KR20040014350A - Setter for ceramic electric parts - Google Patents

Abstract

PURPOSE: To fire all bodies to be fired, mounted on a setter, at a uniform temperature independently of their mounted positions and to obtain electronic components having a uniform property while corresponding to upsizing of the setter, compacting of mounting space, and shortening of firing time. CONSTITUTION: The setter 1 for firing the ceramic electronic components is equipped with a base body comprising a ceramic material containing alumina and mullite as main components and a coated layer which is provided on the base body and prevents the reaction with the bodies to be fired. Further, the base body and the coated layer are constituted by using materials capable of realizing that the coefficient of heat conduction of the whole body at 20°C becomes in a range of 2.7-15.0 W/mxK.

Description

SETTER FOR CERAMIC ELECTRONIC COMPONENTS {SETTER FOR CERAMIC ELECTRIC PARTS}

TECHNICAL FIELD This invention relates to the setter used when manufacturing a ceramic electronic component by baking. More specifically, the present invention relates to a ceramic electronic component firing setter comprising a ceramic base containing alumina and mullite as main components.

Setters for firing ceramic electronic components (hereinafter sometimes simply referred to as "setters") are loaded with plastic bodies (which become electronic components after firing, which are the same below) when producing ceramic electronic components by firing. As the member to be used, it is required not only to react with the material to be degraded in the intended purpose or use environment, but also to have a high resistance to repetition of temperature rising and cooling, that is, high spalling resistance. .

Background Art Conventionally, in the setter for firing such ceramic electronic components, an aggregate composed of alumina particles, a gas composed of mullite having high spalling resistance as an aggregate and a matrix material, and the gas are coated to prevent the reaction between the fired body and the gas. It is widely used to have a coating layer.

Further, in the conventional setter, andalusite mullite constituting the matrix material _{[2 (Al 2 O 3 ·} SiO 2)] , or because the synthetic clay and the alumina (Al ₂ O _3), chemical theory molar ratio (Al ₂ O ₃ / SiO ₂ molar ratio = 1.5) was used.

By the way, such a setter is normally used by being stacked in a plurality of layers on a shelf frame or a handcuff, but in the manufacturing process of a ceramic electronic component, a baking process is a rate-limiting step in production efficiency. For this reason, in recent years, loading of a large amount of a to-be-baked body in a setter is performed with the space | interval of the setter to load close. At the same time, attempts to shorten the firing time have also been studied. Therefore, in such a setter, although not only excellent characteristics, such as spalling resistance, there exists a strong demand for baking a to-be-baked material to a uniform temperature irrespective of the position on which a shelf frame etc. are loaded.

However, the above-described conventional setter has not been considered at all for such a request, and thus has a problem in that spalling resistance is large, but uniform characteristics cannot be obtained for electronic components after firing at the time of firing.

That is, in the conventional setter, since the mullite, which is one of the main constituents of the gas, has a composition of the chemical theory molar ratio, the thermal conductivity is low (in the case of 0% porosity, the thermal conductivity is 6.0 W / m · K), and actually the shelf frame In the case where a plurality of sheets are used and the like, the desired properties may not be obtained because plasticity is insufficient in the fired body loaded on the center portion of the setter where the stacking position is located near the middle in the hierarchical direction.

The present invention has been made in view of the above-described problems, and has a sufficient spalling resistance as a setter, and even if the densification of the loading interval of the setters, the shortening of the firing time, the enlargement of the setters, and the like are carried out, the material to be fired is loaded. It is an object of the present invention to provide a setter for firing ceramic electronic components that can be fired at a uniform temperature regardless of the position, and a product having a uniform characteristic can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS The side view which shows the example which loaded ten setters of this invention through the spacer.

<Explanation of symbols for main parts of drawing>

1: Setter for firing ceramic electronic parts

1a: Setter for firing ceramic electronic parts (5th stage)

2: spacer

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the above-mentioned subject, as a result of the mullite which is one of the main components which comprise a gas, it has a specific composition of high alumina, and has the large spalling resistance required as a setter, The present invention was completed by finding that a setter having high thermal conductivity can be obtained.

That is, the present invention is a setter for firing ceramic electronic components having a coating layer which prevents a reaction between a gas made of a ceramic material mainly composed of alumina and mullite, and an object to be installed on the substrate, wherein the substrate and the whole coating layer are provided. To provide a ceramic electronic component firing setter having a thermal conductivity of 2.70 to 15.00 W / m · K at 20 ° C.

In addition, in this invention, it is preferable that the thermal-diffusion rate in 20 degreeC of the whole base material and a coating layer is 1.25x10 <^-6> -6.1 * 10 <^-6> m <^2> / s, and the thermal conductivity in 1200 degreeC of the whole base material and coating layer is It is preferable that it is 5.0-20.0 W / m * K.

According to the present invention, there is also provided a ceramic electronic component firing setter having a coating layer which prevents a reaction between a gas made of a ceramic material composed mainly of alumina and mullite and an object to be formed on the substrate. The constituent mullite is provided with a ceramic electronic component firing setter having a composition with an Al ₂ O ₃ / SiO ₂ molar ratio of 1.6 to 2.4.

In the present invention, the mullite preferably has a composition having an Al ₂ O ₃ / SiO ₂ molar ratio of 1.8 to 2.1. Moreover, it is preferable that the mass ratio (mullite / alumina) of the alumina which is a main component of an aggregate, and the mullite which is a main component of a matrix material is 15/85-50/50.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described concretely.

The setter of the present invention comprises a base made of alumina and mullite-based ceramic material, and a coating layer provided on the base, and has a thermal conductivity of 2.70 to 15.00 W / m. It is characterized by K.

As a result, even when a plurality of large setters are densely stacked on a shelf frame or the like, all of the plastic bodies loaded in the setters can be fired at a uniform temperature regardless of their mounting positions, without particularly lengthening the firing time. The characteristic nonuniformity of an electronic component can be reduced.

For this reason, as for the setter of this invention, it is more preferable that the thermal conductivity in said 20 degreeC is 2.76 W / m * K or more, and it is especially preferable that it is 2.80 W / m * K or more.

Moreover, in this invention, since the characteristic nonuniformity of the electronic component obtained can be reduced more, the thermal diffusivity in 20 degreeC of a base body and the whole coating layer is 1.25 * 10 <^-6> -6.1 * 10 <^-6> m <^2> / s it is preferred, more preferably from ^{1.40 × 10 -6 ~4.20 × 10 -6} m 2 / s, 1.40 × 10 -6 ~2.0 × 10 -6 m is particularly preferably the ² / s.

Moreover, in this invention, since the sintering temperature can be made uniform at the time of sintering of a to-be-baked body, and the nonuniformity of a product characteristic can be reduced, the thermal conductivity in 1200 degreeC of gas and the whole coating layer is 5.0-20.0 W / m * K. Is preferably.

Hereinafter, a setter having such characteristics will be described in detail.

In the present invention, alumina, which is one of the main components of the base material, has a most stable crystal structure of corundum type, and is excellent in heat resistance, heat shock resistance, and the like, and α-alumina is preferable. Moreover, as a main crystal which uses this (alpha)-alumina, electrolytic alumina, sintered alumina, etc. are mentioned, for example.

Moreover, in this invention, it is preferable that an alumina comprises an aggregate among the ceramic materials which comprise a base body. For this reason, as alumina, it is preferable that particle diameter is 2.0-0.2 mm, and it is more preferable that particle diameter is 1.0-0.5 mm.

Next, in the present invention, the other main component of the ceramic material constituting the base is preferably a composition having an Al ₂ O ₃ / SiO ₂ molar ratio of 1.6 to 2.4, and more preferably 1.7 to 2.1. It is more preferable that it has a composition of 1.8-2.1, and it is especially preferable to have a composition which is 1.8-2.0.

As a result, a product having high thermal conductivity and small characteristic non-uniformity can be obtained while having almost the same spalling resistance as the setter containing mullite having Al ₂ O ₃ / SiO ₂ molar ratio as one of the main components of the gas. I can do it with a setter which can do it.

First of all, the mullite in the present invention may contain a mullite having a chemical theoretical molar ratio. However, it is not preferable to contain a large amount of mullite in a chemical theoretical molar ratio because it lowers the thermal conductivity, and specifically, it is preferably 5% or less of the total mullite.

In addition, in this invention, this mullite may contain a glass phase. However, when the content rate of this glassy phase is high, since heat resistance and heat conductivity are reduced, it is preferable to set it as a trace component, and it is preferable that it is a content rate of 1% or less of all the mullite specifically ,.

Moreover, in this invention, it is preferable that a mullite comprises aggregate and a matrix material among the ceramic materials which comprise a base | substrate. Moreover, it is preferable that it is 2 mm or less, and, as for the particle diameter of this mullite, it is more preferable that it is 1 mm or less.

The gas in the present invention preferably has a mass ratio (mullite / alumina) of mullite, which is the main component of the matrix material and aggregate, and alumina, which is the main component of the aggregate, to be 5/5 or less, more preferably 4/6 or less. It is more preferable that it is 3/7 or less, and it is especially preferable that it is 2/8 or less.

If the mass ratio (mullite / alumina) of the gaseous mullite and alumina is in the above range, it can be setter having high thermal conductivity while having desired spalling resistance, and all the calcined materials loaded on the setter are correlated to their loading position. It can be fired at a uniform temperature without.

However, if the mass ratio of alumina is sharply increased, the spalling resistance of the setter is lowered. Therefore, it is preferable that the mass ratio (mullite / alumina) of mullite, which is the main component of aggregate and matrix material, and alumina, which is the main component of aggregate, is 1/9 or less. Do.

This gas may contain, for example, Na ₂ O, TiO _2, etc. in addition to alumina and mullite as main components. However, when a large amount of these impurities is contained, the deterioration of the thermal conductivity, heat resistance and the like of the setter increases, so it is preferable to be within 0.5% of the material constituting the base.

Moreover, since this gas becomes large in thermal conductivity, it is preferable that porosity is 30% or less, and it is more preferable that porosity is 10% or less.

Next, the coating layer in the present invention may be either a single layer structure composed of one layer alone, or a multilayer structure composed of two or more layers provided with an intermediate layer.

In addition, the coating layer in the present invention may be any material that can prevent the reaction with the fired material, and is preferably made of at least one material selected from the group consisting of zirconia, magnesia, alumina, alumina-zirconia, and spinel. Do.

In the present invention, however, in order to improve the thermal conductivity of the setter, at least one of an intermediate layer and a surface layer of the coating layer composed of one layer alone or the coating layer composed of two or more multilayer structures is composed of alumina or alumina-zirconia. desirable.

On the other hand, it is preferable that the material of a coating layer suitably selects a thing with high non-reactivity according to the material which comprises a to-be-baked body, and when manufacturing a ferrite material, for example, the material of at least 1 sort (s) of zirconia, alumina, or alumina zirconia. It is preferably made of, and when producing a capacitor made of barium titanate, preferably made of zirconia.

In addition, in the coating layer which consists of a multilayer structure, when making a surface layer consist of zirconia in order to improve non-reactivity, it is preferable to comprise an intermediate | middle layer by alumina or alumina zirconia with high thermal conductivity.

Although there is no restriction | limiting in particular also about the thickness of a coating layer in this invention, It is preferable to adjust the thickness in consideration of the thermal conductivity of the material of a coating layer.

Specifically, in the layer having high thermal conductivity, a relatively thick layer may be formed. For example, in a layer made of alumina or alumina-zirconia, it may be provided with a thickness of 100 to 500 µm. On the other hand, in a layer with low thermal conductivity, it is preferable to set it as a comparatively thin layer, for example, in the layer which consists of zirconia, it is preferable to provide it with the thickness of 50-200 micrometers.

Examples of zirconia include stabilized zirconia, partially stabilized zirconia, unstable zirconia, calcium zirconate, and the like added with stabilizers such as CaO, MgO, CeO, or Y ₂ O ₃ . Similarly, as a spinel, magnesia-alumina spinel etc. are mentioned, As an alumina zirconia, the thing which mixed alumina and zirconia or the thing which solid-melted alumina and zirconia is mentioned.

In addition, any of the coating layer of a single layer structure and the coating layer of a multilayer structure can be formed by conventional methods, such as spray coating and spraying, for example, and what is necessary is just to select the appropriate method according to the thickness of the coating layer to form.

As mentioned above, although each component of the setter of this invention was demonstrated, in the setter of this invention, since many to-be-baked bodies are baked simultaneously, it is 5 mm or less in thickness on a shelf plate, a bed plate, or a kiln, More preferably, Even if the firing jig is constructed by densely loading or fixing the setter in a plurality of stages through a spacer having a thickness of 3 mm or less, each of the fired bodies can be fired at the same temperature, and an electronic component having a uniform characteristic can be obtained. have. In addition, since heat can be quickly transferred to the object to be baked, even when a large setter having a dimension of 100 mm x 100 mm or more can be baked at the same temperature, and the firing time can be shortened. It becomes possible to obtain an electronic component of uniform characteristics promptly and in large quantities.

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples.

(Assessment Methods)

① spalling resistance

The setters of each of Examples and Comparative Examples were loaded into a shelf frame, and each setter was placed in a furnace with a sheet of ZrO ₂ (105 mm × 105 mm × 3 mm) loaded therein, and the temperature was raised to 500 ° C. After cooling rapidly at room temperature outside the furnace, the presence of cracks and the length of cracks were visually confirmed.

(Circle) that the generation | occurrence | production of a crack was not seen at all evaluated as (circle), that the crack below 50 mm in length was recognized (circle), and that the crack exceeding 50 mm in length was recognized as x.

② Thermal conductivity, thermal diffusion rate

It measured by the laser flash method based on the method of JISR1611. At this time, as a measurement sample, five pieces each having a cylindrical shape having a diameter of 10 mm in each of the setters of each example and each of the comparative examples were prepared, and the average values of the five samples were evaluated.

③ non-uniformity of product characteristics

As shown in FIG. 1, the setter 1 of each example and each comparative example is loaded 10 steps at intervals of 5 mm via a spacer 2 made of the same material as the setter, and the setter 1a of the fifth stage is loaded. Ten to-be-baked bodies (what will become a ceramic capacitor after firing) were each mounted in the center part and the outer peripheral part of the, and fired at 1300 ° C for 2 hours.

After firing, the capacitance of each ceramic capacitor taken out was measured, and the average value was calculated for each of the ceramic capacitors loaded in the center of the fifth-stage setter and its outer peripheral portion, and the difference was within 1%. The thing of (circle) and larger than 2% was evaluated as x.

④ Al ₂ O ₃ / SiO ₂ molar ratio

The X-ray powder diffraction method confirmed the diffraction angle of 210 planes using ICDD (International Center for Diffraction Data).

(Example 1)

First, 35 mass% of molten alumina (average particle diameter 0.3 mm, maximum particle diameter 1.0 mm), 15 mass% presintered alumina (average particle diameter 2 μm), and sintered mullite (average particle diameter 100.0) having an Al ₂ O ₃ / SiO ₂ molar ratio of 1.7 45 mass% of micrometers, the largest particle diameter of 0.5 mm), and 5 mass% of clay (average particle diameter: 5.0 mm) were mixed, and the ceramic raw material was prepared. Subsequently, 0.5 mass part of methylcellulose and 40 mass parts of water were added as a binder with respect to 100 mass parts of this ceramic raw materials, and it knead | mixed for 20 minutes, and produced clay. Subsequently, this clay was put into the hydraulic press molding machine, and the plate-shaped molded object of 150 mm x 150 mm x 4 mm was obtained by the shaping | molding pressure of 1 t / cm <^2> . Finally, the molded product was dried at 80 ° C. for 8 hours, and then calcined at 1500 ° C. for 2 hours to prepare a plate-shaped gas.

Next, 60 mass% of easy-to-sinter alumina having an average particle diameter of 0.5 µm and 40 mass% of electrolytic alumina having an average particle diameter of 10 µm were mixed, and 30 parts by mass of water was added to 100 parts by mass of the mixed raw material for 12 hours. The mixture was stirred to prepare a slurry for the intermediate layer. Subsequently, the slurry was spray-coated on the surface of the substrate with air pressure of 5 kg / cm ² using a spray gun, and then baked at 1400 ° C. for 2 hours to form an intermediate layer having a thickness of 100 μm.

Subsequently, Y ₂ O ₃ 8 mass% -containing stabilized zirconia particles (stabilization degree 100%) having an average particle diameter of 100 to 200 µm were sprayed onto the surface of the substrate by a water-stabilized plasma spraying apparatus, and a surface layer having a thickness of 200 µm was formed to form a multilayer. A setter of 150 mm x 150 mm x 4.6 mm was prepared with a coating layer of structure.

(Examples 2 to 5 and Comparative Examples 1 to 3)

Setters were prepared in the same manner as in Example 1 except that the ceramic raw materials were prepared by mixing the melted alumina, the pre-sintered alumina, the sintered mullite, and the clay in the mixing ratios shown in Table 1, and the intermediate and surface layers were shown in Table 1, respectively. Prepared. The material composition about each Example and each comparative example is put together in Table 1, and is shown.

(evaluation)

As shown in Table 2, in the setters of Examples 2 to 4 in which the mass ratio (mullite / alumina) of alumina and mullite in the gas was 37/63 to 21/79 or less, the thermal conductivity at 20 ° C. was all 2.86 W / m. The thermal conductivity at K or more, 1200 degreeC was 5.2 or more, and the thermal diffusion rate was 1.40 * 10 <^-6> m <^2> / s or more. In addition, all of the product characteristics nonuniformity was very small, 1% or less.

In addition, in the setter of Example 1 in which the mass ratio of alumina to mullite in the gas (mullite / alumina) was 47/53, and the alumina intermediate layer was provided on the gas, the thermal conductivity at 20 ° C. was 2.76 W / m · K. The thermal diffusivity was 1.26 × 10 ^-6 m ² / s, which was relatively large. In addition, the characteristic nonuniformity of the product was relatively small, 2% or less. Moreover, in the setter of Example 5 which made the mass ratio (mullite / alumina) of alumina and mullite in gas into 5/95, the thermal conductivity in 20 degreeC is 15.00 W / m * K, and the thermal conductivity in 1200 degreeC is 20.1 W. / m · K and thermal diffusivity of 6.68 × 10 ⁻⁶ m ² / s, both characteristics being relatively large. In addition, the characteristic nonuniformity of the product was relatively small, 2% or less.

On the other hand, in the setter of Comparative Example 1 which is the same as in Example 1, except that the alumina intermediate layer was not provided, the thermal conductivity at 20 ° C. was 2.62 W / m · K and the thermal diffusion rate was 1.23 × 10 ⁻⁶ m ² / s. Lower, and product non-uniformity is greater than 2%.

Also, in the setter of Comparative Example 2 which is the same as Example 1 except that the mass ratio (mullite / alumina) of alumina and mullite in the gas was set to 52/48, the thermal conductivity at 20 ° C. was 2.36 W / m · K, heat The diffusion rate was lowered to 1.08 × 10 ⁻⁶ m ² / s, and the product nonuniformity was also greater than 2%.

In the setter of Comparative Example 3 composed of gas only with alumina, the thermal conductivity at 20 ° C. was 17.30 W / m · K and the thermal diffusivity was 6.82 × 10 ⁻⁶ m ² / s, which was very high. Greater than% Moreover, although not specifically shown in the table, in the setter of the comparative example 3, the crack exceeding 50 mm in length was recognized by the spalling resistance test, and spalling resistance was very small. The characteristic of the setter of each Example and each comparative example is put together in Table 2, and is shown.

Thermal Diffusion Rate (× 10 ^-6 m ² / s) Thermal Conductivity (W / mK) Non-uniformity of product characteristics 20 ℃ 1200 ℃ Example 1 1.26 2.76 O Example 2 1.40 2.86 5.2 ◎ Example 3 1.46 3.30 6.8 ◎ Comparative Example 1 1.23 2.62 4.8 x Comparative Example 2 1.08 2.36 x Example 4 4.16 9.60 ◎ Example 5 6.68 15.00 20.1 O Comparative Example 3 6.82 17.30 23.2 x

(Examples 6 to 10 and Comparative Examples 4 and 5)

The ceramic raw materials were prepared by mixing electrolytic alumina, presintered alumina, sintered mullite and clay in the blending ratio shown in Table 1 using the Al ₂ O ₃ / SiO ₂ molar ratios shown in Table 1, respectively. A setter was produced in the same manner as in Example 1 except that no provision was made and the thickness of the surface layer was set to 150 µm. The material composition about each Example and each comparative example is put together in Table 3, and is shown.

(evaluation)

As shown in Table 4, in the setters of Examples 6 to 10 using mullite having an Al ₂ O ₃ / SiO ₂ molar ratio of 1.6 to 2.4, all of the product characteristics had nonuniformity of 2% or less, and the thermal shock limit temperature. The spalling resistance was also large in 500 degreeC or more. In particular, in the setters of Examples 7 to 9 using mullite having an Al ₂ O ₃ / SiO ₂ molar ratio of 1.8 to 2.1, the product characteristic nonuniformity was very small, 1% or less.

In contrast, in the setter of Comparative Example 4 using a mullite having an Al ₂ O ₃ / SiO ₂ molar ratio of 1.5, the characteristic variation of the product was greater than 2%.

In addition, in the setter of Comparative Example 5 using a mullite having an Al ₂ O ₃ / SiO ₂ molar ratio of 2.5, the variation in the properties of the product was small at 2% or less, but the thermal shock limit temperature was 500 ° C or lower, and the spalling resistance was small. . The characteristic of the setter of each Example and each comparative example is put together in Table 4, and is shown.

Non-uniformity of product characteristics Spalling resistance Comparative Example 4 x ◎ Example 6 O ◎ Example 7 ◎ ◎ Example 8 ◎ ◎ Example 9 ◎ ◎ Example 10 ◎ O Comparative Example 5 ◎ x

As described above, according to the present invention, all the plastic bodies loaded in the setter can be fired at a uniform temperature regardless of the loading position, corresponding to the increase in the size of the setter, the densification of the loading interval, and the shortening of the firing time. The setter for ceramic electronic component firing which can obtain the electronic component of uniform characteristic can be provided.

Claims (5)

A setter for firing ceramic electronic components comprising a coating layer which prevents a reaction between a substrate made of a ceramic material composed mainly of alumina and mullite and an object to be formed on the substrate, A thermal conductivity at 20 ° C. of the substrate and the entire coating layer is 2.7 to 15.0 W / m · K. Setter for firing ceramic electronic parts. The setter for ceramic electronic component firing according to claim 1, wherein a thermal diffusion rate at 20 ° C of the base and the coating layer as a whole is 1.25 × 10 ^{−6 to} 6.1 × 10 ⁻⁶ m ² / s. The setter for ceramic electronic component firing according to claim 1 or 2, wherein the thermal conductivity at 1200 캜 of the base and the entire coating layer is 5.0 to 20.0 W / m · K. A setter for firing ceramic electronic components comprising a coating layer which prevents a reaction between a substrate made of a ceramic material composed mainly of alumina and mullite and an object to be formed on the substrate, The mullite is a ceramic electronic component firing setter, characterized in that the Al ₂ O ₃ / SiO ₂ molar ratio of 1.6 to 2.4 composition. 5. The setter for ceramic electronic component firing according to claim 4, wherein the mullite has a composition in which the Al ₂ O ₃ / SiO ₂ molar ratio is 1.8 to 2.1.