JPS6191066A - Manufacture of silicon nitride powder added with oxide of rare earth element on surface - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to rare earth element oxides or rare earth element c13
The present invention relates to a method for producing nitride powder containing 44 oxides of aluminum and 44 oxides, and particularly relates to a method for producing silicon nitride suitable as a raw material for producing a sintered body.

Conventional technologySilicon nitride has various properties such as high strength at high temperatures, high thermal shock resistance, and high corrosion resistance, so it is beginning to be used for high-strength heat-resistant parts. However, the migration speed of nitrogen is extremely low, making it difficult to create a dense sintered body with a theoretical density using a single composition.

In order to alleviate this difficulty, magnesium oxide, beryllium oxide, aluminum oxide, oxides of rare earth elements, etc. have traditionally been added, and during sintering, the additives and silicon nitride are entrained around the silicon nitride particles. A sintering method is used in which silicon nitride reacts with silica to form a high-temperature melt, and densification progresses through the movement of silicon nitride through this melt.

Problems to be Solved by the Invention Conventionally, the method of adding the above-mentioned additives has been to mechanically mix the additive powder and silicon nitride powder using a ball mill or the like. , - is that the additive powder and silicon nitride powder are agglomerated, and the particle size of the additive powder is the same as the particle size of the silicon nitride powder, so it is added around the nitride/fluorine particles during sintering. J, Ru+, +i+ to the silica accompanying the agent and silicon nitride
A uniform mixture of powders with a uniform body shape (9 unknown, silicon nitride powder with additives on the surface of 157 millimeter powder for sintering silicon nitride yarn) It wasn't manufactured.

Means for solving and overcoming the problems The present inventors have developed a nitrided material with additives attached to the surface.
<The Sung Dynasty, who conducted extensive studies on powder, discovered the phenomenon that gel-like hydroxides of rare earth elements and aluminum form on silicon nitride bodies, and discovered that the rare earth element or the combination of it and aluminum. The inventors discovered that by roasting silicon nitride powder to which gelled hydroxide was attached, 17 L/1 rJ of nitride powder with rare earth elements or oxides of rare earth elements and aluminum added thereto could be obtained, and the present invention was completed. .

That is, the structure of the present invention is to mix a gel hydroxide of a rare earth element or a mixed gel hydroxide of a hydroxide of a rare earth element and aluminum hydroxide 11 with silicon nitride powder, A gel-like hydroxide is attached to the surface of silicon powder, and then the mixture is heated. This is a method for producing ζ silicon nitride powder.

The present invention will be explained in detail below.

The silicon nitride powder used in the present invention is not limited to a specific one, and the particle size, gelatinization rate, etc. may be selected depending on the purpose of use, and the effects of the present invention can be achieved no matter what kind of powder is used. There is no change. What is the practical purpose of silicon nitride sintered bodies? ! Since the silicon nitride powder is a material with high temperature and high strength, it is appropriate to use silicon nitride powder as a raw material having an average particle size of about 0.5 μm to 5 μm, which is commonly used for the above purpose.

The rare earth elements referred to in the present invention include lanthanum, cerium-11, plagiodymium, neodymium, samarium, europium, gadolinium, i-lupium, yttrium, thulium,
These are ytterbium, luteboum, erbium, holmium, and dysprosium.

The gel-like hydroxide of aluminum used in the present invention is a rare element or an aqueous solution of aluminum f/I: 1B, for example, chloride, 1'l M J7a
``!r '/) Mineral acid Ja!, Vinegar 1'l!I r=, 1
'M salt' 9 (1) React an aqueous solution of N1112 salt with an alkali, such as aqueous solution of sodium chloride, caustic potash, etc. 1!1
There is a '1-transparent amorphous 7'1 substance C, which forms a paste-like form when dispersed in water ('1').

48. Reaction of aqueous solution of aluminum salt, Il, with alkali aqueous solution IJ, temperature 1σ,
By changing the concentration, 1) etc., the type of force produced changes. Preferably, the temperature is adjusted to 40° C. or lower, and the amount of rare elements or aluminum is adjusted to 0.2 mol/P or less, p l-1
is preferably maintained at 8.5 or above and reacted. The required amount of alkali is diluted,
It is preferable to LV43'L cable or aluminum, and it is necessary to have 3 equivalents or more.

Of course, the gelled hydroxide of rare earth jf1 and aluminum used in the present invention is made purely from gelled hydroxide (although it may not be made of gelled hydroxide, it may also contain some hydroxide). Alternatively, it is also possible to use a mixture containing JJ salt.

As an example of IC gel hydroxide produced by the above method, the X-ray diffraction pattern of yttrium gel hydroxide is shown in Figure 1. X of crystalline water yttrium hydride shown in Figure 2
粍! This clearly differs from the regular diffraction pattern shown in the diffraction chart. In addition, when looking at the infrared absorption spectrum of powder i, which is made by air-drying yttrium gel hydroxide at room temperature, the third
As shown in the figure, the absorption peak caused by hydroxide is broad, and like the infrared absorption spectrum of crystal 71 yttrium hydroxide shown in Figure 4, the absorption peak is broad. The absorption peak caused by the absorption peak in November has become more pronounced in the stomach. Furthermore, after washing the gelled hydroxide of yttrium with water, we analyzed the components of the solution by dissolving it in acid, and found that there was no alkaline component, and there were also acid residues of the yttrium salt used as a feedstock. Because I don't do it,
It can be seen that it is composed of yttrium, flit, L and water. Furthermore, although the gel-like hydroxide of yttrium is translucent when dispersed in water,
Centrifugal sedimentation is possible with 01 straight of about 000 C-, and water can be separated by G3 Gance filter. Judging from these facts, it is predicted that it is a polymer in which many yttrium hydroxide molecules are condensed and polymerized. The above properties apply to gel-like hydroxides of type 1 metals other than isolium and aluminum, as well as gel-like hydroxides containing rare earth elements and two types of metal ions derived from aluminum. Things have 6 things in common.

In the present invention, silicon nitride powder is a material that has a rare earth element or a fine oxide of it and aluminum uniformly deposited on its surface. It is clear from the examples that the attached oxide is not easily peeled off by mechanical separation such as ultrasonic separation, shaking N1, centrifugation, etc. , a mixture of F2 oxide and silicon nitride li and 51i! It is clear that this will happen.

As an example of nitrided powder with oxide attached, Fig. When comparing the electron beam photograph of silicon nitride powder with 5% by weight adhering to the electron beam photograph of the raw material silicon nitride υ) shown in Figure 6, there is almost no difference in particle size and particle shape. .

In other words, the gel-like hydroxide of yttrium is roasted to perfection! No spherical agglomerated particles, which are formed by agglomeration of very round primary particles with a particle size of 0.1 μm or less, which is characteristic of yttrium oxide, were observed (4-1). In this way, when observed using an electron microscope, no yttrium oxide particles were found adhering to the surface of silicon nitride powder, but when the powder was treated with hydrochloric acid, nitric acid, etc., and the treated solution was measured, the resulting solid It is clear that -rthium oxide is present because when the oxide is roasted, 1 to 1 to 10% of oxide (predetermined) is recovered.

From the above results, the structure of the rare earth element or the oxide of the rare earth element and nofluminium of the present invention attached to the surface of the silicon nitride powder is several steps larger than the size of the silicon nitride grains. It is determined by JIE that the rare earth element is small, that is, it is a rare earth element with little agglomeration of primary particles, or fat, in which oxide particles of aluminum and the rare earth element are attached. In particular, the rare earth element or aluminum gel hydroxide used in the present invention differs from crystalline fine particles in that it has a strong As shown in the examples, this is based on the sedimentation rate of the gelled hydroxide slurry and the slurry in which silicon nitride is mixed into the gelled hydroxide slurry. Comparing the precipitated jff l Ii, Toshija is clearly more human, and no matter which part of the precipitated mixed slurry is taken out and analyzed, the ratio of rare earth elements or aluminum to silicon nitride is the same. Furthermore, unlike crystalline substances, the gel-like hydroxide has an indeterminate shape, so it can adhere to the irregularities of the silicon nitride-based surface of the adherend. Therefore, the oxides produced by roasting the deposits are
Unlike 141 which is simply in contact with silicon nitride powder, it is thought that it has a so-called anchor effect and takes a state of being strongly ('J83).

In addition, the rare earth elements referred to in the present invention 1. The hydride d'+ or a mixture of it and aluminum oxide is the
1i, J, Ru analysis C-crystal? 1 and (see 4j and i 1
It also includes the so-called Jl-crystal X'1 oxide.

For the central office ("+"i'), rare"汀1-i'l: ,+
A 112 compound oxide of r and aluminum (1 shallow box) 1 compound of 1 element and 7 normium is produced by roasting 1 gel-like hydroxide and 11 filtration process to 1 oxidation. It is expected that solid solutions, intercompounds, or (component structures) CLb, 11 ~
A compound is a kind of stomach.

In the present invention, in order to produce silicon nitride powder by adhering rare earth elements or oxides of aluminum and rare earth elements, the adhesion properties of gelled hydroxides of rare earth elements or aluminum are utilized.

In other words, rare earth elements or aluminum gelled hydroxyl 1
Hello, similar to ordinary organic polymers, especially poval which has many hydroxyl groups, silicon nitride powder was added to water in which gel-like hydroxide was suspended and stirred. When the head is released afterwards, the gel-like hydroxide that is freely dispersed in the solution disappears, and the solution becomes transparent on the surface of the nitrided wood flour. In this case, the solid content sedimentation volume is almost the same as the sedimentation volume shown by Nitrogen 1 Hikei and Azuma only slurries, and Moraro/
υ, .

Gelled hydroxide is deposited and the sediment is small (1" (J).

By roasting the silicon nitride prepared in this way, the gelled hydroxide thermally decomposes into oxides, and silicon nitride powder with 1119 oxides attached to the surface. The body is i!t.

This manufacturing method will be described in more detail below.

To apply gel hydroxide of a rare earth element or rare earth element and aluminum to the surface of silicon nitride powder, first prepare a predetermined amount of gel hydroxide, and then apply it to the silicon nitride powder. After suspending silicon nitride powder in an aqueous alkali solution, a predetermined amount of a rare earth element or an aqueous solution of it and aluminum is added to the suspension to precipitate a gelled hydroxide. At the same time, silicon nitride powder can be attached to the surface of silicon nitride powder, or silicon nitride powder can be suspended in an aqueous solution of aluminum and aluminum. Aqueous solution of alkali in aqueous solution,
) to precipitate gel-like hydroxide, the same 11,1
Another method is to apply it to the surface of the nitrided/finished powder.

In addition, the composition and composition of the rare earth element or aluminum gel hydroxide to be attached to silicon nitride may be determined from the composition and composition of the oxide to be attached to the nitride powder, and can be determined as desired depending on the intended use of the product. It is lawful.

To separate the silicon nitride powder produced from the above aqueous solution and having the earth base or gelled hydroxide of aluminum attached to its surface, there are commonly used methods such as centrifugal filtration. The solid-liquid valve section 1 is separated using a press filter or the like.

Silicon nitride powder with gelled hydroxides of rare earth elements and aluminum attached to the surface of the present invention (when roasting wood, the roasting atmosphere is an inert atmosphere such as N2, Ar, etc., Any chemical atmosphere can be used, but if the roasting temperature exceeds 1000℃, In', J'
31 An inert atmosphere is used to prevent oxidation of the silicon nitride.
Delicious. The roasting temperature depends on the use of the product, but it needs to be at least 500°C, at which almost no separated gas is generated, and the roasting time varies depending on the roasting temperature, but is 5 to 2 minutes.
Time is enough.

These roasting conditions may be freely set depending on how the oxide (14 structure) to be attached to the surface of the silicon nitride powder is designed.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Examples Example 1 △] Preparation of gel-like ice hydroxide 1i1' In an aqueous solution of 1 M yttrium, dysprosium nitrate, lanthanum nitrate, and aluminum nitrate each at 0.1 mol/β degree at 4°C, 3 moles at 2' degree degree of ammonia water 0.
A temperature of 45 DEG C. was added all at once, and the mixture was stirred for 130 minutes. The resulting gels were separated using a G-3 filter and washed with water.

15! Remove a portion of each gel and incubate with X in the usual manner.
When line diffraction was measured, it was found that each gel-like material showed the characteristics shown in Figure 1. -1-.

Further, a portion of each of the obtained gels was taken out and sufficiently vacuum dried at room temperature, and then the infrared absorption spectrum of each gel was measured, and the results were as shown in the chart shown in FIG.

Also, take out a portion of each gel and dilute each gel.
To acid? As a result, 1i11 acid ions were measured using the usual method, but no nitrate ions were detected in each solution. Furthermore, 7 ammonium ion A in the solutions was measured using a conventional method, but no ammonium ions were detected in each solution.

B1 Adhesion of gel-like hydroxide to the entrance surface of silicon nitride powder Aqueous solution of 0.1 each of yttrium nitrate, (11"l1lf2dysp1]ium, and lanthanum nitrate 4)
3 mol/+2 iPmaro's unshinii in β? water 0.4
Add 5°C all at once, stir at room temperature for 30 minutes, and filter each gel-like substance formed using a G-3 glass filter.
After washing each gel with water, each gel was dispersed in water to form a slurry at 4°C.

When each slurry was left to stand, the sedimentation volume of the gel-like substance was 1
Hour rm after GC3, 5, +2.4861m after 3.11
．． After 24 hours, the temperature reached 2.8°C.

After stirring the 8 liquid again to make a homogeneous slurry, 4.8 mol ((i
72g) was added, thoroughly stirred, and left to stand.

When the sedimentation volume of solids was measured, it was found that 10.1 indirect 3
．． 0J2.4 hours later 2.3. f2. 2 after 24 hours
It was ℃. Moreover, the liquid at the top was transparent.

A portion of the solid content at the top, middle, and upper part of each sedimentation slurry was taken out and the composition of each was measured using a fluorescent X-ray method.
The ratio of La /Si is (0,028 to 20,0
01): It was in the range of (1±0.001>).

C1 Roasted B] Each slurry IQ was filtered and the solid content was reduced to 900%.
It was roasted for 1 hour in an electric furnace whose temperature was controlled to ℃. 1. Each of the powders produced in 1. showed almost no agglomeration and could be used as a raw material.
, : The powder behavior was similar to that of silicon nitride.

When XF11 diffraction of each powder was measured, the peak of the raw material silicon nitride and the peak of yttrium oxide, dysprosium oxide, or lanthanum oxide were found to be I! ! It was noticed. As an example, Fig. 7 shows an X-ray diffraction chart using gelled yttrium hydroxide as the raw material 13+.

(!100 g of each roasted product with a capacity of 1β
Put it in a bottle, add 0.5% of water, and shake it to 30%.
After taking a separate image, water was added to the mixture for 10J2 hours, and the mixture was stirred and then released. After 30 minutes, most of the solids have settled to the bottom and the top
Hfi was slightly cloudy and 0.

The solid content was taken out using a G-5 glass filter, and the weight was measured after drying. The 6 of the Y/Si combination U was 013 (1, DY /St (7) [Q
T! −(7)(, +(7) is °0,210 La /3
The combination of i was 0.22 (l). When the composition of each of these was measured by fluorescent X-ray method, the molar ratio was Y/5i-=1.27, l)y/Si = 3.58,
La /Si -4,45 and Iy.

The upper layer, middle layer, and lower layer of each precipitate (q) were taken out and measured by fluorescent X-ray method, and the composition of each was Y/S r , I) V , /Si 1La /S
The molar ratio of i is (0,028,!-〇,003): (
It was in the range of 1±o,ooi).

Example 2 A method similar to Example 1 was used to prepare gelled yttrium hydroxide (
59) and gelled aluminum hydroxide (AIzOx 1% tX) were prepared, and each slurry was mixed and stirred for 1 t.

Add 90 (l) of the same kind of silicon nitride powder used in Example 1 to the above mixed slurry and mix well.
Divide the solid content into two equal parts and heat each at 900°C for 2 hours at 110°C.
It was roasted at 0°C for 2 hours in a nitrogen atmosphere.

When the X-ray diffraction of the roasted product was measured, the results were shown in Figures 8 and 8, respectively.
The pattern shown in FIG. 9 was shown.

In addition, each roasted product was dispersed in water in the same manner as in Example 1,
The slurry was stirred in a shaker, the slurry was bought statically, and the upper layer, middle layer, and FIiM portion of the solid content accumulated at the bottom were taken out and the composition was measured using fluorescent X-ray method. /Δl /Si molar ratio is (0,023±0.00
2 >,” (0,0514:0.005 > / (
It was in the range of >1±0.001.

Example 3 Aqueous solution of iso-1-lium chloride at a concentration of 0.1 mol/β.
4. Add 0.37 L/βt7JU of caustic soda water to Q.
A gel-like material similar to that in Example 1 was prepared by adding 45 ρ at once. The compositions J3 and 4713 of the gel-like material were measured in the same manner as in Example 1! In fact, it was found that it was the same gel-like material as the one made in the example. This gel-like material was used to adhere to silicon nitride in the same manner as in Example 1-11.
Roasting was performed at 00°C for 1 hour. 17/,: The composition and structure of the powder are 1 in Example 1! It was equivalent to the one given in '7.

Example 4 Aqueous solution 4J2 of 0.1 mol/depth of yttrium nitrate
Inside, the same silicon nitride powder used in Example 1 was added to
mol was added to make a homogeneous suspension without stirring. In the suspension, 0.454 ammonia water of 37 Lua/λ depth is added.
After stirring was continued for 30 minutes, the mixture was heated for several hours. fl) Solid content settles at the bottom of the vessel, and its sedimentation IA
It was detective 2p. The obtained precipitate was filtered through a G-4 glass filter and roasted in air at 900°C for 1 hour. The obtained powder had the same composition and structure as that obtained in Example 1.

Example 5 Concentration is 0.3 mol/! 4.5 p of 1 ammonia water and 4 moles of silicon nitride powder, the same as used in Example 1, were mixed, and while stirring, 0.2 moles of yttrium nitrate aqueous solution of 1 degree of Q fi was added 2J2. After 10 minutes, stirring was stopped. When the concentration of iso-1-lium in the supernatant was measured for 2 hours iQ t'2, no yttrium was detected. After filtering the solid content obtained above (17), it was roasted in air at 900°C for 1 hour.
Example 1 e4 to 111 powder, composition, structure and b!
It turned out that it was the same as the one that was given.

Example 6 Iso-1-lium gel hydroxide and aluminum gel hydroxide were prepared in the same manner as in Example 1, and the same nitride water powder and oxide were prepared using Example 1. Maneuver 1
At 0 suspension ratio, as in Example 1, f=J using <c ii method.
I arrived. .

b) Y203/△l 20:l /Si 3 N4-=
2.5. / 2.5/95 0) Y203 /AI 203 /Si 3 N4=
2/! +/93 c) Yz O3/AI 203 /St I N4=
6.8/5. L/88. ) Y203/Al i03/S! 3 N4-10/
10. '80 Each sample was roasted in air at 900°C for 1115 minutes.

100 g of each juvenile obtained was dispersed in water using the same method as in Example 1 (Kou's method), shaken with a shaker, and then left to stand.The solid content quickly settled to the bottom, and the supernatant liquid inside tY'i
Collect the solid content by cutting and drying. When ffi was measured, a): 0. OQglo)=0.19g
, C): 0.28 (1, 2): 0.3917.

In addition, when the upper layer, middle layer, and F layer of each sedimentation force were sampled and their compositions were measured using Thai light X-ray method, they were found to be Y2O:l/AI 203/S! IN+17)
Ratio; r, a) : (0,011±(1,002)
/(0,024± 0.005)/(1± 0.0
01 ) 口) : (o, oo9±0.002) /(
0,04932 0,0(1!+) / (1±
0,001) C): (0,032±0.00
2> /(0,053L 01005)/(1±
0.001) 2): (0,052±0.002)
/(0,114± 0.005>/ (1± 0.
J3 fell within the range of 001).

In addition, when each X-ray diffraction was measured, the first
It was as shown in Fig. 0, Fig. 11, Fig. 12, and Fig. 13.

Comparative Example 1 5 g of iso1-lium oxide (average particle size 0.6 μm), 59 g of aluminum oxide (average particle size 0.5 μm), and the same silicon nitride used in Example 1 (average particle size 1 yen,
o, 7 μm > 90 (1711), ball mill-e
After mixing for 4 hours, the mixture was dispersed in 10β water, stirred sufficiently for 11 times, and then left to stand.

Applicable after 3 () minutes! Ik'a-I just observed it, the upper part is t! ''/υ When the mixture became white, a gray powder similar to that of the original silicon nitride rope had settled at the bottom.

Take out the cloudy water at the top, layer it, dry the solid content, and weigh 1r! (' als〉L゛shinidokoro 4.:+8!H
There was a knee. When the composition of this b was measured by fluorescence X-ray method, the rI'IF/% ratio of Y203, /AI 20:l /3ixN4 was 1.88/1.73/1.05
It's tea.

In addition, the soil layer, middle layer, and lower layer of the solid matter that had settled at the bottom were taken out, and the composition of each layer was measured by fluorescent X-ray method, and the following results were obtained.

Upper ff1nllY203 /AI 203 /Si 3
N 4 = 2.58/ 2.33/ 1 Middle part = 1.13/ 1,53/'
1 lower layer =0.01/0,008.
/1 As described in detail, according to the present invention, on the h-plane of silicon nitride powder, an oxide layer consisting of rare earth element oxide, or Iζ, and aluminum oxide is strongly and uniformly formed. This silicon nitride powder is excellent as a sintered hematopoietic agent.

[Brief explanation of the drawing]

Figure 1 is an X-ray diffraction pattern of gelled yttrium hydroxide. Figure 2 is an XFA diffraction pattern of crystalline yttrium hydroxide. Figure 3 is a gel of iso1-lium after air drying at room temperature. Figure 4 shows the infrared absorption spectrum of crystalline y1 hydroxide, and Figure 5 shows the infrared absorption spectrum of yttrium hydroxide. Fig. 6 is a photo taken with an electron beam of the raw silicon nitride wood shield used in the preparation of Itsu 1-rea by electron beam; Fig. 7 is a photo taken by electron beam of Example 1- Jj in 01 and in1-lium-
'= mE 21 and U f'l-'! l'l L/person: Nitriding 9i; Rf'I) I tree's X rice! 11 fold 7-1
- Figure 8 shows the 900"CX2 in Example 2.
The X-ray diffraction pattern of silicon nitride wood powder roasted for 04 days, Figure 9 shows J3 in Example 2, 1loO'cx 2
Figure 10 shows the X-ray diffraction of the silicon nitride powder prepared in Example 5 in Jj and r) 1'1. Chart, FIG. 11 is an X-ray diffraction chart of the nitrided 11 powder made from the nitrided 11-sheet f′ [43 in Example 5, and C). X-ray diffraction of the nitrided tip powder prepared in Section 1'1 of Figure 13 shows the actual MI! In Example 5, there is J3, and Article 2) ('1
The X-ray diffraction chart 1- of the silicon nitride powder prepared in 1- is very small. 2゛ Cap 1・ Stem (2θ) (2θ) (2θ) (2θ)

Claims (1)

[Claims] A gel hydroxide of a rare earth element or a mixed gel hydroxide of a hydroxide of a rare earth element and aluminum hydroxide is mixed with silicon nitride powder, and the surface of the silicon nitride powder is an oxide of a rare earth element, characterized in that a gel-like hydroxide is attached to the hydroxide, and then the mixture is roasted;
Or a method for producing silicon nitride powder with a mixture of a rare earth element oxide and aluminum oxide, or a composite oxide of a rare earth element and aluminum attached to the surface.