EP0214291A1
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EP
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Sintered zirconia and process for its production
Assignee: Nippon Soda Co Ltd
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Filing: 1985-07-03
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Granted: —
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Expires: 2005-07-03
Abstract
Abstract High-density sintered zirconia containing a stabilizer such as Y 2 0 3 can be produced through low-temperature sintering by first preparing readily sinterable zirconia powder having a transition metal compound on the surface thereof by adding stabilizer-containing zirconia powder or precursor powder capable of yielding zirconia upon thermal decomposition to a solution or dispersion of a transition metal compound which acts as a sintering accelerator, then adjusting the content of Y 2 0 3 to 1.3 to 2.0 mol % and the content of a tetragonal phase to 65% or more. Thus, a partially stabilized sintered zirconia having a fracture toughness of 10 to 16 MM/m 3/2 can be obtained. A composite product between this partially stabilized zirconia and α-alumina has an extremely high hardness.
Inventors
- 👤 Junichi Morishita
- 👤 Nobuo Kimura
- 👤 Hiromichi Okamura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 09:03
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/48; C04B35/486; C04B35/488; C04B35/4885
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
65 words
A process for the production of an easy-sintering raw material to be used for the production of zirconia ceramics which comprises adding powder principally containing zirconium compound(s) and containing stabilizing agent(s) into a solution or slurry containing at least one kind of transition metal compound(s) to be suspended therein and subsequently removing the solvent from the suspended slurry and drying to obtain the objective product.
Claim 2
Dependent Claim
65 words
A process for the production of an easy-sintering raw material to be used for the production of zirconia ceramics which comprises adding powder principally containing zirconium compound(s) and containing stabilizing agent(s) into a solution or slurry containing at least one kind of transition metal compound(s) to be suspended therein and subsequently removing the solvent from the suspended slurry and drying to obtain the objective product.
Claim 3
Dependent Claim
52 words
The process for the production of an easy sintering raw material powder to be used for the production of zirconia ceramics according to claim 1, wherein the transition metal compound(s) are compound(s) of at least one kind of metal selected from the group consisting of Mn, Fe, Co, Ni, Cu and Zn.
Claim 4
Dependent Claim
63 words
The process for the production of an easy sintering raw material powder to be used for the production of zirconia ceramics according to claim 1, wherein the stabilizing agent is Y 2 0 3 , CaO, MgO, CeO 2 , or yttrium compound, calcium compound, magnesium compound, or cerium compounds which by thermal decomposition may produce Y203, CaO, MgO, or Ce0 2 respectively.
Claim 5
Dependent Claim
92 words
the process for the production of an easy sintering raw material powder to be used for the production of fully stabilized zirconia ceramics, partially stabilized zirconia ceramics, or alumina containing partially stabilized zirconia ceramics according to claim 1, wherein powder principally containing zirconium compound(s) and containing stabilizing agent comprises; (a) fully stabilized zirconia powder, partially stabilized zirconia powder, or alumina containing partially stabilized zirconia powder, or ( b ) a precursor powder which by thermal decomposition may produce fully stabilized zirconia, partially stabilized zirconia or partially stabilized zirconia powder containing alumina respectively.
Claim 6
Dependent Claim
74 words
The process for the production of an easy sintering raw material powder to be used for the production of zirconia ceramics according to claim 1, wherein the atomic ratio of the transition metal to Zr or to Zr plus At in said easy sintering raw material powder is in a range from 0.01 to 1.0%, in which provided " Zr plus Aℓ " is used if such easy sintering raw material powder contains aluminum.
Claim 7
Dependent Claim
61 words
the process for the production of an easy sintering raw material powder to be used for the production of fully stabilized zirconia ceramics or partially stabilized zirconia ceramics according to claim 4, wherein the precursor powder, which by thermal decomposition may produce fully stabilized zirconia, or partially stabilized zirconia, is co-precipitation precipitated from a solution containing zirconium compound(s) and stabilizing agent.
Claim 8
Dependent Claim
75 words
The process for the production of an easy sintering raw material powder to be used for the production of partially stabilized alumina containing zirconia ceramics according to claim 4, wherein the precursor powder, which by thermal decomposition may produce alumina containing partially stabilized zirconia is co-precipitation precipitated from a solution or slurry containing; (a) α-alumina powder or aluminium compounds which by their thermal decomposition may produce alumina, (b) zirconium compounds, and (c) a stabilizing agent.
Claim 9
Dependent Claim
66 words
A process for the production of high density zirconia ceramics which comprises adding the powder principally containing zirconia compounds and containing a stabilizing agent into a solution or slurry containing at least one kind of transition metal compound(s) to be suspended therein and removing the solvent from the suspended slurry and drying to produce raw material powder, and then moulding and sintering said raw material powder.
Claim 10
Dependent Claim
66 words
A process for the production of high density zirconia ceramics which comprises adding the powder principally containing zirconia compounds and containing a stabilizing agent into a solution or slurry containing at least one kind of transition metal compound(s) to be suspended therein and removing the solvent from the suspended slurry and drying to produce raw material powder, and then moulding and sintering said raw material powder.
Claim 11
Dependent Claim
34 words
The process for the production of zirconia ceramics having high density according to claim 8, wherein sintering is conducted under atmospheric pressure at the temperature in a range from 1100°C to 1700 * C.
Claim 12
Dependent Claim
108 words
A process for the production of Y 2 0 3 partially stabilized zirconia ceramics having high density and high tenacity, which comprises suspending Y 2 0 3 partially stabilized zirconia powder having grain size of less than 400 A, and BET specific surface of 2 m 2 /g or more, or precursor powder which by its thermal decomposition may produce said Y 2 0 3 partially stabilized zirconia powder, into a solution or slurry containing at least one kind of transition metal compound(s) and subsequently removing the solvent from the suspended slurry and drying to produce raw material powder, and then moulding and sintering said raw material powder.
Claim 13
Dependent Claim
108 words
A process for the production of Y 2 0 3 partially stabilized zirconia ceramics having high density and high tenacity, which comprises suspending Y 2 0 3 partially stabilized zirconia powder having grain size of less than 400 A, and BET specific surface of 2 m 2 /g or more, or precursor powder which by its thermal decomposition may produce said Y 2 0 3 partially stabilized zirconia powder, into a solution or slurry containing at least one kind of transition metal compound(s) and subsequently removing the solvent from the suspended slurry and drying to produce raw material powder, and then moulding and sintering said raw material powder.
Claim 14
Dependent Claim
51 words
The process for the production of Y 2 0 3 partially stabilized zirconia ceramics having high density and high tenacity, according to claim 10, wherein the transition metal compound(s) are compound(s) of at least one kind of metal selected from the group consisting of Mn, Fe, Co, Ni, Cu and Zn.
Claim 15
Dependent Claim
53 words
The process for the production of Y 2 0 3 partially stabilized zirconia ceramics having high density and high tenacity, according to claim 10, wherein the atomic ratio of the transition metal to Zr in said Y 2 0 3 partially stabilized zirconia ceramics is in the range of from 0.01% to 1.0%
Claim 16
Dependent Claim
46 words
the process for the production of Y 2 0 3 partially stabilized zirconia ceramics having high density and high tenacity, according to claim 10, wherein the precursor powder which may produce, by its thermal decomposition, co-precipitation precipitated from a solution containing zirconium compound(s) and yttrium compound(s).
Claim 17
Dependent Claim
36 words
The process for the production of Y 2 0 3 partially stabilized zirconia ceramics having high density and high tenacity, according to claim 10, wherein sintering is conducted under atmospheric pressure at 1500°C or lower temperature.
Claim 18
Dependent Claim
43 words
Y 2 0 3 partially stabilized zirconia ceramics having high density and high tenacity, which is characterized by Y 2 0 3 content in the range of from 1.3 mol.% to 2.0 mol.%, and the content of tetragonal phase being 65% or more.
Claim 19
Dependent Claim
43 words
Y 2 0 3 partially stabilized zirconia ceramics having high density and high tenacity, which is characterized by Y 2 0 3 content in the range of from 1.3 mol.% to 2.0 mol.%, and the content of tetragonal phase being 65% or more.
Claim 20
Dependent Claim
34 words
Y 2 0 3 partially stabilized zirconia ceramics having high density and high tenacity, according to claim 15, wherein the crystal grain size of ZrO 2 in the ceramics is 0.5 µm or less.
Claim 21
Dependent Claim
32 words
Y 2 0 3 partially stabilized zirconia ceramics having high density and high tenacity, according to claim 15, wherein the density of said zirconia ceramics is 5 .8 g/cm 3 or more.
Claim 22
Dependent Claim
51 words
1 8. Partially stabilized zirconia ceramics containing alumina which is chracterized by the following raio in the composition: partially stabilized zirconia : 99 to 40 mol.% a-alumina : 1 to 60 mol.% transition metal oxide : 0.01 to 1% of the atomic ratio thereof to the combination of Zr and Al
Claim 23
Dependent Claim
51 words
1 8. Partially stabilized zirconia ceramics containing alumina which is chracterized by the following raio in the composition: partially stabilized zirconia : 99 to 40 mol.% a-alumina : 1 to 60 mol.% transition metal oxide : 0.01 to 1% of the atomic ratio thereof to the combination of Zr and Al
Claim 24
Dependent Claim
36 words
Partially stabilized zirconia ceramics containing alumina according to claim 18, wherein partially stabilized zirconia is stabilized by Y 2 O 3 , MgO, CaO, or Ce0 2 , and has tetragonal phase of 65% or more.
Claim 25
Dependent Claim
38 words
Partially stabilized zirconia ceramics containing alumina, according to claim 18, wherein the transition metal oxides are an oxide of at least one kind of metal selected from the group consisting of Mn, Fe, Co, Ni, Cu and Zn.
Claim 26
Dependent Claim
39 words
Partially stabilized zirconia ceramics containing alumina, according to claim 18, wherein the crystal grain size of Zr0 in the ceramics is 2 µm or less, and the crystalgrain size of Al 2 O 3 is 4 µm or less.
Claim 27
Dependent Claim
118 words
A process for the production of zirconia ceramics containing alumina, having the following ratio in the composition: partially stabilized zirconia : 99 to 40 mol.% alumina : 1 to 60 mol.% transition metal oxide : the atomic ratio thereof to the combination of Zr and A1 ranging 0.01 to 1%. which comprises; removing the solvent from the slurry containing (a) partially stabilized zirconia powder or precursor powder which by its thermal decomposition may produce partially stabilized zirconia, (b) a-alumina powder or precursor powder which by its thermal decomposition may produce α-alumina, and (c) transition metal compound(s), and drying so as to produce raw material powder, and, then, moulding the raw material into a shape, and firing to sinter.
Claim 28
Dependent Claim
118 words
A process for the production of zirconia ceramics containing alumina, having the following ratio in the composition: partially stabilized zirconia : 99 to 40 mol.% alumina : 1 to 60 mol.% transition metal oxide : the atomic ratio thereof to the combination of Zr and A1 ranging 0.01 to 1%. which comprises; removing the solvent from the slurry containing (a) partially stabilized zirconia powder or precursor powder which by its thermal decomposition may produce partially stabilized zirconia, (b) a-alumina powder or precursor powder which by its thermal decomposition may produce α-alumina, and (c) transition metal compound(s), and drying so as to produce raw material powder, and, then, moulding the raw material into a shape, and firing to sinter.
Claim 29
Dependent Claim
44 words
the process for the production of partially stabilized zirconia ceramics containing alumina, according to claim 22, wherein the transition metal compound(s) are a compound(s) of at least one kind of metal selected from the group consisting of Mn, Fe, Co, Ni, Cu and Zn.
Claim 30
Dependent Claim
62 words
The process for the production of partially stabilized zirconia ceramics containing alumina, according to claim 22, wherein the raw material powder has grain size of 400 A or less, and BET specific surface of 2 m 2 /g or more, the α-alumina powder has crystal particle size of 1.0 pm'or less, and BET specific surface of 2 m 2 /g or more.
Claim 31
Dependent Claim
36 words
The process for the production of partially stabilized zirconia ceramics containing alumina, according to claim 22, wherein the firing to sinter is carried out under atmospheric pressure at the temperature of 1500 * C or lower.
References Cited (Backward Citations)
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