WO2019061485A1

WO2019061485A1 - Method for preparing europium oxide-doped iron-containing silicon-carbon-nitrogen precursor ceramic

Info

Publication number: WO2019061485A1
Application number: PCT/CN2017/104962
Authority: WO
Inventors: 龚红宇; 刘玉; 张玉军; 冯玉润; 郭学; 林骁; 谢冰莹
Original assignee: 山东大学
Priority date: 2017-09-29
Filing date: 2017-09-30
Publication date: 2019-04-04
Also published as: CN107555999A

Abstract

A method for preparing a europium oxide-doped iron-containing silicon-carbon-nitrogen precursor ceramic, comprising steps of: mixing the raw materials polysilazane, α-methacrylic acid, and dicumyl peroxide; crosslinking and curing; pulverization and ball milling, followed by addition of iron oxide and europium oxide for blending; granulation, molding and sintering. The europium oxide-doped SiCN(Fe) precursor ceramic prepared using a precursor conversion method has good molding properties and high strength. In addition to the introduction of nano-iron oxide into the SiCN precursor ceramic, europium oxide is further doped to exploit the special electronic structure and electromagnetic properties of europium as a rare earth element, significantly improving microwave absorption properties of the SiCN ceramic and increasing electromagnetic loss.

Description

Preparation method of iron-containing silicon carbon-nitrogen precursor ceramic doped with cerium oxide

Technical field

The invention relates to a preparation method of a ferrosilicon-containing carbon-nitrogen absorbing ceramic doped with cerium oxide, belonging to the field of inorganic non-metallic materials.

Background technique

With the rapid development of science and technology, electromagnetic waves from different sources will interfere with each other, affecting the transmission of data, and even lead to damage of electronic devices. Therefore, electromagnetic pollution is seriously affecting people's work and life, and endangering human health. In addition, the competition for weapons and equipment is becoming increasingly fierce, and stealth technology has become an important research topic in the defense and military field. Therefore, electromagnetic absorbing materials have become a research hotspot in recent years.

The electromagnetic absorbing material dissipates the incident electromagnetic wave energy into heat energy, or cancels the electromagnetic wave due to interference. Conventional absorbing materials mainly include ferrites, metal alloys, etc. At present, due to the problems of high density and structural design difficulties of these materials, their applications are greatly limited. Ceramic materials such as SiCN and mullite are new types of absorbing materials and have better absorbing properties.

The precursor-ceramics (Polymer-Derived Ceramics (PDCs)) are ceramic materials obtained by directly pyrolyzing an organic polymer precursor. It combines the advantages of two major materials, organic polymer and ceramics, and has many advantages that are incomparable with traditional ceramic processes such as light weight and easy molding.

The SiCN precursor ceramic prepared by the precursor conversion method using polysilazane as a raw material has been widely concerned for its excellent mechanical properties, temperature resistance, chemical stability, and oxidation resistance. The SiCN precursor ceramic is a dielectric loss absorbing material. In order to increase the magnetic loss and increase the overall loss of the material, a magnetic element M (Fe, Co, Al, etc.) can be introduced into the SiCN precursor ceramic to prepare a SiCN(M) precursor. Body ceramics.

Chinese patent document CN 104944960 A discloses a method for preparing a acetylacetonate iron silicon carbonitride ceramic by a precursor conversion method, comprising the following steps: (1) polysilazane, α-methacrylic acid, diisopropyl peroxide The benzene is uniformly mixed to obtain a mixed solution; (2) the mixed solution is solidified; (3) the solidified material is pulverized by ball milling; (4) the powder is uniformly mixed with iron acetylacetonate; (5) the uniformly mixed powder is pre-mixed. Press forming to obtain a green body; (6) pyrolyzing/sintering the green body at a temperature of 1000 ° C to 1400 ° C. Chinese patent document CN 105000889 A discloses a method for preparing iron-containing silicon carbonitride ceramics by a precursor conversion method, comprising the following steps: (1) mixing polysilazane, α-methacrylic acid and dicumyl peroxide. Uniformly, the mixed solution is obtained; (2) the mixed solution is solidified; (3) the solidified material is pulverized by ball milling; (4) the ball milled powder is uniformly mixed with the nano iron oxide iron; (5) the obtained powder is pre-mixed Press forming to obtain a green body; (6) introducing the green body obtained in the step (5) at a temperature of 1000 ° C to 1400 ° C Row pyrolysis / sintering. The preparation method of the above method is simple, and the prepared absorbing material has certain absorbing properties, but the absorbing performance is not good.

Summary of the invention

In view of the deficiencies of the prior art, especially the defects of the current absorbing properties of the absorbing material, the present invention provides a method for preparing a cerium oxide doped SiCN (Fe) precursor ceramic by a precursor conversion method. The method has the advantages of simple process, low production cost and short preparation period, and the obtained product has high electromagnetic loss and good absorbing performance.

The technical solution of the present invention is as follows:

A method for preparing a cerium oxide-doped iron-containing silicon carbon-nitrogen precursor ceramic, comprising:

a mixing step of a raw material polysilazane, α-methacrylic acid and dicumyl peroxide;

Cross-linking curing step;

After pulverizing the ball mill, adding iron oxide and cerium oxide for mixing step;

Granulation molding and sintering steps.

According to the present invention, preferably, the raw material mixing step is carried out under an inert atmosphere;

Preferably, the mass ratio of the polysilazane: dicumyl peroxide is 96%-98%: 2%-4%, further preferably 98%: 2%; the amount of the α-methacrylic acid added 10%-20% of the total mass of polysilazane and dicumyl peroxide;

Preferably, the polysilazane is HTT1800.

According to the present invention, preferably, in the crosslinking curing step, the crosslinking curing temperature is 400 ° C -600 ° C, further preferably 500 ° C -600 ° C; crosslinking curing time is 2-4 h;

Preferably, the crosslinking curing is carried out under an inert atmosphere.

According to the present invention, it is preferred that the cross-linking curing step is carried out at a temperature increase rate of 2 to 5 ° C/min to a crosslinking curing temperature to carry out crosslinking curing, and more preferably, the heating rate is 3-4 ° C / min. The lower heating rate and higher curing time ensure that the polysilazane is sufficiently crosslinked and solidified to promote the reaction.

According to the present invention, preferably, the iron oxide and cerium oxide are added in the mixing step, the mass ratio of the iron oxide to the powder particles obtained after the pulverizing ball milling is 40%-60%: 40%-60%;

Preferably, the amount of cerium oxide added is 5% to 45% by mass of the material after mixing.

According to the present invention, preferably, in the granulation molding step, the obtained mixture material is press-formed, cold isostatically pressed, and pressed to obtain a green body;

Preferably, the press molding is carried out under a pressure of 10 MPa; the cold isostatic pressing is carried out at 180 MPa, and the pressure is maintained for 300 s.

According to the present invention, preferably, in the sintering step, it is carried out under an inert atmosphere;

Preferably, the sintering temperature is from 1000 ° C to 1400 ° C, and the sintering time is from 2 to 4 h; further preferably, the temperature is raised to the sintering temperature. Sintering was carried out at a rate of temperature increase of 3-5 ° C / min.

According to the invention, preferably, the inert atmosphere is a nitrogen, argon or helium atmosphere.

According to the present invention, a preferred embodiment of the method for preparing the cerium oxide-doped iron-containing silicon carbon-nitrogen precursor ceramic is as follows:

(1) Mixing: mixing the polysilazane, α-methacrylic acid and dicumyl peroxide under an inert atmosphere for 1-2 hours to obtain a mixed solution;

The mass ratio of the polysilazane: dicumyl peroxide is 96%-98%: 2%-4%; the amount of the α-methacrylic acid added is polysilazane and diisopropyl peroxide 10%-20% of the total mass of benzene;

(2) cross-linking curing: the mixed solution obtained in step (1) is cured at 400 ° C -600 ° C, under an inert atmosphere for 2-4 h;

(3) pulverizing ball mill: the material obtained by cross-linking and solidifying in step (2) is pre-pulverized, pulverized by ball milling, and sieved to obtain powder particles;

(4) Mixing: adding nanometer iron oxide powder to the powder particles obtained in the step (3), mixing uniformly to obtain a mixed powder; mixing the cerium oxide powder into the mixed powder of 2%-60% by mass , mixing evenly, to obtain a mixture;

(5) granulation molding: the mixture obtained in the step (4) is press-formed, cold isostatic pressing, pressure holding, to obtain a green body;

(6) Pyrolysis/sintering: the green body obtained in the step (5) is sintered under the protection of an inert gas at a temperature of 1000 ° C to 1400 ° C for 2-4 h to obtain a cerium oxide-doped iron-containing silicon carbon nitride precursor ceramic. .

In the present invention, the polysilazane is commercially available or can be prepared according to the prior art; the α-methacrylic acid is abbreviated as MA, and the dicumyl peroxide is abbreviated as DCP.

The principle of the invention:

Rare earth elements are a class of elements having unpaired 4f electrons that are shielded by the outermost electrons, with a net magnetic moment that is not cancelled and magnetocrystalline anisotropy. Helium is the most active rare earth element with good electrical conductivity. Based on its special electronic structure and electromagnetic properties, it can be introduced into the absorbing material to adjust the electromagnetic parameters and further enhance the absorbing properties of the material.

The SiCN precursor ceramic is a dielectric loss absorbing material. By introducing an iron source, the dielectric loss is increased, and magnetic loss is introduced to realize a diversified loss mechanism and improve the overall electromagnetic loss. As a rare earth element with special electronic structure and electromagnetic properties, cerium oxide is incorporated into the matrix of SiCN (Fe) absorbing material, and the reduced elemental enthalpy can adjust the electromagnetic parameters of the absorbing material to further improve the absorbing properties of the material. purpose.

Fe ₂ O ₃ has a significant effect on the dielectric loss and magnetic loss of the material as well as the absorbing properties compared to other iron sources. Therefore, the present invention uses a SiCN (Fe) precursor ceramic doped with nano Fe ₂ O ₃ as a matrix. The rare earth elements all have unpaired 4f electron elements that are shielded by the outermost electrons, with a net magnetic moment that is not cancelled and magnetocrystalline anisotropy. A certain amount of cerium oxide is incorporated into the SiCN (Fe) precursor ceramic, and the magnetic properties and dielectric properties of the material are changed by the ruthenium reduced in the matrix, thereby increasing the magnetic loss and the dielectric loss, thereby effectively improving the material. Absorbing characteristics.

The beneficial effects of the present invention are as follows:

1. The present invention prepares a yttria-doped SiCN (Fe) precursor ceramic by a precursor conversion method, which has good forming and high strength, and is further doped with cerium oxide on the basis of introducing nano-iron oxide into the SiCN precursor ceramic. Utilizing cerium as a special electronic structure and electromagnetic property of rare earth elements, the microwave absorption performance of SiCN ceramics is obviously improved, and the electromagnetic loss is increased.

2. The invention adopts a precursor conversion method, has low preparation temperature, simple preparation method, low production cost, short preparation period, and good chemical stability and high temperature performance of the obtained material.

3. The cerium oxide-doped iron-containing silicon-carbon-nitrogen precursor ceramic prepared by the invention has excellent absorbing properties, and the sample having a blending amount of 45% has the best absorbing property. The value of tanδ _ε is much higher than other samples, reaching a maximum of 0.63 at 12 GHz, ie, the dielectric loss is the largest. The tan δ _μ value reaches a maximum of 0.6 at 17.4 GHz, ie, the magnetic loss is the largest. The sample reflection loss decreased with frequency, and the sample with 45% of the sample reached a minimum of -9.8 dB at 13.5 GHz.

DRAWINGS

1 is an X-ray diffraction pattern of a cerium oxide-doped SiCN (Fe) precursor ceramic obtained in Example 1 of the present invention.

2 is a SEM photograph of a cerium oxide-doped SiCN (Fe) precursor ceramic obtained in Example 1 of the present invention.

3 is a Raman spectrum diagram of a cerium oxide-doped SiCN (Fe) precursor ceramic obtained in Example 1 of the present invention.

4 is a graph showing a frequency-dielectric loss tan δ _ε of a yttria-doped SiCN (Fe) precursor ceramic obtained in Example 1 of the present invention.

Fig. 5 is a graph showing the frequency-magnetic loss tan δ _{μ of the} yttria-doped SiCN (Fe) precursor ceramic obtained in Example 1 of the present invention.

Fig. 6 is a graph showing the change of the frequency-reflectance R of the yttria-doped SiCN (Fe) precursor ceramic obtained in Example 1 of the present invention.

7 is a graph comparing the frequency-dielectric loss tan δ _{ε of the} yttria-doped SiCN (Fe) precursor ceramics prepared in Examples 1, 2, 3, 4, and 5.

8 is a graph comparing the frequency-magnetic loss tan δ _{μ of the} yttria-doped SiCN (Fe) precursor ceramics prepared in Examples 1, 2, 3, 4, and 5.

Figure 9 is a graph comparing the frequency-reflection loss R of the yttria-doped SiCN(Fe) precursor ceramics prepared in Examples 1, 2, 3, 4, and 5.

Detailed ways

The technical solutions of the present invention are further described below in conjunction with the embodiments, but the scope of protection of the present invention is not limited thereto.

The raw materials used in the examples are all conventional raw materials, and the equipment used is conventional equipment and commercially available products.

The polysilazane used was HTT1800, a commercially available product from Shanghai Haiyi Electronics Co., Ltd.

Example 1

A method for preparing a cerium oxide-doped SiCN(Fe) precursor ceramic by a precursor conversion method, comprising the following steps:

(1) Mixing: under a nitrogen atmosphere, weigh 9.8 g of polysilazane, 1 g of α-methacrylic acid and 0.2 g of dicumyl peroxide and mix for 1 h to obtain a single transparent mixed solution;

The mass ratio of the polysilazane: dicumyl peroxide is 98:2; the amount of the α-methacrylic acid added is 10% of the total mass of the polysilazane and dicumyl peroxide;

(2) cross-linking curing: the mixed solution obtained in step (1) is heated in a vacuum tube furnace under nitrogen atmosphere to crosslink and solidify, from room temperature to 600 ° C for 4 h, the temperature rise and fall rate is 3 ° C / min;

(3) pulverizing ball mill: the material obtained by cross-linking and curing in step (2) is pre-pulverized in an agate mortar, and then pulverized in a vibrating ball mill, and passed through a 100 mesh sieve to obtain powder particles;

(4) Mixing: taking 10.5 g of the powder obtained in the step (3), adding 9.5 g of nano-iron oxide powder, and uniformly mixing to obtain a mixed powder;

The mass ratio of the nanometer iron oxide in the mixed powder to the powder particles obtained in the step (3) is 47.5:52.5;

0.3 g of cerium oxide powder is added to the mixed powder obtained above, and uniformly mixed in an agate mortar to obtain a mixed material; the cerium oxide powder is 15% by mass of the mixed powder;

(5) Granulation molding: the mixture obtained in the step (4) is charged into a mold, uniaxially pressed and formed under a pressure of 10 MPa, and then held under a cold isostatic pressure of 180 MPa for 300 s to obtain a cold isostatic pressing of the green body. , hold pressure, get green;

(6) Pyrolysis/sintering: the green body obtained in the step (5) is placed in a tube furnace, and is pyrolyzed at a temperature of 1100 ° C for 4 h under a nitrogen atmosphere protection, and the temperature is raised at a rate of 3 ° C / min. SiCN (Fe) of yttrium oxide.

X-ray diffraction pattern, SEM photograph, Raman spectrum, dielectric loss tan δ _ε , magnetic loss tan δ _μ and frequency-reflection loss R of the yttria-doped SiCN (Fe) precursor ceramic prepared in this example were measured. The curve comparison map is shown in Figures 1, 2, 3, 4, 5, and 6.

As is apparent from Fig. 1, the obtained product contained the reduced Eu simple substance in addition to the Fe element.

It can be seen from Fig. 2 that the doping of cerium oxide has little change to the structure of the SiCN (Fe) precursor ceramics, and the final product has good dispersibility and no agglomeration of grain adhesion.

As can be seen from Figure 3, free carbon is present in the resulting product.

As can be seen from Figures 4 and 5, the dielectric loss and the magnetic loss fluctuate with frequency, wherein the dielectric loss reaches a maximum value of 0.5 at 12.2 GHz, and the magnetic loss reaches a maximum value of 0.4 at around 11.1 GHz.

As can be seen from Fig. 6, the reflection loss shows a downward trend with frequency, reaching a minimum value of -9 dB at 13.7 GHz.

Example 2

(1) Mixing: under a nitrogen atmosphere, weigh 9.8 g of polysilazane, 2 g of α-methacrylic acid and 0.2 g of dicumyl peroxide and mix for 1 h to obtain a single transparent mixed solution;

The mass ratio of the polysilazane: dicumyl peroxide is 98:2; the amount of the α-methacrylic acid added is 20% of the total mass of the polysilazane and dicumyl peroxide;

(2) cross-linking curing: the mixed solution obtained in step (1) is heated in a vacuum tube furnace under nitrogen atmosphere to crosslink and solidify, from room temperature to 600 ° C for 4 h, the temperature rise and fall rate is 5 ° C / min;

0.7 g of cerium oxide powder is added to the mixed powder obtained above, and uniformly mixed in an agate mortar to obtain a mixed material; the cerium oxide powder is 35% by mass of the mixed powder;

(6) Pyrolysis/sintering: The green body obtained in the step (5) is placed in a tube furnace, and is pyrolyzed at a temperature of 1000 ° C for 4 h under a nitrogen atmosphere, and the temperature is raised at a rate of 3 ° C / min. SiCN (Fe) of yttrium oxide.

Example 3

(1) Mixing: under a nitrogen atmosphere, weigh 9.6 g of polysilazane, 2 g of α-methacrylic acid and 0.4 g of dicumyl peroxide and mix for 1 h to obtain a single transparent mixed solution;

The mass ratio of the polysilazane: dicumyl peroxide is 96:4; the amount of the α-methacrylic acid added is 20% of the total mass of the polysilazane and dicumyl peroxide;

(2) cross-linking curing: the mixed solution obtained in step (1) is heated in a vacuum tube furnace under nitrogen atmosphere to crosslink and solidify, from room temperature to 400 ° C for 3 h, the temperature rise and fall rate is 3 ° C / min;

0.5 g of cerium oxide powder is added to the mixed powder obtained above, and uniformly mixed in an agate mortar to obtain a mixed material; the cerium oxide powder is 25% by mass of the mixed powder;

(6) Pyrolysis/sintering: The green body obtained in the step (5) is placed in a tube furnace, and is pyrolyzed at a temperature of 1200 ° C for 4 h under a nitrogen atmosphere protection at a temperature rising rate of 3 ° C / min. SiCN (Fe) of yttrium oxide.

Example 4

(2) cross-linking curing: the mixed solution obtained in step (1) is heated in a vacuum tube furnace under nitrogen atmosphere to crosslink and solidify, from room temperature to 600 ° C for 2 h, the temperature rise and fall rate is 5 ° C / min;

0.9 g of cerium oxide powder is added to the mixed powder obtained above, and uniformly mixed in an agate mortar to obtain a mixed material; the cerium oxide powder is 45% by mass of the mixed powder;

(6) Pyrolysis/sintering: The green body obtained in the step (5) is placed in a tube furnace, and is pyrolyzed at a temperature of 1300 ° C for 3 h under a nitrogen atmosphere protection at a temperature rising rate of 5 ° C / min. SiCN (Fe) of yttrium oxide.

Example 5

(1) Mixing: under a nitrogen atmosphere, weigh 9.7 g of polysilazane, 2 g of α-methacrylic acid and 0.3 g of dicumyl peroxide and mix for 1 h to obtain a single transparent mixed solution;

The mass ratio of the polysilazane: dicumyl peroxide is 97:3; the amount of the α-methacrylic acid added is 20% of the total mass of the polysilazane and dicumyl peroxide;

(2) cross-linking curing: the mixed solution obtained in step (1) is heated in a vacuum tube furnace under nitrogen atmosphere to crosslink and solidify, from room temperature to 500 ° C for 4 h, the temperature rise and fall rate is 4 ° C / min;

0.1 g of cerium oxide powder is added to the mixed powder obtained above, and uniformly mixed in an agate mortar to obtain a mixed material; the cerium oxide powder is 5% by mass of the mixed powder;

(6) Pyrolysis/sintering: the green body obtained in the step (5) is placed in a tube furnace, and pyrolyzed at a temperature of 1400 ° C for 2 h under a nitrogen atmosphere protection, and the heating rate is 5 ° C / min, that is, doping SiCN (Fe) of yttrium oxide.

The cerium oxide-doped SiCN (Fe) precursor ceramics prepared in Examples 1-5 were subjected to a frequency-dielectric loss tan δ _ε curve comparison test, as shown in FIG.

The cerium oxide-doped SiCN (Fe) precursor ceramics prepared in Examples 1-5 were subjected to a frequency-magnetic loss tan δ _μ curve comparison map test, as shown in FIG.

The cerium oxide-doped SiCN (Fe) precursor ceramics prepared in Examples 1-5 were subjected to a frequency-reflection loss R curve comparison map test as shown in FIG.

It can be seen from Fig. 7 that as the frequency increases, the trend of tan δ _ε changes is roughly similar. In Example 4, the sample value of 45% of the sample is substantially higher than that of other samples, and reaches a maximum of 0.63 at 12 GHz, that is, the dielectric loss is the largest. .

As can be seen from Fig. 8, as the frequency increases, the trend of tan δ _μ changes is substantially similar. In Example 4, the sample with a blending amount of 45% reaches a maximum of 0.6 at 17.4 GHz, that is, the magnetic loss is maximum.

As can be seen from Fig. 9, as the frequency increases, the reflection loss tends to decrease. In the fourth embodiment, the sample with a blending amount of 45% reaches a minimum value of -9.8 dB at 13.5 GHz.

In summary, the absorbing property of the sample of Example 4, which is 45% of the blending amount, is optimal.

Comparative Example 1, no cerium oxide powder was added

As described in Example 1, the difference was that no cerium oxide powder was added. The carbon in the system can reduce the elementality of the ruthenium, increase the conductivity of the sample, and increase the dielectric loss. The coercive force of the crucible is large, and the anisotropy can be enhanced to increase the magnetic loss.

Comparative example 2

As described in Example 1, the difference was that the amount of cerium oxide powder added was increased to 55%. As the amount of cerium oxide incorporated increases, the reduced enthalpy increases, and the conductivity of the sample increases, which increases the dielectric constant. However, if the dielectric constant is increased too much, the impedance matching will be seriously affected, so that the absorbing ability is lowered.

Test example 1

The absorbing properties of Comparative Example 1-2 were tested and combined with the data of absorbing properties of Examples 1-5. The data comparison shows that the amount of cerium oxide incorporated may be the main process parameters affecting the absorbing properties of the sample. In Example 4, the sample with a blending amount of 45% had the largest loss and the best absorbing performance. Its tan δ _ε value is much higher than other samples, reaching a maximum of 0.63 at 12 GHz, that is, the dielectric loss is the largest. The tan δ _μ value is also slightly higher than other samples, reaching a maximum of 0.6 at 17.4 GHz, ie, the magnetic loss is the largest. Its reflection loss reaches a minimum of -9.8 dB at 13.5 GHz. However, when the amount of cerium oxide added is too high, it will affect the absorbing properties, resulting in a decrease in absorbing properties.

It is to be noted that the foregoing is only a few specific embodiments of the present invention, and it is obvious that the present invention is not limited to the above embodiments, and other variations are possible. All modifications which are directly derived or indirectly derived from the disclosure of the present invention are considered to be the scope of the invention.

Claims

A method for preparing a cerium oxide-doped iron-containing silicon carbon-nitrogen precursor ceramic, comprising:

a mixing step of a raw material polysilazane, α-methacrylic acid and dicumyl peroxide;

Cross-linking curing step;

After pulverizing the ball mill, adding iron oxide and cerium oxide for mixing step;

Granulation molding and sintering steps.
The method for preparing a cerium oxide-doped iron-containing silicon-carbon-nitrogen precursor ceramic according to claim 1, wherein the raw material mixing step, the crosslinking curing step and the sintering step are all carried out under an inert atmosphere; preferably, The inert atmosphere described is a nitrogen, argon or helium atmosphere.
The method for preparing a cerium oxide-doped iron-containing silicon carbon-nitrogen precursor ceramic according to claim 1, wherein the polysilazane: dicumyl peroxide has a mass ratio of 96% to 98% : 2% to 4%, the α-methacrylic acid is added in an amount of 10% to 20% by mass based on the total mass of the polysilazane and dicumyl peroxide.
The method for preparing a cerium oxide-doped iron-containing silicon carbonitride precursor ceramic according to claim 1, wherein in the crosslinking curing step, the crosslinking curing temperature is from 400 ° C to 600 ° C.
The method for preparing a cerium oxide-doped iron-containing silicon-carbon-nitrogen precursor ceramic according to claim 1, wherein in the crosslinking curing step, the temperature is raised to a crosslinking curing temperature at a heating rate of 2 to 5 ° C/min. Co-cure.
The method for preparing a cerium oxide-doped iron-containing silicon-carbon-nitrogen precursor ceramic according to claim 1, wherein the iron oxide and the pulverized ball powder obtained after the ball milling are added in the mixing step of adding iron oxide and cerium oxide. The mass ratio is 40%-60%: 40%-60%.
The method for preparing a cerium oxide-doped iron-containing silicon carbon-nitrogen precursor ceramic according to claim 1, wherein the addition of iron oxide and cerium oxide in the mixing step, the amount of cerium oxide added is a mixed material. 5%-45% of the mass.
The method for preparing a cerium oxide-doped iron-containing silicon-carbon-nitrogen precursor ceramic according to claim 1, wherein in the granulation molding step, the obtained mixture is press-formed, cold isostatically pressed, pressure-preserved, and produced. Billet.
The method for preparing a cerium oxide-doped iron-containing silicon carbon-nitrogen precursor ceramic according to claim 8, wherein in the granulation molding step, press molding is performed under a pressure of 10 MPa; cold isostatic pressing is performed at 180 MPa. , pressure for 300s.
The method for preparing a cerium oxide-doped iron-containing silicon-carbon-nitrogen precursor ceramic according to claim 1, wherein in the sintering molding step, the sintering temperature is from 1000 ° C to 1400 ° C, and the sintering time is from 2 to 4 h.