JPS61242956A - High tenacity ceramic alloy - 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 (Industrial Application Field) The present invention relates to a ceramic alloy having high toughness.

(Prior art and its problems) A mixture of two or more metals or non-metals is called a metal alloy or a non-metal alloy, respectively, and a mixture of two or more metal oxides forming a solid solution. is often described as a ceramic alloy. A well-known example of the latter is stabilized or partially stabilized Zr0z.

Regarding the microstructure, two basic types of partially stabilized polycrystalline Zr0z bodies have been discussed in the prior art.

The first type consists of tetragonal Zr0z grains of relatively large size (~30-100 microns), customarily containing dopants, and Z'02's with a submicron-sized tetragonal structure with a low content of dopants inside. Contains sediment,
The Zr0z precipitate has a monoclinic and/or tetragonal structure with a size of approximately 1 to 10 microns along the grain boundaries of the tetragonal grains, thereby allowing Zr0g and one or more stabilizers to be combined. produce microstructures made of ceramic alloys with MvO and/or CaO and/or Y2O3 are usually used as stabilizers. A second type of partially stabilized polycrystalline 2'02 body consists of a ceramic alloy with ZrO2 and one or more submicron grain size stabilizers, most commonly having a tetragonal structure. For this second type of ceramic alloy, CeO2 has been used, but the combination of Y2O3 and M(10) and/or CaO can also be used, but the combination of ZrOz and Ygo3 is more common.Basically, , any number of rare earth metal oxides are also used as alloys.

ZrOz-containing ceramic bodies exhibiting high toughness values included MgO stabilization to produce the above-mentioned microstructures of large grain size. Such ceramic bodies are available in double beam, chevron notch beam, and single edge notch beam types. 10M when measured by test
PaJT- exhibited excessive toughness values. On the contrary, in laboratory tests, the fine-grained 7rOz ceramic alloy described above showed substantially lower toughness values. For example, 3 mol% Y2O
The fine grains of 7"02 containing 3 exhibited a KIG of about 6 MPag, and the fine grains Z stabilized with 2 mol% Y2O3
rO2 showed values not higher than about 10 MPaJi''''.

This difference in fracture toughness can be explained by the microstructure. Therefore, as discussed above, large grain size ceramic bodies not only contain submicron-sized precipitates with a tetragonal structure, but also large size precipitates with a tetragonal and/or monoclinic structure along the grain boundaries. ~1-10 microns). The tetragonal structure of the large grain size precipitate can change to a monoclinic polymorph during cooling from the production temperature of the ceramic body, or to a stress field caused by a propagating crack. Along the grain boundaries of the cubic Zl"Ox transformed into a monoclinic structure, these relatively large sized precipitates change the smaller size of the nice tetragonal precipitates within the tetragonal grains into a monoclinic shape. Optical electron microscopy examination reveals large, i.e. ~100 micron bands of altered precipitate (of large and small particles) around the crack. This is a band with large changes indicating an increase in toughness.

On the contrary, the microstructure of the second type of partially stabilized ZrO2 bodies is quite uniform in grain size and depends on the ignition temperature, time at sintering temperature, grain size and composition of the materials of the starting batch. , varies between about 0.3-1 micron. Since each square particle acts as a single precipitate, no fine particle precipitate is formed. There is no occurrence of large type precipitates along grain boundaries.

As a result, the variation zone around a propagating crack in this type of ceramic body is only of the order of 4 microns or less. The level of toughness must be directly proportional to the square root of the dimension of the band of variation. 2
The toughness measurements described above for two types of ceramic bodies generally confirm the aforementioned predictions.

(Means for solving the problem) Compounds represented by YNb&, YTaO&, MNI)04, and MTaOa (M in the formula represents a large number of rare earth elements with a valence of +3) are heated at room temperature (R .

It is a compound that has a monoclinic structure at T, ) and a tetragonal structure at high temperatures.

The lack of easy nucleation for monoclinic Zr0z growth in finely ground, partially stabilized Zr0g bodies limits the number of grains that can be varied in the wide force field of a propagating crack, which in turn limits the toughness that can be achieved. It is possible to limit the level of The present invention relates to YNbO4 and/or YT
aOa and/or MNjlOa and/or MT
By introducing a partially stabilized Z'O2 into the main body, monoclinic Zr can be introduced as a small second phase or solid solution.
The basic idea is to make the nucleation of o2 easier and to maintain the tetragonal crystal structure at room temperature. This easy nucleation can improve the toughness of the final product through one or more of three hypothesized mechanisms:

In the first mechanism, the resulting material consists of two phases, one containing high levels of YNb 04 and/or YTaOa and/or MNbOi and/or MTa Oa, on cooling or in the stressed part of the propagating crack. Changes to monoclinic symmetry.

This change can be caused by dislocations along the grain boundaries between the two phases and by the generation of local high stress areas from the edges of the change twins, or simply by stress areas associated with the entire grain, especially the change in capacitance during the change. is negative, favoring the transformation of adjacent grains of the ZrO2-rich phase. In the first binary choice, each grain with a high content of YNbOa and/or YTaOi and/or MNb 04 and/or MTaO* is distributed in a manner similar to large-sized precipitates along the grain boundaries of cubic Zr0z. , behaves as seen in the microstructure of ceramic alloys with compositions in the Zr0z MoO system.

In the second mechanism, the resulting material consists of a single-phase solid solution in which YNI)Oa and/or YTaOm and/or MNbOa and/or MTao4 lower the elastic energy barrier to the formation of the monoclinic phase. Adjust the anisotropic thermal expansion coefficient and lattice constant of the tetragonal and monoclinic phases of the solid solution, or YNI)Ot and/or YTaO4 and/or MNI)On and/or MTaom "lower" the lattice constant. This lowers the elastic constant and the Peyerls response barrier, thus ultimately increasing the probability of monoclinic Zrag growth and satisfactory nucleation in the stressed portion of the crack, and thus increasing the toughness.

A third mechanism involves the formation of two phases within a single particle by Subinodal decomposition or defined methods, producing a ceramic alloy as shown intermediate between the 211 mechanisms described above.

Although studies of the products of the invention by scanning and transmission electron microscopy have shown that the composition of some materials consists of a binary sum, the second and third postulated mechanisms are also viable. Therefore, the final mechanism underlying the improved toughness of the final product was not elucidated.

Preferred embodiments of the present invention include ZrO2 partially stabilized with 0.9-9 mol% YO3/2, with a total of about 0.5-8 mol% derived from each of the following ranges: YNbO
a and/or YTa 04, but YNI)
04 and/or YTaOi are expressed in weight percent based on oxide and consist of 0.5-76% Nb2O5 and/or 0.85-12% Ta205.
2% NbzOs+Tados and 2.4-12.9
% (7) Y z O3e content, the main second phase in the third matrix material such as Al2O3, numerous rare earth oxides and MgO.

CaO and Sow's perform the same function and thus improve the nucleation of monoclinic Zr 02 and/or tetragonal Zr 0z from the tetragonal matrix. Therefore, on a molar basis, YNb 04 and/or 7C can replace yttrium in YTaOn. A viable rare earth oxide is La 203.
Ce 02 , Cez O3, Prz03. Nb2O3
,5IzO3,EuzOs,Gd20a,
Tb z O3, Dy 20s.

Hog 03, Erg O3, Ta203, Ybz
03, and Lu z O3, and these cations exhibit a valence of +3, the substitution of the yttrium cations is 1:1, and for these cations with a valence of +2, 3 parts Replace the 2 cation with two +3 yttrium cations.

For some compositions, niobate and/or tantalate can dominate the chemistry of the separate phase, as confirmed by electron microscopy of the final sintered product, and a partial presence of ZrO2 The stabilization is Yz
It will be appreciated that this is done through the presence of known stabilizers such as O3, CeO2, MgO and CaO.

To further explain, the excess YO3 required to produce 0.5-8 mol% (~1-15 wt%) YNbO4
/2 can be included to partially stabilize Zr0g. Therefore, the total amount is 12.9% by weight Y2O3
partially stabilizes Zr0g and further stabilizes Zr02-8
For a composition such as mol % YO3/2-8 mol % YNbOa, it is necessary to provide 14.1 wt % YNbO4. For this composition of 14.1 wt% YNbob, 7
．． 6% by weight NbzO5 is required.

For the following explanation, for a product consisting of Zr0t8 mol% YOs/l-8 mol% YTaOa,
z O3 is required and the larger molecular weight Ta2
According to 0s, 12.0% by weight of Ta206 is required.

As a third example, Zr0z 1 mol% YO3/z-8
For a composition such as mole % YTaOn, approximately 7.3 wt% Y2O3 and 12.71 ffi% Tar's are required.

For more economical use, MgO and/or C
aO can be used to stabilize ZrO2.

Similarly, an excess of the rare earth oxides mentioned above can be used for stabilization purposes, but the cost of doing so becomes very high.

Electron microscopy, electron diffraction of the final product of the invention.

and tetragonal Zr0z when studied by Xa diffraction.

It showed the presence of cubic Zr 02 and monoclinic Zr 0x as well as a second phase dominated by niobate and/or tantalate. The composition of this phase is in fact a solid solution with varying concentrations of 2r O2, Yt O3 and NbzOs and/or Ta205, with the phase composition and the level of the gold phase varying with the overall composition and particle size of the inventive product. It will be understood that

The ceramic alloys of the present invention are extremely useful for increasing the toughness of hard refractory ceramics. Therefore, these small amounts of 5% by volume of alloy substantially improve toughness. That is, the ceramic matrix consists of up to 95% product by volume. Examples of such ceramic matrices are α-alumina and β-alumina.

β″-Alumina, ALz 03 Cr z O3 solid solution.

Mullite, Sialon, Nasicon, Silicon Carbide,
Includes silicon nitride spinel, titanium carbide, titanium diboride, zircon, and zirconium carbide.

When 7r Oz YOs/z YNb 04 is present in a matrix material such as alumina at levels as low as 50% by volume or less, an amount in excess of the amount used to produce YNb Oa (partially stabilized) It must be understood that the YoV2 in the ZrOz-YNb04 phase (used for

The ceramic alloys of the present invention are also useful in producing tough composites containing refractory fibers and/or whiskers. Generally, the fibers and whiskers comprise up to about 80% by volume of the product. A9Lt-03, silicon oxycarbide, mullite.

Spinel, silicon nitride, A5! , N, Ba C, BN
.

zrOx, zircon, and SiC are examples of useful fibers and voice forces.

Although solid solutions can be partially stabilized with O, MOO, Yt 03 and rare earth oxides, these partially stabilized materials, especially at high Hf0z levels, In many cases, the tetragonal phase changes to the monoclinic phase at room temperature. Because of these factors, HfO2 and To4fOt
−Z r Ox WIIlB body as YNbO< and/
or YTaOa and its analogs can be toughened and partially stabilized in a manner similar to Z'02, producing high-toughness alloys, which in turn can be combined with ceramic matrices and/or refractory fibers and/or Or mixed into whisker-containing objects to further improve their toughness.

Comparison of the prior art and the present invention U.S. Pat. No. 3,522,604 discloses that the
7) CaQ and 2-15 wt% NbtO! 5 consisting of 1
~20% by weight of CaQ-NbtOs e,
discloses the production of stabilized ZrO2-containing refractories by firing such compositions at temperatures between 170 G'' and 2100°C, which firing temperatures are much higher than the sintering temperatures used in the present invention. X-ray diffraction analysis of the final product identified the presence of about 10-20% monoclinic ZrO2 and the remaining cubic ZrOi.On the contrary, the sintered product obtained according to the present invention Electron microscopy, m-son diffraction, and X-ray optical diffraction studies have shown that a large amount of Zr0t in the tetragonal phase in most compositions and at least a small mi square in all compositions within the scope of the present invention. Additionally, electron microscopic studies of the products of the invention identified the presence of niobate- and/or tantalate-rich phases for most of the compositions, as well as Zr
It has been identified that the O2-rich components exhibit a tetragonal crystal structure and that these circumstances provide the microstructure necessary for the varying toughness of the products of the invention.

U.S. Pat. No. 4,266.979 has an average particle size of 2 to 10
An aggregate of micron cubic Zr0z particles and an average particle size of 0
．． Zr containing monoclinic Z"02 particles of 2-1 micron
The fabrication of an oxygen sensor ceramic consisting of a solid electrolyte of Ot Y203 is disclosed, in which aggregates of cubic Zr□, are in contact with each other, and monoclinic ZrO2 is formed as aggregates in the interstices between the aggregates of cubic Zr0z. Dispersed.

Nb2O5 and TazOs are not described anywhere.

US Pat. No. 4,298,385 describes the production of high toughness sintered ceramic products. The product is formed from a powder consisting of an isotropic matrix, e.g. AjLz O3, and at least one phase of ceramic embedding material dispersed therein, e.g. particles having an average diameter of 0.3 to 7.25 microns. Consists of ZrO2. In preferred embodiments, the unstabilized Zroz contains embedded material that results in the creation of microcracks in the product.

There is no description anywhere about Nb2O5 and Ta20a.

U.S. Patent No. 4,316,964 has a tetragonal ZR structure in its structure.
Tough and strong A9J20iZ mixed with 02 metastable particles
Regarding the preparation of roz sintered ceramics ab e
a Tetragonal ZR02 particles with a diameter of 2 microns or less 5
Consisting of ~95% by volume, YtO3, CeO2, Er
It consists of a rare earth oxide selected from the group of z03 and l-ago, and the remainder ALzO3.

There is no description anywhere about Nl12O5 and TazOs.

U.S. Pat. No. 4,322,249 describes a matrix, e.g.
It relates to the production of sintered or hot-pressed ceramic articles having Oz dispersed throughout.

N1) There is no description anywhere about zos and TazQs.

U.S. Pat. No. 4,343,909 discloses ceramic compositions useful as inserts for cutting tools.

The composition essentially contains 1-15% Zr 0 by weight.
2, 5-20% T i 82 , 60-90% A
fLz 03.0~2%+7) MgO, J5yo~1
Consists of 0% TiQ2.

There is no description anywhere about NbzOs and Ta2's.

U.S. Patent No. 4,358,516 is β-A Lz 03
, β” A response z 03 , and NatlxZr
zSixP3-XO! Regarding the production of a solid electrolyte consisting of 2, the strength and toughness of the object is improved by incorporating 5-40% by volume of tetragonal ZrO2 with a particle size of less than 2 microns, and in its structure Y203, CeO2.
, Er 203 , and 1-a203.

N1) 20a and TazOs are not described anywhere.

U.S. Pat. No. 4,366,254 describes the construction of a ceramic body suitable as a cutting tool, the ceramic body containing 4-20% by volume ZrO2, 60-90% by volume A
Q, 203 and 3 to 3 selected from the group of carbides, nitrides, and carbonitrides of Group 1V B and VB metals of the Periodic Table and carbides of Group VIB metals.
Consisting of 0% by volume large metal compound.

Nb2O3 and Ta2o! 1 is not mentioned anywhere.

U.S. Patent No. 4,396,724 discloses Azoa, ZrO
2 and WC are described.

There is no mention of NbtOs and TazOs anywhere.

U.S. Patent No. 4,360,598 Y203:Z
A partially stabilized ZrO2 based on ZrO□ and Y2O3 with a molar ratio of r02 of about 2:98 to 7:93 is provided. This object consists of tetragonal Zr Ox and cubic Zr
Has a mixed phase mainly composed of O2, or has a tetragonal 2
It consists of grains with a phase consisting of 1"02, and the average diameter of the grains is not larger than 2 microns.
up to mol% of Yt 03 as QaO, MoO, or Y
b20:s, 80203, Nbzo3. and 81
The focus is on optional substitution with rare earth oxides such as tO3, and the only specific example involves substitution with a rare earth oxide containing Yb2O3. Therefore, there is no disclosure of a final product having a composition within the system defined in the present invention.

U.S. Pat. No. 4,507,394 cites zirconia- and/or hafnia-containing ceramics exhibiting high electrical resistivity and mechanical strength, which are Y03/z
+ 3c O3/z l 8103/l +
ELI 03/2 *Gd 03/2, Tb
O3/l, Dy O3/z, Ho Os/1
mEr03/zeTfllOs/1eYbO3/2eL
u03/l, 5 to 30 mol% of at least one component of group A consisting of CaO and MaO, and 5 to 40 mol% of at least one component of group B consisting of NbOS/2 and/or TaO6/2. , and z “02 and Hf
The ceramic mainly contains 30 to 90 mol% of at least one component of group C consisting of O2, and preferably satisfies the following formula.

In addition, the crystal phase of the ceramic is a tetragonal phase. It is preferable to use it as the main component.

The toughness of none of the ceramics was measured in this patent. The inventor of this patent claims ceramics with high strength, and the highest bending strength measured for these materials was 4789/ltm2. The aforementioned US Pat. No. 4,360,598% describes Zr 0x-Yz 03 ceramics with a predominantly tetragonal crystalline phase. The maximum bending strength cited in this patent is 112N9
/am+2, which is a factor of two times higher than the bending strength of 47tCJ/am'' cited in U.S. Patent No. 4,507,394. No. 4.507,394
It stands to reason that they would have realized that the ceramics described in @ were dramatically less strong than previous ceramics of related composition and crystal structure. The ceramics described in U.S. Pat. No. 4,507,394 are therefore unremarkable apart from high electrical resistivity. Thus, the high toughness material produced by the present invention was completely unexpected and unexpected by those skilled in the art. Additionally, Zr 02 YO37t YNb 04 and/l.

Producing a high toughness alloy from a combination of matrix materials such as 203 is not at all expected, nor is it obvious by US Pat. No. 4,507,394.

DESCRIPTION OF THE PREFERRED EMBODIMENTS YNI)On constitutes a preferred example and the following description relates to this material. Similarly, Zr0z or Y2
ZrO2 partially stabilized by O3 is the preferred Zr0
Contains z and/or H'02 components.

Two common methods are Zr Oz Yt Os -YN
It was used to produce a finely ground sinterable powder of the desired composition in the bO4 system. The first method involves a coprecipitation technique, whereas the second method simply involves Y(NO3)3
・Yttrium in the form of 68tO and Nb (OH
)s and N1) Commercially available Z r Ox -3 mol % Y as base material modified with the addition of niobium in the form of zos
2O3 powder was used.

In the following examples, the density of YNbOa was assumed to be equal to the density of Zr0t, and the volume % of YNbO4 was assumed to be equal to the weight % of YNl)Om.

Co-precipitation method NbCR,s can be dissolved in aqueous HCL and filtered through a 0.3-1 micron filter.

A solution was produced. Since the solution is exposed to air, the niobium can be in the form of a very finely dispersed hydroxide. Zirconyl nitrate and Y(N03) 3 ・6
Hz 0(7) Concentrated aqueous? WleNbCQ,s/H
CIll was added to the solution. High concentrations of niobium require additional HO2, to prevent precipitation of niobium hydroxide,
High concentrations of yttrium required additional water and a small amount of HNO3 to keep the yttrium salt in solution. Due to the large amount of heat generated during the subsequent hydroxide precipitation reaction, the solution was divided into 100-parts. NHaOH was added dropwise, using a large excess to achieve high supersaturation, and precipitation was performed quickly to avoid separation of the cations. Supersaturation, on the other hand, results in high nucleation rates resulting in hydroxide particles that are very finely ground and mix well to form gels. The precipitated gel was then treated with aqueous NHa OHM with a state of 10 or more.
If desired, the gel was placed in a centrifuge vessel and shaken for several minutes, and then the gel was separated from the wash water by centrifugation. Washing is necessary to remove the N1-140fL salt remaining in the gel. The water trapped in the gel was then removed by lyophilization.

The material was then calcined at 1000° C. for 2 hours and vibromilled using calcined isopropyl alcohol slurry Conia beads. The slurry was passed through a screen to extract the beads and the powder was dried. Moisten the powder slightly with isopropyl alcohol and make a diameter 7.
27 as (0.5 inch) low pressure around the building as one axis,
That is, about 70.3 to 357.5 Kg/al (10
00~5000Dsi) and balanced at 3163.
It was cooled to 5Kg/cj (45000pS i ).

In a modification of this method, a commercially available Zr ox -3 mole % Y203 powder was dispersed in methanol and the appropriate layer of Nb Cla was dissolved in the slurry. After shaking the slurry vigorously, Nl-1401-1 was mixed into it and shaking the slurry vigorously again, ZrOz3 mol% YzO3 plus niobium hydroxide [Nb(OH)a
] and the precipitate was centrifuged.

The material was washed several times with NHnOH-containing methanol to keep the particles at a high level and then separated from the washings by centrifugation.

The material was then calcined at 700°C for 2 hours. Appropriate amount of Y
(NO3)3.6H20 was dissolved in methanol and the calcined powder was mixed into the methanol solution.

The methanol is slowly evaporated at slightly elevated temperatures,
The slurry was stirred occasionally. Again, add 70% of the powder
Calcined at 0° C. for 2 hours, the calcined material was compressed into buildings as described above. Table 7. The compositions listed in I[, and ■ were produced by dispersion of commercially available 7r Ot-3 mol% YzO3 and precipitation of niobium hydroxide from niobium chloride, of which only Examples 11 and 16 were prepared for 2 days. Vibratory milling was used to improve composition uniformity.

11 In this technology, ZrOz2 mol% YtOs-4 wt%
YNb 04 was converted from powdered ZrOz 3 mol% Y2 03 to methanol and powdered zrOx -3 mol% Yg.
A calculated amount of Nb20 for powder reagent is added to the slurry consisting of O3,
The slurry was prepared by simply mixing and vibratory milling using 2"02 beads for 2.5 days. The slurry was passed through a screen to remove the beads, the methanol was slowly evaporated from the slurry, and the resulting powder was milled for 2 hours. Calcined at 700°C. Approximately 12.7.

(2 inches) in diameter, about 10.3 to 357.5 Kg/Cl! (10o
o~5.

00psi) and at equilibrium 3183.58'l/
cd (45,000 psi). No dispersants or binders were used in the manufacture of the building.

Buildings prepared by coprecipitation methods or simple addition techniques were sintered according to various schedules. A small amount was heated and cooled at a heating and cooling rate of 100°C/hour for 2 hours (g1100
After pre-sintering heat treatment at 0°C, it was fired in a vacuum furnace at a heating and cooling rate of 800°C/hour at a temperature of 1300° to 1G00°C for 2 hours. Calcinate other items in air at 1400°C or 1450°C for 2 hours, heating rate of ioo°C/hour to 1000°C, heating rate of 50°C/hour to 1400°C.
or 1450°C, at a cooling rate of 100°C/hour.

When one component is added (ZrOz 2 mol% Y203-
4-ply 1% YNb Oa), m diameter 50.8s++ (
2 inches) and thickness 9.525as+ (3
/8 inch) specimen size in the form of a disk. Three 47.625 as+ (1-i inch) diameter disks were placed at low pressure, approximately 70.3'J/
cd (10001)St), and the equilibrium Ni 31
Cooled to G3.5 to 9/al (45000 psi).

One of the following three schedules for one compressed disk
sintered using: (a) heating in air at 50°C/h between chamber i1 (R,T, ~25°C) and 150°C; 1 at 100°C/h;
Heating to 000°C: heating to 1420°C at 50°C/hour = holding at 1420°C for 2 hours; cooling to room temperature at 100°C/hour: (b) Heating and cooling rates in air are the same as above, but From 1420°C, hold at 1390°C for 2 hours; and (C) heat in air at 800°C for 2 hours; cool to room temperature and leave in vacuum oven; heat at 400°C/hour to 800°C; 800°C / II Near Heating to 146.0'C = Holding at 1460°C for 2 hours: 80 at 800°C/hour
Cooling to 0°C = Cooling to room temperature at 400°C/hour.

Approximately 12.7 m (2 in) in diameter and 7,93 in cross section
8am (5/16 inch) additional type Zl”Oz
One disk of 2 mol% Y203-4 wt% YNb Oa was heated to 427.8 9/cd at 1450°C for 2 hours.
It was vacuum heat pressed into a graphite mold at a pressure of (6000 psi). Heating rate is approximately 00℃/hour and cooling rate is approximately 0
The temperature was 0°C/hour. It was compressed at 600° to 700°C during heating and loosened at about 500°C during cooling.

Artificial shows some compositions prepared in the course of the above research. Examples 3-8 and 18 were derived by coprecipitation process: Examples 9-16 were derived from commercially available Zr0z
Nb(OH
) a and NHaOl-1 were precipitated: Example 17 added Nb2O5 to commercially available Zroz 3 mol% Y2O3. Table 1 shows the results of the wet chemical analysis carried out on some of the examples, expressed in weight percent based on oxide. 1fO2 content indicates impurities in the Zr0z component.

5-1 Yu Chikarasue-nuri-gumi
(Zr 02 5.5 mol% YO3/2-5.25 mol% YNb Os) '6 Zr0
z3 mol% Y203 +25 wt% YNb04 (ZrO
z 5 mol% YO3/2-14.3 mol% YN
bOa>'7 Zl'02 3 mol% Y203+so layer% YNbOa (Zr 02
3.8 mol% YO3/2-33.3 mol% YN110a
) '8 zro2-2 mol%
Y203 +4wt% YNbo4 (Zr 02-3.8
Mol%YO312-2mol%YNllOa)
19 Zr0z3 mol% Y203
+4wt%YNtlO4Kuni Supervisor-1--
(Zr 02-4.8 mol% YO31t -2 mol% Y
NI) Oa )4 2rOz 2.5 mol% Y203 +6 wt% YNbOs(Zr 02
4.7 mol% YO3/2 3.1 mol% YNtl 0
4) 5 Zr Of -3.5 mol%
Y203+4tlibR%YNbOa(Zr ox −
e, emol%YO3/2 2mol%YNb Oa)6
zro2-2 mol% Y203+4 wt%
YNbOa (Zr 02-3.8 mol% YO3/2 2
Mol% YNb Oa ) 7 Zr0z
2 mol% Y20s + 4 wt% YNbOa (Zr Ox
-3,8 mol% YO3/2-2 mol% YNb Oa
)8 Zr 02-o, 25 mol% Y2
03 +16 interweight %I)Ot(Zr Oz -0,
5mol/L/%YO3/2-8.7mol%YNb 04
) 川 1 ″ 川 i 〆 〜 川 ; 2 古＝1 ト−−−− 011−〜 川 11 = 1 ； ２ 〆 PaJ j c; ``-1 dJ pus 0 ~ noise = 1 -17'', = 1 kudzu 6 Table ■ shows the temperature at which the artificial composition was sintered for 2 hours, and the Vickers hardness of the sintered sample (directly measured). The fracture toughness (K-C) values calculated using the following formula b\ expressed in (GPa) and MPaf are collectively shown. 200G P
The Young's modulus of a was estimated by calculation.

K,, -0,016(E'hP'h dC-(,ts
) E in the formula -200GPa; P-5, 1o, 3o
, or a load of 9 on 50; d-indentation diagonal: C-indicates the crack length from the center of the indentation effect.

7.854P H-hardness, H- crushed and polished sintered sample, 5.10.30 and 5
A microhardness test was conducted using a load of 0 to 9. All measurements in Table ■ were performed using a 10 Kg load, but a 30 Kg load was used for the sample marked with one star, a 50 Kg load was used for the samples marked with two stars, and a 5 Kg load was used for YNbOt. was used.

Yirouho Sintered warm sputum Vickers hardness KX
Cl ・1300℃ 11.8
15.21400℃ 11.6
17.61450℃ 12,2
14.11500'C11,314,4 1550℃ 10,9 17.0
1 1450℃* 17.1
10.51500℃* 17.0
12.11550℃* 17.0
13,21 1450℃**
17.8 7.415oO℃**
i3,s 6・21550℃**
17.2 9.42 145
0℃ 12.2 4.51460
℃ 17.6 5.11500'
C11,64,9 1550℃ 11,66.4 16oO℃ 17.6 5.93
1400℃ 17.1
4.81460℃ 17.3
4.61(2)'CIo, 3 8.016
00'C* 10.5 5.44
1400'C10,05,61450℃
9.3 6.61460℃
9.1 9.51500'C8,49,
5 1550℃ 8,2 17.81
G00'CB, 5 5.4 mm
At? ``Fallen Mutter KIc5 1400
℃ 10,5 5.01450℃
9,3 8.31460℃
9,1 11J15oO℃ 8,4
17.81550℃ 8,417
．． 0 16oO℃ 10,1 7.2614
00℃ 10,1 2.21450℃
9,9 2.51500'C9,3
2,5 1600'C6,92,6 71400℃ 9,11,9 1460'C9,2< 2.1 1600"C9,42,4 81400'C10,114,1 14ω"C9,816,0 1460'C *9,2 16.0
1600℃ 11.6 3.79
1450℃ 17.1 6.31
460℃ 10.9 12.4150
0℃ 17.1 9.01550℃
10.4 12.31600℃
10.4 10.410 1450
℃ 10.4 7.71460℃
10゜1 17.71500℃
10.4 12.51550℃ 10
．． 2 17.61600℃ 8.2
7.4 Suse amt: 'Mushi ≦ Gourd K style 11
1300℃ 9.3 10.
31400"C9,315,7 1450℃ 9,6 15.215
00℃ 8,4 5.51550
°C 8.4 6.312
1450℃ 9.8 15.5
1460℃ 9.3 16.51
500℃ 9.4 15.31
550℃ 9゜813゜9 Taku■℃7.63.3 13 1450℃ 11,0
9,21460℃ 9,8
13.615oO℃ 10.8
17.71550℃ 10.2
17.81600℃9,1 3.
514 1450℃ 10,4
13.71460'C9,813,6 1500℃ 10.5 14.
21550℃ 9,8 12.
7ieoo℃ 5.7 7.
4Is 1450℃ 17.3
5.01460'C9,610,2 1500℃ 17.0 7.0
1550℃ 9,8 17.7
1600” CIo, 5 17.7m example
a! iJI! ! n Kzc16
1450℃ 10.4 113.
21500℃ 10.4 15.
31550℃ 10.1 14.
71600℃ 9,8 16.1
16 1450℃* 10.5
15.01500℃* 10.1
16.81550℃* 10j
17.516 1450℃**
11,2 14.915oO℃**
10,8 16.01550℃*
* 10,5 18.517
1390℃ (air) -> 14.014
20℃(air) ->14.01460℃
(vacucng) 9.8
15.41450℃ (hot pressed)
->14.018 1400'C Microcracks 1460°C 1000°C 19 >16 (C'C3, 52, 2 samples were all sintered until the pores were closed and tested by optical microscope, approximately 97% of the theoretical value In most samples, the larger area appeared to have a density of 100% of the theoretical value, but in many cases the pore density was even larger. The range was from less than 0.5 microns to more than 2 microns.

gllJ by coprecipitation process to precipitate commercially available ZrOz 3 mol% Y2O3 and NHaOH, and further after calcination,
The milled microstructures were found to be uniform in overall composition and particle size.

The comparison of Examples 1 and 16 is of particular interest.

The toughness of Example 1 (ZrOz, 2 mol% Y2O3) decreases as the score load increases. In contrast, the measured toughness of Example 16 (ZrOz 2 mol % Y2O3 + 4 wt. % YNbOa) remains essentially constant as the indentation load increases. Such behavior is substantially reduced by the addition of YNbO4
This is considered evidence that the toughness of the 02Y203 composition has been found to be improved.

Comparison of Example 2 and Examples 3 to 5.9 and 10 shows that YN
When bO4 is included, the base ZrOz3 mol% Y2O3
It shows that the toughness imparted to the body increases considerably. However, Examples 6 and 7 show that the addition of YNbOi must be kept below 20% by weight to improve toughness.

Example 18 shows that at very low Y2O3 levels, YNb
It is shown that even with the addition of O4, the tetragonal phase changes to the monoclinic phase upon cooling from the sintering temperature, resulting in microcracked bodies.

Examples 3, 7 and 8 sintered for 2 hours at 1400°C, 1460°C or 1600°C, and Examples 4 and 5 sintered for 2 hours at 1400°C and 1600°C were polished in NHaF-HF. etched and then examined under a scanning electron microscope. A main crystalline phase and a minority crystalline phase were observed, the latter being more easily etched and having a larger grain size than the main crystalline phase. The apparent area fraction of this second phase increases with increasing concentrations of YNb04 and Y203;
increased with the increase of sintering temperature. Ammonium niphride etches the cubic phase of ZrOz, and this phase has a higher content of stabilizer (Y2O2) than the tetragonal phase of zrOz, since the latter phase contains a lower m content of stabilizer.
7r 02 Y203-YNb This phase with larger O4 grain size has a high concentration of Y203, while the finer grain size phase is a tetragonal product.

Several results can be drawn from the above experimental data. 1st
The sintered body of Zr0z3 mol% Y2O3 has a pressure of 6 MPa, /
The sintered YNbO4 body shows a fracture toughness of around 2 MPa5-, but the sintered body made of a combination of these components can exhibit a fracture toughness level exceeding t2.5 MPaW. can. Compositions containing lower levels of Yz03, i.e. Zr0z2mol%Y
At or below addition levels of 2O3 and YNbO, fracture toughness values can exceed 15 Mpa,/ii-. Second, the inclusion of an amount of YNbOa equal to the addition of 0.5 fi wt% YNbOa to Zr0g3 mol% Y2O3 has no obvious effect on the properties exhibited by the sintered 7:r 02 Y203 body. It is not enough to give. The third is Zr0z 3 mol%
Y during the amount equal to 25% by weight added to Y2O3
The incorporation of NbO4 has a very detrimental effect on the toughness exhibited by the Zf'02 Y2O2 sinter.

Table IV shows another group of compositions w4!1 during the above research process. The composition includes ZrO2-Y2O2 with and without addition of YNbOa. Each sample was prepared using the ammonium hydroxide precipitation method described above, except for Example 20.
Zr 02 2 mol% Y2O3゜7rOt 2,5
Mol% Y203, Zr02-3 Mol% Yz03. Alternatively, Zr0z 6 mol % Y2O3 powder, which is commercially available, was used. All of these precipitates were vibrated for two days. In Example 20, Nb2O5 was converted into commercially available Z''
02 powder and vibration-pulverized for 2 days. 7rQ, -2.5 mol% YzOs of Example 21 is a commercially available product.

5-One-layer Σaddition example
Composition
and 20 2r 02-2.
5 wt% Nb 20s (Zr 02 2.3 mol% N
bOf1/2) 3C
21Zr 02-2.5 mol% Y203 (commercial product)
(Zr 02-4.9 mol% YO3/2)
3+22 Zr0
2-5 mol% Y2O3 (Zr 02-9.5 mol% YO
3/2) 3223
Zr 02-7.5 mol% Y2O3 (Z
r O2-14 mol% YO3/2)
3:24 Zr0z
1 mol% Y203 + 12 wt% YNb04 (Z
r 02-7.9 mol% YO3/2-6.4 mol% YN
b Os ) 3/25 Zr 02
-2 mol% Y203 + 8 wt% YNbOt(Zr 02
-3.8mol%YO3/z 4.2-El%YNb
04) 3!26 Zr 02-
2 mol% Yz O:s + 10 wt% YNb 0a (Z
r 02-3.7 mol% YO3/2-5.3 mol% YN
b 04) 3C27ZrO2-3Mo) Lt%Y
203 +15Iffi%YNb 0a (Zr 02-
5.4 mol% YO3/2 8.1 mol% YNb Oa
> 3ii! i Decoration --- One layer ZrO25 mol% Y2O3 + 10fffffi% YN
I) 04 (Zr 02-9 mol% YO3/, -5,2 mol% YNb 04 ) ZrOz 5 mol% Y2O3+
15 wt% YNbOi (Zr Of -a, s mol% Y
O3/2 8.1 mol% YNb Ot ) Zr O2
-7,5 mol% Y203 +10 wt% YNI) Oa(
Zr 02-13.2 mol% YO3/2-5.2 mol%
YNb 04 ) ZrOz 2% by weight YNbOa (Zr02-1 mol% YNb 04 ) Zr02-6% by weight YNtlOn (Zr O2-3, 1 mol% YNbOa) Zr 02
+10 mol% b 0a (Zr 02-5.3 mol% YNb O4) Zr O2 + 14 mol% YNbOa (Zr 02-7.S mol% YNb 04) ZrOz
-0.5 mol% Y203 +3 wt% YNb 04<Z
r0z 1 mol% YO3721, 5 mol% YNb
Os > Zr O2-0.5 mol% Y203+7 wt%
YNb 04 (zr 02-1 mo) Lt%YO3/2
-3.6 mol% YNb 04 ) Example
Salmon-111-038 Zr 02-0.
5mol%Y203 +11mff1%YNb 04(Z
r 02-0.9 mol% YCh72 5.8 mol% YN
b Oa >39 Zr0z -1 mol%Y
20a +2 wt% YNbOa (ZrO22 mol% YO
3/2 1 mol% YNb 04 ) 40
Zr0z 1 mol% YzO3 + 4fiffi% YNb
O4 (ZrOz 7.9mol%YO3/2 2mol%YNII 04)41 Zr0z
1 mol% Y203 + 8 wt% YNbOa (Zr (
h 7.9 mol% YO3/2-4.2 mol% YNb
04 ) 42 Zr Ox 1 mo/
L/%YZ O3+181ffi%YNb 0a(Zr
O2-1, 8 mol% YO3/2', 9 mol% Y
Nb 04) 43 Zr 02-7.5-
Eru%Yz Oa +21iffi%YNb04(Zr
02-2.9Ele%Y03/z 1mol%YNb
Oa)44 Zr0z 2 mol% Y2
03 +2wt% YNb 04 (Zr 02 3.9
Mol% YO3/2-1 Mol% YNb 04 ) 45
2r 02-3 mol% Y203 +18% by weight
YNbOa (Zr 02-5.2 mol% YO3/2
9.9 mol% YNbOt)46 Zr
Oz 1,1 mol%Yz O3+161ffi%Y
Nb 04 (ZrOz 2 mol% YO3/2-8.7
Mol% YNb Oa ) (Zr Oz -1a Mol% Y
O3/2 8 mol% NbO! 1/2) Approximately 12.7111
Pills with a diameter of 1 (0.5 inches) were compressed and sintered in the manner described above. Each sample was sintered in vacuum for 2 hours at the temperatures listed in Table 1 using a heating and cooling rate of 800°C/square. Vickers hard FJ! Measured value (GPa) and M
The fracture toughness value (K, ) calculated by Pa/i- is 5K
A 10Kg load was used to derive the results, except for the samples marked with an asterisk, which used a g load.

Leaving-V Barrier: Sintering temperature: Vickers hardness: K.

20 1400'C Microcracks 1500°C 1600°C 〃 21 1300'C12,45,21400'
CI2,0 5.01450℃
11,8 5.115oO℃ 1
1,8 5.11550℃ 17
．． 6 5.81600'C11,07,4 221400℃ 12,4 2.
91500℃ 12.0 3.4
1600"C14,03,9 231400℃ 17.6 2.
01500℃ 17.9 2.2
16oO℃* 12.2 7.9
24 1400℃ 8,4
13.91450℃ 8.4
13.9isoo℃ 8.4
13.91550℃ 8.0 1
3,21600'C micro-crack force H Kishinjo ζ fallen second base mutter K engineering C251300'
C10,45,5 1400'C10,310,9 1450℃ 9,8 14.1150
0℃ 10,1 13.91550℃
8.4 7.716oO℃
Microcracks 26 1300℃ 8,4
5.31400℃ 10.1
7.81450℃ 9.9 1
2.61500℃ 9.5 13
．． 81550℃ B, 2 5.0
Quick■℃ Microcracks 27 1400℃ 11,8
5.2isoo℃ 9,8
7,216oO℃ 8.5 9
．． 228 1400℃ 12.4
3,715oO℃ 11,6
4.31600'C11,04,5 291400℃ It, 6 3.
51500'C10,64,3 16oO℃ 17.6 4.73
0 1400℃1: 10,7
2,615oO℃ 10.4
3.21600℃ 10.4
3.7 Rikiyaku Rokuuntonku” Nipeika Ktc
31 1400'C11, 32, 31500℃
12,4 2.1 ω℃＊
17.4 2゜032 130
0'C Microcracks 14oO℃ 1500℃ 1600℃ 33 1300'C Microcracks 14oO℃ 1000℃ 1600℃ 34 1300℃ Microcracks 1400
℃ 1500'C 1eoo'c 35 1300℃ slight zJJl crack 14
00'C 1500℃ 1600"C 361300'C Microcracks 14oO℃ 1500'C' 1000℃ 1600℃ Example 1 melon Kx37
1300℃ Microcracks 1400"C 1500'C 1600℃ 38 1300'C Microcracks 1400'C' 15oO℃ 柘■℃〃 39 1300℃ Microcracks 1400
℃ 1000℃ 柘ω℃ 40 1300℃ Microcracks 14oO
℃〃 1soo℃ 1600℃ 〃 41 1300"C micro crack 1400℃ 1500'Cv 16oO℃ 42 1300"C8, 44, 91400℃
9,8 4,915oO℃
9, 1 5.6 柘ω'C 9, 16, 4 Wariku Deka Seiton Ku” Nipu fox K shame 43
1300℃ 10,1 15.4140
0℃ 9,4 9. Qisoo℃
9,3 5.3 柘■℃ Microcracks 44 1300'C12,48,914oO℃
17.6 12.61500℃
10.8 15.71600℃
10,4 15.145
1300℃ 9.8 2.8
1400℃ 10.9 2.91
5oO℃ 10.4 3,6 spear■
'C10,44,0 461300℃ g, 9 4.9
1400℃ 9,8 5.215
00℃ 9,3 7.21600
C 9.1 8.1 Several conclusions can be drawn by exploring the above data.

First, Examples 32-41 show that when the added amount of YNbO4 is equal to or less than 10 wt%, a slight excess (greater than 1 mol%) of Y203 is required to form a body that is completely free from microcracks. It is clear that it is necessary. Examples 24.42 and 46 show that a large amount (approximately 12 wt% or more) of YNb 04 was added to Zr02.
When added to -1 mol % Y2O3, bodies are obtained that are completely free of microcracks. This is about 2 mol% Y to avoid microcracks from occurring during cooling from the sintering temperature.
This is in contrast to the binary system ZrO2Y2O3, which requires 2O3. Therefore, Z "02" known in the art
Besides enhancing the toughness changes that toughen the YzO3 composition (~2-7 mol% Y2O3), the inclusion of small amounts of YNl)04 provides a partial stabilizing effect.

This phenomenon does not require a slight excess of Y2O3 to perform the same function as desired.

Second, 7rO with a Y203 content of about 5 mol% or less
Although the addition of YNbO< to a 2-Y203 composition can improve its toughness at higher levels of YzO3, i.e., about 7.5 mol% Y203, such additions do not promote toughness. I don't think so. The latter situation appears to be troubled by the fact that the composition essentially forms a cubic crystal structure. That is, this is due to the lack of tetragonal ZrO2 in the product. This state was obtained in Example 31 in which 10 wt% YNb 04 was added to ZrQ, -7.5 mol% Y2O3.
It is clear that

Third, Z “02” which is not doped only with NbzOs
(Example 30) to produce a highly microcracked body of essentially monoclinic structure. Therefore, even if only NbzOs is added to Zr0z, the toughness will not be deteriorated.

FIG. 1 shows the composition range in which the resulting microcracked bodies or completely intact bodies were tested after sintering the composition at the temperature range mentioned above. FIG. 1 shows the measured jl height toughness for specific compositions. The highest toughness material of 8.5 M PaJi'' or higher is the addition of 0.25 mol% or more YNbOa (0.5% by weight) and up to about 8 mol% YNbO4 (up to about 15% by weight). have something

High toughness occurs only at approximately 9 mol% or less YO3/l (4.7 mol% or less YtO3), ignoring the addition of YNbOa. This last phenomenon appears to be due to the amount of cubic phase being too high and the amount of tetragonal crystals converting to monoclinic being too low.

From the artificial ~V and the data shown in Figure 1, 0.5 mol% (1% by weight) was added to
A minimum amount of YNbOa equal to that included in 7 g (approximately 7.1-4.7 mol% YtO3) appears to be necessary to significantly increase the toughness of the resulting product, and approximately 8 mol % or less (approximately 15% by weight) of Zr0z-approximately 0.8
~8 mol% YO3/2! (approximately 0.4 to 4.5 mol%
YNl)On equal to the amount incorporated into Y2O3) appeared to contain the preferred maximum amount. In particular, the amount of YNbO4 increases and excess YO3/2 can be reduced. A preferred method is about 3-10% by weight YNt)04 (about 7.5
~5-E-le%) to ZrOz-about 1-3 mol% YzOs
It is believed that using an amount of YNbOi equal to the amount added to (approximately 2-6 mol% Y O3/2) significantly increases toughness.

Mase et al., in US Pat. No. 4,507,394, describe that zirconia, niopia (tantala) and ittria (rare earth oxide) compositions exhibit high electrical resistance. The four compositions they tested are shown in Table ■. The inventor also writes in columns 5, 6, and 7 of U.S. Pat. No. 4,507,394.
．． These compositions were tested according to the description given in 8 and 10.

5--M + 3fljm% A fez O: + (Zr 02 7.1 mol % Nb 06/2-11 mol % Eu Nb 04 ) Note: The dash (') sign refers to the composition of Mase et al. (Mase et al. U.S. Patent No. 4,507,3
For easy comparison with No. 94), it is used to show that
The above four compositions were distinguished from the large number of compositions tested in this work.

The same commercially available ZrO2 powder without addition of Y2O3 used in the previous sample was also used here.

Commercially available Taxes, NbzOs, AfLtO3
,Y(NO3)3 6Hz O and EU(NO3
)3-68zO was used. ZrO2, NI) gOs or Ta 20s + and Y (NO3>36H2
0 or Eu(NO3)368zO were mixed by wet process and the mixture was completely dried.

The mixture was calcined to 800°C. For example, sample number'2
', A57. Zo3 sintering accelerator was added. 4 composition was then compression molded using 0.5% by weight polyethylene glycol for 20-200 hours, the resulting powder was then calcined at 1325°C for 2 hours in air. Another sample was compression molded and prefired in air at 1000°C, then fired in vacuum at 1325°C for 2 hours.

The samples were examined by optical microscopy, and one composition that did not produce micro/JX cracks was polished and fracture toughness was measured in the same manner as used for the synthetic to ■ samples described above. Table Vl shows the results.

--M トI K1Lc 纺2z髂 Sintering temperature Sintering atmosphere ΩdanaMP
aJ11' 1325℃ Air
Microcrack 1325℃ Vacuum Microcrack 2' 1325℃ Air Microcrack 1325℃ Vacuum Microcrack 3'
1325℃ Air 7,3 8.11325℃
Vacuum 7,3 7,3 22' 1325℃ Air Microcracks 1325℃ Vacuum Microcracks table■
shows that only one of these four compositions was free of microcracks when described by Mase et al. Microcracks in compositions 1', 2', and 22' were caused by small amounts or no excess of ittria (0 to 0.
5 mol% YOs/z). Composition 3' without microcracks shows no exceptional toughness8. I
MPaJ'j- and the hardness is 7.3G Pa,
This is inferior to all the ceramics described in Artificial to V, except for YNbOa of Example 19, which did not microcrack.

Of particular interest is the composition of Example 4G in Tables II and V. This composition is the same as 3' of Tables Vl and vl with NbzO5 replacing 7a 20s. Example 4G is simply 8. The maximum toughness of IMPaff is 17.7 MPaJ'i''' to 18.5 MPaJ found in various compositions with a small amount of YN04 added to the Zr0z-Y203 ceramic tested in this work.
This is not exceptional when compared to the toughness of i''.

Comparing all of the compositions tested by Mase et al. with artificial to Vl data, with the exception of Composition 31, the substances were found to be extremely low at approximately 5
It has a toughness of MP85 or less and has microcracks. 8, IMPai achieved by composition 3', as mentioned above.
The toughness of Example 46 and the Niopia-like Example 46 are not remarkable in relation to the toughness achieved by compositions with small amounts of YNbOa added to the ZrO2Y2O3 ceramic alloy.

To investigate the use of compounds other than YNbo4 to increase the toughness of zirconia-containing bodies analogous to yttrium niobate, several compositions shown in Table
and in mole %). The composition includes those in which yttrium is partially or completely replaced with an element showing the valence of yttrium, and niobium in which the valence of niobium is replaced.
Including those that are partially or completely replaced with elements that show.

The resulting compound exhibited a structure and fire resistance similar to YNbOa. [For these experiments, the molar volume of these rare earth niobate and/or tantalate was twice the molar volume of ZrO□. Therefore, for example, if Z "5 in 02
Volume % LaNb0a is 2.5 mol% in Zr0z
is equal to LaNb0a. ] Each sample was prepared using the ammonium hydroxide precipitation technique outlined above. Building specimens approximately 0.5 inches in diameter were compacted and sintered in the manner described above.

Each sample was sintered for 2 hours at the temperature shown in Table 3.

Pickard hardness measurements (GPa) and MPa, ri
The fracture toughness value (K 7.) calculated using 10 PCg load was derived.

■Example Composition
Ωdanaぢ]S47 90% (Zr 02-3mo) I
i%Y2O3) 1300℃ 10.6 4.5+10
%YTa O41400℃ 10.7 12.6(Z
r 02-7.3 mol% YO3/2 1500℃
ffi m fission-5,2-E-le% YTa 04 ) 4896% (Zr 02-2 mol% Yz Oa ) 1
300℃ 11.3 13.4+4%YTaOs
1400'CIo, 7 15.5 (Z
r 02-3.8 mol% YO3/2 1500℃
9,5 7.1-2 mol% YTaOa) 49 90% (ZrOz-2Mo/Lz%Y203)
1300℃ 10.1 6.4+10%YTa 0
4 1400℃ 9.8 13.8
(Zr 02-3.7 mol% YO3/2 1500℃
Microcracks - 5,3 mo/L, % YTa 04 ) 5090% (Zr 02-3 mol % Y20s ) 13
00℃ 10.4 4.9+10%Y(Nbo,tT
ao, 5) Oa 1400℃ 10,9 5,4
[Zr 02-7.3 mol% YO3/2 1500℃
9.8 12.7-5.2 mol% Y <TaosN
bos) 1600°C Microcracks 04] 5195% (Zr 02-3 mol% Y203) 13
00℃ 9.8 5.2+5%l, a Nb Oa
1400℃ 10.4 12.1 (Z
r 02-5.7 mol% YO3/2 1500℃
Microcracks - 2,6 mol% la Nb 04 )
1600℃ Micro crack actual example
52 95% (Zr Oz
-3mo/Lz%Y203 >1300'CIo, 9
4.5+5%Nd Nb Oa 1
400℃ 10.9 12.0 (Zr 0z-5,7
t-le%YO3/2isoo'c Microcracks-2,
6'Eru%NdNbOa) 1600'C
ta small m1453 95% (Zr 02-3 mo/l
/%Y203) 1300'C11,64,3+5%
(Ybo, gGdo, g)NbOa 1400℃
17.9 4.8 [Zr 02-5.7 mol% YO3/
2 1500°C 10.9 17.5-2.6 mol% (Ybas Gda, +; ) 1600'C Microcracks Nb Oa] 5494% (Zr 02.-3 mol% 100
0°C 9.1 6.1 [Yb Gd ] z 03
) 1400'CIo, 7 9.8+6%
(Ybo, 5Gda, g) NbOa 1500℃
Microcracks czr02-5.6 mol% 160
0℃ Microcracks (Yba, s Gdo, tt)
03/2-3.1 mol% (Ybo, g Gd o, t
) As is clear from the study of Nb Oa Table 2, various rare earth elements can be replaced with yttrium, tantalum can be replaced with niobium, and the toughness of zirconia-containing bodies doped with yttrium can be improved. No harmful effects when possible. YNbO4 thus constitutes the most preferred reinforcement, while YTa 04 and YN
I) A mixture of Om and YTa 04 can be handled,
Also rare earth niobate (MNbOa), rare earth tantalate (MTaQ number), and YNbOi and/or YTaO4 and MNI)04 and/or MTaO
The same applies to mixtures of n.

Furthermore, Example 54 shows that the rare earth oxides are both YNl)O
It has been shown that itria can be completely substituted in a, similar to "partially stabilized" dopants in zirconia. Since the exact distribution of cations among the possible phases of these alloys is not known, Examples 57, 52 and 53 contain more than 1/3 of the total amount of yttria.
3, proves that it can be replaced by Nd 203 or Yb Gd O3. Ce 02, pr 20
3. It was reasoned to assume that various rare earth oxides and mixtures of rare earth oxides, including La 203 and NdzO3, could completely replace yttria in these compositions.

Due to the inherent high toughness values exhibited by the above 7r 02 Y203 YNb O4 ceramic alloy, its use as a reinforcing agent in various highly refractory ceramic matrices has been investigated.

A quick rough survey of a wide range of ceramic matrices was conducted to determine general efficacy.

For research purposes, the following three compositions Zr02-
YzO3YNbOa powder was used with a modification of the coprecipitation method outlined above, including precipitation with NHAO.

The three compositions are zrOz-2 mol% Yt O3+81
Amount % YNb Oa, Zr O2-2 mol% Y2O3
+10 wt% YNI) Oa, and ZrO21 mol% Y
2O3+12% by weight YNbO4. zr Ot
Y203 YNI) Other powder samples of Oa composition,
That is, zr Ox −2 mol% Y2O3 + 4 wt% Y
NI)Oa was prepared using the oxide addition method described above.

As detailed below, these powders include alumina powder, magnesium-rich spinel powder, alumina-rich spinel powder, zircon powder, titanium difluoride powder, zirconium carbide powder, mullite powder, silicon carbide powder and Combined with silicon carbide whiskers.

The resulting powder mixture as well as the matrix material samples were vibratory milled for 24 hours in isopropyl alcohol using relatively large Zr'02 milling media.

Approximately 12.7. A building with a diameter of (0.5 inches),
Approximately 70.3-357.57 (IF/c
i (1000-5000 psi) and compressed this building to 3163.5/(g/cd (45000
Cold pressure was applied to equilibrium at psi). Thereafter, the building was precalcined in air for 2 hours to 1000°C and then sintered in a vacuum furnace for 2 hours at a temperature of 1450° to 1650°C. Heating and cooling rates for the sintering studies were 800° C./hour.

Carbides, borides, and oxides were heated at 1450°C or 1650°C for 2 hours at 287.2Ng/cd (4000p
hot pressed in an induction heated hot press using graphite molds on vacuum at a pressure of
inch) disk. The sintered, hot-pressed samples were ground and polished to a 1 micron diamond finish, and the samples were examined by optical microscopy.

Microhardness tests were conducted on polished discs using a 1 oKy load. The elastic modulus of zirconia ystrium niobate was set to 200 GPa. The elastic modulus of alumina is 3800
It was set as Pa. The elastic modulus of spinel was 260 GPa.

The elastic modulus of zircon was set to 2000 Pa. The elastic modulus of titanium diboride was 515 GPa. The elastic modulus of zirconium carbide was set to 410 GPa. The elastic modulus of mullite was set to 2000 Pa. The elastic modulus of the silicon carbide powder and the silicon carbide Huis force was set to 450 Gpa. For compositions containing various combinations of oxides and non-oxides, the modulus of the alloy was a simple linear combination (by volume) of the moduli of the components.

Fracture toughness was calculated from the above formula.

Several examples of sintered alumina zirconia ytrium niobate compositions were tested by X-ray diffraction.

The X-ray diffraction scan was limited to 20 regions ranging from 26° to 36° using the Cu radiation. The amount of tetragonal zirconia-yttrium-niobate phase and the amount of monoclinic zirconia-yttrium-niobate phase were qualitatively calculated from the relative peak heights of the phases in the 2θ region.

In the case of the zirconia φ yttrium niobate-silicon carbide whisker composition, the voice force and the zirconia
Yttrium niobate powder was vibrated with distilled water for 24 hours. Two types of ZrOg-YNllO*/Glass/S
In preparing the iC whisker composition, the glass powder was approximately 33.3% A9,203, 33.3% Si02 by weight.
, iH Yohi 33.3% Yz O3h', A Lua 03 and 5iQ2 were ground together, glass powder and Y(N
O3)3 ・6820 distilled water slurry was prepared and 50
The remaining material was calcined at 0°C. after that,
Glass powder, silicon carbide powder, and zirconia yttrium niobate powder were vibrationally milled in distilled water using zirconia milling media for 48 hours. The powders obtained for all three compositions were dried and granulated;
287.2Kg/at 1450℃ in a graphite mold for 2 hours
Vacuum heat pressure was applied at ci (4000 psi). The elastic modulus of the added glass was 69Qpa.

Alumina - zirconia yttrium niobate, lint - In addition to the above-mentioned powder combination of alumina and zirconia yttrium niobate, two types of AQ = zOs 7r
The 02 Y203-YNb Os composition was coprecipitated and sintered as described above for the other coprecipitated samples. Two compositions are recorded below as Examples A and B. These 2
The powder proportion of the seed composition was varied using a modified coprecipitation technique involving precipitation with NHaOH and the addition of Nb2O6 and Y2O3. These two compositions are recorded below as Examples C and D.

Alumina and zirconia yztrium niobate 3
The seed powder combinations are tabulated below as Examples E, F and G, and the alumina alone sample as Example Day.

Table ■ is calculated from the composition (volume %) of each sample, the temperature at which the sample was sintered, and the above formula, and Mpa, /ii
The fracture toughness value expressed as (KLC/) and the measured Vickers hardness value (GPa) are shown. As mentioned earlier,
All sintered samples were ground and polished prior to microhardness measurements using a 101 g load.

-rX Dust box Composition Sintering temperature
Ωdan LK style A 20% (Zr 0x-3 mol% Y2
03) 1450℃ 15.2 4.3+ 7.2
5%YNb Oa 1”℃ 12.2
4.7+ 78.75%A
1650℃ 12,6 4,2 [343% (Zr 0
2-3 mol% Y203) 1450°C 14.8
5.1+3%YNb Os 1500
℃ 13.5 4.8 + 54% 8Q, 2 to 03
1550℃ 13.1 6.61600”
CI2.4 6.5 1650°C 12.7 5.7 C18% (Zr 02-0 mol% Y203) 145
0℃ 12.4 6.9+6%YNb 04
1550℃ micro crack +16% A5! ,g
03 1650℃D 40% (Zr
02-2 mol% Y203) 1450°C 13,
5 4.7+8%YNb Oa 15
50℃ 13.5 6.7+52%A9. t 03
1650℃ 12.0 6,4E
21% (Zr Oz -1 mol% Y203) 14
50℃ 17.6 5.6+4%YNb 04155
0℃ 14.5 5.4+75%A9J203165
0℃ 12.4 6.7 Example Cosmetic L-1
Shōkojyo Mother Shiniyo F 45% (Zr 02-2T Nil%
Y203) 1450℃ 12.7 6.2+5%
YNb Os 1550℃ 12゜27.8+50%A9Jz 031650℃ 17.
5 8.7G 72% (Zr 02-2 mol% Y2
03) 1450℃ 12,0 11,5+3%Y
Nb 04 1500'CI2,4 1
2,5 → -25%△ corresponding 2031550℃ 12,2
12.21600℃ 9,8 3.6 1650℃ 9,8 4,4 H100%A9J203 1450℃ Perforated 15
00'CI5,4 4.5 1550℃ 15.0 4,3 Sum ω''C14,55,0 1650℃ 15,0 5,4 The ALzO3 sample sintered at 1450℃ has a high effectiveness rate;
The material sintered at 1500°C showed a considerable efficiency.

However, when firing at 1450℃, if a small amount of 25% by volume zirconia + yttrium niobate is added,
Ceramic alloys are fully densified. Furthermore, the grain size of the alloy was significantly smaller than that seen in the AR,2o3 sample. Therefore, Zr0z YNI)Oa
The inclusion of sintering promotes sintering, while grain growth is inhibited by the addition of a second phase.

As is clear from Table IX, the toughness of all samples containing zirconia yttrium niobate is A9Jt.
Although the toughness was greater than that of the o3 sample, the opposite was true regarding the hardness. 75% zirconia yztrium
The toughness of samples containing niobate was determined when the composition was heated to 1600°C.
It decreased dramatically when sintered at 1650°C. The hardness values also decreased considerably at these two sintering temperatures.

Scanning electron microscopy revealed that the co-precipitated composition had a slightly more uniform spatial distribution of alumina and zirconia-yttrium-niobate phases than the mixed material. Also, the particle size of the coprecipitated material was slightly smaller than for a given sintering temperature. Finally, it is clear that the zirconia yttrium niobate trapped within the AQ, 2O3 particles in the coprecipitated chimples are more intragranular particles.

Wet chemical analysis was performed on the two coprecipitated samples and the results are summarized in Table X. HfO2 is an impurity in the ZrO2 material.

Table X A 77.425.10.922.180.43B 4
4,144,81,974,320.84 The sample of Example C was sintered at a high temperature of 1450°C or higher, and although severe microcracks occurred during the hardness test and the indentation pressure was applied, it did not show reliable hardness or toughness. Couldn't get value.

X-ray diffraction analysis of multiple samples shows tetragonal and monoclinic Z
"With respect to the content of 02 and YNbOa, i.e. objects containing more than 50% by volume of AQ, go3 and 50% by volume
For the following A9J203-containing objects, we have shown that there are two basic modes of high toughness microstructure.

To illustrate, Example G (75% by volume zirconia yttrium niobate) is a zirconia yttrium niobate.
It showed a diffraction pattern completely similar to that of niobate alone (including the peak of A9.zos, of course).

Samples that exhibited high toughness demonstrated very little or no monoclinic phase. The low toughness samples still contained the tetragonal phase as the predominant part, but a significant amount of the monoclinic phase was present. In contrast, samples containing about 50% by volume or less zirconia ytrium niobate did not exhibit the highest toughness when the diffraction pattern indicated the presence of only the tetragonal phase. The toughest samples contained about 20-50% by volume of zirconia yttrium niobate in the sample in the monoclinic state.

When the majority of Zirnia yttrium was in the monoclinic phase, the samples showed microcracks and low toughness.

Table X is lii! 2 shows compositions further combined with alumina-containing powders that exhibit strength and toughness effects.

This combination V was tabulated in volume % along with the temperature at which each sample was sintered, the measured Vickers hardness (GPa), and the fracture toughness value (Kxc) measured in MPara. Microhardness was also measured using a 1ON9 load after each sintered pill was crushed and polished.

(Example Composition Sintering temperature pK)
a 1ylpa 1mI 15%7r 0215
50℃ 17.6 7.185%A exemption 203
1650℃ 11.3 7.4J 2
5% Zr 02 1550℃ 12.0
7,7+75%A 203 1650℃
17.6 <8.6K 25% (Zr 02-
1 mol% 1550℃ 13.5 5.9Yz O
s) 1650℃ 10,9 5
．． 4+75%A9J1103 1 50%7r 021450℃ Micro crack +5
0%A9Jz 03 1550℃〃16
50°C 〃 M 50% (Zr 02-2 mol% 1450
℃ 12.9 6.8Y20. ＞
1550℃ 13.0 10.2 + 50%A exemption 203
1650℃ 12.7 6.9N
75%Zr Q21450℃ Microcracks +25%A5
Lz 03 1550°C 〃1650°C 0 75% (Zr 02-2 mol% 1450°C
12.4 7.5Y20s) 1
550℃ 12,2 8.9+25%A9Jz 03
1650℃ 12.0 17.2P
24% (ZrO, -2,3 mol% 1450°C Microcracks Nb 0slt) 1550°C
〃+16%A 203 1650℃Q
24% (Zr02 -11 mol% 1450℃
Microcracks Nb 057g) 15
50℃ +76%A 03 16
50℃ 〃HKtc Example Composition Sintering temperature Ω above'
aMPa J-R14, 5%7r 021550℃ 1
4.0 7.800, 5%YNb Os 1
650℃ +85%A for chipping 203
Difficult to measure S 14% Zr 02
1550℃ 14.0 5.7+1%Y
Nb Oa 1650℃ +85%A due to chipping zo3 W14 difficult to determine T
12% Zr 02 1550℃
17,1 4.3+3%YNb Oa 1
650℃ 15.4 5.9+85%AQ, z 03 U 24%Zr 02 1550℃
10.9 6.7+1%YNbOs
1650℃ 10.9 10.0+75%AQ, z0
3V 22%Zr 021550℃12.2<5
．． 7+3%YNb Oa 1650℃9.
3 9.175%A 203 W 19%Zr 02 1550℃
14,0 4,4+6%YNb 04 1
650℃ 12.0 6,0+15%A203X 24% (Zr02-1mol% 1550℃
14,2 5. OY2 03 ) + 1%YNb
04 1B50℃ 12.4 6.1+7
5% A 203 Y 22% (Zr Ox -1 mol% 155
0℃ 14.0 5.7Y203)+3%YNb
041650℃ 14.0 4. G+15%A response 20
3 2 19% (Zr 02-1-Ele% 1550
℃ 14.5 4. OY203)+5%YNb Oa
1650°C 13.7 4.1 + 15% A exemption 203 The tests in Tables IX and Xl showed a number of conclusions.

First, the addition of yttrium niobate can improve the toughness of 50-15 volume % zirconia partially stabilized with 50-25 volume % alumina and 2 mole % yttrium at the same temperature. This is clear when comparing the paired samples G-0 and FM.

Second, if you add some yttrium niobate,
15 or 25% by volume zirconia or zirconia
Increases the toughness of the composition with the Ittria phase. Addition of small amounts of yttrium niobate at 15 and 25% by volume to the zirconia-yttria-yttrium niobate phase (single phase or multi-phase) increases toughness, while large amounts reduce toughness. Example ■ vs. Examples R, S and T
; Example J vs. U, ■ and W; and Example vs. Example X.

Y and Zo Thirdly, in Examples P and Q, when Niopia alone is added to the alumina-zirconia ceramic alloy, no microcracked bodies are formed.

Fourth, adding yttrium or yttrium niobate-free zirconia to alumina at a level of 15-25% by volume toughens the alumina, Examples ■ and Jl, while levels of 50-75% by volume Examples M and Oo are severely microcracked, and when zirconia with N, 2 mol % ittria is added to alumina at a level of 50-15 vol M%, the material is microcracking free and strengthened. These data are based on zirconia
For the yttria-alumina system, the adjustment of a small number of yttria components has been shown to have a decisive influence on the mechanical integrity and toughness of the object.

The data in Tables IX and Xl show that adjusting the composition containing yttrium niobate in a manner similar to that of the zirconia-yttria-alumina system described above still has a decisive effect on toughness. In particular, a small amount of yttrium niobate increases toughness, but a large amount of YN
b 04 apparently serves to stabilize the tetragonal phase and prevents its transformation to the monoclinic phase, thus reducing the toughness. This effect is not obvious and would not have been expected by those skilled in the art.

Spinel - Spinel rich in zirconia, yttrium, niobe, and thomagnesia is 28.9% by weight.
MgQ, 77.1%A-203 as main component, alumina-rich spinel with weight% MQQ of 26.65%
, 73.35% AQ, mainly composed of zo3. Toughness (MPa, Kz in the formula /"ir") and Vickers hardness (GPa) data as a function of sintering temperature and composition for ceramic alloy samples are shown in Table XI below, as for magnesia-rich spinel samples, Table Xi is shown as an alumina-rich spinel sample. Values for sintered samples of each spinel alone are also shown for comparison.

Ex-X Example Composition Sintering temperature 0!
Omega! AA 21% (Zr 02-1 mol%
Y203) 1450℃ 11.8 3.7+4%Y
Nb 04 1550℃ 17.6
2.4+15% spinel 1650℃
Microcracks BB 45% (Zr Ox -2 mol% Yz O3) 1450°C 12.0 5,1+5
%YNb 04 1550℃ 10,
4 6.1+50% Spinel 165
0°C Microcracks CG 72% (Zr 02-2 mol% Y203) 1450°C 10.6 9.9+
3%YNb 04 1500℃ 10
,8 14.0+25% spinel 1
550℃ 10.4 7.2ieoo'c Microcracks DD 100% Shine/L,
1550℃ 10,3 2.716GO'C8,02
,5 1650°C 10.4 2.3 Spinel alone does not sinter to high density at temperatures of 1450° and 1500°C, but alloy samples did have high density after firing at these temperatures. Zirconia Yztrium
All samples containing niobate were extremely microcracked after firing to 1650°C. The hardness of the alloy sample is slightly greater than that of spinel alone, and the toughness of the alloy sample is approximately twice that of spinel at 50 volume percent zirconia yttrium niobate fraction and above.

-Jl Example Composition Sintering temperature
GPaKzcEE 21% (Zr 02-1 mol%
Y203) 1450℃ 10,9 3゜9+4%
YNb O4+75% spinel 1550℃ 8.8
2.91650℃ Microcracks FF 45% (Zr Oz -2 mol% Y203
) 1450℃ 10.9 4.8+5%YNb 0
4 +50% Spinel 1550℃ 6.9 2.5
1650°C Microcracks GO72% (Zr 02-2 mol% Y203) 14
50℃ 10.4 8.2+3%YNbO,+25%
Subine/L, 1500'C11,112,7155
0℃ 10.0 13.0 柘■℃ Microcracks HH100% Schinel 1500℃ 9.8 2.31
550°C 8.1 3.4 1600'C6,7 - 1650°C 8.4 3.3 Spinel alone did not sinter to high density at 1450°C, but ceramic alloys do when fired at this temperature. , showed good density. Of course, the hardness of the alloy sample
It was slightly higher than that of spinel alone and showed the same tendency to decrease with increasing firing temperature. The toughness of the alloy samples was slightly higher than that of spinel alone at low levels of zirconia yttrium niobate addition, but increased sharply at additions of 50% by volume and above. The optical microscope uses sintered spinel-zirconia yttrium.
The grain size of the niobate alloy was shown to be significantly smaller than that present in the sintered spinel sample. The same observation was made for alumina-zirconia-yttrium-niobate alloys.

Zircon - zirconia yztrium niobe, tow powder zircon sample at 1450℃ and 150℃
It did not sinter to high density at 0°C. The zircon powder used in this study was coarser than the alumina and spinel powders used above, so that when the particles were sintered at 1450°C, the sample containing 25% by volume zirconia yttrium niobate was completely There were enough people gathered to avoid crowding. At high temperatures, zircon alone samples began to dissociate under reduced pressure in the vacuum furnace. Thus, the zircon samples fired at 1600°C and 1650°C demonstrated more porosity, especially in the areas near the sample surface, than the zircon bodies sintered at 1550°C. These porous areas contain a large amount of secondary
phases, such as Zr0z and grain boundary silicate phases. Other regions inside the sample were less porous and were evident to contain small amounts of Zr0z and silicate phases. The alloy samples did not appear to be highly porous when sintered at high temperatures. The presence of zirconia yztrium niobate appears to suppress zircon dissociation.

The toughness (MPa, KIQ of the /i-formula) and Vickers hardness (GPa) data as a function of sintering temperature and composition in the capacitor of the ceramic alloy samples are shown in Table X below.
Shown in IV. The values for sintered samples of zircon alone are also shown in the table for comparison.

-J [Example Composition Sintering temperature
ΩOishokukan ■1 21% (Zr 02-1 mol% Y203
) 1450℃ 5.9 5.5+4%YNb 0
4 +75% zircon 1550℃ 8,4 5.1
1650℃ Microcracks JJ 45% (Zr 02-2 mol% Y203)
1450℃ 10,4 4.9+5%YNb 04
+50% zircon 1550℃ 10.1 5.5
1650℃ Microcracks KK 72% (Zr Oz -2 mol% Y203
) 1450℃ 10.9 9.0+3%YNbOa
+25% Zircon 15oo℃9.34.81550℃
8.9 5.1 1600℃ 9.0 5.4 1650℃ Microcracks L1oo% Zircon 1500℃ 6,9 2.81
550°C 8.4 3.1 1600°C 8.0 2.7 1650°C g, 0 2,9 Of course, the alloy sample was slightly harder than zircon alone and fairly tough without problems.

Samples of zirconium carbide alone and samples of different levels of three zirconium carbide-zirconia yttrium niobate ceramic alloys were hot pressed to high density at 1450°C. Toughness (MPa/
'i'' formula) and Vickers hardness (GPa)
The data are shown in Table Xv below as a function of volume % composition.

Leave--xy Mid-route composition Ω top!
"94MM 21% (Zr 02-1 mol% Y
2O3) -5,2+4%YNb Oa +75
%7r Ca, ttNN 45% (ZrOx-2 mol% Y203) 12.7 8.1+5% YN
b 04 +25% Zr C,.

00 69% (Zr Ot -2 mol% Y203)
17.3 6.7+6%YNb 04 +25
%Zr c6. v9PP 100%7r cll,
t9 10,4 4.9Table X
As is clear from v, the ceramic alloy is zirconium.
It was slightly harder and stronger than carbide alone.

Mullite - Zirconia Yztrium Niobe, Table X■ shows the composition of each sample (volume %), the temperature at which the sample was sintered, Vickers hardness measurement (GPa) and MP
The fracture toughness values (K, c) calculated using the aJT formula are shown. After grinding and polishing each sintered sample in a manner similar to the samples described above, microhardness measurements were performed using a 1ONy load.

Composition Sintering temperature
Omega King! Mu stem QQ 24%Zr0z+1%YNb 04
1450℃ Perforated ÷ 15% Mullite
1550℃ 8.4 4.51650℃ 8.9
5. I RR24% (Zr02-2 mol% Y203) 14
50℃ Pore +1% YNbO, +75% Mullite 1550℃ 17.3 3.788 48% (Z
r Oz -2 mol% Y203) 1450°C 9.
5 5.2+2%YNbOa +so% Mullite 15
50℃ 9.8 4.91650℃ Microcracks TT 72% (Zr 02-2 mol% Yt O3)
1450℃ 10,7 7.0+3%YNb 04
+25% mullite 1550℃ 8.9 4.31
650℃ Microcracks UU1oO% Mullite 1450℃ With holes 1550
C. Porous 1650.degree. C. 10.7 2.1 The above data show that the toughness of mullite bodies is significantly improved by zirconia yttrium niobate and that zirconia yttrium niobate can promote the sintering of mullite bodies.

SiC powder - zirconia yttrium niobate Table ■ shows the composition of each sample (volume %), the temperature at which the sample was hot-pressed, and the measured Vickers hardness (GPa)
and the fracture toughness value (K'
1C). After each hot pressure body was ground and polished, the microhardness was measured using a 10 Ky load.

! LJC Example Composition Heat Pressure Temperature
Ω■] [5W 100%Si C1650℃ Perforated W
24% (Zr 02-2 mol% Yz O3) 1
650℃ 12,4 5.4+1%YNbO4+75
%5iC XX 48% (Zr 02-2 mol% Yz O3)
1450℃ 9,8 7.3+2%YNbO4+5
0% 5iC YY 73% (Zr Ox -2 mol% Yt Os
) 1450℃ 12.4 5.6+3%YNbO
a +24% 5iC 8iC could not be hot pressed to a fully dense body at the temperatures and pressures that would produce a dense composition of 5iC-zirconia yttrium niobate. Approximately 2 to 2 technical documents
Toughness values of commercially available SiC between 4 MPa/''ii were recorded. The data in Table X■ shows that the addition of zirconia yttrium niobate increases the toughness of the giC body.

SiC Whisker Zirconia Yttrium One sample consisting of SiC voice force and zirconia yttrium niobate, and two samples consisting of SiC whiskers, zirconia yttrium niobate and 15% by volume of the above glass were hot pressed to 1450°C.

Glass was mixed in to facilitate the production of dense objects. capacity%
The Vickers hardness fJt (GPa) and toughness (MPa5 formula) as a function of composition are shown in Table X■ below.

5-1 Example Composition GPa
KxcZZ 72% (Zr O2-2-E
/L+%Y20s) 12.6 8.5+3
%YNbO4 + 25% Voiska AAA 34% (Zr 02-2 mol% Yt O3)
13.0 6.4+1%YNbO4+15%
Glass + 50% Whisker BBB 57% (Zr 02-2Mo/L/%Y203
) 17.7 5.2+3%'1'Nb Q4
+15% glass + 25% whiskani titanium diboride-zirconia yttrium niobate Table
a) and toughness (Kz of MPa/i'' formula) data not shown. The toughness of titanium diboride is 4 MPari'' or less. When pure titanium diboride was subjected to the same heat-pressure process, the material did not become dense.

lby composition riohke
”9pen CCG 21% (Zr 02-1mo/lz%Y
203) 13.1 8.4+4%YNbO
a +75%Ti B2DD0 45% (Zr 02-
2mo/lz%Y2O3) 17.0 -+5
%YNbOa 50%Tt BzEEE69% (
Zr 02-2 mol% Yz O3) 10.4
7.7 + 6% YNb Oa + 75% Ti 82 Although above we have referred to sintered objects produced by methods similar to hot pressing and sintering, the term object also applies to objects such as beads, coatings, fibers, honeycombs, and sheets. A wide variety of methods are known in the art, such as arc melting, chemical vapor deposition, extrusion.

Includes those manufactured using methods including plasma spray, skull melting, and zone melting. For example, the hardness and toughness exhibited by the materials of the invention encourage their use as friction resistance and thermal barrier coatings.

Based on the above preferred example, the polygon 0-P shown in FIG.
-Q-R-8-T-U = V-W-X-Y-2-0 has been found to encompass compositions that can be practiced in the present invention. Y
The polygons were derived based on the following parameters where O3/2 is an additive that produces partial stabilization.

(a) YNbOa and/or YTaO, and/
Also, HA M N b 04 O and /* or MTa.

Y when the amount of 4 is about 0.5 to 4.4 mol%.

3/2 ranges from about 2.2 to 9 mole percent.

(b) the amount of YNbOa and/or YTaOa and/or MNtlOa and/or MTaO4 is about 4;
．． When it is 4-5 mol%, YO3/2 is about 7.2-9
The range is mole %.

(c) When m of YNb04 and/or YTaOa and/or MNbO4 and/or MTa04 is 5-6 mol%, YO3/2 is about 7.2-8
．． It is in the range of 6 mol%.

(d) YNbOa and/or YTaOa and/or MNI) On and/or MTa When l of 04 is about 6-7 mol%, Y03/2 is about 0. ~8.6
The range is mole %.

(e) When the amount of YNbOa and/or YTaOa and/or MNbOa and/or MTa04 is about 7-8 mol%, YO3/2 is about 0.8-8
The range is mole %.

[Brief explanation of drawings]

FIG. 1 is a graph showing examples of compositions investigated in the present invention to distinguish areas of the sintered body where microcracks are a significant problem in producing a flawless body. The toughness value is expressed by the formula vpa,/ii-, and the values measured for each as-is sample are recorded. Figure 2 shows a button 0-P that confines the region of the composition of the present invention that can be manipulated when obtaining a high-toughness sintered body as it is.
-Q-R-8-T-LJ-V-W-X-y-zo. %Y03/2□ F7g, 2 Commissioner of the Patent Office April 1, 1986
No. 582, Title of Invention "High Toughness Ceramic Alloy 3, Amended Person's Case No. 1" Patent Applicant Location Corning, New York, United States of America
(No address) Name Corning Glass Works 4, Agent 5-2-15 Roppongi, Minato-ku, Tokyo 106 Date of amendment order None 6 Number of inventions increased by amendment None 7, ?
11 Positive object Drawing Plane A-2 @ 14'70'7r, 7t, r-8-37-re %
Yo3ノ2-11mo, 1v % YOs t 2-11-hν, 2

Claims (1)

[Claims] 1) YNbO_4 and/or YTaO_4 and/or MNbO_4 and/or MTaO_4 (M in the formula is Mg^+^2, Ca^+^2, Sc^+^3,
and/or La^+^3, Ce^+^4, Ce^+
^3, Pr^+^3, Nd^+^3, Sm^+^3, E
u^+^3, Gd^+^3, Tb^+^3, Dy^+^
3, Ho^+^3, Er^+^3, Tm^+^3, Yb
^+^3, and Lu^+^3, the latter being substituted for Y, and two +
2 cations are substituted for 3 +3Y cations)
A toughening agent selected from the group of about 0.5
ZrO exhibits high toughness by containing ~8 mol%
_2, partially stabilized ZrO_2, ZrO_2-HfO
_2 solid solution, partially stabilized ZrO_2-HfO_2 solid solution, partially stabilized HfO_2, and a ceramic alloy having at least one member from the group of HfO_2 as a main component. 2) YO_3_/_2 is the polygon O-P-Q in Figure 2
2. A ceramic alloy according to claim 1, which is a partially stabilizing additive having a composition within -R-S-T-U-V-W-X-Y-Z-O. 3) The toughening agent is comprised of approximately 2.4-12.9% Y_2O_3, and 0.5-7.6% Nb_2O_5 and/or 0.5% by weight, expressed on an oxide basis.
0.5-1 consisting of 85-12.0% Ta_2O_5
Ceramic alloy according to claim 2, which is selected from the group of YNbO_4 and/or YTaO_4, the main components of which are 2.0% Nb_2O_5 + Ta_2O_5. 4) YNbO_4 and/or YTaO_4 and/or MNbO_4 and/or MTaO_4 (M in the formula is Mo^+^2, Ca^+^2, Sc^+^3,
and/or La^+^3, Ce^+^4, Ce^+
^3, Pr^+^3, Nd^+^3, Sm^+^3, E
u^+^3, Gd^+^3, Tb^+^3, Dy^+^
3, Ho^+^3, Er^+^3, Tm^+^3, Yb
^+^3, and Lu^+^3, the latter being substituted for Y, and two +
2 cations are substituted for 3 +3Y cations)
A toughening agent selected from the group of about 0.5
ZrO exhibits high toughness by containing ~8 mol%
_2, partially stabilized ZrO_2, ZrO_2-HfO
_2 solid solution, partially stabilized ZrO_2-HfO_2 solid solution, partially stabilized HrO_2, and at least 5% by volume of a ceramic alloy based on at least one member of the group HfO_2, and the remainder being a hard refractory ceramic. Ceramic body with improved toughness based on. 5) The hard refractory ceramic is α-alumina, β-
Alumina, β”-alumina, Al_2O_3-Cr_2
5. The ceramic body of claim 4, comprising at least one member of the group consisting of O_3 solid solution, mullite, sialon, nasicon, silicon carbide, silicon nitride, spinel, titanium carbide, titanium diboride, zircon, and zirconium carbide. 6) YNbO_4 and/or YTaO_4 and/or MNbO_4 and/or MTaO_4 (M in the formula is Mg^+^2, Ca^+^2, Sc^+^3,
and/or La^+^3, Ce^+^4, Ce^+
^3, Pr^+^3, Nd^+^3, Sm, ^+^3,
Eu^+^3, Gd^+^3, Tb^+^3, Dy^+
^3, Ho^+^3, Er^+^3, Tm^+^3, Y
indicates a rare earth metal selected from the group consisting of b^+^3, and Lu^+^3, the latter being substituted for Y, and two ^+^2 cations being substituted for three +3Y cations. ) ZrO_2, partially stabilized ZrO_2, and ZrO_2- exhibiting high toughness by containing about 0.5 to 8 mol% of a toughening agent selected from the group based on the oxide.
HrO_2 solid solution, partially stabilized ZrO_2-HfO
_2 solid solution, partially stabilized HfO_2, and HfO
Ceramic composite of improved toughness based on at least 5% by volume of a ceramic alloy based on at least one member of the group __2 and up to 80% by volume of refractory ceramic fibers and/or whiskers. 7) Claims in which the fiber and/or whisker comprises at least one member of the group consisting of alumina, mullite, sialon, silicon carbide, silicon nitride, AlN, BN, B_4C, ZrO_2, zircon, silicon oxycarbide, and spinel. The ceramic composite according to item 6. 8) The ceramic composite according to claim 6, further comprising a hard refractory ceramic. 9) The hard refractory ceramic is made of α-alumina, β
-Alumina, β''-Alumina, Al_2O_3-Cr_
9. The ceramic composite according to claim 8, comprising at least one member of the group consisting of 2O_3 solid solution, mullite, sialon, nasicon, silicon carbide, silicon nitride, spinel, titanium carbide, titanium diboride, zircon, and zirconium carbide. 10) Claim 9, wherein said fibers and/or whiskers are comprised of at least one member of the group consisting of alumina, mullite, sialon, silicon carbide, silicon nitride, AlN, BN, B_4C, ZrO_2, zircon, silicon oxycarbide, and spinel. Ceramic composites as described in Section.