JPH11337268A - Baking setter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a baking setter for more reducing a reaction with a material to be baked. SOLUTION: A material of the setter is made of a cubic system zirconia. The zirconia is obtained by preparing a completely stabilized zirconia containing Y, CaO, MgO or rare earth element of 6 to 10 mol.%. Since the baking setter contains almost all of the completely stabilizied zirconia, it has less reaction even by baking a PZT or the like, thereby improving its stain resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a setter used for firing electronic material parts and the like.

[0002]

2. Description of the Related Art For example, PZT (PbZrTiO3)
And the like as a raw material, a raw material powder is formed into an unfired ceramic formed body, and the unfired ceramic formed body is placed on a firing setter, and 800 to 1400 is placed on the setter. It was made by sintering in a sintering furnace at ℃. However, a Pt containing a low melting point and a low boiling point element, for example, Pb by a setter made of a ceramic such as ordinary alumina or mullite.
When the ZT piezoelectric ceramic is fired, a part of Pb evaporates to the surroundings during the firing, reacts with ceramics such as alumina, and is contaminated, causing a problem that the electric characteristics are lowered and the life of the setter is shortened.

A conventional zirconia setter is obtained by adding 3 mol% of Y to zirconia as a stabilizing material and calcining the zirconia, and is a mixed crystal of tetragonal and monoclinic. Fewer but still inadequate.

[0004]

The inventor of the present invention has investigated the reaction between the green ceramic compact and the setter in detail, and found that the crystal structure of the surface portion of the setter to which the compact has adhered has changed. Noticed. Therefore, considering stabilizing the crystal of the zirconia setter, examining the crystal structure of zirconia, reaching the cubic zirconia of the present invention, and confirming that the reaction with the unfired ceramic molded body was extremely small, The invention has been completed.

That is, the sintering setter of the present invention is characterized in that its material is made of cubic zirconia. More specifically, the sintering setter of the present invention is made of a material containing Y, CaO, MgO, or a rare earth element.
It is preferably fully stabilized zirconia containing from 10 to 10 mol%. Ce is preferable as the rare earth element.

[0006]

[Operation and Effect] The setter of the present invention is made of cubic zirconia. Since cubic zirconia is extremely stable, the reaction with the object to be fired is extremely small. For this reason, the firing setter of the present invention can be used stably without reacting with the object to be fired for a long time. In particular, it is extremely suitable for firing PZT, has little reaction with PZT, improves stain resistance, and has a long life.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The sintering setter of the present invention is obtained by adding Y, CaO, MgO or a rare earth element to zirconia.
It is made by mixing and mixing to form a predetermined shape and firing. The optimum mixing amount is 8 mol%. As a result, cubic zirconia becomes 90% or more, and it becomes fully stabilized zirconia.

[0008] Rare earth elements (La, Ce, Nd, ...)
When selecting, it is better to select Ce. Better stabilized zirconia was obtained when Ce was mixed with zirconia. The shape of the setter may be a flat plate or a plate having an upper surface and a lower surface parallel to each other and having a concave portion for accommodating the object to be fired on one surface. Since the latter is used in an overlapping manner, the concave portion is covered and closed by the use, so that the baked object stored in the concave portion has a small amount of transpiration even in PZT or the like containing an easily transpirable element such as Pb. Therefore, there is less reaction with the setter.

[0009]

The present invention will be described in more detail with reference to Examples of the present invention. FIG. 1 shows a cross section in which two firing setters of the present embodiment are stacked. The firing setter 1 has a concave portion 3 on the upper surface of a plate-like body 2 whose upper surface and lower surface are parallel to each other, and a closed space 4 is formed by stacking. The bottom surface of the recess 3 is parallel to both the upper and lower surfaces of the flat plate 2, and the shape of the opening is rectangular. Reference numeral 5 denotes a fired body having a diameter of 25 mm and a thickness of 0.1 mm.
It is a 75 mm PZT molded body. The firing setter 1
After mixing 8 mol% of Y powder with zirconia powder, placing it in a mold and press-molding with a pressure of 1 ton / cm ² ,
It was fired in a firing furnace at 1450 ° C. for 2 hours. The dimensions of the recess 3 are 105 mm in width and 80 m in depth.
m, depth 1 mm. The to-be-fired body 5 having the above-described size is placed in the concave portion 3 having the above-described size in four rows in the width direction and three rows in the depth direction.
The empty setter 1 is set so that the sides thereof coincide with each other, that is, the recess 3 becomes a closed space 4.
Were laminated.

The whole is put into a firing furnace in an air atmosphere, and the PZT
5 was fired. In the case of the present example, 90% or more is made of cubic zirconia because the setter contains 8 mol% of Y in zirconia, and no reaction or contamination was observed even when PZT was fired. Further, in the case of the present embodiment, the volume of the closed space 4 is 8400 mm ³ , and the total volume of the twelve pieces 5 to be fired in the closed space 4 is 4418 mm ^3. The space not occupied by the body 5 is 3982 mm ³ (3.982 cm ³ ). Since the vacant space in the closed space 4 is narrow as described above, the inside of the closed space 4 reaches a saturated vapor pressure due to slight evaporation from the object 5 and cannot evaporate any more. The composition showed little change and showed good piezoelectric properties.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view in which two firing setters of Example 1 are stacked.

[Explanation of symbols]

1. Setter for firing 2. Plate-shaped body 3. Concave part 4. Closed space 5. Object to be fired

Claims (3)

[Claims] 1. A firing setter made of ceramics, on which an unfired ceramic molded body is placed and fired,
A firing setter characterized in that the material is made of cubic zirconia. 2. The firing setter according to claim 1, wherein said material is Y, CaO, MgO, or fully stabilized zirconia containing 6 to 10 mol% of a rare earth element. 3. The firing setter according to claim 2, wherein said rare earth element is Ce.