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Magnesium oxide and yttrium oxide stabilized square polycrystal zirconium oxide ceramics and its preparing process

A technology of tetragonal zirconia and polycrystalline ceramics, applied in the field of zirconia ceramics, can solve the problems that hinder the development and application of PSZ ceramics, poor thermal shock resistance, degradation, etc., achieve good comprehensive mechanical properties, simplify the production process, and reduce the sintering temperature Effect

Inactive Publication Date: 2002-09-18
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, 3Y-TZP has performance degradation during hydrothermal treatment. In the range of 150-250 ° C, the spontaneous phase transition from tetragonal phase to monoclinic phase, and poor thermal shock resistance [P.H.Rieth, J.S.Reed and A.W.Naumann, Fabrication and flexural strength of ultra-fine-grained yttria-stabilized zirconia, Bulletin of Am.Ceram.Soc.Vol.55, pp.717-723(1977)]
by Y 2 o 3 The (Mg, Y)-PSZ ceramics obtained by co-doping with MgO can effectively inhibit the degradation of properties during hydrothermal treatment [F.Meschke, N.Claussen, G.D.Portu, and J.Rodel, phase stability of fine-grained (Mg, Y)-PSZ, J.Am.Ceram.Soc., Vol.78[7], 1997-1999(1995)], however, the shortcomings of PSZ technology still seriously hinder the development and application of PSZ ceramics

Method used

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  • Magnesium oxide and yttrium oxide stabilized square polycrystal zirconium oxide ceramics and its preparing process
  • Magnesium oxide and yttrium oxide stabilized square polycrystal zirconium oxide ceramics and its preparing process
  • Magnesium oxide and yttrium oxide stabilized square polycrystal zirconium oxide ceramics and its preparing process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Combine 0.5vol% ultrafine YAS sintering aid with (Mg, Y)-TZP powder ((14mol%)MgO-(1.5mol%)Y 2 o 3 -(balance)ZrO 2 ) Mechanical ball milling for about 12 hours, drying, adding 3% concentration of PVA as a binder to granulate, dry pressing at 60 MPa, and isostatic pressing at 200 MPa to obtain a green body. Then place the green billet in a silicon molybdenum rod furnace at a rate of 2°C / min to 1400°C for 2 hours, then cool down with the furnace. The sintered body was processed into a 3×3×35mm sample, and the flexural strength was measured by the three-point bending method (σ f ) (Instrument: INSTRON 1195 / universal material testing machine; loading rate: 0.5mm / min; span: 30mm; the data of one sample is evaluated by no less than 5 test strips.). σ f Calculated by the following formula:

[0032] σ f =3PL / 2bh 2

[0033] σ f : Bending strength; P: Critical load at break; L: Span (30mm); b: Sample width (4mm); h: Sample thickness (3mm).

[0034] Fracture toughness was...

Embodiment 2

[0038] Heterogeneous co-precipitation introduces 0.5Vol% ultrafine YAS: (14mol%)MgO-(1.5mol%)Y 2 o 3 -(balance)ZrO 2 After the salt solution (concentration range 0.5M) of corresponding yttrium chloride, magnesium nitrate and zirconium oxychloride is mixed homogeneously, add the precipitation in the ammoniacal liquor that has uniformly dispersed the ultrafine YAS of 0.5Vol%, then wash 6 times, finally in Drying at 100°C and calcining at 750°C for 2 hours to obtain (Mg,Y)-TZP powder, see Example 1 for other shaping and sintering. The flexural strength and fracture toughness of (Mg, Y)-TZP ceramics obtained in this example are 818±25MPa and 8.3±0.4MPa·m respectively 1 / 2 . The X-ray diagram of the cross-section of the polished surface is as follows: Figure 4As shown, the phase of the sintered body is a tetragonal phase, and there are a large number of monomer phases on the surface of the cross-section. The SEM photos of the cross-section are shown in Figure 5 shown.

Embodiment 3

[0040] Other processes are the same as in Example 2, but sintered at 1300° C. and kept for 2 hours. The flexural strength and fracture toughness of (Mg, Y)-TZP ceramics obtained in this example are 661 ± 30 MPa and 7.3 ± 0.3 MPa m respectively 1 / 2 .

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Abstract

A magnesium oxide and yttrium oxide costabilized square polycrystal zirconium oxide ceramics (Mg, Y)-TZP is prepared from MgO (5-14 mol%), Y2O3 (0.5-2 mol%) and ZrO2 through preparing nano (Mg, Y)-TZP powder, adding non-crystal YSA (0.5-10 vol%), gramulating, dry pressing and cintering at 1250-1400 deg.C. The said (Mg, Y)-T2P ceramics has 200-400 nm of grain size, 384-818 MPa of bending strength and 5.2-8.3 MPa.M1 / 2 of breaking toughness. Its advantages are simple process, low sinter temp and excellent mechanical performance.

Description

technical field [0001] The invention relates to a tetragonal zirconia polycrystalline ceramic (Mg, Y)-TZP ceramic co-stabilized by magnesium oxide and yttrium oxide and a preparation method thereof. It belongs to the field of zirconia ceramics. Background technique [0002] Before 1975, the application of zirconia ceramics was limited to refractory materials. People did not have much interest in developing zirconia ceramics as engineering ceramics, mainly due to the tetragonal phase (t) → monoclinic phase (m) at around 1200 ° C martensitic transformation. When the sintered body is cooled below about 1200 °C, this phase transformation will occur, and the shear strain and volume expansion generated are sufficient to cause the fracture and destruction of the sintered body. However, due to the intrinsic physical and chemical properties of zirconia, such as high hardness, wear resistance, low coefficient of friction, chemical inertness, electrical properties (insulation and con...

Claims

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Application Information

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IPC IPC(8): C04B35/48C04B35/488C04B35/622C04B35/64
Inventor 荣天君黄校先王士维郭景坤黄晓巍章健
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI