JPH01284475A - Low melting metal treating means - Google Patents

Abstract

PURPOSE:To produce the title treating means having high hardness, strength, etc., and a long life by using a sintered body of titanium boride ceramics specified in compsn. and porosity to form the part of the low melting metal treating means where said means comes into contact with a low melting metal. CONSTITUTION:The low melting metal treating means, for example, a nozzle 10 for casting is disposed with a protective layer 12 consisting of the sintered body of the titanium boride on the inside surface of the nozzle body 11 which comes into contact with the low melting metal. This protective layer 12 is formed by disposing a matrix layer 30 formed by mixing and solutionizing of the boride of nickel and titanium carbide between titanium boride particles 20 and has <=5% porosity. The ratio of the coefft. rho1 of thermal expansion of the protective layer 12 and the coefft. rho2 of thermal expansion of the nozzle body 11 is preferably about 1/4<=rho1/rho2<=4. The long-life nozzle 10 for casting having the contact part improved in Vickers hardness, deflective strength, porosity, thermal impact resistance, etc., to the molten metal is thereby obtd.

Description

Detailed Description of the Invention (1) Object of the Invention [Field of Industrial Application] The present invention relates to a low melting point molten metal processing tool, and in particular to a low melting point molten metal processing tool such as at least molten aluminum using a titanium boride ceramic sintered body. The present invention relates to a low melting point molten metal processing tool formed with a portion that comes into contact with the metal.

[Conventional technology] Conventionally, this type of low melting point molten metal processing tool.

Aluminum→-A l, 03 or tungsten carbide w
It was proposed that the material be formed by sintering C or the like.

[Problems to be solved] However, with conventional low melting point molten metal processing tools, (1)
Alumina Δ1. If Off, Vickers hardness or 150
It is small at 01h, and the bending strength is from room temperature to +200°.
The C range was small at 400 to +50 MPa, the porosity was large at 1.0%, and the thermal impact resistance was low at about 275°C, and the corrosion resistance was poor. (ii) In the case of tungsten carbide WC, the Vickers hardness is as low as 40011V, and the bending strength is extremely low at 70klPa at room temperature, and in addition, it has extremely low corrosion resistance. Because it was inferior to

Therefore, it has recently been proposed to form a low melting point molten metal processing tool by sintering silicon nitride, Si3N. In this case, alumina Al2O.

Alternatively, compared to the case of sintering tungsten carbide WC, it was possible to improve the bending strength and thermal shock resistance, but the Vickers hardness deteriorated and the corrosion resistance was slightly inferior, so it still remained low. Melting point molten metal processing tools were brittle and had the disadvantage of not having a long life.

Therefore, in order to solve these drawbacks, the present invention improves the Vickers hardness, flexural strength, thermal shock resistance, etc. by forming at least the part that contacts low melting point molten metal with a titanium boride ceramic sintered body. It is an object of the present invention to provide a low melting point molten metal processing tool that does not require preheating during use and has a long service life.

(2) Structure of the Invention [Means for Solving the Problems] The means for solving the problems provided by the present invention is as follows. A matrix layer mixed with titanium carbide in solid solution is disposed between titanium boride particles and is in contact with at least the low melting point molten metal by a titanium boride ceramic sintered body having a porosity of 5% or less. ``Low melting point molten metal processing tool'' characterized in that it is formed with a molten metal part.

[Function] The low melting point molten metal processing tool according to the present invention has a matrix layer in which a solid solution of 2 nickel boride and titanium carbide is mixed and disposed between titanium boride particles and has a porosity of 5% or less. Since at least the part that comes into contact with the low melting point molten metal is formed of the titanium boride ceramic sintered body, the Vickers hardness, bending strength, porosity 3, and thermal shock of the part that comes into contact with the low melting point molten metal are improved. 13 resistances and more! It has the effect of 'i', and even when used
It also has the effect of sufficiently suppressing the reaction with low melting point molten metals, and as a result, has the effect of achieving a longer service life.

[Example] Next, the present invention will be specifically described with reference to the accompanying drawings. For convenience, a nozzle for M manufacturing will be described as a specific example of the low melting point molten metal processing tool according to the present invention.

FIG. 1 is a partial sectional view showing a casting nozzle as an embodiment of the low melting point molten metal processing tool according to the present invention,
A protective layer 12 formed of a titanium boride ceramic sintered body is disposed on the inner circumferential surface of the nozzle body 11, and the nozzle body 11 has a thermal expansion coefficient close to that of the titanium boride ceramic sintered body. It is made of a material that has

FIG. 2 is an enlarged sectional view showing a protective layer disposed on the inner circumferential surface of the nozzle body of the embodiment shown in FIG.

FIG. 3 is an optical WJ micrograph showing the structure of the surface of the polished protective layer of Example 1 [A], and shows the case of Example 5.

FIG. 4 is a scanning electron micrograph showing the -'' weave on the fractured surface of the protective layer in the example shown in FIG. 1, and shows the case of Example 5.

5 [J is an optical +A microphotograph showing the structure of the surface of the etched protective layer of Example 5 in FIG.
The case is shown below.

No. 6 ['A] is a scanning electron micrograph showing the structure of the surface of the etched protective layer of the embodiment shown in FIG. 1, and shows the case of embodiment 5.

FIG. 7 is a graph showing the results of X-ray diffraction analysis performed on the protective layer of the fjS1 diagram example, and is
In the case of S, the horizontal axis represents the XMA diffraction angle and the vertical axis represents the X-ray diffraction intensity.

FIG. 8 is a scanning electron WJ microphotograph showing the structure of the fractured surface of the protective layer of the #) 1 manufacturing nozzle shown as Comparative Example 1.

No. 91J is a partial cross section U showing another casting nozzle as another embodiment of low melting point molten metal processing according to the present invention.
, 4, the nozzle body 11° is entirely formed of a titanium boride ceramic sintered body, and the protective layer is removed.

First, the structure and operation of an embodiment of the low-melting point molten metal processing tool according to the first embodiment will be explained in detail.

The coefficient of thermal expansion ρ is close to that of the titanium boride mix sintered body of the low-melting point molten metal processing of the present invention (here, a "casting nozzle" is taken as an example), that is, it is not much different. The nozzle body 11 is made of a material such as a suitable metal (for example, brass) having a coefficient of thermal expansion ρ2 and is not brought into contact with low melting point molten metal; It is formed of a titanium oxide ceramic sintered body and includes a portion that comes into contact with a low melting point molten metal, that is, a protective layer 12. The ratio between the thermal tensile coefficient ρ of the titanium boride ceramic sintered body forming the protective layer 12 and the thermal expansion coefficient ρ2 of the material forming the nozzle body 11 satisfies l/4≦ρ1/ρ2≦4. It's so nice.

A low melting point molten metal processing tool, ie a casting nozzle, is used to supply a low melting point molten metal to a supply means (e.g. ladle).
The low melting point molten metal supplied to the upper opening through the supply means is guided by the inner surface of the protective layer 12 arranged against the inner circumferential surface of the nozzle body 11 and is introduced into the mold from the lower opening. released towards.

At this time, the protective layer 12 is made of a titanium boride ceramic sintered body in which a matrix layer containing a mixed solid solution of nickel boride and titanium carbide is arranged between titanium boride particles and has a porosity of 5% or less. After being formed,
It is possible to prevent the nozzle body 1 from being corroded by the low melting point molten metal, and to avoid mixing the material of the nozzle body 11 with the low melting point molten metal. Also, protective layer I
Since the thermal expansion coefficients of the protective layer 12 and the nozzle body 11 are not much different from each other, it is possible that a large thermal strain will be generated between the protective layer 12 and the nozzle body 11 when processing low melting point molten metal. Therefore, no damage occurs between the protective layer 12 and the nozzle body 11.

In the low melting point molten metal processing, that is, the casting nozzle, titanium tetraboride TiR2 particles 20 and titanium boride TiL particles 20 are bonded within the structure of the protective layer 12 disposed on the inner peripheral surface of the nozzle body 11. It includes a mesh-like bonding layer 30 for

The titanium boride TiB2 particles 20 have an average particle size of 0.5~
It is preferable if the average particle size is 0.5 to 3 m and the maximum particle size is 6 gm. The basis for setting the average particle size of the titanium boride TiR2 particles 2D to 0.5 to H1 μm is that (i) If the average particle size of +j is less than 0.5 μm, the surface oxidation of the titanium boride Ti82 particles 20 may occur. Titanium boride TiB
The aggregation of the particles 20 will significantly inhibit the sintering of the protective layer 12 of the titanium boride ceramic sintered body of the present invention, that is, the casting nozzle, and (ii) the average particle size If it exceeds 10 gm, the driving force for sintering will become smaller and the protection of the casting nozzle will be affected by the unexploded 11 M! It becomes difficult to densify titanium boride Ti8.j12. Existing cracks in the particles 20 are enlarged and the strength of the protective layer 12 of the casting nozzle according to the present invention is reduced. In addition, the reason why the maximum particle size of the titanium boride TiRz particles 20 is 12 gm is that if the maximum particle size exceeds 12 pm, it exists as coarse particles in the protective layer 12 of the casting nozzle publication according to the present invention. Therefore, it is difficult to increase the density or strength of the protective layer 12 of the cast nozzle rice grain according to the present invention.

A grain boundary phase 21 consisting of a mixed solid solution phase of titanium boride TiRz and nickel boride Ni 8 is formed near the grain boundaries of the titanium boride TiB2 particles 20. As a result, the bonding force between the titanium reboride TiL particles 20 and the bonding layer 30 is sufficiently large, and as a result, the strength of the protective layer 12 of the casting nozzle related to unexploded [J], etc. is ensured.

The bonding layer 30 is TiB2+ 2Ni+C→2NiB+TiC or TiBffi+ Ni+C→NiB2+ TiC or TiB2+ 6Ni+C−+ 2Ni:lB+ TiC between nickel Ni, titanium boride TiB2, and carbon: jr, C.
NiB, N1Rz or Xi:l
It is a matrix layer in which titanium oxide (TiC, etc.) is mixed solidly dissolved in (B, etc.), and pores are sufficiently removed. As a result, the bonding force between the titanium boride TiB2 particles 20 is seven times larger, and it is also a protective layer for the casting nozzle!
Since the porosity (that is, the value obtained by dividing the pore volume by the total volume) is 5% or less, the density and strength of the protective layer 12 of the casting nozzle according to the present invention are ensured. There is. Here, the bonding layer or matrix layer 30
The reason why vacancies are substantially removed is that nickel N
The particle size of the boride i, that is, the boride metal NiB, N1Bz, or NiJ, and the particle size of titanium carbide TiC are almost the same, and they are homogeneously mixed and solid-solved with each other.

Furthermore, a manufacturing procedure for an embodiment of the low melting point molten metal processing tool according to the present invention will be explained.

In the first step, a ceramic compound is created by blending titanium boride TiR2 powder, nickel Ni powder, and carbon C powder at an appropriate blending ratio.

That is, (i) the average particle size is 0.5 to 10 μLm (preferably 0.5 to 1 μLm) and the maximum particle size is 12 gm (preferably 1
) with a purity of 9 g wt % or more, and (ii) with an average particle size of 1-5 gm (preferably 1-3 uLm) and a maximum particle size of 12 uLm (preferably 6 μL ) and (iii) a specific surface area of 50 to tSO2/g (preferably 80 to 150s2
/g) with a purity of 99.9% or more and an average particle size of 1
Carbon (0 to 10100nm, preferably lO to 50nm) with a maximum particle size of tSOnm (preferably Ioonm)
For example, carbon black, etc.) are blended with each other to create a ceramic blend. In ceramic formulations, a mixture of nickel Xi and carbon C 0.1
~8gwt% (preferably 2.5~25.0wt%) titanium boride Tie2 or 11~99.9
ffi amount % (preferably 758 to 97.5 weight % to #) is blended. The blending ratio of Nitsukenoi i and carbon C is 14:0.1 to 10 (particularly preferably 14:0.2 to 5) by weight.

The reason why the purity of titanium boride TiBg is set to be 99% by weight or more is to prevent impurities from having an adverse effect during sintering.

The reason why the average particle size of nickel Ni is 1 to 5 pm is that (i) if the average diameter of nickel is less than 1 pm, then Nirakel N
Surface oxidation of i particles or significant WJ, and agglomeration between nickel Ni particles or nickel Ni particles and titanium boride Ti
82 particles or carbon C particles, which significantly inhibits the sintering of the protective layer 12 of the low melting point molten metal processing tool of the present invention, that is, the casting nozzle plate, and (ii) If the average grain size exceeds 5 m, coarse particles may be present in the matrix layer 30 of the protective layer 12 of the casting nozzle according to the present invention or in the grain boundary phase 21 formed near the grain boundaries of the titanium boride TiB2 particles-20. This is because the particles exist in the form of particles and reduce the strength etc. of the protective layer 12 of the casting nozzle related to Unreleased II. The reason why the maximum particle size of nickel Ni is set at 12 Bm is that if the maximum particle size exceeds 12 pm, existing cracks in the nickel Ni particles will be enlarged, which will reduce the strength of the protective layer 12 of the casting nozzle plate according to the present invention. The goal is to reduce the

Also, the reason why the average particle size of carbon C is 10~1100n is as follows: (i) If the average particle size is less than IOnm,
The surface oxidation of the carbon C particles becomes noticeable, and the agglomeration between the carbon C particles becomes significant, which significantly inhibits the sintering of the protective layer 12 of the casting nozzle plate related to unoccurred IJI, and (ii) ) If the average particle size exceeds 00 nm, the particles will exist as coarse particles in the matrix layer 30,
The object of the present invention is to reduce the strength of the protective layer 12 of the casting nozzle. The maximum particle size of carbon C is 1.5
The reason why it is set as 0nm is that if the maximum particle size exceeds lsOnm, it is due to existing cracks in the carbon C particles or titanium carbide TiC caused by reaction with titanium boride TiB2.
Existing cracks in the particles are enlarged, and the strength of the protective layer 12 of the casting nozzle W related to the undeveloped II is reduced.

Furthermore, the reason why the specific surface area of carbon C is said to be 5() to 150 m2/g is that (i) If the specific surface area is less than 50 m27g, the carbon C particles are too large and there is a gap between them and titanium boride TiR2. (ii) If the specific surface area exceeds 150 m2/g, the carbon C particles will aggregate and become difficult to mix with titanium boride Tie and nickel Ni. The problem lies in not being able to do anything.

In the second step, the ceramic mixture is homogeneously mixed using an appropriate mixer to create a ceramic mixture.

In the third step, the ceramic mixture is mixed with a binder (
For example, Bobbinyl alcohol) is placed in an appropriate mold, and then the pressure is adjusted to an appropriate level (for example, 1[lO~800
A pressure of kH/c 2) is applied and uniaxially pressed to produce a ceramic green compact.

In the fourth step, the ceramic green compact is subjected to CIP treatment, that is, room temperature isostatic compression molding treatment, by applying an appropriate pressure (for example, a pressure of 800 to 1500 kg/cm²) to form a ceramic compact.

In the fifth step, the ceramic molded body is placed in a vacuum atmosphere (preferably at an atmospheric pressure of IO-''Torr or less).
, in a non-oxidizing atmosphere (i.e., a neutral or reducing atmosphere) such as an argon atmosphere or a hydrogen gas atmosphere, in an unpressurized state or a pressurized state (100 to 500 kg
2) and sintered at a temperature of 1,500 to 2,000°C (preferably 1,600 to 1,800°C) for an appropriate time to obtain a ceramic sintered body. What is the basis for the non-oxidizing atmosphere?

The purpose is to prevent titanium Ti, boron B, nickel Xi, or carbon C from being oxidized.

In the sixth step, the ceramic sintered body, that is, the protective layer 12, is processed, that is, mainly its inner surface is polished to a desired precision.

In the seventh step, the nozzle body 11 is formed using a metal or the like (for example, !yj copper, etc.) having a thermal expansion coefficient close to that of the protective layer 12.

At about the 8th Tl, the protective layer I2 is attached to the inner circumferential surface of the nozzle body 11 using an appropriate adhesive (for example, an inorganic adhesive, etc.).
Join using.

By the above steps 1--, the low-melting point melting metal processing vessel, that is, the casting nozzle according to the present invention is manufactured.

In addition, regarding the embodiments of the low melting point molten metal processing tool according to the present invention, in order to understand the layer, specific numerical values etc. will be listed and explained. j.

(Go to Example 1-7) Nickel Xi has an average particle diameter of 1 μm and a specific surface area!
Mixture 2.5 made by changing the mixing ratio with carbon black C, which has a purity of 15m'/)z and 99-πX and 1%.
,T, ,l, ;%, 97.5ifJ% of titanium boride Ti1l□ having an average particle size of 3 gm, a maximum particle size b<slm, and a purity of 99% by weight was added. 100 parts of the prepared ceramic mixture was placed in a plastic container together with urethane balls and ]00 parts of ethylene alcohol, and wet mixed for 24 hours.
This produced a ceramic mixture.

The ceramic mixture was kept at a temperature of 60"C for 10 hours and dried for 10 minutes. Thereafter, the ceramic mixture 10
0FfB is polyvinyl alcohol 2 as a binder
The ceramic compact was placed in a suitable mold together with the sample, and uniaxially pressed under a pressure of 300 kg/c weight 2 to obtain a ceramic green compact.

The ceramic green compact was made into a ceramic molded body by applying a pressure of 30 kg/c**2 and subjecting it to CIP treatment, that is, room temperature isostatic compression molding treatment.

Ceramic molded bodies are non-pressurized! A ceramic sintered body was obtained by heating the sample to a temperature of 1700° C. at a heating rate of 15° C./min in an argon atmosphere and maintaining the temperature at 1700° C. for 1 hour.

The ceramic sintered body is processed by finishing, that is, mainly the inner surface. The protective layer was polished to a precision of 1 piece.

On the other hand, the nozzle body was formed using brass having a thermal expansion coefficient close to that of the protective layer 12.

Apply multiple adhesives to the inner surface of the nozzle body 11 using an appropriate UI adhesive (inorganic adhesive here). The I-layer divided bodies were joined together and placed as protection R+12.

As a result, a casting nozzle was created.

The total length of the casting nozzle is 150mm. It was said to be IOm■.

Regarding the protective layer 12 of the casting nozzle, Vickers hardness, bending strength, porosity, coefficient of thermal expansion, thermal conductivity, thermal shock resistance, and low melting point molten metal (molten aluminum here)
The wetting characteristics for each were measured and were as shown in Table 1.

Also, regarding the nozzle body 11 of the casting nozzle.

The Vickers hardness, flexural strength, porosity, coefficient of thermal expansion, and thermal conductivity were measured and found to be as shown in Table 1.

The nozzle for PJ supplies molten aluminum as a low melting point molten metal to its upper opening, and supplies it to the mold from its lower opening while guiding it by the inner peripheral surface of the housing 3) f++2 arranged in the nozzle body 11. did. When used continuously under this condition, the casting nozzle could be used for 90 hours (see "Life" in Table 1).

(Examples 8 to 14) Mixture of nickel Xi and carbon black C 5,0
m ji%, titanium boride Tie2 is 95.0
Examples 1-7 were repeated, respectively, except that % i'11ii and % i'11ii.

# Regarding the protective layer 12 published by PI Building Nozzle, Virakase hardness, bending strength, porosity, thermal expansion coefficient, thermal conductivity 1.8
The impact resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 1.

Further, the Vickers hardness, bending strength, porosity, coefficient of thermal expansion a, and thermal conductivity of the nozzle body 11 of the casting nozzle were measured, and the results were as shown in Table 1.

Further, the life of the casting nozzle nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

(Examples 15 to 21) 92.5 t% of titanium boride TiB2 was added to 7.5% of the mixture of nickel N: and carbon black C.
Examples 1-7 were each repeated, except that B.

For example, the casting nozzle holder is used to optically polish the outer surface of the protective layer 12 that has been polished in Example 18 (the same applies hereinafter).
When I observed the photograph U using a microscopic microscope, it was as shown in Fig. 3. That is, it was found that the bonding layer 30 was arranged in a scattered manner around the titanium boride particles-20, and that the bonding layer 30 had no pores and was dense.

#PI-forming nozzle cutting was performed by breaking the protective layer 12 with a moderate force, and photographing the broken surface using a scanning WJ microscope, as shown in FIG. 4.

That is, it was found that intragranular fracture occurred in the titanium boride Ti82 particles 20 and that the titanium boride Ti112R particles 20 were firmly bonded by the bonding layer 30. Bonding layer] 0 was determined by X-ray diffraction analysis to be titanium boride T
Reaction between iBz, nickel Ni, and carbon black C TiB2+5Ni +C→2Ni, B+ Nickel boride NiJ and titanium carbide TiC produced by Tie
A matrix layer containing a mixed solid solution of (see Figures 5 to 7)
I have made it clear that this is the case.

The outer surface of the casting nozzle was etched by immersing the protective layer 12 in aqua regia heated to 60°C for 3 minutes, and then photographed with an optical microscope. It was as shown. That is, by measuring the diameter of the titanium boride TiB2 particles 20 produced by the bonding layer 30 of the titanium boride TiB2 particles falling off due to the etching process, the average particle diameter of the titanium boride Ti1 (z particles 20 or 2 to IO In other words, it was found that the titanium boride TiB2 particles 20 had hardly grown compared to the initial state. This is because a reaction of +C→2NiffB+ TiC occurs, and the growth of titanium boride TiR2R particles 20 is suppressed.Also, titanium boride TiB
It was also found by X-ray diffraction analysis that a grain boundary phase 21 consisting of a mixed solid solution phase of titanium boride TiBz and nickel boride NiJ was formed near the grain boundary of the z grain 20 (Fig. 7). (attendance).

Regarding the protective layer 12 of the casting nozzle cover, Vickers hardness, bending strength, porosity, coefficient of thermal expansion, thermal conductivity, nols
The resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 1.

Further, the Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity of the nozzle body +1 of the casting nozzle base were measured, and the results were as shown in Table 1.

The life of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

(Examples 22 to 28) Titanium boride Tie 2 was planted at 90.0 weight % with respect to 8 weight % of the mixture of nickel Ni and carbon black C.
Examples 1-7 were each repeated, except that B.

Regarding the protective layer 12 of #pJ construction nozzle, we investigated the Vickers hardness, bending strength, porosity, thermal expansion coefficient, thermal conductivity, thermal shock g resistance, and wetting characteristics against low melting point molten metal (molten aluminum here). When measured, each
It was as shown in the table.

Also, regarding the nozzle body 11 of the PJ construction nozzle.

The Vickers hardness, flexural strength, porosity, coefficient of thermal expansion, and thermal conductivity were measured and found to be as shown in Table 1.

Further, the lifetime of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

(Examples 29 to 35) Mixture of nickel Ni and carbon black C 12.5
Examples 1 to 7 were each repeated, except that 87.5% by weight of titanium boride TiL was blended with respect to the weight %.

Regarding the protective layer 12 of the casting nozzle W, Vickers fracture, bending strength, porosity, coefficient of thermal expansion, thermal conductivity, thermal shock resistance, and low melting point molten metal (molten aluminum here)
The wetting characteristics for each were measured and were as shown in Table 1.

Further, the Vickers hardness, flexural strength, porosity, coefficient of thermal expansion, and thermal conductivity of the nozzle body 11 of the nozzle for M construction were measured, and the results were as shown in Table 1.

Further, the life of the #pI manufacturing nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

(Examples 36 to 42) Mixture of nickel Ni and carbon blank C 15.0
Examples 1 to 7 were repeated, respectively, except that titanium boride TiBz was blended in an amount of gs, otunpu % relative to 1%.

Regarding the protective layer 12 of the yJ construction nozzle, Vickers hardness, bending strength, porosity, M expansion coefficient, thermal conductivity, heat #I
When we measured the resistance and wetting characteristics for low melting point molten metal (here molten aluminum), we found that the first
It was as shown in the table.

Further, the Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity of the nozzle body 11 published by Casting Nozzle were measured, and the results were as shown in Table 1.

Further, the lifetime of the casting nozzle was measured in the same manner as in Examples 1 to 7, and the lifespan was as shown in Table 1.

(Examples 43 to 49) Blunt compound of nickel Ni and carbon black C 17.5
Examples 1 to 7 were each repeated except that 82.5% by weight of titanium boride Tie2 was blended with respect to the Irr amount %.

Regarding the protective layer 12 of the casting nozzle rice grain, Vickers hardness, transverse strength IL porosity, thermal expansion coefficient, 8 conductivity, thermal shock resistance, and low melting point molten gold i! : (here, molten aluminum), we measured the wetting characteristics, and found that the first
It was as shown in the table.

Further, the Vickers hardness, flexural strength, porosity, coefficient of thermal expansion, and thermal conductivity of the nozzle body 11 of the casting nozzle U were measured, and the results were as shown in Table 1.

Further, the life of the casting nozzle nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

(Examples 50 to 56) Mixture of nickel Ni and carbon black C 20.0
80.0% by weight of titanium boride TiB2
Examples 1-7 were each repeated, except that B.

Regarding the protective layer 12 of the casting nozzle U, Vickers hardness, flexural strength, porosity, coefficient of thermal expansion, thermal conductivity, thermal shock resistance, and low melting point molten metal (molten aluminum here)
The wetting characteristics for each were measured and were as shown in Table 1.

Further, the Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity of the nozzle body 11 of the casting nozzle were measured, and the results were as shown in Table 1.

Further, the life of the casting nozzle was measured in the same manner as in Examples 1 to 7, and the lifespan was as shown in Table 1.

Mixture of nickel Ni and carbon black C 22.5
77.5 weight of titanium boride TiR2 relative to the main star%;
Examples 1-7 were each repeated except that 1% was added.

The Vickers hardness, bending strength, porosity, coefficient of thermal expansion, thermal conductivity, thermal impact resistance, and wetting characteristics against low melting point molten metal (molten aluminum here) were measured for the protective layer 12 of the nozzle for project construction. , respectively, as shown in Table 1.

Further, the Vickers hardness If, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity of the nozzle body 11 of the nozzle rice grain for casting were measured, and the results were as shown in Table 1.

Further, the life of the casting nozzle plate was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

(Examples 64 to 70) Mixture of nickel Xi and carbon black C 25.0
75.0% by weight of titanium boride Ti1t with respect to small opening%
Examples 1-7 were each repeated, except that B.

For the protective layer 12 of the #4 Zokawa nozzle, Vickers hardness, bending strength, porosity, coefficient of thermal expansion, thermal conductivity, thermal shock resistance, and wetting characteristics against low melting point molten metal (here molten aluminum) were measured. However, they were as shown in Table 1.

In addition, the Virakase hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity of the nozzle body 11 of the PF manufacturing nozzle were measured, and the results were as shown in Table 1.

Further, the life of the casting nozzle was measured in the same manner as in Examples 1 to 7, and the results were as shown in Table 1.

(Examples 71 to 77) Titanium boride Tie2 was added in an amount of 92.5% to 7.5% by weight of a mixture of nickel Ni and carbon black C.
Examples 1-7 were each repeated, except that the sintering temperature was 150''C.

Regarding the protective layer 12 of the casting nozzle river, the Vickers hardness, bending strength, porosity, thermal expansion coefficient, thermal conductivity, thermal shock resistance, and wetting characteristics against low melting point molten metal i1 (here, molten aluminum) were measured. As a result, the second
It was as shown in the table.

Also, regarding the nozzle body 11 of the casting nozzle.

The Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity were measured and were as shown in Table 2.

#PfJ again? The life of the nozzle for i was measured in the same manner as in Examples 1 to 7, and was as shown in Table 2.

Examples 78-84 Examples 71-77 were repeated, respectively, except that the sintering temperature was 160°C.

The protective layer 12 of the nozzle for project construction was measured for its Vickers hardness, flexural strength, porosity, 8m tensile modulus, thermal conductivity, thermal shock resistance, and wetting characteristics against low-melting point molten metal (molten aluminum here). As a result, the second
It was as shown in the table.

Further, the Vickers hardness, bending strength, porosity, thermal expansion coefficient, and thermal conductivity of the nozzle body 11 of the casting nozzle were measured, and the results were as shown in Table 2.

Further, the life of the casting nozzle was measured in the same manner as in Examples 15 to 2I, and was as shown in Table 2.

(Examples 85-91) Examples 71-77 were repeated, respectively.

Regarding the protective layer 12 of the casting nozzle nozzle, Vickers hardness, transverse strength, porosity, AM tensile coefficient, thermal conductivity, thermal shock resistance, and low melting point molten metal (molten aluminum here)
When we measured the wetting characteristics for each: jS2
It was as shown in the table.

Furthermore, the Vickers hardness, flexural strength, porosity, coefficient of thermal expansion, and thermal conductivity of the nozzle body It for casting nozzles were measured, and the results were as shown in Table 2.

Further, the nozzle life of the casting nozzle was measured in the same manner as in Examples 15 to 21, and was as shown in Table 2.

(Examples 92-98) Examples 71-77 were repeated, respectively.

Regarding the protective layer 12 of the casting nozzle bracket, Vickers hardness, flexural strength, porosity, coefficient of thermal expansion, thermal conductivity, thermal shock resistance, and low melting point molten metal (molten aluminum here)
When the wetting characteristics were measured, the results were as shown in Table 2.

Further, the Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity of the nozzle body 11 of the casting nozzle base were measured, and the results were as shown in Table 2.

The life of the casting nozzle was measured in the same manner as in Examples 71 to 77, and was as shown in Table 2.

Comparative Example 1 Examples 1-70 were repeated except that Nickel N Myo and Carbon Black C were removed from the ceramic formulation.

In other words, titanium boride T with an average particle size of 3gm, a maximum particle size of 6JLm, and a purity of 99% by weight! 82,100 copies,
Polyvinyl alcohol 2 as a binder? A ceramic green compact was produced by placing the powder together with IJ in a suitable mold and applying a pressure of 100 kg/cm'' to uniaxially press the powder.

The ceramic green compact was made into a ceramic molded body by applying a pressure of 300 kg/cm 2 and subjecting it to CIP treatment, that is, room temperature isostatic compression molding treatment.

The ceramic molded body is heated to a temperature of 1700°C at a temperature increase rate of 15°C/min in an argon atmosphere under no pressure, and is maintained at a temperature of 170Q'c for 1 hour to undergo ceramic sintering. As a body.

The ceramic sintered body was finished, that is, the inner surface was mainly polished to a desired precision to obtain a protective layer divided body.

On the other hand, the nozzle body was formed using brass having a thermal expansion coefficient close to that of the protective layer.

A plurality of protective layer segments were each bonded to the inner circumferential surface of the nozzle body using an appropriate adhesive (inorganic adhesive here), and the protective layer was disposed. In this way, a casting nozzle was created.

PJ construction nozzle breaks the protective layer with moderate force,
When the fractured surface was photographed and observed using a scanning type Wk microscope, it was found that titanium boride Ti8. It was found that grain boundary fracture of the particles occurred predominantly, and that the bonds between the titanium boride TiBz particles were not very strong.

In addition, the Vickers hardness, bending strength, porosity, coefficient of thermal expansion, thermal conductivity, thermal shock resistance, and wetting characteristics against low melting point molten metal fjE (molten aluminum here) were measured for the protective layer of the casting nozzle. , respectively the first
It was as shown in the table. Also regarding the nozzle body of the casting nozzle.

The Vickers hardness, flexural strength, porosity, coefficient of thermal expansion, and thermal conductivity were measured and found to be as shown in Table 1.

Further, the lifespan of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

Comparative Example 2 Examples 1-7 were repeated except that carbon black C was removed from the ceramic formulation.

Regarding the protective layer of the casting nozzle, Vickers hardness, bending strength, porosity, S expansion coefficient, and heating element 4*.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 1. Also, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, porosity, etc.
1! ) The expansion coefficient and thermal conductivity were measured and were as shown in Table 1.

Moreover, when the life of the casting nozzle was measured in the same manner as in Examples 1 to 7, it was as shown in the if table.

Comparative Example 3 Examples 8-14 were repeated except that carbon black C was removed from the ceramic formulation.

Maintenance of casting nozzle: Vickers hardness, bending strength, porosity, coefficient of thermal expansion, thermal conductivity for J layer.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 1. In addition, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, porosity,
When the ripeness fi coefficient and thermal conductivity were measured, they were as shown in Table 1.

Further, the life of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

Comparative Example 4 Examples 15-21 were repeated except that carbon black C was removed from the ceramic formulation.

Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity for the protective layer of casting nozzles.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 1. In addition, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 1.

Further, the life of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

Examples 22-28 were repeated except that carbon black C was removed from the ceramic formulation.

Regarding the protective layer of the casting nozzle, Vickers hardness, bending strength, and porosity are 1. @Expansion fta, thermal conductivity.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 1. In addition, regarding the nozzle body of the casting nozzle, the Virakas hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 1.

Further, the life of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

Comparative Example 6 Examples 29-5 were repeated except that carbon black C was removed from the ceramic formulation.

Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and S conductivity for the protective layer of the casting nozzle.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 1. In addition, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 1.

Further, the life of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

Comparative Example 7 Examples 36-42 were repeated except that Carbon Blank C was removed from the ceramic formulation.

Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity for the protective layer of casting nozzles.

Thermal shock resistance and wetting characteristics against low melting point molten metal fi (here molten aluminum) were measured, and the results were as shown in Table 1. Further, the Vickers hardness, bending strength, porosity, thermal expansion coefficient a, and thermal conductivity of the nozzle body of the casting nozzle were measured, and the results were as shown in Table 1.

Further, the lifespan of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

(Comparative Example 8) Examples 43 to 49 were repeated except that carbon black C was removed from the ceramic compound, and the Vickers hardness, transverse strength, porosity,
Thermal expansion coefficient, thermal conductivity.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 1. In addition, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 1.

Further, the life of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

Comparative Example 9 Examples 50-56 were repeated except that carbon black C was removed from the ceramic formulation.

Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity for the protective layer of casting nozzles.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 1. In addition, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 1.

Further, the lifespan of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

Examples 57-63 were repeated except that carbon black C was removed from the ceramic formulation.

Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity for the protective layer of the casting nozzle.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 1. In addition, regarding the nozzle body of the H construction nozzle, Vickers hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 1.

Further, the lifespan of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

Comparative Example 11 Examples 64-70 were repeated except that carbon black C was removed from the ceramic formulation.

Regarding the protective layer of the casting nozzle, Vickers hardness, transverse strength 2 porosity, coefficient of thermal expansion, and thermal conductivity.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 1. In addition, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 1.

Further, the lifespan of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 1.

Comparative Example 12 Examples 71-77 were repeated except that nickel Ni and carbon black C were removed from the ceramic formulation.

The protective layer of the casting nozzle was measured for its Vickers hardness, bending strength, porosity, /SS expansion coefficient, mature thermal conductivity, thermal shock resistance, and wetting characteristics against low melting point molten metal (molten aluminum here). It was as shown in Table 2. Further, the Vickers hardness, flexural strength, porosity 2 coefficient of thermal expansion, and thermal conductivity of the nozzle body of the casting nozzle were measured, and the results were as shown in Table 2.

Further, the life of the PF manufacturing nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 2.

Comparative Example 13 Examples 78-84 were repeated except that nickel Ni and carbon black C were removed from the ceramic formulation.

Maintenance of casting nozzles! Regarding the I layer, Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 2. In addition, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 2.

The life of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 2 (Comparative Example 14), except that nickel Ni and carbon black C were removed from the ceramic compound. Examples 85-91 were repeated.

Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity for the protective layer of casting nozzles.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 2. In addition, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, porosity,
When the thermal expansion coefficient a and thermal conductivity were measured, they were as shown in Table 2.

Further, the lifespan of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 2.

Comparative Example 15 Examples 92-98 were repeated except that nickel Ni and carbon black C were removed from the ceramic formulation.

Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity for the protective layer of casting nozzles.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 2. In addition, regarding the nozzle body of the casting nozzle, the Virakas hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 2.

Further, the lifespan of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 2.

(Comparative Example +6) Examples 71-77 were repeated except that nickel Ni and carbon black C were removed from the ceramic formulation.

Vickers hardness, flexural strength, porosity, coefficient of thermal expansion, and thermal conductivity for the protective layer of g-building nozzles.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 2. In addition, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 2.

Further, the lifespan of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 2.

Comparative Example 17 Examples 78-84 were repeated except that nickel Ni and carbon black C were removed from the ceramic formulation.

Regarding the protective layer of the casting nozzle, Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and 8 conductivity.

81# impact resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured, and the results were as shown in Table 2. Also, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, and porosity are 9. When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 2.

Moreover, when the life of the casting nozzle was measured in the same manner as in Examples 1 to 7, it was as shown in the tJS2 table.

(Comparative Example +8) Examples 85-91 were repeated except that nickel Ni and carbon black C were removed from the ceramic formulation.

Regarding the protective layer of the casting nozzle, Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and 8 conductivity.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 2. In addition, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 2.

Further, the lifespan of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 2.

Examples 92-98 were repeated except that carbon black C was removed from the ceramic formulation.

Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity for the protective layer of casting nozzles.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here molten aluminum) were measured and were as shown in Table 2. In addition, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 2.

Further, the lifespan of the casting nozzle was measured in the same manner as in Examples 1 to 7, and was as shown in Table 2.

Comparative Example 20 Comparative Example 1 described in -E was repeated, except that the ceramic formulation was silicon nitride 5i1N.

Vickers hardness, bending strength, porosity, coefficient of thermal expansion, and thermal conductivity for the protective layer of #8 nozzle.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured and were as shown in Table 3. In addition, regarding the nozzle body of the casting nozzle, Vickers hardness, bending strength 2 porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 3.

In addition, the life of the casting nozzle is as follows in Comparative Example 1 and Example 1.
Measurements were made in the same manner as in 7 to 7, and the results were as shown in Table 3.

Comparative Example 21 Comparative Example 1 above was repeated, except that the ceramic formulation was silicon carbide, SiC.

Vickers hardness, bending strength, porosity, coefficient of thermal expansion, /S conductivity for the protective layer of the casting nozzle.

Thermal shock resistance and wetting characteristics against a low melting point molten metal (here, molten aluminum) were measured, and the results were as shown in Table 3. In addition, regarding the nozzle body of the casting nozzle, the Virakas hardness, bending strength, porosity,
When the thermal expansion coefficient and thermal conductivity were measured, they were as shown in Table 3.

In addition, the life of the casting nozzle is as follows in Comparative Example 1 and Example 1.
When measurements were made in the same manner as in 7 to 7, the results were as shown in Table 3.

As is clear from a comparison of Examples 1 to 98 and Comparative Examples 1 to 21 described above, according to the present invention, a nickel Ni oxide film is applied to the inner peripheral surface of the nozzle body, which contacts the low melting point molten metal. A mixed solid solution matrix layer of titanium boride and titanium carbide is disposed between the titanium boride particles, and
By placing a protective layer made of a titanium boride ceramic sintered body with a porosity of less than In addition, preheating can be avoided during use, and reactions with low melting point molten metals can be sufficiently suppressed, and as a result, its life can be significantly extended. Further, according to the present invention, by forming the nozzle body with a material having a thermal expansion coefficient close to that of the titanium boride ceramic sintered body, thermal strain between the protective layer and the nozzle body can be sufficiently reduced. As a result, its lifespan can be extended.

Further, in the above description, the protective layer is sintered and then placed on the inner peripheral surface of the nozzle body, but the present invention is not limited to this, and the protective layer is placed on the inner peripheral surface of the nozzle body. The protective layer may be formed by disposing the ceramic mixture by coating or the like and then sintering it.

In addition, in the description L, only the part that contacts the low melting point molten metal (the protective layer in the above) is formed of the titanium boride ceramic sintered body, but the present invention is not limited to this. As is clear from FIG. 9, in which the nozzle body 11' of the casting nozzle is entirely made of titanium boride ceramic sintered body, even the parts that are not in contact with the low melting point molten metal are made of titanium boride ceramic. It also includes the case where it is formed from a sintered body.

(3) Effects of the Invention As is clear from the above, the low melting point molten metal processing tool according to the present invention is a low melting point molten metal processing tool that is brought into contact with a low melting point molten metal, and in particular, it is a low melting point molten metal processing tool that comes into contact with a low melting point molten metal. A matrix layer mixed with titanium carbide in solid solution is disposed between the titanium boride particles, and is in contact with at least the low melting point molten metal by a titanium boride ceramic sintered body having a porosity of 5% or less. Because the part that is formed is formed.

(i) It has the effect of improving the Vickers hardness, flexural strength, porosity, thermal shock resistance, etc. of the part that comes into contact with low melting point molten metal, and (i) It has the effect of avoiding preheating during use. has
and (iii) it has the effect of sufficiently suppressing the reaction with low melting point molten metal, and as a result (iv) it has the effect of extending the life.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing a casting nozzle as an embodiment of the low melting point molten metal processing tool according to the present invention, and FIG. FIG. 3 is an enlarged cross-sectional view showing the protective layer 4; FIG.
The figures are a scanning electron micrograph showing the structure of the fractured surface of the protective layer in the example shown in FIG. 1, an optical microscope photo showing the structure of the etched protective layer surface in the example shown in FIG. 1, and FIG. Fig. 1 is a scanning electron micrograph showing the structure of the surface of the etched protection layer of Example A; Figure 8 is a scanning electron micrograph showing the structure of the fractured surface of the protective layer of the casting nozzle shown as Comparative Example 1, and Figure 9 is a scanning electron micrograph showing the structure of the fractured surface of the protective layer of the casting nozzle shown as Comparative Example 1. It is a partial sectional view showing a casting nozzle. Disappearance, wear and tear'...Casting nozzle 11.11'...Nozzle body 12...・・・・・・・・・・・・・・・Tsu,
! II2O3・・・・・・・・・・・・・・・・・・
Titanium boride particles 21・・・・・・・・・・・・・・・
...Grain boundary phase 30...1 River...Matrix layer Patent applicant Niss T.K. Co., Ltd.
Ceramics Research Institute (1 other person) Agent: Takao Fuji, Fig. 3 fl,, %, Cμn] Fig. 4 i'71 Fig. 5 1Ononozu Fig. 6 Fig. 7 0TiB2 Angle Fig. 8

Claims (4)

[Claims] (1) In a low melting point molten metal processing tool that is brought into contact with a low melting point molten metal, a matrix layer in which a mixed solid solution of nickel boride and titanium carbide is disposed between titanium boride particles and has a content of 5% or less A low melting point molten metal processing tool, characterized in that at least a portion that comes into contact with the low melting point molten metal is formed of a titanium boride ceramic sintered body having a porosity of . (2) The portion not in contact with the low melting point molten metal is formed of a material having a thermal expansion coefficient close to that of the titanium boride ceramic sintered body. 1) The low melting point molten metal processing tool described in item 1). (3) A low melting point molten metal according to claim (2), wherein the material having a thermal expansion coefficient close to that of the titanium boride ceramic sintered body is made of brass. Processing tools. (4) The titanium boride particles have an average particle size of 0.5 to 10 μm.
) to (3).