JP2010126416A - Sintered compact and producing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sintered compact where high polishing workability is gained and the occurrence of voids on a working surface is suppressed at a polishing work in the production of a magnetic head slider. <P>SOLUTION: The sintered compact includes a composite oxide containing Al<SB>2</SB>O<SB>3</SB>, TiCO, Al and Ti and at least a crystal phase of C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sintered body, and more particularly to a sintered body suitable for a magnetic head slider and a method for manufacturing the same.

A hard disk drive (HDD) is equipped with a magnetic head slider for writing and reading information to and from the hard disk. The magnetic head slider has a configuration in which a magnetic head is mounted on a substrate. This substrate is generally made of a ceramic sintered body. In recent years, as a ceramic sintered body for a substrate, a high-strength sintered body mainly composed of alumina and titanium carbide, a so-called Altic sintered body is widely known (for example, see Patent Document 1).
JP-A-8-34662

  When manufacturing a magnetic head slider using an AlTiC sintered body, in general, a laminated body including a magnetic head is laminated on a substrate made of an AlTiC sintered body, and then this is cut in parallel with the laminating direction to magnetically. A method of forming an air bearing surface by forming an exposed surface of the head and polishing (lapping) the exposed surface is performed. Conventionally, in this polishing, the AlTiC sintered body has a lower polishing rate than the portion of the laminated body including the magnetic head, so that there are not a few steps in these portions caused by the polishing. Such a step is not preferable because it makes it difficult to control the height (fly height) of the magnetic head relative to the hard disk.

  Therefore, in the lapping process, the step of the air bearing surface due to the difference in polishing rate between the substrate made of the Altic sintered body and the laminate formed on this substrate is reduced, and the air bearing surface is smoothed. Is required.

  In particular, recently, further miniaturization of HDDs has been rapidly progressing. In such miniaturized HDDs, the fly height of the magnetic head tends to be further reduced, so that the air described above is used. Further smoothing of the bearing surface is desired. In order to smooth the air bearing surface, it is conceivable to reduce minute voids that are easily formed by polishing when forming the air bearing surface, in addition to reducing the level difference as described above. However, according to the study by the present inventors, voids tend to be formed more easily as higher polishing processability is obtained in order to eliminate the above-described step difference. It tends to be difficult to achieve both reduction of voids and voids.

  Therefore, the present invention has been made in view of such circumstances, and in polishing processing in manufacturing a magnetic head slider, high polishing workability can be obtained and generation of voids on the processing surface can be suppressed. An object of the present invention is to provide a sintered body.

In order to achieve the above object, the sintered body of the present invention is characterized in that it contains at least Al ₂ O ₃ , TiCO, a composite oxide containing Al and Ti, and a C crystal phase.

Such a sintered body of the present invention first contains a composite oxide containing Al ₂ O ₃ , TiCO, Al and Ti, and further contains a crystalline phase of carbon in the structure of the sintered body. Therefore, in spite of having a composition of a so-called Altic sintered body, the polishing rate is high, and in the polishing process, there is a step between the sintered body and other parts (a laminated body including a magnetic head). Can be small.

  Here, according to the study by the present inventors, when high polishing workability is obtained by a sintered body containing a large amount of carbon, this carbon may be partially agglomerated. It was found that dropping off was one of the causes of voids. On the other hand, according to the sintered body of the present invention, the combination of the four crystal phases as described above allows the carbon to be uniformly dispersed without agglomeration, and also has extremely high abrasiveness. It will be obtained. As a result, it is possible to significantly reduce the generation of voids due to aggregated carbon and the like.

  Therefore, the sintered body for a magnetic head slider of the present invention can not only reduce the level difference between the sintered body and the other parts in the polishing process, but also can greatly reduce the occurrence of voids, so that the processed surface can be reduced. Smoothing can be performed very well. As a result, it is possible to form a magnetic head slider that can sufficiently cope with a fly height that is smaller than the conventional one.

  In the sintered body of the present invention, the lattice constant of TiCO is preferably 432.2 pm or less. By having such a lattice constant, the agglomeration of carbon as described above can be further suppressed and generation of voids can be more effectively reduced.

  In the sintered body for a magnetic head slider of the present invention, the C crystal phase is preferably graphite. The inclusion of C in the form of graphite is advantageous for improving the polishing processability of the sintered body, obtaining a high polishing rate, and reducing the generation of voids.

The present invention also provides a suitable method for producing the sintered body of the present invention. That is, in the method for producing a sintered body of the present invention, Al ₂ O ₃ , TiC and TiO ₂ with respect to 100 parts by mass of Al ₂ O ₃ are 37 to 74 parts by mass of TiC and 13 to 40 of TiO _2. The mixture blended so as to be part by mass is calcined by a hot press method under a pressure condition of 200 kg or more and 500 kg or less. According to such a manufacturing method, it is possible to obtain the sintered body of the present invention that has the above-described configuration, is excellent in polishing workability, and generates less voids.

  According to the present invention, it is possible to provide a sintered body for a magnetic head slider and a method for manufacturing the same, which can obtain high polishing workability and can suppress generation of voids on a processed surface.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[Sintered body]
First, a sintered body according to a preferred embodiment will be described.

The sintered body of the present embodiment is mainly composed of a crystal phase of Al ₂ O ₃ (alumina) and a crystal phase of TiCO, and further includes a crystal phase of a composite oxide containing Al and Ti, and a crystal of carbon (C). It includes a phase and is classified as a so-called artic sintered body. Here, the sintered body is obtained by combining and sintering the raw materials of these components.

The sintered body of the present embodiment preferably contains 20 to 150 parts by mass of TiCO and preferably 0.2 to 9 parts by mass of carbon when Al ₂ O ₃ is 100 parts by mass. If the carbon content is in such a range, particularly excellent polishing processability tends to be obtained, but if it is too small, the polishing processability is lowered, and if it is too much, voids are likely to be generated. .

Specifically, the crystal phase of TiCO has a composition represented by TiC _x O _y (where x + y ≦ 1, x> 0, y> 0), and is a general titanium carbide (TiC ) In which a part of C is replaced by O. The crystal phase of TiCO may be a phase in which C or O is partially lost and vacancies are formed.

Specifically, the sintered body has a configuration including Al ₂ O ₃ crystal grains, TiCO crystal grains, a composite oxide containing Al and Ti dispersed in the vicinity of these grain boundaries, and a crystal phase of C. It is preferable. FIG. 1 is a schematic diagram showing an enlarged cross-sectional configuration of a sintered body according to a preferred embodiment. As shown in FIG. 1, the sintered body 2 is mainly composed of Al ₂ O ₃ crystal grains 110 and TiCO crystal grains 120, and between these crystal grains, a composite oxide containing Al and Ti, A grain boundary 130 in which C is dispersed is formed.

Here, the average diameter of the Al ₂ O ₃ crystal grains 110 is, for example, 0.05 to 0.5 μm, and the average diameter of the TiCO crystal grains 120 is, for example, 0.05 to 0.5 μm. The average diameter of these crystal grains can be determined as follows, for example. First, the sintered body is broken, and the fractured surface is mirror-finished and thermally etched at (sintering temperature−100) ° C. The surface is photographed with a scanning electron microscope at a magnification of 30,000 times, and a radial line is drawn on this photograph. Specifically, for a rectangular photograph of 9 mm in length × 12 mm in width, a straight line of vertical, horizontal, and two diagonal lines is drawn so as to pass through the center (total of straight lines is 51 mm). Then, the intersections at which each straight line crosses the grain boundary is counted, and the average diameter of the Al ₂ O ₃ crystal grains 110 and the TiCO crystal grains 120 is calculated by calculating (total length of straight lines (mm)) / (total number of intersections × photo magnification). Can be requested.

  In the sintered body of the present embodiment, the lattice constant of TiCO is preferably 432.3 pm or less. Here, the lattice constant of TiCO in this specification is, for example, the lattice constant of the portion of the TiCO crystal grain 120 described above, and can be measured as follows. That is, first, X-ray measurement is performed in a range of 2θ = 15 to 90 by mixing a measurement sample obtained by pulverizing a sintered body with Si that is a standard sample (for example, silicon powder for scientific angle standard: RSRP-43275G). I do. For this measurement result, an angle correction of 2θ is performed from the Si diffraction line of the standard sample observed together with the measurement sample. Then, after the angle correction, the lattice constant of the space group Fm3m (TiC crystal structure) is obtained. The calculation of the lattice constant can be performed by a predetermined analysis software. For example, JADEver. 5 can be used. Note that the diffraction lines on the (2, 2, 2) plane of the space group Fm3m near 2θ = 76 ° overlap with the Si diffraction lines. Do not use.

  When the lattice constant of TiCO is within the above range in the sintered body, the carbon contained in the sintered body is relatively uniformly dispersed without agglomeration at the grain boundaries 130 or the like as compared to the case where the lattice constant is outside this range. It tends to be in a state, and this tends to greatly reduce the occurrence of voids due to the agglomerated carbon during polishing of the sintered body 2. In addition, since carbon is uniformly dispersed, the polishing processability of the sintered body 2 is improved over the whole, and for example, there is a tendency that a step between the laminated body including the magnetic head and the like is hardly formed. When the lattice constant of TiCO exceeds 432.3 pm, the amount of C released from the raw material TiC becomes insufficient in the production method described later, and there is a possibility that sufficient work polishing properties may not be obtained.

  The grain boundary 130 contains a composite oxide containing C and Al and Ti as described above, but it is preferable that C in the grain boundary 130 is contained in the state of graphite. C of the grain boundary 130 can be confirmed by, for example, TEM-EDS mapping. When this portion is composed of the space group C6mc by electron beam diffraction, it is confirmed that it is graphite.

Furthermore, the width of the grain boundary 130 (that is, the interval between crystal grains) is preferably 1 to 20 μm, and more preferably 1 to 15 nm. Thereby, particularly good polishing processability can be obtained. In addition to carbon, the grain boundary 130 may contain elements contained in the Al ₂ O ₃ crystal grains 110 and the TiCO crystal grains 120 in a composition and structure different from those of the crystal grains.

Further, the sintered body 2 of the present embodiment, when measured by X-ray diffraction (XRD), the value of TiCO / _Al 2 _{O 3} is the peak area ratio of TiCO for _Al 2 _{O 3} is 1.3 or more 2 It is preferable that it is less than 1. Specifically, when measured by XRD, the (104) plane in the vicinity of 2θ = 35 ° of the space group R3-C of Al ₂ O _{3 and} the vicinity of 2θ = 36 ° of the space group Fm3m of TiCO (111 The value of TiCO / Al ₂ O ₃ can be determined from the peak area ratio of the surface. By satisfying such a condition, compared to a case where such a condition is not satisfied, the carbon is more uniformly dispersed, and the generation of voids tends to be more easily reduced.

In addition, the sintered compact 2 of this embodiment may further contain other components to the extent that it does not affect the characteristics, if necessary, in addition to Al ₂ O ₃ , TiCO, and carbon. Examples of other components include titania (TiO ₂ ). TiO ₂ can, for example, be used as a raw material for a sintered body, as described later, so that carbon can be favorably dispersed in the grain boundaries 130. This TiO ₂ is a sintered body 2 after sintering. It may remain inside. In that case, the content of TiO _2, relative to Al ₂ O 3 100 parts by weight, may be 1 to 8 parts by weight.

Further, the sintered body 2 is not necessarily clearly different composition in _Al 2 _{O 3} crystal grains 110, TiCO grain 120 and grain boundaries 130, for example, carbon is also included in each crystal grain One phase component may be included in the other phase.

[Method for producing sintered body]
Next, a preferred embodiment of the method for manufacturing a sintered body described above will be described.

Al ₂ O ₃ powder and TiC powder are prepared as raw material powders for the sintered body. Further, in the present embodiment, as a material powder, further preparing a TiO ₂ powder. Thereby, in the firing step described later, a reaction between TiC and TiO ₂ can be caused to precipitate carbon (C), and carbon can be well dispersed at the grain boundaries of the sintered body. Carbon materials such as carbon powder and organic substances that generate carbon by firing may be used as the carbon raw material, but in this case, carbon aggregates are likely to be generated in the sintered body, which tends to cause voids. Therefore, in this embodiment, it is preferable to use TiO ₂ without using carbon powder.

Here, the average primary particle diameter of the Al ₂ O ₃ powder is preferably 800 nm or less, more preferably 5 to 800 nm, and even more preferably 100 to 600 nm. Moreover, the average primary particle diameter of the TiC powder is preferably 500 nm or less, more preferably 5 to 500 nm, and further preferably 100 to 400 nm. Furthermore, the average primary particle diameter of the TiO ₂ powder is preferably 200 nm or less.

The suitable blending ratio of these raw material powders is as follows. That is, when the Al ₂ O ₃ powder is 100 parts by mass, the TiC powder is preferably 37 to 74 parts by mass. When the blending amount of the TiC powder is within the above range, Al ₂ O ₃ crystal grains and TiCO crystal grains are formed at a suitable ratio in the sintered body, and excellent strength and electrical or thermal characteristics can be obtained. _It becomes easy to produce reaction with ₂ powder, and carbon comes to be disperse | distributed favorably in a sintered compact. If the amount of TiC added deviates from this range, sufficient polishing processability may not be obtained.

The mixing ratio of the TiO ₂ powder, if it is 13 to 40 parts by weight with respect to _Al 2 _{O 3} powder 100 parts by preferred. By setting the blending ratio of the TiO ₂ powder in such a range, carbon can be favorably dispersed in the grain boundaries of the sintered body, and the preferred value described above for the lattice constant of TiCO in the sintered body It can be. If the amount of TiO ₂ powder is too small, carbon is not sufficiently precipitated in the sintered body and there is a possibility that sufficient polishing processability cannot be obtained. On the other hand, if the amount is too large, carbon may be aggregated and voids may be easily generated.

  Next, the above-mentioned raw material powder is mixed in an organic solvent such as ethanol, IPA, or 95% denatured ethanol to obtain a mixed powder. If water is used as the liquid to be mixed with the raw material powder, water and TiC powder may cause a chemical reaction and the TiC powder may be oxidized. Therefore, it is desirable not to use water.

  Mixing to obtain the mixed powder can be performed using a ball mill or an attritor. The mixing time is preferably about 10 to 100 hours. In addition, as a medium used for mixing with a ball mill or an attritor, for example, an alumina ball having a diameter of about 1 to 20 mm can be used.

  Next, the mixed powder is spray granulated. In the spray granulation, for example, the mixed powder is spray-dried in a warm air made of an inert gas such as nitrogen or argon containing almost no oxygen to obtain a granulated product of the mixed powder. The granulation is preferably performed so that the particle size of the granulated product is about 50 to 200 μm. Moreover, it is preferable that the temperature of the warm air for spray drying is about 60-200 degreeC.

  Then, if necessary, an organic solvent as described above is added to the granulated product to adjust the liquid content of the granulated product, and about 0.1 to 10% by mass of the organic solvent is contained in the granulated product. Make it. In addition, when adjusting the liquid content of the granulated product, it is desirable not to use water as the liquid.

Next, the granulated product is filled into a predetermined mold, and primary molding is performed by, for example, a cold press method to form a molded body having a predetermined shape. The mold is not particularly limited as long as a suitable sintered body shape can be obtained, and examples thereof include a disk-shaped mold having an inner diameter of about 150 mm made of metal or carbon. The unit pressure applied to the granulated product in the cold press may be about 50 to 150 kgf / cm ² (about 5 to 15 MPa).

  Thereafter, a sintered body for a magnetic head slider can be obtained by sintering the molded body thus obtained. The shape of the magnetic head slider material is not particularly limited. For example, if a disk-like substrate or a rectangular substrate having a diameter of 6 inches and a thickness of about 2.5 mm is used, the magnetic head slider is excellent in manufacturing a magnetic head slider described later. Can be applied.

Sintering is performed so that a sintered body having a structure like the above-described sintered body 2 is formed from the raw material powder. In particular, in the sintering, the reaction between TiC used as the raw material and TiO ₂ is performed. It is preferable to make it occur. As a result, carbon derived from this reaction is generated at the grain boundary part of Al ₂ O ₃ crystal grains and TiCO crystal grains formed during sintering. As a result, compared with the case where carbon powder is used as the carbon raw material, carbon is dispersed in a state close to atoms and can be uniformly dispersed without agglomerating at the grain boundary portion to form a thin phase.

  In order to obtain a suitable sintered body, the sintering is preferably performed by a hot press method (hot press firing). That is, it is preferable to fire the compact while compressing it by uniaxial pressing with a pair of opposing punches. In that case, it is preferable to perform sintering while applying a pressure of 200 kg or more and 500 kg or less to the compact. The hot-press method tends to favorably form a TiCO crystal phase in the resulting sintered body. By setting the pressure applied to the molded body within such a range, the reactivity of the molded body is increased and the sinterability can be improved. Therefore, a magnetic head slider material having a sufficient density can be obtained. When this pressure is less than 200 kg, a C phase is hardly formed in the sintered body, and the work polishability tends to be insufficient. In addition, it is not preferable to perform sintering while applying a pressure exceeding 500 kg, because it tends to be extremely difficult in terms of work.

The temperature condition during the sintering is preferably 1450 ° C. or higher and lower than 1750 ° C. By setting the sintering temperature in such a range, a sintered body having a suitable structure tends to be easily obtained. When the sintering temperature is 1650 ° C. or higher, C (graphite) is unlikely to exist in the sintered body, and the work polishability tends to be insufficient. On the other hand, if the sintering temperature is less than 1450 ° C., the sintering becomes insufficient, and there is a possibility that voids are likely to be included in the interior, and there is a possibility that grain dropout occurs during polishing. The sintering temperature may be changed during sintering. The sintering time is preferably about 1 to 3 hours. If the firing temperature or firing time is excessively large, the sintered body becomes two phases of Al ₂ O ₃ —TiC, and the work polishability may be further lowered.

Further, the sintering is preferably performed in a vacuum or in a non-oxidizing atmosphere such as an inert gas atmosphere such as Ar or N ₂ gas. By sintering in a non-oxidizing atmosphere, excessive oxidation, decomposition or volatilization of TiC or the like can be suppressed, and a sintered body having a desired composition can be easily obtained.

[Magnetic head slider]
Next, a magnetic head slider using the above-described sintered body will be described. FIG. 2 is a perspective view showing a magnetic head slider according to a preferred embodiment.

  As shown in FIG. 2, the magnetic head slider 11 of the present embodiment includes a thin film magnetic head 10 and is mounted on, for example, a hard disk device (not shown) including a hard disk. This hard disk device records and reproduces magnetic information by a thin film magnetic head 10 on a recording surface of a hard disk rotating at high speed.

  The magnetic head slider 11 according to the embodiment of the present invention has a substantially rectangular parallelepiped shape. In FIG. 2, the front surface of the magnetic head slider 11 is a recording medium facing surface that is disposed facing the recording surface of the hard disk, and is referred to as an air bearing surface (ABS). Further, an air introduction groove 11a is formed in the air bearing surface S in a direction orthogonal to the track width direction. By forming the air introduction groove 11a on the air bearing surface S, the controllability of fly height (height of the thin film magnetic head 10 with respect to the hard disk) can be improved. In addition, the formation position and shape of the air introduction groove | channel 11a are not limited to what is shown in FIG.

  When the hard disk rotates, the magnetic head slider 11 is floated by the air flow accompanying this rotation, and the air bearing surface S is separated from the recording surface of the hard disk. The air bearing surface S may be coated with DLC (Diamond Like Carbon) or the like.

  The magnetic head slider 11 includes a substrate 13 made of the above-described sintered body and a laminate 14 formed on the substrate 13. The laminate 14 includes the thin film magnetic head 10. In the present embodiment, the substrate 13 has a rectangular parallelepiped shape, and the laminate 14 is formed on the side surface of the substrate 13.

  The upper surface 14a of the laminated body 14 forms the end face of the magnetic head slider 11. The upper surface 14a of the laminated body 14 has recording pads 18a and 18b and reproducing pads 19a and 19b connected to the thin film magnetic head 10. Is attached. The thin film magnetic head 10 is provided in the laminated body 14, and a part of the thin film magnetic head 10 is exposed to the outside from the air bearing surface S. In FIG. 2, the thin film magnetic head 10 embedded in the stacked body 14 is indicated by a solid line in consideration of easy recognition.

  Such a magnetic head slider 11 is mounted on a gimbal 12 and connected to a suspension arm (not shown) to constitute a head gimbal assembly.

  Here, the structure of the magnetic head slider 11 will be described in more detail with reference to FIG. FIG. 3 is a schematic cross-sectional view (II-II schematic cross-sectional view in FIG. 2) in a direction perpendicular to the air bearing surface S and perpendicular to the track width direction in the magnetic head slider 11. As described above, the magnetic head slider 11 includes the substantially rectangular plate-shaped substrate 13 and the stacked body 14 stacked on the side surface of the substrate 13. The laminated body 14 includes a thin film magnetic head 10 and a coat layer 50 surrounding the thin film magnetic head 10.

  The thin film magnetic head 10 includes a GMR (Giant Magneto Resistive) element 40 as a reading element for reading magnetic information of a hard disk and a writing element for writing magnetic information to the hard disk in order from the side closer to the substrate 13. And an inductive electromagnetic transducer 60, which is a composite thin film magnetic head.

  The electromagnetic conversion element 60 employs a so-called in-plane recording method, and includes a lower magnetic pole 61 and an upper magnetic pole 64 in order from the substrate 13 side, and further includes a thin film coil 70.

  The end portions of the lower magnetic pole 61 and the upper magnetic pole 64 on the air bearing surface S side are exposed to the air bearing surface S, and the exposed portions of the lower magnetic pole 61 and the upper magnetic pole 64 are separated by a predetermined distance so that the recording gap G is formed. Forming. On the other hand, the end 64B of the upper magnetic pole 64 on the side away from the air bearing surface S is bent toward the lower magnetic pole 61, and the end 64B is on the side of the lower magnetic pole 61 on the side away from the air bearing surface S. Magnetically connected to the end. As a result, a magnetic circuit sandwiching the gap G by the upper magnetic pole 64 and the lower magnetic pole 61 is formed.

  The thin film coil 70 is disposed so as to surround the end portion 64B of the upper magnetic pole 64, and generates a magnetic field between the recording gaps G by electromagnetic induction, thereby recording magnetic information on the recording surface of the hard disk.

  Although not shown, the GMR element 40 has a multilayer structure and is exposed to the air bearing surface S. The GMR element 40 detects a change in the magnetic field from the hard disk using the magnetoresistive effect and reads magnetic information.

  The GMR element 40 and the electromagnetic conversion element 60 and the upper magnetic pole 64 and the lower magnetic pole 61 are separated from each other by an insulating coat layer 50. The thin film magnetic head 10 itself is also covered with the coat layer 50 except for the air bearing surface S. The coat layer 50 is mainly formed of an insulating material such as alumina. Specifically, an alumina layer formed by sputtering or the like is usually used. Such an alumina layer usually has an amorphous structure.

  The thin film magnetic head 10 may be a vertical recording system instead of the in-plane recording system as described above. Further, instead of the GMR element 40, an AMR (Anisotropic Magneto Resistive) element using an anisotropic magnetoresistive effect, a TMR (Tunnel-type Magneto Resistive) element using a magnetoresistive effect generated at a tunnel junction, or the like may be used. Good.

Further, the coat layer 50 may further include a magnetic layer or the like that magnetically insulates between the GMR element 40 and the electromagnetic conversion element 60.

[Method of manufacturing magnetic head slider]
Next, a method for manufacturing the magnetic head slider 11 as described above will be described.

  First, as shown in FIG. 4, a substrate 13 in which the above-described sintered body is formed in a disk wafer shape is prepared. Next, as shown in FIG. 5A, a laminated structure 100 including the thin film magnetic head 10 and the coat layer 50 is laminated on the substrate 13 by a known method to obtain a laminated structure 100. Here, the multilayer body 14 is formed in the multilayer body 14 such that a large number of thin film magnetic heads 10 are arranged in a matrix.

  Next, the laminated structure 100 is cut into a predetermined shape and size. In the present embodiment, for example, by cutting as shown by the dotted line in FIG. 5A, a plurality of thin film magnetic heads 10 are arranged in a line as shown in FIG. Bars 100B are formed so that the thin film magnetic head 10 is exposed to the side surface 100BS.

  After the formation of the bar 100B, a so-called lapping process is performed in which the air bearing surface S is formed by polishing the side surface 100BS of the bar 100B. In this step, the substrate 13 and the stacked body 14 stacked on the substrate 13 are polished simultaneously and in a direction intersecting the stacking direction (direction of arrow X in FIG. 3).

  Thereafter, an air introduction groove 11a (not shown) is formed in the air bearing surface S by an ion milling method or the like. A plurality of magnetic head sliders 11 each having the thin film magnetic head 10 can be obtained by cutting the bar 100B at an appropriate position so that the thin film magnetic head 10 is included in each bar 100B. Before or after the cutting, a layer such as DLC may be further formed on the air bearing surface.

  In such a method of manufacturing the magnetic head slider 11, since the substrate 13 is formed of the sintered body of the present invention, when the air bearing surface S is formed by polishing the side surface 100BS of the bar 100B described above, The polishing processability of the substrate 13 is high, and the substrate 13 and the laminate 14 can be polished at substantially the same speed. Therefore, a step is hardly formed between the substrate 13 and the laminate 14 on the air bearing surface S, and the air bearing surface S having a smooth surface can be formed.

  In addition, since the substrate 13 is formed of the sintered body of the present invention, generation of voids due to the dropping of carbon aggregates during polishing is extremely difficult to occur. Thereby, the air bearing surface S having a smoother surface can be formed. If the air bearing surface S has voids, impurities may remain in this portion. In some cases, this impurity oozes out and contaminates the air bearing surface S, which may affect recording and reading by the thin film magnetic head 10. On the other hand, according to the present invention, since the formation of voids can be greatly suppressed, there is very little concern about such residual impurities.

  Therefore, according to the method of manufacturing the magnetic head slider 11 of the above-described embodiment, even when a femto slider or a slider having a size smaller than that is formed for mounting on a small HDD, the magnetic head slider 11 is smooth. The air bearing surface S can be formed, and the magnetic head slider 11 that can sufficiently cope with the narrowing of the fly height can be obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples.

[Production of sintered body]
(Examples 1-5, Comparative Examples 1-4)
First, Al ₂ O ₃ powder (average particle size 0.5 μm), TiC powder (average particle size 0.5 μm), and TiO ₂ powder (average particle size 0.3 μm) were prepared as raw material powders.

Next, these raw material powders were mixed in the combinations and blending ratios shown in Table 1 below, and ground and mixed with IPA (isopropyl alcohol; boiling point 82.4 ° C.) for 30 minutes in a ball mill. Was spray granulated at 150 ° C. to obtain a granulated product. Then, the obtained granulated product was primary molded by a cold press method. In the cold press method, a pressure of about 5 MPa (50 kgf / cm ² ) was applied to the granulated product.

Then, the granulated product formed by primary molding was sintered by a hot press method to obtain sintered bodies of Examples 1 to 3 and Comparative Examples 1 and 2, respectively. In this hot pressing method, the sintering atmosphere was evacuated and the sintering time was 1 hour. Moreover, about the sintering temperature and the press pressure (kgf / cm < ² >) added to the granulated product formed primary, it changed as shown in Table 1, respectively.

[Characteristic evaluation]
(Confirmation of the composition of the sintered body)
The compositions of the sintered bodies of Examples 1 to 5 and Comparative Examples 1 to 4 obtained above were measured by TEM-EDS mapping, respectively. Table 2 shows the types of crystal phases confirmed by the measurement.

(Measurement of TiCO lattice constant)
As described above, the lattice constant of TiCO in each of the sintered bodies of Examples 1 to 5 and Comparative Examples 1 and 2 obtained above was calculated by performing X-ray measurement using Si as a standard sample. did. The obtained results are shown in Table 3. For Comparative Examples 3 to 4, the lattice constant of TiC was similarly determined, and the results are shown in the same column of Table 3.

(Measurement of peak area ratio of TiCO / Al ₂ O ₃ )
For each of the sintered bodies of Examples 1-5 and Comparative Examples 1-2, was measured by XRD, it was calculated peak area ratio TiCO / _Al 2 _{O 3} of TiCO for _Al 2 _{O 3.} The obtained results are shown in Table 3. Note that the sintered body of Comparative Example 3-4, the TiC / _Al 2 _{O 3} calculated in the same manner, and the results are shown in the column of the table 3.

(Evaluation of polishing processability and void)
First, in order to evaluate the ease of generation of voids by the sintered bodies of Examples 1 to 5 and Comparative Examples 1 to 4, each sintered body was processed by the following method. That is, each sintered body was cut into sections of about 20 × 20 × 1.8 mm, and the sections were polished (lapped) with a single-side polishing machine using slurry containing diamond particles having a diameter of 0.1 μm. Here, the polishing conditions were a tin plate rotation speed of 37.5 times / min, a load of 2550 g, an Oscar motor rotation speed of 55 times / min, and a polishing time of 10 minutes. The polishing rate required for this polishing is shown in Table 3 below.

And about the grinding | polishing surface in each sintered compact after this process, after wash | cleaning the surface which should be measured, the range of 20 micrometers x 20 micrometers is measured by AFM, Based on this, the maximum height prescribed | regulated to JIS0601-1976 is measured. (Rmax) was determined. The obtained results are shown in Table 3. A smaller value of Rmax means that the polished surface is smoother and less voids are generated. In Table 2, the case where Rmax was smaller than 20 nm was indicated by A, and the case where Rmax was 20 nm or more was indicated by B.

  As shown in Table 1, the sintered bodies of Examples 1 to 5 have both a high polishing rate and a low Rmax compared to Comparative Examples 1 to 4, and have high polishing workability. It was confirmed that the generation of voids during the polishing process can be satisfactorily suppressed.

It is a schematic diagram which expands and shows the cross-sectional structure of the sintered compact of suitable embodiment. It is a perspective view showing a magnetic head slider of a preferred embodiment. It is II-II schematic sectional drawing of the magnetic head slider shown in FIG. It is a perspective view which shows the board | substrate which formed the sintered compact in the disk wafer shape. It is a perspective view following FIG. 3 for demonstrating the manufacturing method of a magnetic head slider.

Explanation of symbols

2 ... sintered body, 10 ... thin film magnetic head, 11 ... slider, 13 ... substrate, 14 ... laminate, 110 ... _Al 2 _{O 3} crystal grains, 120 ... TiC grain, 130 ... grain boundary.

Claims (4)

Al ₂ O _3, TiCO, containing at least a composite oxide and C crystal phase containing Al and Ti, the sintered body, characterized in that.   The sintered body according to claim 1, wherein the lattice constant of TiCO is 432.3 pm or less.   The sintered body according to claim 1, wherein the C crystal phase is graphite. 200 kg or more of a mixture in which Al ₂ O ₃ , TiC, and TiO ₂ are blended so that TiC is 37 to 74 parts by mass and TiO ₂ is 13 to 40 parts by mass with respect to 100 parts by mass of Al ₂ O ₃ . A method for producing a sintered body, characterized by firing by a hot press method under a pressure condition of 500 kg or less.

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