KR20100065719A - Manufacturing method of zro2-al2o3 based ceramic block for tooth-restorative - Google Patents

Abstract

PURPOSE: A manufacturing method of ceramics dental restorative material is provided, which not only maintains the excellent balance of the toughness and intensity by controlling the content of alumina on the zirconia base but also uses the zirconia-alumina complex oxide. CONSTITUTION: A manufacturing method of ceramics dental restorative material using the zirconia-alumina complex oxide includes the steps: a step of adding metal chloride into the zirconia powder dipped by the yttria of 3mol%; a step of adding the zirconia and aluminum chloride hexahydrate(AlCl36H2O) into the distilled water; a step of ball milling for 48 hours after the polyvinyl alcohol is added to the zirconia-alumina Composition powder and the distilled water, and then mixing the mixture which is completely dissolved; a step of manufacturing the zirconia block which is preliminarily sintered by proceeding the pre-sintering after the powder is pressed with the one-axis and compressed by pressing in the even cold pressure; and a step of analyzing the phase of sintered body with SEM.

Description

Manufacturing method of ceramic tooth restoration using zirconia-alumina complex oxide {Manufacturing method of ZrO2-Al2O3 based ceramic block for tooth-restorative}

The present invention relates to an artificial tooth core material used in dental prostheses, and more particularly, cold aisotropic pressing (CIP) and pre-sintering after introducing alumina into zirconia ceramics and adding an organic / inorganic binder. It relates to a core block to be manufactured through).

In addition to the fact that metal-ceramic combinations are disadvantageous in terms of aesthetics in artificial dental materials, the use of metals in the oral cavity has caused many side effects due to the risk of biocompatibility of the metals. The demand for restoration has led to the practical application of all-ceramic ceramics, and the zirconia ceramics have been studied and used as a material for high strength artificial tooth cores.

Compared with metallic materials, ceramic materials have excellent performances such as hardness, wear resistance, heat resistance, corrosion resistance and the like. Among them, zirconia ceramics are used in a wide range of applications because of their unique mechanical and physical properties. Zirconia is used in a fully or partially stabilized form by doping with stabilizing elements such as Y, Ce, Ca and Mg to compensate for the shortcomings. Unlike most other ceramics that are hard and strong but brittle, partially stabilized zirconia ceramics have high hardness and strength as well as high fracture toughness and wear resistance. Partially stabilized zirconia ceramics due to these properties are known to be suitable for use in high-strength applications such as cutting tools, electronics, engine materials, grinding media and optical connecting parts.

Various types of organic / inorganic binders are added in order to facilitate moldability in using yttria stabilized zirconia (YSZ) powder which is used most recently. Examples of well-known organic binders include polyvinyl pyrrolidine, polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride, polyvinyl butyr, polystyrene and mixtures thereof. Inorganic binders include magnesium oxide, ammonium phosphate, colloidal silica, calcium sulfate, ethyl silicate, silica, magnesium phosphate, silica compounds and the like.

Many attempts have been made to prepare alumina-zirconia sintered composites by dispersing zirconia particles on conventional alumina ceramic substrates and to improve their mechanical strength and toughness. However, zirconia added to the production of alumina-zirconia sintered composites by mechanical mixing of two powders has a large initial particle size and a high sintering temperature for densification of alumina. Difficult and uniform dispersion is difficult to improve the mechanical properties. Thus zirconia-alumina The composite oxide material is manufactured by the sol-gel process and hydrothermal synthesis, not the mechanical and physical mixing of the two powders, and the addition of binders to control uniform dispersion and particle size and improve adhesion, without compromising mechanical strength and toughness. It is intended to provide wear resistance and hardness.

The main object of the present invention is to control the content of alumina on the zirconia base to maintain a good balance of strength and toughness, while at the same time zirconia-alumina having excellent wear resistance and hardness To provide a composite block.

The zirconia-alumina composite ceramic material of the present invention comprises a zirconia phase and an alumina phase composed of at least 90 vol% of square zirconia, and the amount of alumina phase in the composite ceramic material is 20 to 70 vol%, preferably 40 to 60 vol%. It contains a phase. When the content of the alumina phase is less than 20 vol%, the mechanical strength and wear resistance of the composite ceramic material cannot be sufficiently improved. On the other hand, when the amount of alumina exceeds 70 vol%, there is a fear that remarkable strength and toughness decrease.

In particular, when the amount of alumina is 40 to 60 vol%, a highly reliable ceramic material having a high level of balance between strength and toughness can be provided.

In the composite ceramic material, the zirconia phase preferably contains 3 to 10 mol% of yttria as a stabilizer.

That is, the method comprises the steps of mixing the stabilized zirconia powder so that the amount of alumina phase is in the range of 20 to 70 vol%; Adding a binder to mold into a desired shape; Sintering the composite ceramic material in an oxygen-containing atmosphere.

Thus, the zirconia-alumina of the present invention The composite oxide material is manufactured by the sol-gel process and hydrothermal synthesis, not the mechanical and physical mixing of the two powders, and the addition of binders to control uniform dispersion and particle size and improve adhesion, without compromising mechanical strength and toughness. It may have wear resistance and hardness.

Example 1

Metal chloride was added to the stabilized zirconia powder doped with 3 mol% of conventional yttria, and polyvinyl alcohol was used as the binder.

Zirconia and aluminum chloride hexahydrate (AlCl ₃ 6H ₂ O) were added to the distilled water, and the ratio of alumina was 40 vol%. The mixture was reacted at 80 ° C. under acidic conditions in a closed system by sol-gel synthesis to coat alumina particles on the surface of zirconia powder, and then distilled water was dried.

Polyvinyl alcohol was added to the prepared zirconia-alumina composite powder and distilled water, and then the mixture was completely dissolved, followed by ball milling for 48 hours to reduce the secondary particle size and enhance adhesion between the powders. After the uniaxial pressing of the powder, it was compressed by cold isostatic pressing and preliminarily sintered to prepare a presintered zirconia block, and after the core fabrication, atmospheric sintering was performed.

The phase of the sintered body was analyzed by SEM and the crystal phase of alumina was identified using XRD. Flexural strength was measured for three-point bending strength and hardness was measured for Vickers hardness.

[Example 2]

In the same process as in Example 1 to synthesize a powder and to prepare a sintered body, the type of binder added was changed to polyvinyl pyrrolidine (PVP).

Example 3

In the same process as in Example 1 to synthesize a powder and to prepare a sintered body, the type of binder added was changed to polyethylene glycol (PEG).

Comparative Example 1

Flexural strength and Vickers hardness of blocks prepared by adding polyvinyl alcohol and sintering to commercially available zirconia powder were measured.

Comparative Example 2

Powders were synthesized in the same manner as in Example 1 to prepare a sintered body, but without adding a binder.

Table 1

ZrO ₂ phase (mol%) Al ₂ O ₃ phase (vol%) bookbinder Y ₂ O ₃ Comparative Example 1 3 0 PVA Comparative Example 2 3 40 X Example 1 3 40 PVA Example 2 3 40 PVP Example 3 3 40 PEG

[Table 2]

Bending strength (MPa) Vickers Hardness (Hv) Comparative Example 1 1000 1100 Comparative Example 2 950 1100 Example 1 1000 1200 Example 2 1050 1350 Example 3 1030 1300

1 is a SEM photograph of a binder added to a zirconia-alumina composite oxide material of the present invention.

Claims (1)

As zirconia-alumina composite ceramic material, The composite ceramic material has a structure in which 40 to 60 vol% of alumina is synthesized and coated by a sol-gel process on a zirconia particle surface, Easily moldable zirconia-alumina composite ceramic block prepared by cold isotropic pressing (CIP) and pre-sintering after adding an organic / inorganic binder.

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