JPH0131469B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention serves as a bonding medium for special refractory materials.
Relatively stable acidic aqueous colloidal zirconiazo
related to using the file. Well-known methods i.e. binders and gels
The solidifying agent is mixed with the refractory material and the mixture is chemically solidified.
or gel to form a bond and then the object
The firing method is the traditional method for manufacturing ceramic objects.
It has been used. Typically, many objects
is sodium silicate, potassium silicate, colloid
De-shaped silica and hydrolyzed ethyl silicate
It has been manufactured as a binding material. However, the most
To obtain objects with greater fire resistance, more
A binder that leaves a refractory oxide of . parable
For example, alumina and zirconia are high temperature materials for refractory materials.
generate a combination of U.S. Patent No. 4,025,350 discloses a water-soluble zirconium salt
Liquid gelation inducer and gelation retardant and fireproofing
Can be used with powder to form refractory articles.
and This composition reduces cost increases
and requires additional gelling agent to suppress the problem.
Essential. In addition, by-products of gelation of zirconium salts
Items will need to be removed during firing. Ma
Additionally, the cost of zirconium salt vs. oxide is added.
Ru. U.S. Patent No. 4,201,594 discloses that the refractory material is made of zirconium.
bind with salt, and mix gelling agent and gel retarder.
It states that it is to be entered. For the same reason, these
compositions are less desirable. U.S. Pat. No. 2,984,576 discloses that the percent solids in the dispersed phase
Zirconia or Huff whose rate is at least 30%
An unfired mixture of refractory materials bonded with near sol
It is listed. This patent describes the invention's stable acidic
Special refractory materials effective for use with zirconia sol
Not listed, only binders for various refractory materials
It is listed. U.S. Patent No. 3,758,316 discloses refractory powder and binder precursor
describes a method of producing a refractory material from a substance, and
The binder precursor includes colloidal zirconia.
However, it also requires the addition of a gelling agent. The basic principle of the present invention is that fireproofing material and fine particle
Stable acidic zirco with size and acidic PH
By creating a refractory mixture consisting of nearsol and
Ru. The refractory material should be placed in the active part and, if necessary, in proportion.
It consists of relatively inert parts. Highly refractory material against zirconia sol
It would be relatively inert. However, a certain number
The refractory material is completely inert to zirconia sol.
Rather than sex, it actually reacts with this sol to create a sol.
Gel. very rapid or slow gel
is the specific type of active refractory material, its particle size min.
fabric, and its distribution in the refractory mixture.
Can be built. Activity to cause gelation with zirconia sol
Some examples of refractory materials include alkali metals and
Aluminates, silicates, and silicates of alkali earth metals
Konate, stannate, titanate, zirconia
silicates and oxides of um. specific example
are: calcined magnesium oxide,
Electrically fused magnesium oxide, calci oxide
aluminum, electrically fused calcium oxide, aluminum
monocalcium aluminate, calcium aluminate cement
crystals, molten kinazo, high alkali glass, aluminum
Magnesium luminate, magnesium aluminum silicate
magnesium, magnesium zirconate, silicic acid
Magnesium, magnesium zirconium silicate
Magnesium ferrite, Magnesium titanate
Magnesium stannate, Calcium zirconate
silium, calcium silicate, calcium silicate
ruconium, calcium titanate, calci stannate
barium zirconium, barium silicate
Luminium, barium aluminate, barium silicate
muzirconium, barium stannate, barium titanate
barium silicate, stolone zirconate
thium, strontium stannate, stron silicate
Thirium zirconium, strontium silicate,
Strontium aluminum ate, strontium titanate
Rontium, electrically fused calcium oxide ammonium
crystallized zirconia, electrically fused magnesia oxide
Um-stabilized zirconia, iron chromite, zeolet
Zeolex 23, Wolastonite, Bent
night, strontium aluminate, fuerste
light, calcium aluminum silicate, firefly
stone, fluorbarite, zirconia
Lithium aluminate, lithium aluminate, lithium silicate
lithium, lithium aluminum silicate, titanate
Lithium, lithium zirconium silicate, and
Other refractory materials that are reactive with zirconia sol. go
Some relatively non-reactive refractory materials are:
Yes: monoclinic zirconia, hafnia, alumina,
Bauxite, mullite, sillimanite, zirco
ceria, thoria, silicon nitride, silica, and
oxides of alkali metals and alkaline earth metals
or contain impurities that can react with zirconium sol.
Other substances that are not present in large quantities during production. This system was developed using aluminosilicate, low alkali gas, etc.
lath, alumina, zirconia, silica, and seeds
Species of organic fibers, such as cotton, rayon, nylon
binding material for various fibers made from other synthetic fibers
It can also be used as Examples used in this specification
The aqueous zirconia sol has a pH range of approximately 0.3 to 6.0.
It is acidic. The particle size of zirconia particles is generally small.
The diameter is approximately 25 millimeters or less. Sol is nitrate
Stabilized by acids such as hydrochloric acid, acetic acid, etc.
The gelling effect of the sol's "active" refractory material is due to the acid and
Due to the reaction with “active” refractory materials to form “salts”
It is believed that this reaction increases the PH and this
This reduces sol stability. Also, the formed salt
catalyzes the gelation of the sol. This gelation reaction is
Combining firewood to form a strong object. Several factors were combined with zirconia sol
Controls the properties of the refractory material body. of such factors
Examples include the type of acid in the sol, sol particle size and material.
age, percentage of zirconia in the sol, percentage of zirconia in the mixture
Percentage and type of “active” refractory material and its particle size
fabric, temperature, and mixing conditions. Listing of potential “active” refractories is often
Alkali metals or alkaline earths in the construction of refractory materials
oxides of similar metals, or “active” refractories
shows that it reacts with acid. Role of reacting with sol
The presence of such an “active” refractory material
oxidation, or some types of fireproofing materials.
It will serve as a sintering aid for the system.
cormorant. Relative scratch hardness of bonded refractory material after firing
is a measure of the sintering effect of the “active” refractory material.
to play the role of One procedure utilizing the present invention is to
mixed with at least one “active” refractory material.
Manufacture cast fireproof shapes.
It is to create. The remainder of the refractory material is relatively inert.
Refractory materials can be included. odor in some cases
Depending on the nature of the active refractory, the total refractory
can be of active type. in other cases
The “active” refractory is the total refractory in the mixture.
It can be a very small portion of. activated refractory material
The particle size distribution and chemical properties of “active” refractory materials
These are the two main factors that determine the amount of ingredients. Various refractory molded articles are cast according to the present invention and produced.
commercial products, e.g. metal melting crucibles, boat tanks
pouring pot, pouring pot, pouring tip, tube, rod,
Slabs, bricks, sheaths, furnace accessories, furnace car tops, flat
Furnace door exterior, furnace parts, injection nozzles, furnace liners, etc.
can be manufactured. gold using such a mixture
It is also possible to cast tooth molds and jewelry molds for metal casting.
Wear. In particular, some of these mixtures
Superalloys, stainless steel, niobium, tantalum, and titanium
Suitable for tan and molybdenum casting molds. high temperature
Inert refractory materials, or low activity “active” refractories.
Fire materials, such as zirconia, hafnia, aluminum
By selecting Na, Ittoria, and Lantana.
has an extremely high PCE value and the above-mentioned reaction.
Templates with low activity towards some of the active metals
can be made. Press and pull the refractory building as needed.
To make it by subsequent solidification or gelation,
``Solid'' or ``gel'' at a time determined by
It is possible to create a press mixture that oxidizes. Cast onto a belt or mold, then gel or
is a thin film made from a mixture that can be solidified.
can be made into thick films. mold
or by dipping or spraying the coating onto the object.
can be applied and then allowed to gel. The mixture according to the invention can be shaped by injection molding.
Can be formed into pieces. Current ceramic injection molding technology
The technique is usually to make the refractory material body easier to form.
requires various temporary bonding materials. for example
Expensive waxes, resins, plastics, etc.
Ru. These organic materials burn to release hot binders.
shrinkage occurs while organic material is lost.
Koru. The present invention provides a “live” bond within the refractory body.
Provide a fired bond. Using this technology, various
complex structures such as spindles, nozzles, etc.
Ceramic core for metal casting, Ceramic ctor
Bottle blades, shell mold parts for metal casting, and
and to form various other objects as necessary.
Can be used for The main application of the invention is to
Making a cast refractory object that hardens or gels
It is. The proportion of “active” refractory material required in the mass
It can be adjusted according to the solidification time. This percentage is
Varies with certain “active” refractories. Next
Then, add an appropriate amount of zirconia to the resulting refractory mixture.
Mix with sol to achieve high pour consistency
-, consistency), injected or cast into a mold,
It can be solidified. Particle size distribution of refractory mixtures
desired result, strength, sedimentation and gelation within the mold
Can be changed according to time. Usually to the type
Appropriate time to mix refractory material thoroughly before pouring
It is advantageous to allow some time to pass. This is the size of the mold
Depends on the size and the equipment handling the mixture.
When using manual mixing in small volumes, the mixing is usually
Performed within a very short period of time, e.g. within 1-2 minutes
You can then adjust the mixture to make it very
Able to gel or solidify rapidly. comparison
Relatively fast time of 5 to 30 minutes for the production of objects.
Gel time is preferred. remove foam from mixture
and incorporating suitable wetting agents and antifoaming agents.
It is possible to create a mass that is relatively free of bubbles and voids.
would be desirable. Wet the mass completely and pour
It takes time to degas before shaping. Ideal
gelation should occur as soon as possible after injection.
It is possible. To illustrate the invention, the data in Table 1
refractory materials, for example, mixed with plate alumina,
Can produce a specific solidification or gelation time
can. Indicates the percentage of active refractory material. fireproof material,
20% ZrO₂Zirco containing and having a pH of 0.6
Mix with Niazol. The alumina part is 50%
Small plate alumina of 325 mesh or less and 50%
Composed of small plate-shaped alumina of 60 mesh or less
(obtained from Alcoa). activated refractory
The percentage of refractory materials used in the final mixture
Calculate based on measurements. All the samples shown in Table 1 have excellent green strength.
and separately 1200〓(648.9℃) and 1800〓
(982.2℃), 2000〓(1093℃) and 2500〓
(1371°C) provides excellent firing
It had strength. A series of experiments similar to those in Table 1 were performed according to Table 2.
The plate-shaped alumina refractory material base material was
% of 325 meshes or less and 75% of 60 meshes
It was made up of small things smaller than a tsushiyu.
This table describes various mixtures with activated refractory materials.
The gelation time is shown below. These are shown in Table 1.
mixed with the same zirconia sol used in
Ta. After gelation, these samples showed excellent
It has green strength, and after firing under the same temperature conditions,
It had excellent firing strength. in all cases
The strength at 2500〓 (1371℃) is 2500
〓(1371℃) than those fired at a lower temperature
It was big. Some unique properties of the composition are listed in Table 1.
Approved for things. Series of specimens, approximately thick
1 inch (2.54cm) wide, 1 inch (2.54cm) wide and
The length is 2.375 inches (6.033 cm) in Table 1.
prepared in the mold using the same composition as the one prepared.
Ta. Let them solidify after gelling for 30 minutes, then mold them.
I took it out. After removing from the mold, empty the specimen.
Air dry overnight, then oven at 120°C for 4 hours.
Dry to remove all water from the build, then
It was placed in a desiccator for cooling. Next to that
It was taken out and measured immediately. All specimens are
Due to the dimensions of the mold, it may have shrunk by approximately 0.5 to 1%.
Admitted. After the specimens are dry, heat them to 1200
〓Heat to (648.9℃) and maintain at that temperature for 2 hours
Then, it was allowed to cool to room temperature and measured again. After measurement,
Reheat the test piece to 1800㎓ (982.2℃) and
The samples were held for 2 hours at a time, cooled, and then remeasured.
This same heating is done separately to 2000〓(1093℃) and
2500〓 (1371℃) and then measure the specimen
did. For many specimens, very small
significant and measurable permanent dilatation has occurred;
was recognized. As the data in Table 2 shows, permanent
The specific expansion was obtained for a certain number of cast specimens.
It was. Negative values indicate contraction. The rest of the numbers are permanent
shows the expansion of As observed from this table, some substantial
Swelling occurs for some types of samples. These swellings
tension is not necessarily related to the proportion of active refractory material.
is clearly due to the presence of activated refractory material. Each group
The compounds likely work and are obtained in different ways.
Producing different reaction products governs the amount of expansion.
Ru. This shows that the system bonded with this zirconia sol is
Minimize shrinkage while firing the refractory body using
Ru. Typically, during firing of refractory materials to high temperatures there is considerable
When sintering occurs, considerable shrinkage occurs along with sintering.
Koru. Some compositions in the table below are 2500〓
Even when calcined at (1371℃), the yield is relatively low.
It is recognized that it shows shrinkage. Table 3 shows 25% of 325
Particles smaller than 60 mesh and 75% of particles smaller than 60 mesh
The plate-like alumina containing the
"Conducted on test specimens used with refractory materials"
A similar series of measurements is also shown. The following examples demonstrate how acid-stabilized zirconia sol and
Examples of other refractory materials used in
"Refractory" indicates the use of fireproof materials. Example Composition: Electrically fused calcium oxide stabilized dill oxide
Conium-325 mesh 3g Melted magnesium oxide - 325 mesh 1g Plate-shaped alumina 60 mesh or less 150g Plate alumina-28+48 mesh 120g This refractory composition contains 20% ZrO₂acid containing
Mixed with 35ml of stabilized zirconia sol. Next
Then I poured it into a rubber mold. The gelation time is
It was determined to be approximately 5 minutes. After 30 minutes, mold the sample.
and then cut with a diamond saw.
and cut into specimens for measuring the modulus of rupture. child
The green strength of the mixture was approximately 57 psi.
Fire the sample to 2500㎓ (1371℃) and hold for 2 hours.
cooled to room temperature, and the modulus of rupture was determined to be 575psi.
determined. Similarly, bake at 2700〓 (1482℃) for 2 hours.
and then cooled to give a rupture coefficient of 910 psi.
It was. Bake at 2900㎓ (1593℃) for 2 hours and cool.
A rupture coefficient of 1888 psi was obtained. Example Composition: Plate alumina 325 mesh 240g 2g electrically fused magnesium oxide Add this to 45 ml of the same volume as in the example.
Mixed with zirconia sol. About this mixture
The gelation time was 4.5 minutes. life destroyer
I didn't measure the number, but it was 2000〓 (1093℃) at 2 o'clock.
The inter-fired and cooled specimens had a rupture modulus of 234 psi.
Indicated. Bake at 2500ん (1371℃) for 2 hours and cool.
The rupture coefficient was then 1164 psi. 2700〓
(1482℃) for 2 hours and cooled to 2995psi.
The rupture coefficient was obtained. 2 o'clock at 2900〓 (1593℃)
Interfired specimens showed a rupture modulus of 5674psi
Ta. Example Composition: EF zirconium oxide, calcium stabilized
-325 mesh 170g -50+100 mesh -325 mesh 160g -12+35 mesh -325 mesh 80g This fireproof composition was used in the examples.
Mixed with 30ml of zirconia sol. Gel time
It was hot in 8 minutes. Bake the specimen at a specific temperature for 2 hours
After cooling and testing, the rupture coefficient is as follows:
be: modulus of rupture, psi Unfired 278 2000〓(1093℃) 479 2500〓(1371℃) 1888 2700〓(1482℃) 2019 2900〓(1593℃) 2623 Examples, and test specimens from
Before firing and after each firing, when measured, the next permanent
The percentage of expansion (+) or contraction (-) is shown: Example Firing temperature, 〓(℃) 2000 (1093) +0.08 −0.09 −0.11 2500 (1371) +0.29 −0.46 −0.51 2700 (1482) +0.40 −1.60 −0.50 The occurrence of some permanent swelling may occur with some compositions.
Eliminate or minimize settling and drying shrinkage
This promotes dimensional accuracy in printed objects.
could be increased. The following is a typical scenario in which the present invention can be used.
Here is an example of the Ermold system: Composition: Electrically fused calcium oxide stabilized dill oxide
Conium 2000g 20% ZrO₂500g of zirconia sol containing Concentrated hydrochloric acid 17ml Wetting agent - Sterox NJ 15 drops This slurry was prepared using Zahn #4 cup.
Prepared to have a viscosity of 34 seconds when measured by
did. Sheet of wax, approximately 1/8 inch thick
(0.318cm) x 2.5" wide (6.35cm) x 5.5" long
(13.97 cm), is immersed in this slurry and then
−50 of the same composition used in the lever slurry.
While the +100 mesh zirconia is wet,
Applied immediately. After immersing several specimens,
The slurry was diluted with zirconia sol and the viscosity was increased for 15 seconds.
degree, and after drying the first soak overnight,
Additional soaking was applied. The second coating is still wet.
While making it the same composition as the material in this slurry
-12+35 mesh relatively coarse zirconia grains
It was coated with. Repeat this for additional coatings,
Then apply the final sealing coat, totaling 6 coats.
(stucco) layer and seven slurry layers were formed. Last
By dipping, twice daily dipping was applied. Next
The soaked test piece was dried for 2 days and waxed.
Melted. The specimen is then 1 inch (2.54 cm) wide.
Cut, dry and then tested for green strength
did. Six specimens were tested with an average failure of 500 psi.
Fracture coefficient values were obtained. Add additional specimens to 2000〓(1093
Bake for 2 hours at various temperatures starting from
I put it back together and tested it. Fired at 2000〓(1093℃)
After that, the MOR was 220psi. 2200〓(1204℃)
After firing to and cooling to room temperature, the MOR is 300psi
It was hot. After firing at 2500〓(1371℃), MOR is
Increased to 1200psi. As shown by this,
Regarding the shell mold composition using the present invention
Substantial strength was obtained.

[Table] Umu

【table】

【table】

【table】

Claims (1)

Claims: 1. A refractory mixture comprising an acid-stabilized aqueous zirconia sol and an effective amount of an active refractory material to gel the sol. 2 Acid-stabilized aqueous zirconia sols and the group consisting of alkali metal and alkaline earth metal aluminates, silicates, zirconates, stannates, titanates, silicates and oxides of zirconium. A refractory mixture according to claim 1, comprising an active refractory material selected from the following. 3. The refractory mixture according to claim 1 or 2, further comprising an inert refractory material.