CN117229066A - Ceramic sintered body, method for producing same, and nozzle member - Google Patents
Ceramic sintered body, method for producing same, and nozzle member Download PDFInfo
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- CN117229066A CN117229066A CN202311162462.9A CN202311162462A CN117229066A CN 117229066 A CN117229066 A CN 117229066A CN 202311162462 A CN202311162462 A CN 202311162462A CN 117229066 A CN117229066 A CN 117229066A
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- sintered body
- ceramic sintered
- boron nitride
- nitride powder
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- 239000000919 ceramic Substances 0.000 title claims abstract description 144
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 26
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims abstract description 71
- 229910052582 BN Inorganic materials 0.000 claims abstract description 69
- 229910052581 Si3N4 Inorganic materials 0.000 claims abstract description 51
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims abstract description 51
- 239000000843 powder Substances 0.000 claims description 73
- 238000005245 sintering Methods 0.000 claims description 37
- 229910052751 metal Inorganic materials 0.000 claims description 26
- 239000002184 metal Substances 0.000 claims description 26
- 239000000203 mixture Substances 0.000 claims description 17
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 16
- 238000010304 firing Methods 0.000 claims description 16
- 229910052760 oxygen Inorganic materials 0.000 claims description 16
- 239000001301 oxygen Substances 0.000 claims description 16
- 239000002245 particle Substances 0.000 claims description 16
- 238000000465 moulding Methods 0.000 claims description 10
- 239000012298 atmosphere Substances 0.000 claims description 4
- 238000000034 method Methods 0.000 claims description 3
- 230000035939 shock Effects 0.000 description 26
- 238000005299 abrasion Methods 0.000 description 22
- 238000005259 measurement Methods 0.000 description 18
- 238000005452 bending Methods 0.000 description 17
- 238000003825 pressing Methods 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 13
- 238000011156 evaluation Methods 0.000 description 13
- 229910045601 alloy Inorganic materials 0.000 description 12
- 239000000956 alloy Substances 0.000 description 12
- 229910000808 amorphous metal alloy Inorganic materials 0.000 description 10
- 238000002156 mixing Methods 0.000 description 10
- 239000000463 material Substances 0.000 description 8
- 238000012545 processing Methods 0.000 description 8
- 238000005266 casting Methods 0.000 description 7
- 230000008859 change Effects 0.000 description 7
- 238000012360 testing method Methods 0.000 description 6
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000001816 cooling Methods 0.000 description 4
- 239000000395 magnesium oxide Substances 0.000 description 4
- 239000006247 magnetic powder Substances 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000009694 cold isostatic pressing Methods 0.000 description 3
- 238000005087 graphitization Methods 0.000 description 3
- 238000007731 hot pressing Methods 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 3
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 3
- 230000009257 reactivity Effects 0.000 description 3
- 230000008646 thermal stress Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- 238000007088 Archimedes method Methods 0.000 description 2
- 229910018540 Si C Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
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- 239000012535 impurity Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000013507 mapping Methods 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 229910010271 silicon carbide Inorganic materials 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 238000001238 wet grinding Methods 0.000 description 2
- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 229910000287 alkaline earth metal oxide Inorganic materials 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical group [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229910052810 boron oxide Inorganic materials 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000009837 dry grinding Methods 0.000 description 1
- 238000007580 dry-mixing Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- -1 inorganic acid salts Chemical class 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000005058 metal casting Methods 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 239000012046 mixed solvent Substances 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000013001 point bending Methods 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000011164 primary particle Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 229910001404 rare earth metal oxide Inorganic materials 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- GCLGEJMYGQKIIW-UHFFFAOYSA-H sodium hexametaphosphate Chemical compound [Na]OP1(=O)OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])O1 GCLGEJMYGQKIIW-UHFFFAOYSA-H 0.000 description 1
- 235000019982 sodium hexametaphosphate Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000001577 tetrasodium phosphonato phosphate Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 238000004846 x-ray emission Methods 0.000 description 1
- 229910001928 zirconium oxide Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/50—Pouring-nozzles
- B22D41/52—Manufacturing or repairing thereof
- B22D41/54—Manufacturing or repairing thereof characterised by the materials used therefor
Abstract
The present application relates to a ceramic sintered body, a method for producing the same, and a nozzle member. The present application provides a ceramic sintered body comprising boron nitride and silicon nitride, wherein the total content of boron nitride and silicon nitride is 80 to 90 mass%, the mass ratio of boron nitride to the total of boron nitride and silicon nitride is 35 to 45 mass%, and the Brinell hardness of the ceramic sintered body is 400 to 570HL.
Description
The present application is a divisional application of chinese patent application No.202080007546.3 (PCT application No. PCT/JP 2020/003500) having a filing date of 30/1/2020, and having the title of "ceramic sintered body and method for producing the same, and nozzle member".
Technical Field
The present disclosure relates to a ceramic sintered body, a method of manufacturing the same, and a nozzle member.
Background
Technical developments have been made to promote energy saving of hybrid vehicles, air conditioners, and the like. As a material that plays a part of the roles, amorphous alloy is exemplified. The amorphous alloy is used as a material for a soft magnetic core in a magnetic head, a transformer, a coil, or the like.
The amorphous alloy used as the material of the soft magnetic core is produced by, for example, the following single roll method. The molten metal is sprayed onto the outer peripheral surface of a cooling roll composed of an alloy having high thermal conductivity. In the ejection, a nozzle member having a slit formed therein is used. The ejected molten metal is quenched on the outer peripheral surface of the roll and formed into a thin strip shape.
In order to efficiently produce an amorphous alloy obtained by quenching a molten metal, it is necessary to continuously supply a certain amount of molten metal to a cooling roll for a long period of time. Therefore, it is necessary to stably and continuously supply a certain amount of molten metal from the nozzle member for supplying molten metal to the cooling roll. In order to maintain the quality of the alloy strip, the nozzle member for supplying the molten metal is periodically replaced as a consumable.
Among the components for supplying the molten metal, particularly the nozzle component having a slit serving as a discharge hole, it is necessary to be made of a material that can withstand the discharge of the molten metal for a long period of time. Therefore, as a material excellent in corrosion resistance, abrasion resistance, and thermal shock resistance, a composite material formed of a material such as boron nitride, silicon nitride, or zirconium oxide is used.
For example, patent document 1 proposes a molten metal casting nozzle composed of a sintered body containing boron nitride, zirconia, alumina and/or aluminum nitride, and boron oxide.
Patent document 2 proposes a nozzle in which 3 to 10 parts by weight of a sintering aid made of magnesium oxide and/or yttrium oxide is added to 100 parts by weight of a mixture made of 50 to 70% by weight of silicon nitride, 10 to 30% by weight of boron nitride, and 5 to 25% by weight of aluminum oxide.
Patent document 3 proposes a free-cutting ceramic comprising silicon nitride and a metal oxideA ceramic comprising a main component of boron nitride and a subcomponent of a reactant as a sintering aid, and having a flexural strength of 200MPa or more and a linear thermal expansion coefficient of 4X 10 at 25 to 300 DEG C -6 And/or lower.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 03-264156
Patent document 2: japanese patent laid-open No. 03-133554
Patent document 3: japanese patent laid-open No. 2002-356374
Disclosure of Invention
Problems to be solved by the application
In sintering ceramics containing materials difficult to sinter, such as boron nitride, hot pressing is often used as in patent document 2. However, if the scale-like particles such as boron nitride are hot pressed and sintered, anisotropy occurs due to the orientation of the scale-like particles. Therefore, there is a risk that the physical properties of the sintered body are greatly different depending on the direction. In addition, since only a simple-shaped member such as a disk or a gusset can be manufactured, there is a problem in that the post-processing becomes complicated, which is also a high cost. Therefore, a material that can be sufficiently sintered even by normal pressure firing is required.
However, ceramic sintered bodies, such as nozzle members for supplying molten metal, which can maintain sufficient thermal shock resistance and abrasion resistance even when used under severe conditions, are extremely limited. In addition, in the case of processing into a complicated shape such as a nozzle, not only it is necessary to sufficiently sinter by normal pressure firing, but also the sintered body itself is required to have excellent workability.
Accordingly, the present disclosure provides a ceramic sintered body excellent in workability, thermal shock resistance, and abrasion resistance, and a method for producing the same. Further, a nozzle member excellent in thermal shock resistance and abrasion resistance is provided.
Means for solving the problems
One aspect of the present disclosure relates to a ceramic sintered body that contains boron nitride and silicon nitride, and has a total content of boron nitride and silicon nitride of 80 to 90 mass%, a mass ratio of boron nitride to the total of boron nitride and silicon nitride of 35 to 45 mass%, and a Leeb Hardness (HL) of 400 to 570HL. The ceramic sintered body is excellent in workability, thermal shock resistance and abrasion resistance.
The ceramic sintered body was set to have a hardness of H measured in 2 directions perpendicular to each other 1 H and H 2 Time (wherein H 1 ≥H 2 ) The following formula (1) can be satisfied. By reducing the anisotropy of the hardness in this way, the variation in workability, thermal shock resistance, and abrasion resistance can be reduced. In addition, the non-uniformity of thermal stress generated in the ceramic sintered body at the time of temperature change is reduced, and the thermal shock resistance is further improved.
H 1 /H 2 <1.2 (1)
The ceramic sintered body may have a relative density of 60 to 73%. This makes it possible to achieve both sufficient strength and excellent workability at a high level.
A method for manufacturing a ceramic sintered body according to one aspect of the present disclosure includes the steps of: a step of preparing a mixture containing boron nitride powder, silicon nitride powder, and a sintering aid, a step of molding the mixture to obtain a molded body, and a step of firing the molded body under normal pressure in an inert atmosphere to obtain a ceramic sintered body; the total content of the boron nitride powder and the silicon nitride powder in the mixture is 80 to 90 mass%, and the mass ratio of boron nitride to the total of the boron nitride powder and the silicon nitride powder is 35 to 45 mass%, and the Brinell hardness of the ceramic sintered body is 400 to 570HL. The ceramic sintered body produced by the production method is excellent in workability, thermal shock resistance and abrasion resistance.
The total oxygen content of the boron nitride powder in the above production method may be 1.0 mass% or more, and the average particle diameter D50 of the silicon nitride powder may be 1.6 μm or less. By using such powder, liquid phase sintering can be promoted, generation of coarse particles can be suppressed, and a ceramic sintered body having high strength can be obtained even by atmospheric pressure firing.
One aspect of the present disclosure relates to a nozzle member having a slit through which molten metal passes and composed of any of the ceramic sintered bodies described above. The nozzle member is excellent in thermal shock resistance and abrasion resistance.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present disclosure, a ceramic sintered body excellent in workability, thermal shock resistance, and abrasion resistance and a method for producing the same can be provided. Further, a nozzle member excellent in thermal shock resistance and abrasion resistance can be provided.
Drawings
Fig. 1 is a perspective view of a ceramic sintered body according to an embodiment.
Fig. 2 is a schematic view showing an example of an apparatus for producing an amorphous alloy.
Fig. 3 is a perspective view of a nozzle member according to an embodiment.
FIG. 4 is a graph showing the relationship between the evaluation directions of the Rich hardness, bending strength and linear expansion coefficient and the compression direction of the molded article in the examples.
FIG. 5 is a cross-sectional view of a ceramic sintered body used for reactivity evaluation in examples.
Detailed Description
Embodiments of the present disclosure will be described below with reference to the drawings as appropriate. The following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following. In the description, elements having the same elements or the same functions are denoted by the same reference numerals, and overlapping description is omitted in some cases. The positional relationship between the upper, lower, left, right, etc. is set based on the positional relationship shown in the drawings unless otherwise specified. The dimensional ratios of the elements are not limited to the ratios shown in the drawings.
Fig. 1 is a perspective view of a ceramic sintered body according to an embodiment. The ceramic sintered body 10 contains boron nitride, silicon nitride, and a sintering aid. The mass ratio of boron nitride to the total of boron nitride and silicon nitride is 35 to 45 mass%. The upper limit of the mass ratio may be 43 mass% from the viewpoint of sufficiently improving the flexural strength of the ceramic sintered body 10. The lower limit of the mass ratio may be 37 mass% from the viewpoint of further improving the workability of the ceramic sintered body 10.
The ceramic sintered body 10 may contain subcomponents derived from a sintering aid in addition to boron nitride and silicon nitride. As the subcomponent, a usual sintering aid is exemplified. Examples thereof include alkaline earth oxides such as magnesium oxide and calcium oxide, rare earth oxides such as aluminum oxide, silicon oxide and yttrium oxide, and composite oxides such as spinel. In addition, a vitreous grain boundary phase generated by a reaction of the sintering aid and the oxide in manufacturing the ceramic sintered body 10 may be included.
The total content of boron nitride and silicon nitride in the ceramic sintered body 10 is 80 to 90 mass%. The total content may be 80 to 85 mass% from the viewpoint of further improving the flexural strength of the ceramic sintered body 10. The total content of boron nitride and silicon nitride in the ceramic sintered body 10 can be determined by X-ray diffraction.
The ceramic sintered body 10 may have a relative density of 60 to 73% or 63 to 71% from the viewpoint of achieving a high level of both sufficient bending strength and excellent workability. The relative density can be determined by archimedes method.
The ceramic sintered body 10 has a hardness of 400 to 570HL. The hardness of the ceramic sintered body 10 (rebound hardness) can be measured using a commercially available hardness meter. The measurement is performed on a platform. From the viewpoint of obtaining sufficient repetition accuracy, the flatness of the test piece for measurement was adjusted to 30 μm and the parallelism was adjusted to 30 μm or less.
The lower limit of the hardness of the ceramic sintered body 10 may be 420HL or 440HL from the viewpoint of further improving the wear resistance and prolonging the life. The upper limit of the hardness of the ceramic sintered body 10 may be 555HL or 520HL from the viewpoint of improving the machinability.
When the ceramic sintered body has anisotropy, the brinell hardness may be different depending on the measurement direction. For example, relative to the pressing direction during moldingThe brinell hardness measured in the parallel direction (i.e., the brinell hardness measured in the pressing direction) was set to H 1 . On the other hand, the hardness of the mold measured in the direction perpendicular to the pressing direction (i.e., the hardness of the mold measured in the direction perpendicular to the pressing direction) is referred to as H 2 . In this case, it is usually H 1 ＞H 2 . In the case of such a ceramic sintered body having anisotropy, the hardness of the ceramic sintered body satisfies the above range as measured from any direction.
H measured in 2 directions perpendicular to each other from the viewpoint of reducing anisotropy of the ceramic sintered body 1 H and H 2 (wherein H 1 ≥H 2 ) The following formula (1) can be satisfied. By reducing the anisotropy of the ceramic sintered body in this way, the variation in workability, thermal shock resistance, and abrasion resistance can be reduced. In addition, the non-uniformity of thermal stress generated in the ceramic sintered body at the time of temperature change is reduced, and the thermal shock resistance is further improved.
H 1 /H 2 <1.2 (1)
In the case of a ceramic sintered body whose pressing direction is unknown, the brinell hardness may be measured for each axial direction of XYZ axes in fig. 1. In the case where the hardness of Rich varies depending on the axial direction, the maximum hardness of Rich may be defined as H 1 The minimum hardness of Rich is defined as H 2 . When the hardness of the ceramic sintered body is not different depending on the axial direction, the ceramic sintered body is isotropic and becomes H 1 ＝H 2 . In the case where the ceramic sintered body is cylindrical, the ceramic sintered body may be cut into a prism shape and the hardness of the ceramic sintered body may be measured in each axial direction of XYZ axes.
The flexural strength of the ceramic sintered body 10 was 3-point flexural strength measured according to JIS R1601:2008 using a commercially available flexural strength meter. From the viewpoint of improving reliability, the bending strength may be 100MPa or more or 110MPa or more. From the viewpoint of ease of manufacturing the ceramic sintered body 10, the bending strength may be 250MPa or less or 220MPa or less.
Having anisotropy in ceramic sintered bodyIn some cases, the bending strength may be different depending on the measurement direction. The bending strength of the ceramic sintered body when a load is applied in a parallel direction with respect to the pressing direction at the time of molding is S 1 The bending strength when a load is applied in the vertical direction with respect to the pressing direction is S 2 In this case, it is usually S 1 ＞S 2 . The flexural strength of the ceramic sintered body having such anisotropy is preferably such that the above range is satisfied when measured by applying a load in any direction.
S measured by applying a load in 2 directions perpendicular to each other from the viewpoint of reducing anisotropy of the ceramic sintered body 1 S and S 2 (wherein S 1 ≥S 2 ) The following formula (2) can be satisfied. By reducing the anisotropy of the bending strength of the ceramic sintered body in this way, the reliability can be further improved.
S 1 /S 2 <1.2 (2)
In the case of a ceramic sintered body in which the pressing direction is unknown, the bending strength when a load is applied in the parallel direction with respect to each axial direction of the XYZ axes in fig. 1 may be measured. In the case where the bending strength is different depending on the direction of the load, the maximum bending strength may be regarded as S 1 The minimum bending strength is regarded as S 2 . When the bending strength is not different depending on the direction of the load, the ceramic sintered body is isotropic and becomes S 1 ＝S 2 . In the case where the ceramic sintered body is cylindrical, the ceramic sintered body may be cut into a prism shape, and a load may be applied in parallel to each axial direction of the XYZ axes to measure the flexural strength.
The linear expansion coefficient of the ceramic sintered body 10 was measured in accordance with JIS R1618:2002. The linear expansion coefficient was obtained from the change in the length of the test piece when the temperature was changed from room temperature (20 ℃) to 1200 ℃. The linear expansion coefficient of the ceramic sintered body 10 may be 4ppm/K or less or 3ppm/K or less from the viewpoint of further improving the thermal shock resistance. The lower limit of the ceramic sintered body 10 may be 1ppm/K from the viewpoint of ease of manufacture.
When the ceramic sintered body has anisotropy, the linear expansion coefficient may be different depending on the measurement direction. For example, the linear expansion coefficient when the length change is measured in the parallel direction with respect to the pressing direction at the time of molding is E 1 . On the other hand, the linear expansion coefficient when the length change is measured in the vertical direction with respect to the pressurizing direction is E 2 . In this case, it is usually E 1 ＞E 2 . The linear expansion coefficient of the ceramic sintered body having anisotropy as described above preferably satisfies the above range when measured from any direction.
E measured in 2 directions perpendicular to each other from the viewpoint of reducing anisotropy of the ceramic sintered body 1 E and E 2 (wherein E 1 ≥E 2 ) The following formula (3) can be satisfied. By reducing the anisotropy of the ceramic sintered body in this way, the non-uniformity of thermal stress generated in the ceramic sintered body at the time of temperature change is reduced, and the thermal shock resistance is further improved.
E 1 /E 2 <1.2 (3)
In the case of a ceramic sintered body whose pressing direction is unknown, the linear expansion coefficients when the length along each axial direction of the XYZ axes in fig. 1 is measured may be measured separately. In the case where the linear expansion coefficient differs according to the difference in the axial direction, the maximum linear expansion coefficient may be defined as E 1 The minimum linear expansion coefficient is defined as E 2 . When the linear expansion coefficient is not different depending on the axial direction, E is the result 1 ＝E 2 . In the case where the ceramic sintered body is cylindrical, the ceramic sintered body may be cut into a prism shape, and the linear expansion coefficients when the length along each axial direction of the XYZ axes is measured may be measured separately.
The ceramic sintered body 10 is excellent in workability, thermal shock resistance and abrasion resistance. Since the workability is excellent, it can be processed into various shapes by dry processing. In addition, the shape of the hole may be adjusted by a cross cutting process. Therefore, the present application can be applied to, for example, a nozzle member for supplying molten metal.
An embodiment of a method for producing the ceramic sintered body 10 is described below. The manufacturing method of the present embodiment includes the steps of: a step of preparing a mixture containing boron nitride powder, silicon nitride powder and a sintering aid, a step of molding the mixture to obtain a molded body, and a step of firing the molded body under normal pressure in an inert atmosphere to obtain a ceramic sintered body.
In the mixture, the mass ratio of boron nitride to the total of the boron nitride powder and the silicon nitride powder is 35 to 45 mass%. The upper limit of the mass ratio may be 43 mass% from the viewpoint of improving the flexural strength of the obtained ceramic sintered body. The lower limit of the mass ratio may be 37 mass% from the viewpoint of further improving the workability of the obtained ceramic sintered body and sufficiently reducing the linear expansion coefficient.
The total content of the boron nitride powder and the silicon nitride powder in the mixture is 80 to 90 mass%. Thus, the content of the sintering aid can be adjusted to an appropriate range. The total content may be 80 to 85 mass% from the viewpoint of further improving the flexural strength of the obtained ceramic sintered body. The content of the sintering aid in the mixture may be 10 to 20% by mass or 15 to 20% by mass. By setting the content of the sintering aid to the above lower limit value or more, sintering can be promoted even when boron nitride having a difficult sinterability is contained, and a ceramic sintered body having a high density can be obtained. In addition, the density is also increased by promoting liquid phase sintering of silicon nitride. By setting the content of the sintering aid to the above upper limit or less, the linear expansion coefficient of the obtained ceramic sintered body is sufficiently reduced, and the thermal shock resistance is improved.
The boron nitride powder and the silicon nitride powder may have an oxide layer on the powder surface. Such oxide layers may react with the sintering aid upon firing to form a glassy grain boundary phase.
The silicon nitride powder may be crystallized. On the other hand, if a boron nitride powder of crystallized hexagonal system (h-BN) is used, anisotropy is liable to occur in the ceramic sintered body depending on the flake shape of the boron nitride particles. Thus, the boron nitride powder may be an amorphous boron nitride powder that is not crystallized. When the boron nitride powder is amorphous, the Graphitization Index (GI) obtained by the following points is preferably 5.0 or more.
The graphitization index (GI: graphitization Index) is obtained by calculating the integrated intensity ratio (i.e., area ratio) of the (100), (101) and (102) planes of the X-ray diffraction pattern (J.Thomas et al, J.Am.chem. Soc.84,4619 (1962)).
Gi= [ area { (100) + (101) } ]/[ area (102) ]
When the boron nitride particles are completely crystallized, the GI is considered to be 1.60. Among them, in the case of hexagonal boron nitride powder having a crystalline flake shape in which particles sufficiently grow with high crystallinity, since the particles are easily oriented, GI is further reduced. That is, GI is an index of crystallinity of the hexagonal boron nitride powder in a flake shape, and the smaller the value, the higher the crystallinity. In the case of a boron nitride powder having a GI of 5.0 or more, the primary particles of boron nitride have low crystallinity. Therefore, the anisotropy of the ceramic sintered body using such boron nitride powder can be reduced. GI can be controlled by crystallization temperature.
GI can be measured, for example, using "D8 ADVANCE Super Speed" (manufactured by Bruker AXS Inc.). As a pretreatment for measurement, boron nitride powder is pulverized using an agate mortar or the like as necessary. Then, the boron nitride powder was press-molded to prepare a molded article. The X-rays are irradiated so as to be symmetrical to each other with respect to the normal line of the plane of the in-plane direction of the molded body. The X-ray source used for the measurement was CuK. Alpha. Radiation, the tube voltage was 45kV, and the tube current was 360mA.
The lower limit of the total oxygen content of the boron nitride powder may be 1.0 mass% or 1.2 mass% from the viewpoint of promoting liquid phase sintering by suppressing the decrease in the reaction sites with the sintering aid and the viewpoint of reducing the linear expansion coefficient of the ceramic sintered body. The upper limit of the total oxygen content of the boron nitride powder may be 3.0 mass% or 2.6 mass% from the viewpoint of the easiness of obtaining. From the same viewpoint, the total oxygen content of the silicon nitride powder may be 0.1 to 2.5% by mass or 0.5 to 1.5% by mass. The total oxygen content of the boron nitride powder and the silicon nitride powder can be measured by using an O/N joint measuring instrument (trade name: EMGA-620W/C) manufactured by horiba manufacturing company.
The upper limit of the average particle diameter D50 of the silicon nitride powder may be 1.6 μm, 1.2 μm, or 1.0 μm from the viewpoint of sufficiently suppressing abnormal grain growth and sufficiently improving the strength of the ceramic sintered body. The lower limit of the average particle diameter D50 may be 0.6 μm from the viewpoint of suppressing aggregation of the powder. The content of Fe in the silicon nitride powder may be 0.15 mass% or less or 0.05 mass% or less from the viewpoint of improving the strength of the ceramic sintered body and suppressing the reaction with the molten metal when used as a nozzle member.
The preparation of the mixture may be carried out by dry grinding and dry mixing. In this case, the structure of the ceramic sintered body obtained by aggregation of the raw material powder is likely to become uneven. Therefore, wet grinding and wet mixing are preferably performed using a ball mill or the like. In addition, a device having a high dispersion force such as a bead mill can be used. The liquid medium used for wet grinding and wet mixing may be an organic solvent, for example, an alcohol. In order to further improve the moldability, the organic binder may be blended in an amount of 3 mass% or less relative to the solid content, and the mixture may be granulated by a spray dryer.
The obtained mixture was press-molded into a predetermined shape. The molding may be performed using, for example, a Cold Isostatic Pressing (CIP) device from the viewpoint of obtaining a ceramic sintered body having reduced anisotropy. In the case where the bulk density of the mixture is high and moldability is low, the molding may be performed before CIP. The molding shape is not particularly limited, and may be, for example, a prismatic shape or a cylindrical shape.
The obtained molded article was fired under an inert atmosphere at normal pressure (atmospheric pressure). The firing temperature may be 1650 to 1850℃or 1700 to 1800 ℃. By firing at least the lower limit, sintering is facilitated, and the ceramic sintered body can be sufficiently densified. By firing at or below the upper limit, decomposition of silicon nitride can be suppressed. The time for holding at the firing temperature may be 1 to 10 hours or 2 to 8 hours. In the case of using the mixture subjected to granulation, degreasing may be performed by heating to a temperature in the range of 400 to 600 ℃ before firing.
Thus, the ceramic sintered body 10 can be obtained. As described above, the ceramic sintered body 10 has a hardness of 400 to 570HL. By carrying out the above production method by normal pressure molding, ceramic sintered bodies having excellent workability, thermal shock resistance and abrasion resistance and various shapes can be produced easily.
Fig. 2 is a schematic diagram showing an example of an apparatus for producing an amorphous alloy. The ceramic sintered body 10 may be used as a nozzle member 12 (nozzle) through which the molten alloy (molten metal) shown in fig. 2 passes. The manufacturing apparatus 100 includes: furnace 20, pouring cup 30, nozzle member 12 mounted at the front end of pouring cup 30, casting roll 40, casting control section 50, and winding section 60. In the melting furnace 20, for example, a molten alloy 80 having a temperature of 1300 to 1400 ℃ is poured into the tundish 30.
Fig. 3 is a perspective view of the nozzle member 12 according to one embodiment. The nozzle member 12 has a slit 14 formed by a through hole at a central portion thereof. The molten alloy 80 is supplied onto the circumferential surfaces of the casting rolls 40 through the slits 14 formed in the nozzle member 12 in the manner shown in fig. 2. Molten alloy 80 is quenched at the surfaces of casting rolls 40 to form thin alloy strip 82. Thereafter, the alloy strip 82 passes through the casting control portion 50 and is wound onto rolls in the winding portion 60. In this way, thin strips of amorphous alloy are produced.
The nozzle member 12 is composed of the ceramic sintered body 10, and therefore is excellent in corrosion resistance, abrasion resistance, and thermal shock resistance. Therefore, the nozzle member 12 can be made longer in life, and an amorphous alloy can be manufactured efficiently and stably. In addition, since the ceramic sintered body 10 can be produced by normal pressure firing, the production cost of the amorphous alloy can be reduced. Further, since the ceramic sintered body 10 is excellent in workability, the slit 14 can be easily formed, and the machining cost can be reduced.
Since the ceramic sintered body 10 is excellent in workability, it can be processed by dry processing. Although the processing can be performed by wet processing, oil components and organic and inorganic acid salts contained in a coolant or the like at the time of processing tend to adhere to the surface of the ceramic sintered body 10 or to intrude into pores inside. It is difficult to completely remove these components in washing and the like. If such components remain on the surface or inside of the ceramic sintered body, there is a risk of reaction with molten metal or mixing as impurities when used for the nozzle member 12 or the like. Therefore, the ceramic sintered body 10 which can be processed by dry processing can be preferably used for various applications in view of reducing the contamination of impurities.
In the above, some embodiments are described, but the present disclosure is not limited to the above embodiments at all. For example, the nozzle member 12 is not limited to the manufacturing apparatus shown in fig. 2, and can be used in various manufacturing apparatuses as a nozzle member for supplying molten metal.
Examples
The content of the present disclosure will be described in more detail with reference to examples and comparative examples, but the present disclosure is not limited to the following examples.
[ production of ceramic sintered body ]
Examples 1 to 3
Amorphous boron nitride powder (total oxygen amount: 1.10 mass%, GI:5.0 or more) and silicon nitride powder (average particle diameter D50:0.73 μm, fe content: 0.02 mass%, total oxygen amount: 0.82 mass%) were blended so as to be the mass ratio (BN/(BN+SN)) shown in Table 1 (BN: boron nitride, SN: silicon nitride).
The average particle diameter D50 of the silicon nitride powder was measured as follows. To a mixed solvent prepared by mixing 2ml of a 20 mass% aqueous solution of sodium hexametaphosphate with 200ml of pure water, 60mg of a measurement sample of silicon nitride powder was added. Then, mixing and dispersing were carried out for 3 minutes by an ultrasonic homogenizer (trade name: US-300, manufactured by Japanese refiner). Thereafter, the average particle diameter D50 was measured using Microtrac (trade name: MT3300EXII, manufactured by Nikkiso Co., ltd.). Pure water was used as solvent for the Microtrac circulator. The concentration of silicon nitride powder in the sample was measured using this pure water adjustment. The measurement results of the average particle diameter D50 are shown in table 1.
The Fe content of the silicon nitride powder was analyzed as follows. The measurement sample was prepared by compacting silicon nitride powder using an aluminum ring. The Fe content of the measurement sample was measured using a fluorescent X-ray (XRF) analyzer (manufactured by Rigaku Corporation, trade name: primus II). The results are shown in Table 1.
The boron nitride powder, the silicon nitride powder, and the sintering aid were blended so that the blending amount of the sintering aid was 20 mass% with respect to the total of these, to obtain a compound. In the detailed components of the sintering aid, alumina was set to 4.9 mass% and yttria was set to 15.1 mass%.
The slurry was prepared by wet ball mill mixing of the complex with methanol as a liquid medium. The obtained slurry was dried by a vacuum dryer to remove the solvent, and then pulverized by a ball mill. Thereafter, sieving was performed using a sieve having a mesh size of 150. Mu.m. The mixed powder under the screen was subjected to press molding by CIP under 100MPa to obtain a molded body. The obtained molded body was subjected to atmospheric firing at 1800℃for 4 hours in a nitrogen atmosphere to obtain a ceramic sintered body (diameter: 350mm, height: 40 mm) in a cylindrical shape. The content ratio of the nitride component and the sintering aid component in the ceramic sintered body is the same as the mixing ratio of the raw materials.
Example 4, 5
A ceramic sintered body was obtained in the same manner as in example 2, except that the blending amount of the sintering aid with respect to the total of the boron nitride powder, the silicon nitride powder and the sintering aid was changed as shown in table 1, and an amorphous boron nitride powder having a total oxygen content of 1.46 mass% was used.
Examples 6 to 10
A ceramic sintered body was obtained in the same manner as in example 2, except that boron nitride powder having the total oxygen amount shown in table 1 was used.
Example 11
Ceramic sintered bodies were obtained in the same manner as in example 2, except that the amount of the sintering aid to be blended with respect to the total of the nitride powder and the sintering aid was changed as shown in table 1, and amorphous boron nitride powder (GI: 5.0 or more) having the total oxygen amount shown in table 1 was used. In the detailed components of the sintering aid, 3.0 mass% of alumina, 9.6 mass% of yttrium oxide, and 2.4 mass% of magnesium oxide were used.
Examples 12 to 14
A ceramic sintered body was obtained in the same manner as in example 10, except that silicon nitride powder having an average particle diameter D50, a total oxygen content, and a Fe content shown in table 1 was used.
Comparative examples 1 to 3
A ceramic sintered body was obtained in the same manner as in example 1, except that the blending ratio of the boron nitride powder and the silicon nitride powder was set to the mass ratio shown in table 1.
Comparative examples 4 and 5
Ceramic sintered bodies were obtained in the same manner as in example 2, except that the amount of the sintering aid to be blended was changed to the total of the boron nitride powder, the silicon nitride powder and the sintering aid as shown in table 1.
Comparative example 6
A ceramic sintered body was obtained in the same manner as in example 3, except that boron nitride powder having an oxygen content shown in table 1 was used.
Comparative example 7
Ceramic sintered bodies were obtained in the same manner as in example 3, except that the amount of the sintering aid to be blended with respect to the total of the boron nitride powder, the silicon nitride powder and the sintering aid was changed as shown in table 1, the boron nitride powder having the oxygen content shown in table 1 was used, and firing was performed at 1750 ℃ and 20MPa for 4 hours using hot pressing.
Comparative example 8
Ceramic sintered bodies were obtained in the same manner as in example 1, except that the amount of the sintering aid to be blended with respect to the total of the boron nitride powder, the silicon nitride powder and the sintering aid was changed as shown in table 1, the boron nitride powder having the oxygen content shown in table 1 was used, and firing was performed at 1750 ℃ and 20MPa for 4 hours using hot pressing.
TABLE 1
In the table, "a" of the sintering aid means alumina, "Y" means yttria, and "M" means magnesia.
[ evaluation of ceramic sintered body ]
< relative Density >
The relative density of the ceramic sintered body was measured by archimedes method. The results are shown in Table 2.
< hardness of Li >
The ceramic sintered bodies of each example and each comparative example were processed into prismatic shapes to obtain test pieces (flatness: 30 μm or less, parallelism: 30 μm or less) for measurement. Using a commercially available Richter (K)&M instruments, manufactured by Ltd, device name: KH-260plus&DL) and the hardness of the test piece was measured. As shown in fig. 4, the hardness measured in the pressing direction when the molded article is produced is H 1 And the hardness when measured in the direction perpendicular to the pressurizing direction is H 2 . The measurement results are shown in Table 2.
< bending Strength >
The ceramic sintered bodies of each example and each comparative example were processed into a predetermined shape to prepare test pieces for measurement. The 3-point bending strength was measured according to JIS R1601:2008 using a commercially available bending strength meter (apparatus name: AUTOGRAPH AG2000D, manufactured by Shimadzu corporation). As shown in fig. 4, the bending strength when a load is applied in the parallel direction with respect to the pressing direction at the time of producing the molded body is S 1 And the bending strength when a load is applied in the vertical direction with respect to the pressing direction is S 2 . The measurement results are shown in Table 2.
< linear expansion Rate >)
The ceramic sintered bodies of each example and each comparative example were processed into a predetermined shape to prepare test pieces for measurement. The linear expansion coefficient was measured by using a commercially available linear expansion coefficient measuring device (manufactured by NETZSCH, device name: DIL 402) according to JIS R1618:2002. As shown in FIG. 4, the measurement was performed in a flat state with respect to the pressing direction at the time of producing the molded articleThe linear expansion coefficient when the length in the row direction is changed is E 1 And assuming E as the linear expansion coefficient when the length change in the vertical direction with respect to the pressurizing direction is measured 2 . The measurement results are shown in Table 3.
< evaluation of reactivity >)
Fig. 5 is a cross-sectional view of a prismatic ceramic sintered body for reactivity evaluation. As shown in fig. 5, a recess 16 having a diameter of 10mm×a depth of 10mm was formed in the central portion of the ceramic sintered body 10. The recess 16 was filled with a Epson Atmix Corporation magnetic powder (trade name: KUAMET6B 2). The ceramic sintered body filled with the magnetic powder was heated to 1300 ℃ under an argon atmosphere and held for 1 hour.
After cooling, the ceramic sintered body 10 is embedded with an epoxy resin and cut along the surface passing through the recess 16. Then, a cut surface including a contact portion between the magnetic powder and the inner wall of the recess 16 was observed by using a scanning electron microscope (trade name: JSM-6010LA, manufactured by japan electronics corporation). In the observation, the element mapping (elemental mapping) was performed by energy dispersive X-ray spectroscopy (SEM-EDS), and it was determined whether or not the alloy element of the magnetic powder diffused into the ceramic sintered body 10. The case where diffusion could not be detected was evaluated as "a", and the case where diffusion could be detected was evaluated as "B". The evaluation results are shown in Table 3.
< evaluation of processability >)
The ceramic sintered bodies of the examples and comparative examples were processed by dry processing to produce nozzle members. Specifically, first, the ceramic sintered body was processed into a prismatic shape (184 mm×35mm×32 mm). Thereafter, slits having a width of 140mm and a thickness of 0.5mm were formed in the processed ceramic sintered body. The workability was evaluated according to the following criteria based on dimensional tolerances of the width of the slit formed.
A: the dimensional tolerance is + -0.05 mm or less.
B: the dimensional tolerance is more than +/-0.05 mm and less than +/-0.10.
C: the dimensional tolerance is greater than + -0.10 mm.
< evaluation of thermal shock resistance and abrasion resistance >
The ceramic sintered body was processed into a prismatic shape (184 mm. Times.35 mm. Times.32 mm) in the same manner as in the evaluation of the workability. Slits having a width of 140mm and a thickness of 0.5mm were formed in the processed ceramic sintered body. An Fe-B-Si-C amorphous alloy ribbon is produced by continuously passing an Fe-B-Si-C amorphous molten metal through a slit. The molten metal outflow was measured until the thickness of the alloy ribbon became out of the range of 24 μm.+ -. 2. Mu.m. That is, the more the amount of molten metal flowing out, the more excellent the abrasion resistance of the ceramic sintered body.
The case where the molten metal outflow amount was maintained within the above range until the predetermined target value was reached and no irregularities could be visually detected on the slit inner surface was evaluated as "a". The case where the molten metal outflow amount was maintained within the above range until the target value was reached, but the irregularities were visually detected on the slit inner surface was evaluated as "B". The molten metal outflow amount was evaluated as "C" when it was out of the above range before reaching the above target value. The case where a crack was generated in the ceramic sintered body immediately after the start of the outflow of the molten metal was evaluated as "D". The evaluation results are shown in Table 3. The ratio of the molten metal outflow amount to the target value (100%) is also shown for the case of evaluation of "C".
TABLE 2
TABLE 3
In comparative example 2, since dimensional tolerance was large, the thermal shock resistance and the abrasion resistance were not evaluated. In example 14 and comparative example 1, the results of the "evaluation of thermal shock resistance and abrasion resistance" were "B", but the irregularities on the inner surfaces of the slits in comparative example 1 were larger.
The ceramic sintered body of each example was evaluated for workability as "a". The evaluation of the thermal shock resistance and the abrasion resistance was "a" or "B". In addition, the anisotropy is low. As described above, it was confirmed that the ceramic sintered body of the example was excellent in workability, thermal shock resistance, and abrasion resistance. From the results of examples 6 to 9, it was confirmed that the relative density, the brinell hardness and the flexural strength were improved and the linear expansion coefficient was decreased by increasing the total oxygen content of the boron nitride powder. From the results of examples 12 to 14, it was confirmed that when the average particle diameter D50 of the silicon nitride powder was large, the relative density was lowered and the flexural strength was lowered.
Industrial applicability
According to the present disclosure, there are provided a ceramic sintered body excellent in workability, thermal shock resistance and abrasion resistance, and a method for producing the same. Further, a nozzle member excellent in thermal shock resistance and abrasion resistance is provided.
Description of the reference numerals
10 … ceramic sintered body, 12 … nozzle member, 14 … slit, 16 … recess, 20 … furnace, 30 … tundish, 40 … casting roll, 50 … casting control portion, 60 … winding portion, 80 … molten alloy, 82 … alloy ribbon, 100 … manufacturing apparatus.
Claims (6)
1. A ceramic sintered body which is a ceramic sintered body containing boron nitride and silicon nitride, wherein,
the total content of the boron nitride and the silicon nitride is 80 to 90 mass%,
the mass ratio of the boron nitride to the total of the boron nitride and the silicon nitride is 35 to 45 mass%,
the ceramic sintered body has a Brinell hardness of 400-570 HL.
2. The ceramic sintered body according to claim 1, wherein the hardness of each of the ceramic sintered body measured in 2 directions perpendicular to each other is H 1 H and H 2 Time (wherein H 1 ≥H 2 ) Satisfies the following formula (1),
H 1 /H 2 <1.2 (1)。
3. the ceramic sintered body according to claim 1 or 2, which has a relative density of 60 to 73%.
4. A method for producing a ceramic sintered body, comprising the steps of:
a step of preparing a mixture containing boron nitride powder, silicon nitride powder, and a sintering aid,
a step of molding the mixture to obtain a molded article, and
a step of firing the molded body under normal pressure in an inert atmosphere to obtain a ceramic sintered body;
in the above-mentioned method of manufacture,
the total content of the boron nitride powder and the silicon nitride powder in the mixture is 80 to 90 mass%, and the mass ratio of the boron nitride to the total of the boron nitride powder and the silicon nitride powder is 35 to 45 mass%,
the ceramic sintered body has a Brinell hardness of 400-570 HL.
5. The method according to claim 4, wherein the total oxygen content of the boron nitride powder is 1.0 mass% or more,
the average particle diameter D50 of the silicon nitride powder is 1.6 μm or less.
6. A nozzle member having a slit for passing the molten metal therethrough,
a ceramic sintered body according to any one of claims 1 to 3.
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| JPS5626772A (en) * | 1979-08-14 | 1981-03-14 | Sumitomo Electric Industries | Sintered body for superhard tool and manufacture thereof |
| JPS6022676B2 (en) * | 1980-02-23 | 1985-06-03 | 日本鋼管株式会社 | Silicon nitride/boron nitride composite sintered body and its manufacturing method |
| US4640336A (en) * | 1984-10-01 | 1987-02-03 | Toshiba Ceramics Co., Ltd. | Refractory for continuous casting |
| JPS61266360A (en) * | 1985-05-21 | 1986-11-26 | 株式会社東芝 | Manufacture of silicon nitride ceramic sintered body |
| JPS61286045A (en) * | 1985-06-12 | 1986-12-16 | Mitsubishi Heavy Ind Ltd | Continuous casting device |
| CN1006886B (en) * | 1987-07-06 | 1990-02-21 | 国家建筑材料工业局山东工业陶瓷研究设计院 | Silicone nitride/boron nitride composite and prepn. thereof |
| CN1049326A (en) * | 1989-08-11 | 1991-02-20 | 国家建筑材料工业局山东工业陶瓷研究设计院 | Anti slaking composition material based on boron nitride and manufacture method thereof |
| JPH03133554A (en) * | 1989-10-19 | 1991-06-06 | Kawasaki Steel Corp | Continuous casting nozzle |
| JP2520190B2 (en) * | 1990-08-17 | 1996-07-31 | 日立造船株式会社 | Refractory manufacturing method for continuous casting equipment |
| JPH05170549A (en) * | 1991-12-26 | 1993-07-09 | Kawasaki Refract Co Ltd | Refractory material for continuous casting and its production |
| JP2938319B2 (en) * | 1993-08-27 | 1999-08-23 | 新日本製鐵株式会社 | Side dam for continuous casting of wide thin slab |
| JPH09239504A (en) * | 1996-03-04 | 1997-09-16 | Shinagawa Refract Co Ltd | Submerged nozzle for continuous casting of steel containing high oxygen |
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| CN106007731B (en) * | 2016-05-18 | 2018-08-31 | 扬州北方三山工业陶瓷有限公司 | A kind of high tenacity ceramic nozzle material and preparation method thereof |
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