JPS62283885A - Porous refractory formed body for burning functional parts - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to the firing of ceramics, glasses, various metal oxides, etc. as furnace linings, shelves, trays, etc. The present invention relates to a light, heat-resistant porous refractory molded body that can be used.

(Prior Art) Recently, in the electronics industry, mechanical parts such as sensors, capacitors, and IC boards are being made of ceramics. Above all, alumina and silicon Vide! 1
etc. and barium titanate etc.'
11, and magnetic materials made of composite oxides such as iron, barium, or strontium are considered promising. These ceramics and metal oxides have excellent properties such as electrical insulation, semiconductivity, heat resistance, wear resistance, high strength, and high magnetic force, and their uses are likely to be expanded in the future. After mixing raw materials, these machine parts are formed into various shapes by extrusion molding, injection molding, casting molding, press molding, etc., and then rM
The product is produced in a furnace made of hot bricks, placed on shelves and baking trays. Mullite, alumina, zirconia, cordierite, silicon carbide, and silica refractories are used for the lining, shelves, firing trays, etc. of these furnaces.

[Problem that the invention seeks to solve]

Conventionally, the baking trays for high-quality parts such as ceramics have all been formed by a method such as a press, and then fired at a high temperature. The unit prices of these functional parts, such as ceramics, have fallen significantly, and there has been an urgent need to reduce production costs. However, each member used in a conventional firing furnace has a high bulk density, and therefore a large amount of energy is required to heat the member itself. In addition, since trays are heavy, there is a limit to how many trays can be stacked when baking in multiple stages. Furthermore, it was difficult to make the temperature distribution uniform between the upper and lower stages in the furnace. Furthermore, if the firing speed was increased or the cooling/heating cycle was accelerated, the firing tray would crack, resulting in poor productivity. Furthermore, even if attempts were made to reduce the volume occupied by the baking tray in order to increase thermal efficiency by making the baking zone smaller, conventional baking trays could not be manufactured with a thickness below a certain level due to problems such as warpage. On the other hand, heat-resistant inorganic materials such as ceramic fiber M! A lightweight molded product is known that is made by slurrying a large amount of wood and an inorganic binder (for example, silica sol, viscosity, Seviolite, etc.) and molding it using a wet papermaking method. However, this molded product not only lacks surface smoothness, but also has an inorganic binder or heat-resistant inorganic material. Since it is only filled between the lattices of In, it may warp or become weak due to hot softening or shrinkage of the In, and the fibers themselves may fall off and become powder, making it difficult to maintain precision. The use of high-purity ceramics in a firing furnace was unsuitable.

As mentioned above, conventional fire-resistant insulating bricks, shelf boards, and heat-resistant trays account for a large amount of energy costs and consumables costs, and molded products made of the fire-resistant inorganic material AM lack strength and tend to powder. , worsen the working environment,
There was also the problem of insufficient surface smoothness.

Also, IC! When firing machine parts such as plates, ferrite, and glass substrate rods, these parts are large and require smoothness, so jigs such as baking shelves and floor plates must be made of high-strength, High surface smoothness and no warping were essential conditions.

Furthermore, Pb and Z contained in ferrite, glass substrates, etc.
Since substances such as n and Mn are highly reactive, especially alumina
In order to prevent reactions with 5i02 contained in siliceous bricks and ZrO□, which is commonly used as bedding powder, high-purity alumina shelf boards and alumina bedding powder were used for firing. Therefore, as mentioned above, the alumina shelf board is heavy and causes a large loss of thermal energy, and there are also problems in that the alumina powder is not smooth enough or the powder adheres to the back side of the product, resulting in defects.

In other words, in order to solve these problems, the present invention has developed an energy-saving, lightweight, strong, precise and high-purity material that is excellent in resistance to thermal changes, and has improved surface smoothness and working environment. The object of the present invention is to provide a porous refractory molded body for firing the mechanical parts.

(Means for Solving the Problems) That is, the present invention essentially consists of heat-resistant inorganic fibers, an inorganic binder, and a fire-resistant powder! [af of ceramics, glasses, metal oxides, etc. made by sintering and molding oxides]
In the porous refractory molded body for firing I parts, the density of the molded body is 0.6 to 1.5 g/cm', the bending strength at room temperature is 120 to 3 flQkgf/crrr', and the machine part is loaded. The surface has a surface roughness of R+++sx of 2 to 40 gm, and a purity of A or 203 of 95 to 10.
The present invention relates to a porous refractory molded body for firing functional parts, characterized in that it is coated with an alumina coating of 0% alumina powder with a thickness of 50 to 1000 gm.

(Function) The porous refractory molded product of the present invention has a large number of continuous pores in the molded product because it is mainly composed of heat-resistant inorganic m-fibers. The thermal conductivity is also as low as 0.15 to 0.30 cal/■hr°C, contributing to a reduction in the amount of heat stored during firing and a reduction in firing time, which not only lowers energy costs, but also It is possible to improve the quality of objects to be burned. Specifically, a density of 0.6 to 1.5 g/crn' is preferable, and a density of 1-0 to lug/crn' is particularly preferable. If it is less than 0.6 g/am', the strength is insufficient. Therefore, if it exceeds 1.5 g/cm'', the amount of heat storage cannot be reduced, which is not preferable.

In addition, the porous refractory molded article of the present invention has a refractory powder and/or an inorganic binder filled between the ams of heat-resistant inorganic fibers,
These refractory powders and/or inorganic binders are
~1 [By sintering at a temperature of ioooC,
It is possible to obtain a molded product having a stronger structure than the conventional molded product mainly composed of W&male material. The bending strength at room temperature is required to prevent the molded body from pulverizing and to use it as various parts of the firing furnace such as shelves, floor plates, linings, etc. for firing large and heavy functional parts such as IC substrates, ferrite, and glass substrates. 120 to 100kg/cm2, especially 150-250k
g/c is preferred and is achieved by sintering the inorganic binder and the refractory powder. 12
If it is less than 0 kg/crn', the strength will be insufficient, and :1O
Even if the weight exceeds 11 kg/c, no substantial benefit can be obtained.

The refractory powder is alumina, alumina/silica,
One or more of zirconia, magnesia, and titania are preferable because they have a high refractory temperature. Specifically, alumina, mullite, kaolinite, Kibushi clay, and Frogme clay.

Sillimanite, steatite, ) orsterite, zirconia, magnesia, spinel, titania, etc. are preferable, and the inorganic binder of the present invention is preferably selected from silica-soda-based, calcium borate-based, and silica-based frits, For example, feldspar, mica powder, boric acid, glass powder, silica stone, etc. are preferable. In particular, silica-based binders are most suitable because they can provide strong bonding strength without extremely lowering the heat resistance temperature. However, since 5iOz is highly reactive with ferrite and glass substrates, it may be necessary to apply an alumina coating.

Furthermore, IC substrate, ferrite, glass substrate or pressure 7r! A bed plate with excellent surface smoothness and parallelism is necessary for firing elements, etc. However, the surface of the conventional bed plate made of fireproof and insulating bricks is too uneven, and the plate made of fired bricks tends to warp during firing. There is a problem in that this may cause defects in the fired product.

The porous refractory molded article of the present invention has fine pores because it contains heat-resistant inorganic fibers, and its surface is formed by fine irregularities, and has good processability, so it obtains sufficient surface smoothness. be able to. Specifically, the surface roughness of the coated surface R□5 is preferably 2 to 40 gm, preferably 10 to 25 gm. If it is less than 2 μm, it will result in poor thinness, which is undesirable, and if it exceeds 40 pm, it will cause unevenness on the fired product, which is not preferred. In particular, 2 to 20 uLm is optimal for firing IC substrates and glass substrates, and 20 to 40 gm is optimal for firing ferrite and piezoelectric elements. Here, since the non-fibrous substances in the heat-resistant inorganic fibers eliminate the smoothness of the surface of the molded product, the porous refractory of the present invention has O81 to 8% by weight.
Is it necessary to do the following? If it is less than 0.1% W4, no real profit will be obtained, and if it exceeds 8%, smoothness will be insufficient, which is not desirable. Also, regarding the sled, use the heat-resistant inorganic material mentioned above! The voids formed by the a-fibers alleviate the thermal stress that occurs during heating and cooling, so warping during use can be completely eliminated.In addition, by selecting the particle size of the refractory powder, warping can be prevented. It is possible to eliminate it.

In the alumina coating, it is important to reduce the SiO□ component as much as possible to prevent reactions with ferrite and glass substrates, and alumina powder consisting of Al2OY with a purity of 95 to 100% is sintered to form a coating layer. Preferably.

If the A l 2 Off purity is less than 95%, it is undesirable as it will not be possible to prevent reactions with ferrite and glass substrates.Also, in order to prevent reactions with the 5if2 component contained in the base material, the coating layer should be as thin as possible. It is preferable that it be dense.

The alumina powder is used in the form of various commonly used powders, aqueous solutions or sol, or various alcoholates, such as basic aluminum chloride and basic aluminum acetate di-alumina sol, and is converted into alumina powder after heating. However, in general, Na, O, Sin, Few O, etc. are contained as components other than An and O. Coating can be done by spraying, smearing, roller coating, or dipping. The coach ink layer is made of the above-mentioned Pb, Z
It is preferable that the coating be as dense as possible in order to suppress the diffusion of highly evaporative substances such as n, Mn, etc.
It is formed by baking at a temperature of 0 to 1600°C.

Furthermore, the thickness of the alumina coating layer is 5(1-
10004m is suitable, especially 150-300gm
is optimal. If the film thickness is less than 50 uLm, the diffusion of the highly volatile substance cannot be sufficiently suppressed, and
Exceeding this is uneconomical and undesirable.

The heat-resistant inorganic fiber has A2O content of 40 to 60% by weight.
, 5i02 is preferably an amorphous silica-alumina fiber consisting of 10 to 60% by weight since it is inexpensive.
Since it contains about 0% by weight of non-fibrous materials with a size of 45 tons or more, the content of 1# fibers can be reduced to 0.1 to 8% by weight by classifying in air or water. It is necessary to reduce it to before use. In addition, the blended layer is 20
~50% by weight is preferred. If it is less than 20% by weight, the weight reduction will not be sufficient, and if it exceeds 50% by weight, the strength will be insufficient, which is undesirable.

The inorganic binder is preferably blended in an amount of 1 to 15% by weight. If it is less than 1% by weight, sintering will not proceed sufficiently and the strength will be insufficient, and if it exceeds 15% by weight, the density will become high and the thermal shock resistance will become poor, which is not preferable.

Further, it is preferable that the refractory powder is blended in an amount of 50 to 80% by weight. If it is less than 50% by weight, the strength will be insufficient, and 80%
If it exceeds % by weight, the density becomes high and the thermal shock resistance becomes poor, which is not preferable.

The porous refractory molded body for firing functional parts of the present invention can be prepared by kneading the heat-resistant inorganic fibers, the refractory powder, and the inorganic binder in the conventional manner or dispersing them in water to form a slurry solution, and then vacuuming the mold. The fibers can be uniformly dispersed, and the fibers can be uniformly dispersed by forming the fibers by molding, casting, or paper-making, or preferably by forming into a slurry solution and then molding by mold vacuum suction or paper-making. After molding, dry, polish the surface, spray alumina coating, roller coat,
1 after coating by methods such as hega-coating or dipping
The porous refractory of the present invention can be obtained by firing at 500 to 1600°C. Alternatively, a porous refractory molded product with no heat release 11 can be obtained by firing after molding, coating, baking, and finally polishing.

Hereinafter, Examples of the present invention will be explained along with Comparative Examples.
do.

(Example) #Non-va by classifying it as a non-thermal a￥1 fiber in water! Party A, O, which controlled the content of l-like substances to 3%
S (1% by weight, SiOz 50% by weight) of non-quality silica-alumina fibers, alumina as a refractory powder, and calcined diatomaceous earth as an inorganic binder.
Sintered at 600℃ for 1 hour, bulk density 1.1g/cr
A molded body of rr' was obtained. This molded body has an A fL of 20
Alumina powder with a purity of 90.95, 9.5%, and a particle size of 1 gm (the remainder is 5iO2) is dispersed in a 1% by weight methylcellulose aqueous solution, and then sprayed onto the surface of the molded body to form coatings of various thicknesses. A layer was formed, and then the coating layer was baked at 1600°C''rt.The baking was done after IUOssX 1010Os
After processing and polishing to a size of 5 mm, the surface smoothness was examined using a surface roughness meter and R11 was measured. In addition, the molded body was
It was refired at 400'C for 24 hours, and dimensional changes after firing were measured with a dial gauge to examine warpage. Furthermore, the bending strength of the molded body was determined using an autograph manufactured by Shimadzu Corporation with the test piece size lO (radius) x 5 Gm * (length) x 5-1 (
thickness), span length 30■■, bending speed 10s*/■i
Measured at n.

Manganese-zinc ferrite was taken as the object to be fired, and placed on the coating surface of the molded body at 1200°C for 3 hours.
This operation was repeated 10 times, and the warp and reaction of the fired product were examined. And the measurement results are shown in the first page.

Examples 1 to 4 were based on the present invention and all showed good results. Comparative Examples 1 and 2 have a low alumina ratio in the powder forming the coating, Comparative Example 3 has a low Al t O' x-ray purity of the alumina powder, Comparative Example 4 has no alumina coating, Comparative Example 5 and 6 are
The film thickness was not suitable, and it was not possible to prevent warping and reactions during ferrite firing.

Next, the porous refractory according to the present invention was used as a base plate for firing a glass substrate component, and its reactivity was investigated.

Harm] Amorphous silica/alumina M&fiber 20ffi containing D1 mutually non-fibrous material at 3% by weight, A or t O350@-ya%, and Si0□50% by weight! 1 part, 70 parts by weight of alumina powder and 10 parts by weight of calcined diatomaceous powder were mixed in 0 parts by weight of wood.
! 1. After that, add polyacrylamide and a flocculant, vacuum suction and dry. 180 m x 15 t.
The resulting shape was obtained. After firing this formed body at 1600°C for 1 hour, it was cut and polished into a size of lsQmm x 1li (single state x 10t).Ant
For 1110 parts by weight of alumina powder with a purity of 99.5%, 100 parts by weight of a 1% methyl cellulose solution
Spray the coating solution by adding 100% and 100% after drying.
The coating layer was baked at 600°C for 1 hour.

The coating surface is polished with a grinding stone to a surface roughness of R14.
It was made into a bottom plate of ZO end m. The density of this board is 1.2g/
cm', bending strength L6 [1 kg/crn', and coating thickness 2QOgm. About 120 g of crystallized glass 7, II' plate was placed on this base plate and fired at 1300°C for 2 hours, and this operation was repeated 10 times to examine warpage of the base plate and crystallized glass substrate. The results showed good results, with no problems such as reactions between the crystallized glass substrate and the bottom plate, cracking or warping of the bottom plate, etc. In addition, the amount of heat stored in the floor plate was reduced, making it resistant to rapid heating and cooling, making it possible to approximately double the production speed.

(Effects of the Invention) As described above, according to the present invention, the following effects can be obtained.

(1) Productivity during firing of ceramic functional parts can be improved.

(2) There is no deformation of functional parts, and post-processing can be omitted, reducing costs.

(3) Reactions between functional parts and firing jigs are suppressed, improving product yield.

(4) Prevents pulverization of the firing jig, improves the working environment, and allows firing of high-precision, high-purity ceramics.

Claims (1)

[Claims] (1) In porous refractory molded bodies for firing functional parts such as ceramics, glasses, and metal oxides, which are formed by sintering and molding a composition consisting essentially of heat-resistant inorganic fibers, inorganic binders, and refractory powders. , the density of the molded body is 0.6 to 1.
5g/cm^2, bending strength at room temperature 120-30
0 kg/cm^2, and the surface on which the functional parts are loaded has a surface roughness R_m_a_x of 2 to 40 μm,
A porous refractory molded body for firing functional parts, characterized in that it is coated with an alumina coating having a thickness of 50 to 1000 μm and made of alumina powder with an Al_2O_3 purity of 95 to 100%.