JPS6191065A - High strength alpha-sialon sintered body - 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 the Invention The present invention relates to a high strength α-sialon sintered body. For more information on the history, see the first edition of high-temperature structural materials, or machine tools that require mechanical strength and wear resistance.

The present invention relates to a high-strength α-sialon sintered body that can be used for mechanical parts such as shafts and mechanical seals, and cutting tools.

As a conventional sialon, general formula 5i6-2AI20□N8-
2 (However, 2 is o < z × a, and β cannot be indicated by J, which represents 2.
-Sialon was developed, and then α-Sialon was discovered as a shieldable Sialon. α-Sia o7 is represented by M)((Si, Alh2(0, Na6) in the general formula,
The crystal structure is α-3i3N, with Al at the Si position and H
At the same time, O is rubbed into the position and dissolved in solid solution, and at the same time, other elements enter between the lattices and are dissolved in solid solution. As this invading solid solution element, Li
, Na, Ca, YAg, Y and frost elements.

One of the inventors of the present invention, Mitomo 3, previously developed the hot press method (Japanese Patent Laid-Open No. 56-129
No. 667) and pressureless sintering method (4!
However, the pressureless sintering method, which is easy to manufacture and can easily produce crude molded products, leaves 3 to 5% of pores and cannot produce high-strength sintered bodies. There was a problem.

Purpose of the Invention The present invention has been made to solve the above problems.
For this purpose, it is an object to provide a high-strength α-sialon sintered body that can have a high degree of 9 degrees even by pressureless sintering.

Structure of the Invention The present inventors have achieved the above object. As a result of research, it was found that there is a range of compositions that yield extremely high strength sintered bodies among the overall compositions containing the α-sialon phase. General formula M)(
(Si, M1) In the α-sialon sintered body represented by 12(0+N)u, N is Li, Ca*Mg
.

Y and a rare earth element selected alone or in a mixture, and when X is O < x < 0.5, a composite structure of α-sialon crystals and β-3i3N crystals is formed. It was found that the α-sialon sintered body has superior mechanical properties and high strength compared to a sintered body having a single α-sialon composition. The present invention was completed based on this knowledge.

The gist of the present invention is that in the α-sialon sintered body represented by the general formula Mx(SitAj!h2(0+Nh6), y is Li, Ca
, Mg, Y and rare earth elements -
! and a Fi mixture with X of 0<x (1,5 il
HfQ, whose mineral composition is α-sialon and β-3
i5N, consisting of α-sialon crystal and β-Si3
It is a high-strength α-sialon sintered body characterized by having a complex structure of N crystals.

In the present invention, when the value of X exceeds 0.5, the Q assembly consists only of α-sialon. Count of X is 0<x<
α-Sialon and β-Si3 only in the range of 0.5
N4, α-sialon crystal and β-Si3N
, which forms a composite structure of crystals, resulting in high strength.

Li, Oa, Mg, Y, and rare earth elements are used alone or in combination.The total amount thereof must be within the range of 0<x<0.5.

As X becomes smaller, the incidence of α-sialon decreases.

The α-sia O7 bamboo sintered material of the present invention can be easily phonographed by heating it to 1600 to 1900"C in a non-oxidizing atmosphere of 1 atm.
The manufacturing method is shown by the general formula Mx(Si, Alh2(0+Nh
The raw material powder mixture for producing the α-sialon sintered body shown in 6 (however, MHLi, Ca, Mg,
Single or a mixture selected from Y and rare earth elements,
X represents o < X <;, 0.5. )make.

That is, silicon nitride, aluminum nitride, and the above-mentioned oxides or thermal components produce M oxides, such as carbonates, oxalates, etc.
Mix the hydroxide salts to form a mixture. These raw materials are mixed in a vibration mill or ball mill.

Grind and mix thoroughly using another grinding mixer. The particles are preferably fine particles having an average primary particle size of 1 μm or less. This is dried to make a molding material, or the slurry is made into granules using a spray dryer or the like and used as a molding raw material. Average grain size of granules: 17t50~70μ
It is preferable that it is m. The molding method may be any method such as mold molding, slurry molding, hydrostatic pressing (CIP), q, one-shot molding, or the like. adult body l
It is best to use a high-density door.

The raw materials silicon nitride and α-sialon decompose under high humidity, so in order to prevent this, s n'! For example, the molded product is mainly made of silicon nitride powder or silicon nitride in a graphite crucible, and aluminum nitride, Li,
It is preferable to cover with a mixture of powders that produce an α-sialon sintered body, such as Na, (a), Mg, Y, and Inadoru Genbal.

Sintering in non-oxidizing Bo atmosphere at 1 atm pressure 1600~1900
°C1 Preferably 1700-1850°C for 15 minutes to 3
Sinter for an hour, preferably 1 to 2 hours. However, it goes without saying that sintering may also be performed by a gas pressure sintering method or a hot press method. As a result, a high-density, high-strength (X-sialon sintered body) can be easily obtained.

The density is 95% or more relative γ;
-S L5N4 phase frame structure1. It was a flash in my head. And as a result of observation with scanning type τ1 condylar latitude,
α-Sialon crystal, β-3, tJ, t,
Did the 11 crystals intersect with each other? At j+, lit, ':H was formed. If you show the continuation of the photo, it is a photo of RIA. Mimi n, A Id Yo, 5 (Si, A/
), 2 (0, Nl, 6 with 5% by weight of MgO added), β-3i, N, are included in the needle (), and the growth of the needle (with a small diameter) The small crystal is α-Sialon. Photo Bld for comparison Y., 6 (S:
L, At), 2(01)++, composition of 6, 10
It consists of 0% α-siacne phase. As a result of measuring the strength of the α-sialon sintered body of the present invention according to the JIS method, the strength is 80 Kp/an' or more, and if it exceeds 9/2 in 100, it is good! I was jealous. This strength cannot be obtained by the conventional pressure sintering method for α-sialon sintered bodies.

The value of -1 hardness is comparable to that of alumina, which is conventionally considered to have a high degree of steepness, and the value of 1 hardness has also been improved.

11 Examples・1°Circulation 1: Si3N, (grain Jf': 11tm or less, cation impurity n, 5% or more F), AIN (grain d"j,
2 t1m or less, cation nont'u '4'7J11
．． For 5'; ty, use I, 1,000) Y2O, (1 μm or less, pure 109.8%), and for AtN raw material for 4'y, use (+4
Using hexane as a medium, the A I N with a pitch of less than 1μ
W) The end? 1).

Using these RJIs, the general formula % formula % AIN I Y2O5 of α-sialon is blended at a predetermined tlj, and silicon nitride z? Vibration mill (solvent Hecan, silicon nitride ↓ Sega ball)
So mix for 5 hours and get the mixture? It's rp.

Conversion analysis of mixtures (SEN and laser method J t-,'
For J fruits, the diameter was 1 μm or less, and 80% were 0.5 μm or less.

The mixture is formed using a cold isostatic press (CIP) 2t
After processing to 060 x 10- at a temperature of 060 x 10-cm2, sintering was performed at 1750°C for 2 hours using an atmospheric pressure sintering method to form an ε viscous material. A 3X4X40rn test piece was prepared by cutting and surface grinding, and the bending strength PL was determined. The results are shown in Table Group 1.1. As the results show, in the 91 region where X is small, the average intensity is 67 k' = 9 /
Eleven sintered bodies with vnvn2 or higher were obtained, and this value is higher than the strength of conventional pressureless sintered bodies of fIIIitP.

Example 2゜By the same force method as Example 1? Sleek Si, N4゜A
In addition to IN, Y2O, and raw materials, MgO (1ttm or less,
(purity 99.9%) is used, and the general formula of α-sialon composition is %, of which Y. Ladle in 22, and the rest of X (If you get stuck, introduce
0.2, 0.25.

A blending composition was prepared to have a composition of 0.3 and mixed for 5 hours in a silicon nitride vibration mill silicon nitride ball (in molten ILy hexane).b'v-type 4': L 2 ton 7cm
A sintered body was obtained in the same manner as in Example 1 using CIP 2, and the same test as in Example 1 was conducted - the result! C is the second
It was as shown in the table. That l'H! ! ': As shown, the conventional α-sialon substance i1' with x = 0.2
It was observed that the addition of IKgO improved density, strength, and α-SiAlON content 7f-8 ratio compared to l-bonds.In particular, strength...1 showed an average bending strength of 80 min/i2 or more These values are extremely higher than the strength of the conventional α-sialon composition hydrogen body.

Example 3゜j, +4 made in the method described in Example 2 with 7r≧, pressure 6
"1-η;11."
It was placed in a lead crucible and heated with silicon nitride powder. Place the crucible in a pressure-resistant container, y of 1200 K9/cm2, i-y
It was baked at 1900°C for 1 hour. I (1 grilled t
The characteristics of 7 specimens were investigated by the same test as in Example 2, and the characteristics are shown in Table 1.3. Nj shown in Example 2,! ! ', compared with α-sialon content,
The 51st imperial edict showed that both the relative density and bending strength had improved.

Example 4 Using the same method as in Example 1, klN, 0, and CaC were determined.
General formula of a-Sialon) 1) ((Si, Ath2(
0, Nb2 x 7'li x≦0.5, of which Ca is x = 0.2 and Mg is 0.0.
('15, t), 1, 0.15, 0.2.

A blending composition was prepared so as to have a concentration of 0.25 and 0.3, and Example 1. A sintered body was obtained in the same manner as in Example 2. As a result, as shown in Table 4, improvements in density and strength were observed.

Example 5゜% Example] Toli? l Column 11 direction i D, J: Li,
5izN, ,AIN.

Y2O,,ojhiL+i,lfitl='7 L3-2
co, (Fi119ql+, 5It.

The general formula M) ((
Si, Al) + 2 (0, Nb2, Y as M) and L
l, and a predetermined '1. A composition of iJ was prepared, and a sintered body was prepared in the same manner as in Examples 1 and 2.
:Obtained.

As a result, as shown in Table 5, a strong improvement of 1rV was obtained.

Table 5! 7i! How long does J+ last? As shown above, α-41 of the present invention
l'L body (supply body, α-Sialon crystal and 71-S
Do the crystals of i and N intersect with each other? j5shif? ：Composite assembly; ・Here L') Because of the first formation, compared to the conventional α-xialonite burnout body, it has a high density P(, high strength, extra hardness, and fracture resistance. I'm annoyed by the stopped effect that comes with Lni.

4.Fffj of Squad 1 Blood A simple explanatory photo AA is an α-sialon of the invention and an 11° condyle fine sharpening tool of f sintered body, photo B is an α-sialon medium for comparison, f,・I product Kagoshi Kenshunei 7. : 7j, deruuuushit 1ji Renmu person Komaj (V
Past I 1:;j Now ('5'! し ￥ し j,.

11←(−吋A'er id
[Prominence F111 Item' White j:', i4.
f# A, PtE agent patent attorney
゛ Existing -1 block continuation 1 mountain positive: I
F rc, tn6o: r s n ni / s co “+:
:'lIj Director Uga Michiku 11t 1':J'1/・Fuaki [...591 Patent Rabbit: A113090 No. 2
Origin qo name a High strength α-sire...quality sintered body tt city corrected & ・Relationship with i, i'l Patent applicant () 2-5-2 Nagata-cho, Chiyoda-ku, Tokyo (1
) Correct the description, page 3, line 2, 1, purpose K J to 1, ``The purpose is''.

(2) IM's n-, z on page 5, line 7
"Monster," he corrected.

(3) Insert "obtained" before "1α-Sialon" on page 6, line 1.

(4) ``Density X-ray diffraction'' in line 7 from the bottom of No. 800 is corrected to ``1 density, X-ray diffraction''.

(5) Same page 14, line 2 1' AIN J to f Si, N4. AI
NJ.

Page 16, line 2, 1' 512 Na J [Si3N, J and correction procedure correction book January/7, 1985

Claims (1)

[Claims] 1. General formula M_X(Si, Al)_1_2(O,N)_
In the α-sialon sintered body denoted by 1_6, M
is selected from Li, Ca, Mg, Y, and rare earth elements, and x is in the range of 0<x≦0.5, and the mineral composition is α-sialon and β-Si_3N.
_4, α-sialon crystal and β-Si_3N
A high-strength α-sialon sintered body comprising a composite structure of crystals according to _4.