JPH0656537A - Lightweight zirconia-based firing jig material - Google Patents

Abstract

PURPOSE:To provide a lightweight zirconia-based firing jig material having improved spalling and creep resistance, further enhanced durability and the range of its use extended to lightweight large-sized housing and trays. CONSTITUTION:This lightweight zirconia-based firing jig material consists of 30-90 pts.wt. lime stabilized zirconia, 10-70 pts.wt. unstabilized zirconia and 0.5-10 pts.wt. MgO or Y2O3 as a stabilizing agent basing on 100 pts.wt., in total, of the lime stabilized zirconia and unstabilized zirconia, has 25-50% apparent porosity and may further contain zirconia fibers and/or hollow zirconia granules and polyethylene beads, a hot-melt adhesive, crushed walnut shells, crushed peach seeds, etc., as a weight reducing material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight zirconia-based firing tool material used for firing electronic ceramics.

[0002]

2. Description of the Related Art The firing of electronic ceramics is performed by using various tool materials according to their characteristics. Above all,
Various low temperature melting additives are added to develop the electrical characteristics. A zirconia setter is used to prevent the reaction. Among the tools for firing electronic ceramics,
Zirconia has excellent reaction resistance and has a relatively low coefficient of thermal expansion, and is used in various fields. However, in many cases, the cause of disposal in its use is a pattern of crack generation, crack growth, and cracking due to repeated temperature changes due to its low thermal conductivity. Therefore, in order to improve the durability, methods of reducing the size of the setter and suppressing the growth of cracks by installing slits have been adopted.

[0003]

DISCLOSURE OF THE INVENTION The object of the present invention is to improve the spalling resistance and creep resistance, to further improve the durability, and to extend the range of use with a large and large-sized casket and shelf board. An object is to provide a lightweight zirconia-based firing tool material.

[0004]

That is, the lightweight zirconia firing tool material according to the present invention is a lime-stabilized zirconia 3
Zirconia selected from the group consisting of 0 to 90 parts by weight, 10 to 70 parts by weight of unstable zirconia, 100 parts by weight of the total amount of lime-stabilized zirconia and unstabilized zirconia, and MgO, Y ₂ O _{3 and the} like. Stabilizer 0.5 on the outside
10 to 10 parts by weight and apparent porosity 25 to 50%
It is characterized by being within the range of.

The lightweight zirconia-based firing tool material according to the present invention comprises 30 to 90 parts by weight of lime-stabilized zirconia,
10 to 70 parts by weight of unstable zirconia, 50 parts by weight or less of zirconia hollow particles and / or zirconia fibers,
A zirconia stabilizing material selected from the group consisting of MgO, Y ₂ O _{3 and the} like is externally applied to 100 parts by weight of the total amount of lime-stabilized zirconia and unstabilized zirconia and optionally zirconia hollow particles and / or zirconia fibers. 0.5-10 parts by weight and apparent porosity of 25-
It is characterized by being in the range of 50%.

The lightweight zirconia-based firing tool material according to the present invention includes polyethylene beads, hot-melt adhesives, crushed walnut shells, crushed peach seeds as a weight-reducing material, excluding the zirconia stabilizer of the above compound. 1 to 20 parts by weight may be contained with respect to 100 parts by weight.

[0007]

The first feature of the light-weight zirconia burning tool material of the present invention is that when lime-stabilized zirconia and unstable zirconia are blended and fired at 1700 ° C. or higher, the lime-stabilized zirconia grain surface dissociates and becomes microscopic. The point is to generate cracks, which enhances resistance to cracking due to thermal shock.

The lime-stabilized zirconia used for the lightweight zirconia firing tool material of the present invention has a stabilization degree of 50 to 1.
It is preferable to use the one of 00%. Lime-stabilized zirconia is used in combination with particles of 14 to 48 mesh and fine powder passing through 350 mesh. The lime-stabilized zirconia particles act as an aggregate, and the light-weight zirconia firing tool material obtained can be made porous by having a particle size configuration having such a particle size gap.

The amount of lime-stabilized zirconia added and compounded is in the range of 30 to 90% by weight. Addition / mixing amount is 90
If the content exceeds 30% by weight, the strength is deteriorated, and if the content is less than 30% by weight, microcracks are less likely to be generated on the grain surface of the lime-stabilized zirconia due to dissociation and the spalling property due to thermal shock is deteriorated.

The unstabilized zirconia used in the lightweight zirconia firing tool material of the present invention is not particularly limited as long as it is a fine powder having a ZrO ₂ content of 95% or more and passing through 350 mesh. For example, it exists naturally. Battereite
(baddeleyite) or the like can be used.

The amount of unstabilized zirconia added and compounded is 10
Within the range of 70 parts by weight. If the amount added / blended is less than 10 parts by weight, the effect of adding unstable zirconia is not obtained, and if it exceeds 70 parts by weight, firing cracks may occur even if the zirconia stabilizer is added, which is not preferable. .

Stabilized zirconia is Y ₂ O ₃ , MgO, Ca
There is a stabilized O product. When unstable zirconia is added and fired, CaO-stabilized zirconia is most easily dissociated on the grain surface, and microcracks are generated on the grain surface. However, in order to stabilize the unstable zirconia, it is necessary to add a zirconia stabilizer having a higher degree of stabilization than CaO. MgO, Y ₂ O ₃ or the like can be used as the zirconia stabilizing material. The amount of zirconia stabilizer added and compounded is in the range of 0.5 to 10 parts by weight based on the total amount of lime-stabilized zirconia and unstabilized zirconia.

The lightweight zirconia according to claim 1, wherein a binder is added to the mixture of the lime-stabilized zirconia, the unstabilized zirconia and the zirconia stabilizing material as described above, and the mixture is molded into a predetermined shape and baked. A quality firing tool material can be obtained.

As the binder, those which are transformed into zirconia by firing such as zirconia sol or zirconium compound aqueous solution, for example, zirconyl acetate, zirconyl nitrate or the like, which disappears during firing to become pores;
Synthetic polymers such as polyvinyl alcohol and polyethylene oxide can be used. Here, the amount of binder added and compounded to change to zircony by firing is about 5 to 10 parts by weight, and this is a lightweight zirconia that requires relatively uniform tightening such as a shelf plate formed at a pressure of 20 MPa or less. It is preferably used in producing a quality firing tool material. The amount of the synthetic polymer binder added and compounded is about 2 to 5% by weight, which is suitable for molding a casket or the like at a pressure of 70 MPa or less.

The lightweight zirconia-based firing tool material of the present invention can be obtained by firing a molded body having a predetermined shape at a temperature of 1700 ° C. or higher in the atmosphere.

The light weight zirconia firing tool material of the present invention has an apparent porosity of 25 to 50% after firing. Here, if the apparent porosity is less than 25%, the effect of weight reduction is not obtained, and the spalling resistance is also reduced, which is not preferable. Further, if it exceeds 50%, the thermal conductivity is low and the thermal shock resistance is also reduced, which is not preferable.

The second characteristic of the lightweight zirconia-based firing tool material of the present invention is that the specific gravity of the tool material obtained by adding / blending zirconia hollow particles and / or zirconia fiber in an amount of 50 parts by weight or less as appropriate. It is to improve bending strength and creep resistance while further reducing
If the amount of zirconia hollow particles and / or zirconia fibers added / blended exceeds 50% by weight, springback may occur during molding, and laminating may occur, which is not preferable. Zirconia fiber has a diameter of 3 to 1
It is possible to use one having a length of about 5 μm and a length of about 0.1 to 30 mm. Further, Y ₂ O ₃ , MgO, CaO and an unstable product can be used as a stabilizer for the zirconia fiber, if necessary.

Y ₂ is used as a stabilizer for the hollow particles of zirconia.
O ₃ , MgO, CaO and unstable products can be used if necessary. Zirconia hollow particles for use as aggregate 1
It is desirable to use grains of 4-48 mesh.

The third characteristic of the light-weight zirconia firing tool material of the present invention is polyethylene beads having a particle size of 35 to 100 mesh, hot melt adhesive particles, walnut shell crushed product,
It is to add crushed peach seeds to further reduce the weight.

As the weight-reducing material such as polyethylene beads, hot-melt type adhesive particles, or other organic spheres, crushed walnut shells, and crushed peach seeds, those having a particle size of 35 to 100 mesh are used. The amount of these added / blended varies depending on the specific gravity of the weight-reducing material, but is in the range of 5 to 20 parts by weight. If the amount of addition / compounding exceeds 20 parts by weight, laminating occurs due to springback during molding, which is not preferable.

The light weight zirconia firing tool material of the present invention, which is obtained by adding and blending zirconia fibers and / or zirconia hollow particles and other light weight materials, is suitable for the intended use as described above. It can be obtained by blending a binder, molding and firing.

The lightweight zirconia-based firing tool material of the present invention suppresses abnormal expansion and contraction in the entire operating temperature range and, at the same time, dissociates the grain surface of the lime-stabilized zirconia raw material as described above, whereby an appropriate amount of microcracks is obtained. To improve the thermal shock resistance by creating a low elastic structure, and by using a lighter weight material, it is possible to use it as a tool material for baking as a lighter, large-sized casket or shelf board. Especially.

[0023]

【Example】

Examples Various formulations (parts by weight) shown in Tables 1 to 3 below were molded and fired in air at 1700 ° C. for 3 hours. Various characteristics of the obtained sample are also shown in Tables 1 to 3.

Examples Nos. 1 to 6 have different ratios of lime-stabilized zirconia and yttria-stabilized zirconia fibers. When the blending ratio of zirconia fiber is increased, the number of times of use is increased, and the effect of zirconia fiber is exhibited. In order to maintain spalling resistance, it is preferable to increase the porosity when the compounding ratio of zirconia fibers is small. Further, a micrograph showing the structure of Example No. 6 after firing at 1700 ° C. is shown in FIG. It can be seen from FIG. 1 that fine microcracks are generated on the surface of the lime-stabilized zirconia particles.

[0025]

[Table 1]

As the zirconia fiber, a stabilized lime product can be used in addition to the yttria stabilized product. Further, it is possible to further reduce the weight by using a hot-melt type adhesive or peach seed as the weight-reducing material.

[0027]

[Table 2]

[0028]

[Table 3]

[0029]

The following results were obtained with the lightweight zirconia-based calcination tool material of the present invention: The surface of lime-stabilized zirconia grains was obtained by combining lime-stabilized zirconia and unstable zirconia and firing them. The thermal shock resistance was improved by generating microcracks due to dissociation in polyethylene; polyethylene beads, hot-melt adhesive particles, and peach, which have improved creep resistance due to zirconia fibers and / or zirconia hollow particles and are burnt off during firing. The weight can be further reduced by using a lightweight material such as crushed seeds, and it can be used as a large sagger and shelf. As a result, the lightweight zirconia-based firing tool material of the present invention has a wider range of application as compared with the conventional zirconia-based firing tool material, and a firing tool material having high durability can be obtained.

[Brief description of drawings]

FIG. 1 is a micrograph showing the structure of Example No. 6 after firing at 1700 ° C.

Claims (3)

[Claims] 1. From 90 to 90 parts by weight of lime-stabilized zirconia and 10 to 70 parts by weight of unstabilized zirconia, MgO and Y ₂ O ₃ are added to 100 parts by weight of the total amount of lime-stabilized zirconia and unstabilized zirconia. A lightweight zirconia calcined tool material, characterized in that it comprises 0.5 to 10 parts by weight of a selected zirconia stabilizing material on the outside and has an apparent porosity in the range of 25 to 50%. 2. Lime-stabilized zirconia 30 to 90 parts by weight, unstable zirconia 10 to 70 parts by weight, hollow zirconia particles and / or zirconia fiber 50 parts by weight or less, and lime-stabilized zirconia and unstabilized zirconia and, if necessary, MgO, Y ₂ O _{3 based on} 100 parts by weight of the total amount of zirconia hollow particles and / or zirconia fibers
Zirconia stabilizer selected from 0.5 to 1
A lightweight zirconia-based firing tool material comprising 0 parts by weight and having an apparent porosity in the range of 25 to 50%. 3. The lightweight zirconia firing tool material according to claim 1 or 2 is used as a lightweight material, polyethylene beads,
1 to 20 parts by weight of a hot melt type adhesive, walnut shell crushed product, peach seed crushed product based on 100 parts by weight of lime-stabilized zirconia, unstable zirconia and, if necessary, zirconia fiber and / or zirconia hollow particles A lightweight zirconia-based firing tool material characterized in that