Fe-Si-B-Nb target

Abstract

Provided is an Fe-Si-B-Nb-based target which is such that abrasion and damage of the tip of a cutting tool, the occurrence of cracking and chipping of the target body, and formation of bumps and recesses on the target surface can be suppressed during machining of the target.　The Fe-Si-B-Nb-based target has a composition formula, in terms of atomic ratio, expressed by Fe100-X-Y-ZSiXBYNbZ, wherein 15 ≤ X + Y ≤ 35, 0.3 ≤ X / Y ≤ 2.0, 1 ≤ Z ≤ 20 and the balance inevitable impurities, and has an average Vickers hardness value of 200 to 1,100 HV as measured at five measurement points. The Vickers hardness is preferably in the range of 500 to 1,000 HV.

Description

[Technical field]

[0001] The present invention relates to an Fe-Si-B-Nb based target used for forming, for example, a soft magnetic film. [Background technology]

[0002] Various products, including electronic devices, are becoming smaller and lighter, and functional thin films are being applied. For example, Patent Document 1 proposes a soft magnetic film suitable for the core material of magnetic heads and the like, which contains Fe as the main component, a metal element selected from the group consisting of Nb, Nb-Ta, and Ta, a semimetal element selected from the group consisting of B (boron) and B-Si, and N (nitrogen). This soft magnetic film made of Fe-Si-B-Nb-N has excellent soft magnetic properties such as low coercive force, low magnetostriction, and high saturation magnetic flux density, good thermal stability, and is also excellent in corrosion resistance and wear resistance, making it a useful technology.

[0003] The soft magnetic film composed of the above-mentioned Fe-Si-B-Nb-N can be formed by, for example, a sputtering method. Specifically, a method has been proposed in which a Fe-Si-B-Nb alloy containing Fe as a main component, a metal element selected from the group consisting of Nb, Nb-Ta, and Ta, and a metalloid element selected from the group consisting of B and B-Si is used as a target, nitrogen gas is periodically mixed into an inert sputtering gas such as Ar, and a film with a composition modulated in the thickness direction is formed, and then the film is heat-treated. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2-163911 Summary of the Invention [Problem to be solved by the invention]

[0005] The Fe-Si-B-Nb alloy target disclosed in Patent Document 1 is a so-called difficult-to-cut material, which is highly likely to crack, chip, or fall off during machining to cut the target into the desired shape and dimensions. This can lead to wear and damage to the cutting tool tip during machining, which can induce unevenness on the surface of the target obtained, and in some cases, can even damage the target body.

[0006] The object of the present invention is to provide an Fe-Si-B-Nb-based target (hereinafter also simply referred to as "target") that can suppress wear and damage to the tip of a cutting tool, suppress the occurrence of cracks and chips in the target body, and suppress the occurrence of unevenness on the target surface during machining of the target. [Means for solving the problem]

[0007] The target of the present invention has a composition formula of Fe 100-X-Y-Z S X B Y Nb Z , 15≦X+Y≦35, 0.3≦X / Y≦2.0, 1≦Z≦20, with the remainder consisting of unavoidable impurities. The average Vickers hardness measured at five measurement points is 200 to 1100 HV.

[0008] The target of the present invention preferably has an average Vickers hardness measured at the above five measurement points of 500 to 1000 HV. Effect of the Invention

[0009] The present invention can suppress wear and damage to the cutting tool tip, cracks and chips in the target body, and unevenness on the target surface during machining of the target, making it a useful technique for manufacturing members with excellent soft magnetic properties, thermal stability, corrosion resistance, wear resistance, etc. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The target of the present invention has a Vickers hardness, as specified by JIS Z 2244, in the range of 200 to 1100 HV. The target of the present invention has a specific range of 200 to 1100 HV for the average Vickers hardness measured at five measurement points, so that when machining such as cutting and polishing is performed to obtain the target shape and dimensions, cracks and chips in the target body can be suppressed, and the occurrence of surface irregularities can also be suppressed. Therefore, the target of the present invention has a smooth surface, and can suppress the induction of abnormal discharge and the scattering of nodules to adhere to the treated material. It is preferable that all of the Vickers hardnesses measured at the above five measurement points are in the specific range of 200 to 1100 HV.

[0011] Furthermore, by making the Vickers hardness of the target of the present invention 200 HV or more, it is possible to suppress the generation of built-up edges in the tips of milling machines, lathes, etc. In other words, the target of the present invention suppresses the gradual increase in the cutting depth of the tip that accompanies the growth of the built-up edge as the cutting process proceeds, and in addition to being able to reduce the dimensional difference of the target between the start and end of cutting, it is also possible to suppress damage to the tip that accompanies peeling of the built-up edge.

[0012] In addition, if a low-hardness portion exists in the erosion region of the target, for example, in the Fe-based alloy matrix phase, only the low-hardness portion may remain or fall off, and the surface of the erosion region of the target may become rough, which may easily become a starting point of abnormal discharge during film formation. For this reason, the target of the present invention has a Vickers hardness of 200 HV or more. For the same reason as above, the target according to the embodiment of the present invention preferably has a Vickers hardness of 500 HV or more, more preferably 550 HV or more.

[0013] The target of the present invention can suppress the wear amount of the tip of a milling machine, lathe, etc., by making the Vickers hardness 1100HV or less. That is, as the cutting process of the target of the present invention progresses, the cutting depth of the tip due to the wear of the tip gradually decreases, and the dimensional difference of the target between the start and end of cutting can be suppressed from increasing, and the damage of the tip can also be suppressed. For the same reason as above, the target according to the embodiment of the present invention preferably has a Vickers hardness of 1000HV or less, and more preferably 950HV or less.

[0014] The Vickers hardness in the present invention means that the average value of the Vickers hardness measured at any five measurement points on the erosion surface of the target is in the range of 200 to 1100 HV from the viewpoint of suppressing the occurrence of cracks and chips in the target body as described above and also suppressing the occurrence of abnormal discharge during film formation. The Vickers hardness is measured at a total of five points, including any four positions corresponding to the outer periphery and a position corresponding to the center, in the planar direction of the erosion surface of the target. At this time, the load is 9.8 N and the pressure time is 10 seconds. Moreover, from the viewpoint of achieving a Vickers hardness of 200 to 1100 HV, the target according to the embodiment of the present invention preferably does not have an Fe-Si-B-Nb based composite compound phase in the metal structure.

[0015] The target of the present invention contains Fe, Si, B and Nb, with the remainder being unavoidable impurities. The contents of Si, B and Nb can be appropriately adjusted within a range that does not significantly impair the soft magnetic properties, thermal stability, corrosion resistance and wear resistance. Specifically, the composition formula in atomic ratio is Fe 100-X-Y-Z S X B Y Nb Z , 15≦X+Y≦35, 0.3≦X / Y≦2.0, 1≦Z≦20, and the remainder consisting of unavoidable impurities. In the target of the present invention, a soft magnetic film with low coercivity can be obtained by setting the total amount of Si and B, i.e., X+Y in the composition formula, to 15 or more. For the same reasons as above, it is preferable that the target according to the embodiment of the present invention has X+Y of 20 or more. Furthermore, the target of the present invention can provide a soft magnetic film with high saturation magnetic flux density by setting X+Y to 35 or less. For the same reasons as above, it is preferable that the target according to the embodiment of the present invention has X+Y of 33 or less.

[0016] The target of the present invention can obtain a thermally stable soft magnetic film by adjusting the ratio of Si to B, i.e., X / Y in the composition formula, to 0.3 or more and 2.0 or less. For the same reasons as above, it is preferable that the target according to the embodiment of the present invention has X / Y of 0.7 or more and 1.6 or less.

[0017] The target of the present invention can obtain a soft magnetic film having corrosion resistance by setting the Nb content, i.e., Z in the composition formula, to 1 or more. For the same reasons as above, it is preferable that the target according to the embodiment of the present invention has Z of 3 or more. Furthermore, in the target of the present invention, a soft magnetic film having a high saturation magnetic flux density can be obtained by setting Z to 20 or less. For the same reasons as above, it is preferable that the target according to the embodiment of the present invention has Z of 10 or less. Incidentally, in the target of the present invention, the same effect as above can be obtained even by substituting a part or all of Nb with Ta.

[0018] The target of the present invention can be obtained, for example, by a powder sintering method. Specifically, the target can be obtained by pressure sintering a mixed powder obtained by mixing a pure metal powder and an alloy powder so as to have the above-mentioned component composition. As the alloy powder, it is preferable to use Fe-Si alloy powder, Fe-B alloy powder, Fe-Nb alloy powder, Fe-Si-B alloy powder, Fe-Si-Nb alloy powder, or Fe-B-Nb alloy powder in order to minimize the formation of a Fe-Si-B-Nb-based composite compound phase in the metal structure of the target. As the pressure sintering, for example, a hot isostatic press (HIP) method, a hot press method, an electric current sintering method, or the like can be applied.

[0019] The pressure sintering is preferably carried out under conditions of a sintering temperature of 700 to 1300° C., a pressing pressure of 30 to 200 MPa, and a time of 1 to 10 hours. By setting the sintering temperature at 700°C or higher, the sintering of the powder can be promoted and the generation of voids can be suppressed, while by setting the sintering temperature at 1300°C or lower, the melting of the powder can be suppressed. Furthermore, by setting the pressure at 30 MPa or more, the progress of sintering can be promoted and the occurrence of voids can be suppressed, while by setting the pressure at 200 MPa or less, the introduction of residual stress into the target during sintering can be suppressed, and the occurrence of cracks after sintering can be suppressed. In addition, by setting the sintering time to 1 hour or more, the progress of sintering can be promoted and the generation of voids can be suppressed, and by setting the sintering time to 10 hours or less, the decrease in manufacturing efficiency can be suppressed. EXAMPLES

[0020] First, Fe powder, Si powder, B powder and Nb powder were prepared. Then, in order to obtain a target of Example 1 of the present invention, the composition formula in atomic ratio was Fe 67 S 13.5 B 14.5The powders prepared above were weighed and mixed in a V-type mixer to obtain a mixed powder, so that the composition was Nb5, (X+Y=28, X / Y=0.9, Z=5). The mixed powder was then filled into a soft iron capsule and degassed and sealed at 450°C for 4 hours. The capsule was then pressure-sintered by HIP at 750°C, 122 MPa, and 1 hour to produce a sintered body.

[0021] In order to obtain a target of Example 2 of the present invention, the composition formula in atomic ratio is Fe 70.5 S 14.2 B 15.3 Gas atomized powder and Nb powder were prepared to form the alloy composition. The composition formula in atomic ratio was Fe 67 S 13.5 B 14.5 The powders prepared above were weighed so that the composition was Nb5, (X+Y=28, X / Y=0.9, Z=5), and then mixed in a V-type mixer to obtain a mixed powder. The mixed powder was then filled into a capsule made of soft iron and degassed and sealed at 450°C for 4 hours. The capsule was then pressure-sintered by HIP at 950°C, 122 MPa, and 1 hour to produce a sintered body.

[0022] In order to obtain a target of Example 3 of the present invention, Fe powder, Si powder, B powder and Nb powder were prepared, and the composition formula in atomic ratio was Fe 66 -Si8-B 17 The powders prepared above were weighed so that the composition was -Nb9, (X+Y=25, X / Y=0.5, Z=9), and then mixed in a V-type mixer to obtain a mixed powder. The mixed powder was then filled into a capsule made of soft iron and degassed and sealed at 450°C for 4 hours. The capsule was then pressure-sintered by HIP at 750°C, 122 MPa, and 1 hour to produce a sintered body.

[0023] In order to obtain a target of Example 4 of the present invention, Fe powder, Si powder, B powder and Nb powder were prepared, and the composition formula in atomic ratio was Fe 84 -Si 3.5 -B 11.5The powders prepared above were weighed so that the composition was -Nb1, (X+Y=15, X / Y=0.3, Z=1), and then mixed in a V-type mixer to obtain a mixed powder. The mixed powder was then filled into a capsule made of soft iron and degassed and sealed at 450°C for 4 hours. The capsule was then pressure-sintered by HIP at 950°C, 122 MPa, and 1 hour to produce a sintered body.

[0024] In order to obtain a target of Example 5 of the present invention, Fe powder, Si powder, B powder and Nb powder were prepared, and the composition formula in atomic ratio was Fe 45 -Si 23.3 -B 11.7 -Nb 20 The powders prepared above were weighed so that (X+Y=35, X / Y=2.0, Z=20) and then mixed in a V-type mixer to obtain a mixed powder. The mixed powder was then filled into a soft iron capsule and degassed and sealed at 450°C for 4 hours. The capsule was then pressure-sintered by HIP at 950°C, 122 MPa, and 1 hour to produce a sintered body.

[0025] In order to obtain a target of Example 6 of the present invention, Fe powder, Si powder, B powder and Nb powder were prepared, and the composition formula in atomic ratio was Fe 80 -Si5-B 10 The powders prepared above were weighed so that the composition was -Nb5, (X+Y=15, X / Y=0.5, Z=5), and then mixed in a V-type mixer to obtain a mixed powder. The mixed powder was then filled into a capsule made of soft iron and degassed and sealed at 450°C for 4 hours. The capsule was then pressure-sintered by HIP at 950°C, 122 MPa, and 1 hour to produce a sintered body.

[0026] In order to obtain a target for comparison, the composition formula in atomic ratio is Fe 67 -Si 13.5 -B 14.5Gas atomized powder of -Nb5, (X+Y=28, X / Y=0.9, Z=5) was prepared, filled into a soft iron capsule, and degassed and sealed at 450℃ for 4 hours.The capsule was then pressure sintered by HIP at 950℃, 122MPa, and 1 hour to produce a sintered body.

[0027] The sintered bodies obtained above were each machined to produce targets. In this case, it was confirmed that no cracks were generated during machining in the targets of invention examples 1 to 6, and no irregularities were generated on the surface after finishing, resulting in a smooth surface. On the other hand, in the comparative example, cracks occurred during machining, and it was not possible to machine the target into the target shape.

[0028] For each of the sintered bodies obtained above, the Vickers hardness was measured at a total of five locations, including four locations corresponding to the outer periphery and one location corresponding to the center, in the planar direction of the surface that would become the erosion surface of the target. The measurement interval was set at a distance that would not affect the measurement between indentations. The Vickers hardness was measured in accordance with JIS Z 2244 using MVK-E manufactured by Akashi Seisakusho Co., Ltd., with a load of 9.8 N and a pressure time of 10 seconds. The results are shown in Table 1.

[0029] [Table 1]

[0030] The targets serving as comparative examples had an average Vickers hardness of more than 1100 HV. In contrast, it was confirmed that the targets of Inventive Examples 1 to 6 all had an average Vickers hardness in the range of 200 to 1100 HV. This confirmed that the target of the present invention is a target that is suppressed from cracking or chipping during machining, and has a smooth surface without unevenness after finish machining. This suggests that the target of the present invention is useful as a target for forming a soft magnetic film that is suppressed from inducing abnormal discharge and from scattering nodules and adhering to the treated material.

Claims

【Request 1】 The atomic ratio of the composition formula is Fe １００－Ｘ－Ｙ－Ｚ S Ｘ B Ｙ Nb Ｚ , 15≦X+Y≦35, 0.7≦X / Y≦1.6, 1≦Z≦20, with the remainder consisting of unavoidable impurities, and an average Vickers hardness measured at five measurement points of 550 to 950 HV.

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