Fe-Pt based magnetic material sintered compact

Abstract

Provided is an FePt based magnetic material sintered compact, comprising BN and SiO.sub.2 as non-magnetic materials, wherein Si and O are present in a region where B or N is present at a cut surface of the sintered compact. An object of the present invention is to provide a high density sputtering target which enables production of a magnetic thin film for heat-assisted magnetic recording media, and also reduces the amount of particles generated during sputtering.

Claims

1. A FePt based magnetic material sintered compact, consisting of iron and platinum forming sintered FePt alloy and particles of hexagonal BN and SiO.sub.2 dispersed in the sintered FePt alloy, wherein, in an element mapping image obtained by a Field Emission Electron Probe Micro Analyzer (FE-EPMA) of a cross-sectional surface of the sintered compact, elements of Si and O are detected in the same area as that where elements of B and N are detected, and wherein, in X-ray diffraction analysis of a cross-sectional surface of the sintered compact which is parallel to a pressurized face of the sintered compact, an X-ray diffraction peak from (002) plane of hexagonal BN is present, and an X-ray diffraction peak from (101) plane of cristobalite has an intensity ratio of 1.40 or less to a back-ground intensity of the (101) X-ray diffraction peak.

2. The FePt based magnetic material sintered compact according to claim 1, wherein the X-ray diffraction peak from (002) plane of hexagonal BN has an intensity ratio of 1.50 or more to a back-ground intensity of the (002) X-ray diffraction peak.

3. The FePt based magnetic material sintered compact according to claim 2, wherein the sintered compact has a content of Pt in an amount of 5 mol % or more and 60 mol % or less, a content of BN in an amount of 1 mol % or more and 50 mol % or less, a content of SiO.sub.2 in an amount of 0.5 mol % or more and 20 mol % or less, and remainder of content of Fe.

4. The FePt based magnetic material sintered compact according to claim 3, wherein the content of SiO.sub.2 has a ratio of 1% or more relative to the content of hexagonal BN.

5. The FePt based magnetic material sintered compact according to claim 1, wherein a content of SiO.sub.2 in the sintered compact has a ratio of 1% or more relative to a content of hexagonal BN.

6. The FePt based magnetic material sintered compact according to claim 1, wherein the sintered compact has a content of Pt in an amount of 5 mol % or more and 60 mol % or less, a content of BN in an amount of 1 mol % or more and 50 mol % or less, a content of SiO.sub.2 in an amount of 0.5 mol % or more and 20 mol % or less, and remainder of content of Fe.

7. The FePt based magnetic material sintered compact according to claim 1, wherein the sintered compact is made from raw material powders of Fe powder and Pt powder, or FePt powder, and BN powder and SiO.sub.2 powder having a grain diameter of 0.5 to 10 m.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows element mapping obtained with FE-EPMA of a sintered compact from Example 1.

(2) FIG. 2 shows element mapping obtained with FE-EPMA of a sintered compact from Example 2.

(3) FIG. 3 shows an X-ray diffraction profile of the sintered compact from Example 1 (top panel).

(4) FIG. 4 shows an X-ray diffraction profile of a sintered compact from Comparative Example 1 (top panel).

(5) FIG. 5 shows an X-ray diffraction profile of the sintered compact from Example 2 (top panel).

(6) FIG. 6 shows an X-ray diffraction profile of a sintered compact from Comparative Example 2 (top panel).

DETAILED DESCRIPTION

(7) The FePt based magnetic material sintered compact according to the present invention contains BN and SiO.sub.2 as non-magnetic materials, and is characterized by the presence of Si and O in a region where B or N is present at a cut surface of the sintered compact.

(8) Although hexagonal BN shows excellent performance as a lubricant as described above, the density of a BN-containing sintered compact is difficult to be increased because of poor sinterability. However, the sinterability can be significantly improved in a case where BN and SiO.sub.2 are contained and mutually dispersed as compared with a case where BN is contained alone. A detailed mechanism why such a phenomenon occurs is not clearly understood. Nonetheless, this appears to be resulted from a high compatibility of SiO.sub.2 and B as widely known that a softening temperature of SiO.sub.2 glass is lowered when boric acid (B) is added to the SiO.sub.2 glass.

(9) Whether Si and O are present in a region where B or N is present at a cut surface of a sintered compact can be confirmed by element mapping created with a FE-EPMA (Field Emission Electron Probe Micro Analyzer). Specifically, complete or partial overlap between a region where B and N are present and a region where Si and O are present in element mapping can be indicative of the presence of these elements in the same region. Further, the presence of Si and O observed in a region where B and N are present suggests that BN and SiO.sub.2 are solid dissolved.

(10) In X-ray diffraction of a cut surface relative to a pressurized surface of the FePt based magnetic material sintered compact according to the present invention, an X-ray diffraction peak of the (002) plane of hexagonal BN appears, and an X-ray diffraction peak intensity ratio of the (101) plane of cristobalite, which is crystallized SiO.sub.2, is preferably 1.40 or less relative to a background intensity. That is, in a case where a sintered compact is processed into a sputtering target, the generation of microcracks in the target can be controlled by allowing an X-ray diffraction peak intensity ratio of the (101) plane of cristobalite, which is SiO.sub.2, to be 1.40 or more in X-ray diffraction at a cut surface parallel to a sputtering surface of the target.

(11) An X-ray diffraction peak of the (101) plane of cristobalite, which is crystallized SiO.sub.2, is observed at 21.98. Further, a method of calculating the background intensity is as follows: ((the average value of X-ray diffraction intensities observed between 20.5 and 21.5)+(the average value of X-ray diffraction intensities observed between 22.5 and 23.5))/2.

(12) In X-ray diffraction at a cut surface relative to a pressurized surface of the FePt based magnetic material sintered compact according to the present invention, an X-ray diffraction peak intensity ratio of the (002) plane of hexagonal BN is preferably 1.50 or more relative to a background intensity. That is, in a case where a sintered compact is processed into a sputtering target, the generation of microcracks in the target can be controlled by allowing an X-ray diffraction peak intensity ratio of the (002) plane of hexagonal BN to be 1.50 or more in X-ray diffraction at a cut surface parallel to a sputtering surface of the target.

(13) An X-ray diffraction peak of the (002) plane of hexagonal BN is observed at 26.75. Further, a method of calculating the background intensity is as follows: ((the average value of X-ray diffraction intensities observed between 25.5 and 26.5)+(the average value of X-ray diffraction intensities observed between 27.5 and 28.5))/2.

(14) In the FePt based magnetic material sintered compact according to the present invention, the content of SiO.sub.2 relative to the content of hexagonal BN is preferably 1% or more. Sinterability can be further improved by allowing the content of SiO.sub.2 relative to hexagonal BN to be 1% or more.

(15) In the FePt based magnetic material sintered compact according to the present invention, the content of Pt is preferably 5 mol % or more and 60 mol % or less. Good magnetic properties can be obtained by allowing the content to be 5 mol % or more and 60 mol % or less. Further, the content of BN is preferably 1 mol % or more and 50 mol % or less, and the content of SiO.sub.2 is preferably 0.5 mol % or more and 20 mol % or less. The contents of these non-magnetic materials within the above numerical ranges can improve magnetic insulation. Further, dispersed C grains in an alloy are effective. The C content of 0.5 mol % or more and 40 mol % or less can improve magnetic insulation.

(16) The FePt based magnetic material sintered compact according to the present invention may contain one or more elements selected from the group consisting of B, Ru, Ag, Au and Cu as an additive element in a total amount of 0.5 mol % or more and 10.0 mol % or less. Moreover, one or more inorganic materials selected from the group consisting of oxides, nitrides, carbides and carbon nitrides may be added as an additive into the FePt based magnetic material sintered compact according to the present invention if desired. These additive elements and additive materials are effective components in order to improve magnetic properties of a film after sputtering.

(17) The FePt based magnetic material sintered compact according to the present invention may be manufactured, for example, by the following method.

(18) Each of raw material powders (a Fe powder, a Pt powder, a BN powder and a SiO.sub.2 powder) is prepared for production. Further, each of raw material powders of the above additive ingredients is prepared if desired. Note that quartz or an amorphous material is preferably used for the SiO.sub.2 powder. Use of cristobalite as a SiO.sub.2 powder is not preferred because - transition occurs at 250 C., causing change in volume. As a result of this, SiO.sub.2 itself may have microcracks, which may cause abnormal electric discharge.

(19) For these powders, those with a grain diameter of 0.5 m or more and 10 m or less are preferably used. Since oxidation is promoted to cause the increased concentration of oxygen in a sputtering target when the grain diameter of each raw material powder is too small, the grain diameter of 0.5 m or more is preferred. On the other hand, since fine dispersion of each component in an alloy becomes difficult when the grain diameter of each raw material powder is too large, the grain diameter of 10 m or less is further preferred.

(20) Further, an alloy powder (a FePt powder and the like) may be used as a raw material powder. In particular, an alloy powder containing Pt is effective because the amount of oxygen in a raw material powder can be decreased, depending on its composition. Also in a case where an alloy powder is used, the powder having a grain diameter of 0.5 m or more and 10 m or less is preferably used.

(21) Next, the above powders are weighed out to give a desired composition, and then ground and mixed by a known method. At this time, in order to interdiffuse a BN powder and a SiO.sub.2 powder, both powders are preferably mixed in a state of fine powders. More effective mixing can be achieved by mixing the both while grinding. For mixing and grinding, use of a ball mill, a medium agitation mill and the like are particularly effective.

(22) A mixed powder obtained in this way is molded and sintered by hot press. In addition to hot press, the plasma discharge sintering method and the hot isostatic sintering method may be used. In many cases, a holding temperature for sintering is within a range between 800 C. and 1400 C., depending on the composition of a sputtering target.

(23) Then, a sintered compact removed from the hot press is subjected to hot isostatic pressing process. Hot isostatic pressing process is effective for improving the density of a sintered compact. In many cases, a holding temperature for hot isostatic pressing process is within a range between 800 C. and 1200 C., depending on the composition of a sintered compact. Further, pressing force is set at 100 MPa or more.

(24) A sputtering target can be manufactured by processing a sintered compact obtained in this way with a lathe into a desired shape.

(25) As described above, a FePt based magnetic material sintered compact and sputtering target containing BN and SiO.sub.2 as non-magnetic materials in which Si and O are present in a region where B or N is present at a cut surface of the sintered compact can be manufactured.

EXAMPLES

(26) In the followings, the present invention will be described with reference to Examples and Comparative Examples. Note that Examples are presented for merely illustrative purposes, and the present invention shall in no way be limited by them. That is, the present invention is limited only by the claims, and shall encompass various modifications other than those in Examples of the present invention.

Example 1

(27) As raw material powders, a Fe powder, a Pt powder, an Ag powder, a SiO.sub.2 powder and a BN powder were prepared. These powders were weighed out to give 65(50Fe-45Pt-5Ag)-5SiO.sub.2-30BN (mol %).

(28) Next, the weighed powders were introduced into a 5-liter medium agitation mill along with zirconia balls as grinding media, and rotated (a rotation speed of 300 rpm) for 2 hours to perform mixing and grinding. Then a carbon mold was filled with a mixed powder removed from the medium agitation mill, and hot press was performed.

(29) The conditions of hot press were as follows: vacuum atmosphere, a rate of temperature increase of 300 C./hour, a holding temperature of 950 C. and a holding time of 2 hours, and pressure was applied at 30 MPa from the beginning of temperature increase through the end of holding. After the end of holding, it was kept in the chamber to allow natural cooling.

(30) Next, a sintered compact removed from the hot press mold was subjected to hot isostatic pressing process. The conditions for the hot isostatic pressing process were as follows: a rate of temperature increase of 300 C./hour, a holding temperature of 950 C. and a holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and maintained at 150 MPa during holding at 950 C. After the end of holding, it was kept in the furnace to allow natural cooling.

(31) The density of the sintered compact manufactured in this way was measured by the Archimedes method to calculate a relative density. The result was 97.9%.

(32) An edge of the obtained sintered compact was cut out, and a cut surface was polished to analyze its structure with an FE-EPMA. FIG. 1 shows measurement results from element mapping of the cut surface of the sintered compact obtained in this way. As shown in FIG. 1, the presence of Si and O was observed at a location where B or N was present, demonstrating that solid dissolution of BN and SiO.sub.2 was progressed.

(33) Further, as a result of analyzing a cut surface of the sintered compact by the X-ray diffraction method (XRD), an X-ray diffraction peak intensity ratio of the (002) plane of BN was 5.46, and an X-ray diffraction peak intensity ratio of the (101) plane of SiO.sub.2 cristobalite was 1.38.

(34) Next, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and then mounted on a magnetron sputtering equipment (Canon Anelva Corporation, a C-3010 sputtering system) to perform sputtering. The sputtering conditions were as follows: an input power of 1 kW and an Ar gas pressure of 1.7 MPa, and pre-sputtering was performed at 2 kWhr. Then deposition was performed on a Si substrate having a diameter of 4 inches for 20 seconds. Subsequently, the number of particles adhering on the substrate was measured with a particle counter. At this time, the number of particles was 20.

Comparative Example 1

(35) As an example in which BN alone was contained, a Fe powder, a Pt powder, an Ag powder and a BN powder were prepared as raw material powders in Comparative Example 1. These powders were weighed out to give 60(50Fe-45Pt-5Ag)-40BN (mol %).

(36) Next, the weighed powders were introduced into a 5-liter medium agitation mill along with zirconia balls as grinding media, and rotated (a rotation speed of 300 rpm) for 2 hours to perform mixing and grinding. Then a carbon mold was filled with a mixed powder removed from the medium agitation mill, and hot press was performed.

(37) The conditions of hot press were similar to those in Example 1: vacuum atmosphere, a rate of temperature increase of 300 C./hour, a holding temperature of 950 C. and a holding time of 2 hours, and pressure was applied at 30 MPa from the beginning of temperature increase through the end of holding. After the end of holding, it was kept in the chamber to allow natural cooling.

(38) Next, a sintered compact removed from the hot press mold was subjected to hot isostatic pressing process. The conditions for hot isostatic pressing process were similar to those in Example 1: a rate of temperature increase of 300 C./hour, a holding temperature of 950 C. and a holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and maintained at 150 MPa during holding at 950 C. After the end of holding, it was kept in the furnace to allow natural cooling.

(39) The density of the sintered compact manufactured in this way was measured by the Archimedes method to calculate a relative density. The result was 96.1%, showing a decrease as compared with Example 1. Note that as a result of analyzing a cut surface of the sintered compact by the X-ray diffraction method (XRD), an X-ray diffraction peak intensity ratio of the (002) plane of BN was 5.42.

(40) Next, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and then mounted on a magnetron sputtering equipment (Canon Anelva Corporation, a C-3010 sputtering system) to perform sputtering as in Example 1. Subsequently, the number of particles adhering on the substrate was measured with a particle counter. At this time, the number of particles was 840, showing a significant increase as compared with Example 1.

Example 2

(41) As raw material powders, a Fe powder, a Pt powder, a SiO.sub.2 powder and a BN powder were prepared. These powders were weighed out to give 70(50Fe-50Pt)-5SiO.sub.2-25BN (mol %).

(42) Next, the weighed powders were introduced into a 5-liter medium agitation mill along with zirconia balls as grinding media, and rotated (a rotation speed of 300 rpm) for 2 hours to perform mixing and grinding. Then a carbon mold was filled with a mixed powder removed from the medium agitation mill, and hot press was performed.

(43) The conditions of hot press were similar to those in Example 1: vacuum atmosphere, a rate of temperature increase of 300 C./hour, a holding temperature of 950 C. and a holding time of 2 hours, and pressure was applied at 30 MPa from the beginning of temperature increase through the end of holding. After the end of holding, it was kept in the chamber to allow natural cooling.

(44) Next, a sintered compact removed from the hot press mold was subjected to hot isostatic pressing process. The conditions for hot isostatic pressing process were similar to those in Example 1: a rate of temperature increase of 300 C./hour, a holding temperature of 950 C. and a holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and maintained at 150 MPa during holding at 950 C. After the end of holding, it was kept in the furnace to allow natural cooling.

(45) The density of the sintered compact manufactured in this way was measured by the Archimedes method to calculate a relative density. The result was 98.3%.

(46) An edge of the obtained sintered compact was cut out, and a cut surface was polished as in Example 1 to analyze its structure with an FE-EPMA. As a result, the presence of Si and O was observed at a location where B or N was present, demonstrating that solid dissolution of BN and SiO.sub.2 was progressed. Further, as a result of analyzing a cut surface of the sintered compact by the X-ray diffraction method (XRD), an X-ray diffraction peak intensity ratio of the (002) plane of BN was 17.98, and an X-ray diffraction peak intensity ratio of the (101) plane of SiO.sub.2 cristobalite was 1.27.

(47) Next, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and then mounted on a magnetron sputtering equipment (Canon Anelva Corporation, a C-3010 sputtering system) to perform sputtering as in Example 1. Subsequently, the number of particles adhering on the substrate was measured with a particle counter. At this time, the number of particles was 31.

Comparative Example 2

(48) As an example in which BN alone was contained, a Fe powder, a Pt powder, an Ag powder and a BN powder were prepared as raw material powders in Comparative Example 2. These powders were weighed out to give 70(50Fe-50Pt)-30BN (mol %).

(49) Next, the weighed powders were introduced into a 5-liter medium agitation mill along with zirconia balls as grinding media, and rotated (a rotation speed of 300 rpm) for 2 hours to perform mixing and grinding. Then a carbon mold was filled with a mixed powder removed from the medium agitation mill, and hot press was performed.

(50) The conditions of hot press were similar to those in Example 1: vacuum atmosphere, a rate of temperature increase of 300 C./hour, a holding temperature of 950 C. and a holding time of 2 hours, and pressure was applied at 30 MPa from the beginning of temperature increase through the end of holding. After the end of holding, it was kept in the chamber to allow natural cooling.

(51) Next, a sintered compact removed from the hot press mold was subjected to hot isostatic pressing process. The conditions for hot isostatic pressing process were similar to those in Example 1: a rate of temperature increase of 300 C./hour, a holding temperature of 950 C. and a holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and maintained at 150 MPa during holding at 950 C. After the end of holding, it was kept in the furnace to allow natural cooling.

(52) The density of the sintered compact manufactured in this way was measured by the Archimedes method to calculate a relative density. The result was 96.7%, showing a decrease as compared with Example 2. Note that as a result of analyzing a cut surface of the sintered compact by the X-ray diffraction method (XRD), an X-ray diffraction peak intensity ratio of the (002) plane of BN was 21.4.

(53) Next, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and then mounted on a magnetron sputtering equipment (Canon Melva Corporation, a C-3010 sputtering system) to perform sputtering as in Example 1. Subsequently, the number of particles adhering on the substrate was measured with a particle counter. At this time, the number of particles was 795, showing a significant increase as compared with Example 2.

Example 3

(54) As raw material powders, a Fe powder, a Pt powder, a Cu powder, a SiO.sub.2 powder, a BN powder, a TiO.sub.2 powder and an MgO powder were prepared. These powders were weighed out to give 73(30Fe-60Pt-10Cu)-5SiO.sub.2-20BN-1TiO.sub.2-1MgO (mol %).

(55) Next, the weighed powders were introduced into a 5-liter medium agitation mill along with zirconia balls as grinding media, and rotated (a rotation speed of 300 rpm) for 2 hours to perform mixing and grinding. Then a carbon mold was filled with a mixed powder removed from the medium agitation mill, and hot press was performed.

(56) The conditions of hot press were similar to those in Example 1: vacuum atmosphere, the rate of temperature increase of 300 C./hour, holding temperature of 1060 C. and holding time of 2 hours, and pressure was applied at 30 MPa from the beginning of temperature increase through the end of holding. After the end of holding, it was kept in the chamber to allow natural cooling.

(57) Next, a sintered compact removed from the hot press mold was subjected to hot isostatic pressing process. The conditions for hot isostatic pressing process were similar to those in Example 1: a rate of temperature increase of 300 C./hour, a holding temperature of 1100 C. and a holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and maintained at 150 MPa during holding at 1100 C. After the end of holding, it was kept in the furnace to allow natural cooling.

(58) The density of the sintered compact manufactured in this way was measured by the Archimedes method to calculate a relative density. The result was 98.6%.

(59) An edge of the obtained sintered compact was cut out, and a cut surface was polished as in Example 1 to analyze its structure with an FE-EPMA. As a result, the presence of Si and O was observed at a location where B or N was present, demonstrating that solid dissolution of BN and SiO.sub.2 was progressed. Further, as a result of analyzing a cut surface of the sintered compact by the X-ray diffraction method (XRD), an X-ray diffraction peak intensity ratio of the (002) plane of BN was 7.24, and an X-ray diffraction peak intensity ratio of the (101) plane of SiO.sub.2 cristobalite was 1.32.

(60) Next, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and then mounted on a magnetron sputtering equipment (Canon Anelva Corporation, a C-3010 sputtering system) to perform sputtering as in Example 1. Subsequently, the number of particles adhering on the substrate was measured with a particle counter. At this time, the number of particles was 16.

Comparative Example 3

(61) As an example in which BN alone was contained, a Fe powder, a Pt powder, a Cu powder, a BN powder, a TiO.sub.2 powder and an MgO powder were prepared as raw material powders in Comparative Example 3. These powders were weighed out to give 78(30Fe-60Pt-10Cu)-20BN-1TiO.sub.2-1MgO (mol %).

(62) Next, the weighed powders were introduced into a 5-liter medium agitation mill along with zirconia balls as grinding media, and rotated (a rotation speed of 300 rpm) for 2 hours to perform mixing and grinding. Then a carbon mold was filled with a mixed powder removed from the medium agitation mill, and hot press was performed.

(63) The conditions of hot press were similar to those in Example 1: vacuum atmosphere, the rate of temperature increase of 300 C./hour, holding temperature of 1060 C. and holding time of 2 hours, and pressure was applied at 30 MPa from the beginning of temperature increase through the end of holding. After the end of holding, it was kept in the chamber to allow natural cooling.

(64) Next, a sintered compact removed from the hot press mold was subjected to hot isostatic pressing process. The conditions for hot isostatic pressing process were similar to those in Example 1: a rate of temperature increase at 300 C./hour, a holding temperature of 1100 C. and a holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and maintained at 150 MPa during holding at 1100 C. After the end of holding, it was kept in the furnace to allow natural cooling.

(65) The density of the sintered compact manufactured in this way was measured by the Archimedes method to calculate a relative density. The result was 96.3%, showing a decrease as compared with Example 3. Note that as a result of analyzing a cut surface of the sintered compact by the X-ray diffraction method (XRD), an X-ray diffraction peak intensity ratio of the (002) plane of BN was 7.38.

(66) Next, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and then mounted on a magnetron sputtering equipment (Canon Anelva Corporation, a C-3010 sputtering system) to perform sputtering as in Example 1. Subsequently, the number of particles adhering on the substrate was measured with a particle counter. At this time, the number of particles was 645, showing a significant increase as compared with Example 3.

Example 4

(67) As raw material powders, a Fe powder, a Pt powder, a B powder, a Ru powder, a SiO.sub.2 powder and a BN powder were prepared. These powders were weighed out to give 75(70Fe-20Pt-5B-5Ru)-5SiO.sub.2-20BN (mol %).

(68) Next, the weighed powders were introduced into a 5-liter medium agitation mill along with zirconia balls as grinding media, and rotated (a rotation speed of 300 rpm) for 2 hours to perform mixing and grinding. Then a carbon mold was filled with a mixed powder removed from the medium agitation mill, and hot press was performed.

(69) The conditions of hot press were similar to those in Example 1: vacuum atmosphere, the rate of temperature increase of 300 C./hour, holding temperature of 1100 C. and holding time of 2 hours, and pressure was applied at 30 MPa from the beginning of temperature increase through the end of holding. After the end of holding, it was kept in the chamber to allow natural cooling.

(70) Next, a sintered compact removed from the hot press mold was subjected to hot isostatic pressing process. The conditions for hot isostatic pressing process were similar to those in Example 1: a rate of temperature increase at 300 C./hour, a holding temperature of 1100 C. and a holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and maintained at 150 MPa during holding at 1100 C. After the end of holding, it was kept in the furnace to allow natural cooling.

(71) The density of the sintered compact manufactured in this way was measured by the Archimedes method to calculate a relative density. The result was 97.9%.

(72) An edge of the obtained sintered compact was cut out, and a cut surface was polished as in Example 1 to analyze its structure with an FE-EPMA. As a result, the presence of Si and O was observed at a location where B or N was present, demonstrating that solid dissolution of BN and SiO.sub.2 was progressed. Further, as a result of analyzing a cut surface of the sintered compact by the X-ray diffraction method (XRD), an X-ray diffraction peak intensity ratio of the (002) plane of BN was 10.82, and an X-ray diffraction peak intensity ratio of the (101) plane of SiO.sub.2 cristobalite was 1.18.

(73) Next, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and then mounted on a magnetron sputtering equipment (Canon Anelva Corporation, a C-3010 sputtering system) to perform sputtering as in Example 1. Subsequently, the number of particles adhering on the substrate was measured with a particle counter. At this time, the number of particles was 33.

Comparative Example 4

(74) As an example in which BN alone was contained, a Fe powder, a Pt powder, a B powder, a Ru powder and a BN powder were prepared as raw material powders in Comparative Example 4. These powders were weighed out to give 80(70Fe-20Pt-5B-5Ru)-20BN (mol %).

(75) Next, the weighed powders were introduced into a 5-liter medium agitation mill along with zirconia balls as grinding media, and rotated (a rotation speed of 300 rpm) for 2 hours to perform mixing and grinding. Then a carbon mold was filled with a mixed powder removed from the medium agitation mill, and hot press was performed.

(76) The conditions of hot press were similar to those in Example 1: vacuum atmosphere, the rate of temperature increase of 300 C./hour, holding temperature of 1200 C. and holding time of 2 hours, and pressure was applied at 30 MPa from the beginning of temperature increase through the end of holding. After the end of holding, it was kept in the chamber to allow natural cooling.

(77) Next, a sintered compact removed from the hot press mold was subjected to hot isostatic pressing process. The conditions for hot isostatic pressing process were similar to those in Example 1: a rate of temperature increase of 300 C./hour, a holding temperature of 1100 C. and a holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and maintained at 150 MPa during holding at 1100 C. After the end of holding, it was kept in the furnace to allow natural cooling.

(78) The density of the sintered compact manufactured in this way was measured by the Archimedes method to calculate a relative density. The result was 96.2%, showing a decrease as compared with Example 4. Note that as a result of analyzing a cut surface of the sintered compact by the X-ray diffraction method (XRD), an X-ray diffraction peak intensity ratio of the (002) plane of BN was 10.59.

(79) Next, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and then mounted on a magnetron sputtering equipment (Canon Anelva Corporation, a C-3010 sputtering system) to perform sputtering as in Example 1. Subsequently, the number of particles adhering on the substrate was measured with a particle counter. At this time, the number of particles was 816, showing a significant increase as compared with Example 4.

Example 5

(80) As raw material powders, a Fe powder, a Pt powder, an Au powder, a SiO.sub.2 powder, a BN powder and a SiC powder were prepared. These powders were weighed out to give 74(48Fe-48Pt-4Au)-5SiO.sub.2-20BN-1SiC (mol %).

(81) Next, the weighed powders were introduced into a 5-liter medium agitation mill along with zirconia balls as grinding media, and rotated (a rotation speed of 300 rpm) for 2 hours to perform mixing and grinding. Then a carbon mold was filled with a mixed powder removed from the medium agitation mill, and hot press was performed.

(82) The conditions of hot press were similar to those in Example 1: vacuum atmosphere, the rate of temperature increase of 300 C./hour, holding temperature of 1050 C. and holding time of 2 hours, and pressure was applied at 30 MPa from the beginning of temperature increase through the end of holding. After the end of holding, it was kept in the chamber to allow natural cooling.

(83) Next, a sintered compact removed from the hot press mold was subjected to hot isostatic pressing process. The conditions for hot isostatic pressing process were similar to those in Example 1: a rate of temperature increase of 300 C./hour, a holding temperature of 950 C. and a holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and maintained at 150 MPa during holding at 950 C. After the end of holding, it was kept in the furnace to allow natural cooling.

(84) The density of the sintered compact manufactured in this way was measured by the Archimedes method to calculate a relative density. The result was 97.6%.

(85) An edge of the obtained sintered compact was cut out, and a cut surface was polished as in Example 1 to analyze its structure with an FE-EPMA. As a result, the presence of Si and O was observed at a location where B or N was present, demonstrating that solid dissolution of BN and SiO.sub.2 was progressed. Further, as a result of analyzing a cut surface of the sintered compact by the X-ray diffraction method (XRD), an X-ray diffraction peak intensity ratio of the (002) plane of BN was 5.96, and an X-ray diffraction peak intensity ratio of the (101) plane of SiO.sub.2 cristobalite was 1.24.

(86) Next, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and then mounted on a magnetron sputtering equipment (Canon Anelva Corporation, a C-3010 sputtering system) to perform sputtering as in Example 1. Subsequently, the number of particles adhering on the substrate was measured with a particle counter. At this time, the number of particles was 36.

Comparative Example 5

(87) As an example in which BN alone was contained, a Fe powder, a Pt powder, an Au powder, a BN powder and a SiC powder were prepared as raw material powders in Comparative Example 5. These powders were weighed out to give 79(48Fe-48Fe-4Au)-20BN-1SiC (mol %).

(88) Next, the weighed powders were introduced into a 5-liter medium agitation mill along with zirconia balls as grinding media, and rotated (a rotation speed of 300 rpm) for 2 hours to perform mixing and grinding. Then a carbon mold was filled with a mixed powder removed from the medium agitation mill, and hot press was performed.

(89) The conditions of hot press were similar to those in Example 1: vacuum atmosphere, the rate of temperature increase of 300 C./hour, holding temperature of 1050 C. and holding time of 2 hours, and pressure was applied at 30 MPa from the beginning of temperature increase through the end of holding. After the end of holding, it was kept in the chamber to allow natural cooling.

(90) Next, a sintered compact removed from the hot press mold was subjected to hot isostatic pressing process. The conditions for hot isostatic pressing process were similar to those in Example 1: a rate of temperature increase of 300 C./hour, a holding temperature of 950 C. and a holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and maintained at 150 MPa during holding at 950 C. After the end of holding, it was kept in the furnace to allow natural cooling.

(91) The density of the sintered compact manufactured in this way was measured by the Archimedes method to calculate a relative density. The result was 95.3%, showing a decrease as compared with Example 5. Note that as a result of analyzing a cut surface of the sintered compact by the X-ray diffraction method (XRD), an X-ray diffraction peak intensity ratio of the (002) plane of BN was 5.86.

(92) Next, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and then mounted on a magnetron sputtering equipment (Canon Anelva Corporation, a C-3010 sputtering system) to perform sputtering as in Example 1. Subsequently, the number of particles adhering on the substrate was measured with a particle counter. At this time, the number of particles was 942, showing a significant increase as compared with Example 5.

(93) As demonstrated by the above results, the sputtering targets according to the present invention, in which the high density of the sputtering target was maintained by inclusion of SiO.sub.2 along with hexagonal BN as non-magnetic materials, showed a superior effect in that the number of particles generated during sputtering can be significantly suppressed.

(94) TABLE-US-00001 TABLE 1 X-ray diffraction X-ray diffraction peak peak intensity ratio Relative intensity ratio of of SiO2 cristobalite density Number of Composition Ratio (mol %) BN (002) plane (101) plane (%) particles Example 1 65(50Fe45Pt5Ag)5SiO.sub.230BN 5.46 1.38 97.9 20 Comparative 60(50Fe45Pt5Ag)40BN 5.42 96.1 840 Example 1 Example 2 70(50Fe50Pt)5SiO.sub.225BN 17.98 1.27 98.3 31 Comparative 70(50Fe50Pt)30BN 21.4 96.7 795 Example 2 Example 3 73(30Fe60Pt10Cu)5SiO.sub.220BN1TiO21MgO 7.24 1.32 98.6 16 Comparative 78(30Fe60Pt10Cu)20BN1TiO21MgO 7.38 96.3 645 Example 3 Example 4 75(70Fe20Pt5B5Ru)5SiO.sub.220BN 10.82 1.18 97.9 33 Comparative 80(70Fe20Pt5B5Ru)20BN 10.59 96.2 816 Example 4 Example 5 74(48Fe48Pt4Au)5SiO.sub.220BN1SiC 5.96 1.24 97.6 36 Comparative 79(48Fe48Pt4Au)20BN1SiC 5.86 95.3 942 Example 5

(95) Advantageously, the FePt based sintered compact according to the present invention, in which BN is used as a non-magnetic material, can provide a high density sputtering target in which the amount of particles generated during sputtering is reduced. Therefore, it is useful as a sputtering target used for deposition of a magnetic thin film having a granular structure.