TW201636318A - Ceramic fiber and method of fabricating the same - Google Patents

Abstract

A ceramic fiber and a method of fabricating the same are provided. An amorphous-silicon-containing composite powder is mixed with aluminum oxide gel to form spinning material. The composite powder includes aluminum oxide, silicon dioxide, and magnesium oxide or calcium oxide. A content of the aluminum oxide is between 15 to 50 parts by weight, a content of the silicon dioxide is between 35 to 60 parts by weight, a content of the magnesium oxide is between 1 to 6 parts by weight, and a content of the calcium oxide is between 6 to 20 parts by weight, based on 100 parts by weight of the composite powder. The spinning material is spinned to form a fiber. A sintering treatment is performed to the fiber, wherein the temperature of the sintering treatment is between 1000 DEG C to 1300 DEG C.

Description

Ceramic fiber and manufacturing method thereof

This invention relates to a fiber and a method of making same, and more particularly to a ceramic fiber and a method of making same.

In recent years, due to the high temperature resistance of ceramic fibers, the demand has increased year by year. Ceramic fibers can be used not only as industrial insulation textiles, but also in high temperature sintering furnace insulation materials such as steel, petrochemical or solar crystal.

Generally, in the production process of ceramic fibers, the spinning material is usually subjected to a spinning step to form fibers, followed by sintering treatment to obtain ceramic fibers. However, the above sintering treatment often requires a large amount of energy. Further, the above-described sintering treatment is usually carried out at a high temperature exceeding 1300 ° C, which tends to excessively grow crystal grains in the ceramic fibers, thereby forming excessive large crystal grains, thereby affecting the structural stability of the formed ceramic fibers. Therefore, how to reduce the temperature of the sintering process and thereby reduce the cost is a subject of current research.

The present invention provides a method of producing a ceramic fiber which can reduce the temperature of the sintering process.

The present invention provides a ceramic fiber having a high heat resistant temperature.

The method for producing a ceramic fiber of the present invention comprises the following steps. The amorphous cerium-containing composite powder is mixed with an alumina gel to form a spinning material, wherein the composite powder includes: alumina, ceria, and magnesia or calcium oxide. The content of alumina is between 15 parts by weight and 50 parts by weight based on 100 parts by weight of the composite powder; the content of cerium oxide is between 35 parts by weight and 60 parts by weight; the content of magnesium oxide is between 1 and 1 part by weight; Between parts by weight and 6 parts by weight; the content of calcium oxide is between 6 parts by weight and 20 parts by weight. The spinning material is spun to form fibers. And sintering the fiber, the temperature of the sintering process is between 1000 ° C and 1300 ° C.

In an embodiment of the invention, the composite powder further comprises iron oxide, wherein the content of the iron oxide is between 6 parts by weight and 16 parts by weight based on 100 parts by weight of the cerium oxide.

In an embodiment of the invention, the composite powder further comprises titanium oxide, wherein the content of the titanium oxide is between 2 parts by weight and 6 parts by weight based on 100 parts by weight of the cerium oxide.

In an embodiment of the invention, the composite powder further comprises potassium oxide, wherein the potassium oxide is contained in an amount of from 1 part by weight to 2 parts by weight based on 100 parts by weight of the cerium oxide.

In an embodiment of the invention, the composite powder is, for example, coal ash, kaolin Or clay.

In an embodiment of the invention, the shape of the composite powder is, for example, a sphere, a sheet, a floc, a pellet, or a combination thereof.

In an embodiment of the invention, the composite powder has a particle size of, for example, between 0.05 microns and 3 microns.

In an embodiment of the invention, the composite powder further comprises quartz.

In an embodiment of the invention, the sintering treatment time is, for example, between 10 minutes and 24 hours.

The ceramic fibers of the present invention include mullite, alumina, and quartz. The content of mullite is between 35 parts by weight and 40 parts by weight based on 100 parts by weight of the ceramic fiber; the content of alumina is between 50 parts by weight and 60 parts by weight; and the content of quartz is 0.1 part by weight. Between 3 parts by weight.

In an embodiment of the invention, the crystals contained in the ceramic fiber have an average crystal grain size of, for example, between 25 nm and 50 nm.

Based on the above, in the method for producing a ceramic fiber of the present invention, since the composite powder containing amorphous cerium is added, it not only has the effect of low-temperature sintering, but also suppresses the growth of crystal grains at a high temperature, thereby enhancing the consolidation of the fiber. Characteristic, therefore, the ceramic fiber produced by this method has a high heat resistant temperature. Further, in the method for producing a ceramic fiber of the present invention, since the temperature of the sintering treatment is low, the production cost can be reduced.

The above described features and advantages of the invention will be apparent from the following description.

S10, S12, S14‧‧ steps

1 is a flow chart of a method of manufacturing ceramic fibers according to an embodiment of the invention.

1 is a flow chart of a method of manufacturing ceramic fibers according to an embodiment of the invention. Referring to FIG. 1, step S10 is performed to mix the amorphous cerium-containing composite powder with an alumina gel to form a spinning material. In the present embodiment, a method of mixing the amorphous cerium-containing composite powder with an alumina gel is, for example, a sol-gel method or a prepolymerization method.

The alumina gel is, for example, an aqueous gel. In the case of using an aqueous alumina gel, the alumina gel and the composite powder can be uniformly mixed without using a water-soluble densification aid, and excellent process stability can be achieved, but the present invention is not limited thereto. In addition, in the process of mixing the alumina gel with the amorphous cerium-containing composite powder, the amorphous cerium-containing composite powder can be used as a fine crystallization aid, thereby effectively reducing the melting point of the alumina gel. This facilitates the subsequent sintering process steps, which will be described in detail below.

The composite powder containing amorphous ruthenium includes alumina, cerium oxide, and magnesium oxide or calcium oxide. More specifically, the content of alumina is between 15 and 50 parts by weight based on 100 parts by weight of the composite powder; the content of cerium oxide is between 35 and 60 parts by weight, and the content of magnesium oxide is between Between 1 part by weight and 6 parts by weight, the content of calcium oxide is between 6 parts by weight and 20 parts by weight.

In another embodiment, the amorphous cerium-containing composite powder may further include iron oxide, wherein the content of the iron oxide is between 6 parts by weight and 16 parts by weight based on 100 parts by weight of the above-mentioned cerium oxide. In still another embodiment, the amorphous cerium-containing composite powder may further include titanium oxide, wherein the content of the titanium oxide is between 2 parts by weight and 6 parts by weight based on 100 parts by weight of the above-mentioned cerium oxide. In other embodiments, the amorphous cerium-containing composite powder may further include potassium oxide, wherein the potassium oxide is contained in an amount of from 1 part by weight to 2 parts by weight based on 100 parts by weight of the above-mentioned cerium oxide. Further, quartz may be included in the amorphous cerium-containing composite powder of the present invention, wherein the content of the quartz is between 1 part by weight and 10 parts by weight based on 100 parts by weight of the composite powder.

The composite powder containing amorphous ruthenium is, for example, coal ash, kaolin or clay. In an embodiment in which the composite powder containing amorphous cerium is coal ash, the composite powder comprises 25 parts by weight of alumina, 50 parts by weight of the total of 100 parts by weight of the composite powder (ie, coal ash). Cerium oxide, 6 parts by weight of iron oxide, 2 parts by weight of titanium oxide, 1.5 parts by weight of magnesium oxide, and 0.5 parts by weight of potassium oxide. In this embodiment, the coal ash is obtained, for example, by direct mixing or by recovery from coal combustion by-products. Therefore, if coal ash is used as the amorphous cerium-containing composite powder of the present invention, the advantage of resource reuse can be achieved, but the present invention is not limited thereto.

Further, the shape of the composite powder containing amorphous ruthenium is, for example, spherical, flake, floc, granular or a combination thereof. The size of the composite powder containing amorphous ruthenium is, for example, between 0.05 μm and 3 μm, preferably between 0.2 μm and 0.5 μm.

Before the composite powder containing amorphous cerium is mixed with the alumina gel, the composite powder containing the amorphous cerium may be first subjected to powder refining treatment and surface treatment. Above The powder refining treatment and surface treatment can avoid agglomeration caused by the mixing of the composite powder and the alumina gel, resulting in uneven mixing. The powder refining treatment is, for example, a wet ball milling method, a high energy ball milling method, a high pressure homogenization treatment method, or a high velocity gas collision refining method. The surface treatment is, for example, a decane treatment, a surfactant treatment or an alkali-excited surface treatment. In the embodiment in which the surface treatment step is a decane treatment, the agglomeration phenomenon can be effectively avoided to achieve a preferable dispersion effect. In the embodiment in which the surface treatment is a surface treatment in which the surface of the composite powder is surface-grafted with a coupling agent or a catalytic aid, the affinity of the composite powder and the alumina gel can be improved, and the composite powder can be lowered. The adverse effects of the body on the mechanical properties of the subsequently formed ceramic fibers.

Referring to Figure 1, proceeding to step S12, the spinning material is spun to form fibers. Further, after spinning, the formed fibers may be subjected to a low-temperature dehydration step, and the fibers subjected to low-temperature dehydration treatment are fibers based on an alumina gel and including a composite powder containing amorphous ruthenium. In the embodiment of the low-temperature dehydration step, the conditions are, for example, an evaporation temperature of 150 ° C to 600 ° C, a heating temperature increase rate of 0.1 ° C / min to 100 ° C / min, and a drying time of 0.5 minutes to 30 minutes. The above drying conditions can provide effective reaction activation energy, and promote the phase transition reaction of the fiber from the polymer gel state to the amorphous ceramic fiber to be suitable for the subsequent sintering process.

Referring to FIG. 1, proceeding to step S14, the fibers are sintered to form ceramic fibers, wherein the sintering treatment temperature is between 1000 ° C and 1300 ° C, and the sintering treatment time is between 10 minutes and 24 hours.

The ceramic fiber formed after the sintering treatment has a crystal structure composed of a plurality of components. In one embodiment, the composition of the ceramic fiber comprises mullite, alumina, And quartz. More specifically, the content of mullite is between 30 parts by weight and 40 parts by weight based on 100 parts by weight of the ceramic fiber, and the content of alumina (including crystalline alumina and amorphous alumina) is between Between 50 parts by weight and 60 parts by weight, the content of quartz is between 0.1 part by weight and 3 parts by weight. In other embodiments, the composition of the ceramic fibers further includes other functional additives in an amount between 6 parts by weight and 8 parts by weight, such as calcium oxide, iron oxide, titanium oxide or potassium oxide. Further, the crystals contained in the ceramic fibers have an average crystal grain size of, for example, between 25 nm and 50 nm, and the ceramic fibers have an average diameter of, for example, between 10 μm and 15 μm.

Since the composite powder containing amorphous yttrium in the fiber has the function of low temperature assisted sintering and suppressing grain growth at a high temperature, the effect of solidification characteristics of the ceramic fiber can be improved after sintering. More specifically, a fiber which is based on an alumina gel and includes a composite powder containing an amorphous cerium is subjected to a sintering treatment, since the amorphous yttrium-containing composite powder has a small crystal grain, and is sintered. The structure and morphology of the ceramic fiber obtained after the treatment can be kept unchanged, and the high temperature stability is also better. On the other hand, if a fiber having only an alumina gel as a base is subjected to a sintering treatment, the fiber structure and type change after sintering, and the grain size grows remarkably. It can be seen that the addition of the amorphous powder-containing composite powder can effectively reduce the crystal grain size after the sintering treatment and achieve the fine crystallizing effect.

On the other hand, the addition of functional additives such as calcium oxide, iron oxide, titanium oxide or potassium oxide to the material to be sintered can reduce the atomic cross-diffusion activation energy barrier during sintering, thereby helping to use alumina gel as The substrate and the fiber comprising the composite powder containing amorphous germanium can achieve a better sintering effect at a lower sintering temperature, and can also greatly improve the high temperature resistance of the ceramic fiber after the sintering treatment.

The properties of the ceramic fiber of the present invention will be described below by using Examples 1-3 and Comparative Examples 1-3.

As shown in Table 1 below, the ceramic fibers of Examples 1 to 3 of the present invention were composed of 48 parts by weight of alumina and 52 parts by weight of composite powder, and the sintering temperature, sintering time, and fibers of the ceramic fiber after sintering treatment. The composition, the composition of the ceramic fiber, the average crystal grain size, and the heat resistance temperature of the ceramic fiber are shown in Table 1.

As can be seen from the above Table 1, Examples 1 to 3 of the present invention include amorphous germanium. The ceramic fiber formed by the composite powder fibers can form a fiber type at a lower sintering temperature (1000 ° C to 1300 ° C), and the formed ceramic fiber has a higher heat resistance temperature (1350 ° C). In contrast, in Comparative Examples 1 to 3, only the fibers having the alumina gel as the base were used, and at the lower sintering temperature (1000 ° C to 1300 ° C), Comparative Example 2 and Comparative Example 3 were in the form of fragmentation, and it was impossible to Form a fiber form. Although Comparative Example 1 can form a fiber type, since the composition type includes only amorphous alumina, the formed alumina fiber has a heat resistance temperature of only 1100 °C.

Therefore, the ceramic fiber formed by the sintering of the fiber containing the amorphous cerium composite powder of the present invention after sintering at a lower temperature has a large crystal grain, a small grain boundary, a low strength, a poor structural stability, and a heat resistant temperature. Lower. On the contrary, the ceramic fiber formed by adding the amorphous cerium-containing composite powder of the present invention to the ceramic fiber after the lower temperature sintering treatment has fine crystal grains, many grain boundaries, high strength, good structural stability and heat-resistant temperature. Higher.

As described above, in the method for producing a ceramic fiber of the present invention, since the added composite powder has a low-temperature sintering effect and can suppress the growth of crystal grains, the consolidation property of the fiber can be improved, and the obtained The heat resistance temperature of the ceramic fiber is also high.

Further, in the method for producing a ceramic fiber of the present invention, the alumina gel mixed with the amorphous cerium-containing composite powder is an aqueous gel, so that it is not necessary to use a water-soluble densification aid to make it non-containing. The composite powder of the wafer is uniformly mixed and achieves excellent process stability to enhance the performance of its subsequent products.

Further, in the method for producing a ceramic fiber of the present invention, The sintering temperature is low, so the manufacturing cost of the ceramic fiber can be reduced.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

S10, S12, S14‧‧ steps

Claims (11)

A method for producing a ceramic fiber, comprising: mixing a composite powder containing amorphous cerium with an alumina gel to form a spinning material, wherein the composite powder comprises: alumina; cerium oxide; and magnesium oxide or oxidation Calcium, wherein the alumina content is between 15 parts by weight and 50 parts by weight, and the cerium oxide content is between 35 parts by weight and 60 parts by weight, based on 100 parts by weight of the composite powder, The content of the magnesium oxide is between 1 part by weight and 6 parts by weight, and the content of the calcium oxide is between 6 parts by weight and 20 parts by weight; spinning the spinning material to form a fiber; The fiber is subjected to a sintering treatment, and the temperature of the sintering treatment is between 1000 ° C and 1300 ° C. The method for producing a ceramic fiber according to claim 1, wherein the composite powder further comprises iron oxide, wherein the iron oxide content is 6 weight based on 100 parts by weight of the cerium oxide. Parts to between 16 parts by weight. The method for producing a ceramic fiber according to claim 1, wherein the composite powder further comprises titanium oxide, wherein the titanium oxide has a content of 2 parts by weight based on 100 parts by weight of the cerium oxide. Between parts and 6 parts by weight. The method for producing a ceramic fiber according to claim 1, wherein The composite powder further includes potassium oxide, wherein the content of the potassium oxide is between 1 part by weight and 2 parts by weight based on 100 parts by weight of the cerium oxide. The method for producing a ceramic fiber according to the above aspect of the invention, wherein the composite powder comprises coal ash, kaolin or clay. The method for producing a ceramic fiber according to the above aspect of the invention, wherein the shape of the composite powder comprises a spherical shape, a sheet shape, a flocculent shape, a granular shape or a combination thereof. The method for producing a ceramic fiber according to claim 1, wherein the composite powder has a particle diameter of between 0.05 μm and 3 μm. The method for producing a ceramic fiber according to claim 1, wherein the composite powder further comprises quartz. The method for producing a ceramic fiber according to claim 1, wherein the sintering treatment is carried out for a period of from 10 minutes to 24 hours. a ceramic fiber comprising: mullite; alumina; and quartz, wherein the mullite content is between 30 parts by weight and 40 parts by weight based on 100 parts by weight of the ceramic fiber; The content is between 50 parts by weight and 60 parts by weight, and the quartz content is between 0.1 part by weight and 3 parts by weight. The ceramic fiber according to claim 10, wherein the ceramic fiber contains crystals having an average crystal grain size of between 25 nm and 50 nm.