction S2 of the surface showing the cross-sectional area at (ab surface) of the measurement sample 174 or more That is obtained by the production method of the anisotropic sliding member, the Side surfaces have a high hardness and Young's modulus than the unoriented structure having the same composition in (ab plane), the wear resistance of at S1 direction An anisotropic sliding member for wear-resistant mechanical parts that is at least 87 times the non-oriented hematite that is a sliding member.