阅读说明：本技术 一种晶界增强型氮化物结合碳化硅窑具 (Crystal boundary enhanced nitride combined silicon carbide kiln furniture ) 是由 曹会彦 张新华 万龙刚 程竹 李�杰 黄志刚 石会营 吴吉光 许海洋 相宇博 于 2021-01-25 设计创作，主要内容包括：本发明涉及一种晶界增强型氮化物结合碳化硅窑具,晶界增强型氮化物结合碳化硅窑具以氮化物+氧化物薄膜为结合相,碳化硅为主晶相；晶界增强型氮化物结合碳化硅窑具由10~20%的氮化物、3~10%的氧化物薄膜和70~87%的碳化硅组成；其中氮化物中包含有由氢化非晶硅在1400~1550℃氮气气氛下通过氮化反应生成的氮化物和另一种氮化物；由氢化非晶硅在1400~1550℃氮气气氛下通过氮化反应生成的氮化物在晶界增强型氮化物结合碳化硅窑具的含量为1~10%。本发明具有导热系数高、高温强度高、抗氧化性能好的特点,有利于棚板、立柱等相关窑具材料长期使用条件下力学性能的稳定。(The invention relates to a crystal boundary enhanced nitride combined silicon carbide kiln furniture, which takes a nitride + oxide film as a combined phase and silicon carbide as a main crystal phase; the crystal boundary enhanced nitride-combined silicon carbide kiln furniture is composed of 10-20% of nitride, 3-10% of oxide film and 70-87% of silicon carbide; wherein the nitride comprises a nitride generated by a nitridation reaction of hydrogenated amorphous silicon at 1400-1550 ℃ in a nitrogen atmosphere and another nitride; the content of nitride generated by the nitridation reaction of hydrogenated amorphous silicon at 1400-1550 ℃ in the crystal boundary enhanced nitride-bonded silicon carbide kiln furniture is 1-10%. The invention has the characteristics of high heat conductivity coefficient, high-temperature strength and good oxidation resistance, and is beneficial to the stability of mechanical properties of the kiln furniture materials such as the shed plate, the upright post and the like under the long-term use condition.)

1. A crystal boundary enhanced nitride combined silicon carbide kiln tool is characterized in that the crystal boundary enhanced nitride combined silicon carbide kiln tool takes a nitride + oxide film as a combined phase and silicon carbide as a main crystal phase; the crystal boundary enhanced nitride-combined silicon carbide kiln furniture is composed of 10-20% of nitride, 3-10% of oxide film and 70-87% of silicon carbide; wherein the nitride comprises a nitride generated by a nitridation reaction of hydrogenated amorphous silicon at 1400-1550 ℃ in a nitrogen atmosphere and another nitride; the content of nitride generated by the nitridation reaction of hydrogenated amorphous silicon at 1400-1550 ℃ in the crystal boundary enhanced nitride-bonded silicon carbide kiln furniture is 1-10%.

2. The grain boundary enhanced nitride bonded silicon carbide kiln furniture according to claim 1, wherein the another nitride is one of silicon nitride, silicon oxynitride or sialon directly introduced.

3. The grain boundary-enhanced nitride-bonded silicon carbide kiln furniture as claimed in claim 1, wherein the other nitride is formed by introducing Si powder and performing in-situ nitridation reaction.

4. The grain boundary-enhanced nitride-bonded silicon carbide kiln furniture as claimed in claim 1, wherein the oxide film is formed of SiO by air oxidation of nitride or silicon carbide₂Is a predominantly one oxidation product.

5. The grain boundary enhanced nitride bonded silicon carbide kiln furniture as claimed in claim 1, wherein the critical grain size of the hydrogenated amorphous silicon is less than 100 nm.

6. The crystal boundary-enhanced nitride-bonded silicon carbide kiln furniture as claimed in claim 1, wherein the oxide film is subjected to interface enhancement treatment by directly replacing nitrogen with air after the nitridation reaction is finished and maintaining the temperature at 1400-1550 ℃, and a uniform and dense oxide protective film is formed on the surface of the completely developed nitride crystal.

Technical Field

The invention relates to a silicon carbide refractory material, in particular to a crystal boundary enhanced nitride-bonded silicon carbide refractory material which is a key kiln furniture supporting material used in the industries of alumina porcelain solving, lining brick and the like, and specifically relates to a crystal boundary enhanced nitride-bonded silicon carbide kiln furniture.

Background

The nitride-combined silicon carbide kiln furniture has high market share in the alumina ceramic ball industry, particularly has high cost performance for the application in the medium and high alumina ceramic ball industry with the firing temperature of 1500-1580 ℃ and the alumina content of 92% and 95%, and monopolizes the industry for more than ten years. The normal loss (in terms of alumina porcelain ball yield) due to oxidation decay of the silicon carbide material is about 6.5 kg/ton, and the excellent product can reach 3.5 kg/ton. When the kiln furniture is abnormally damaged due to the quality problem (generally, early fracture or yield reduction caused by dirty polluted products caused by excessive impurity content), the loss of the kiln furniture can reach 20 kg/ton. The supporting mode commonly adopted in the industry is 'upright post + shed plate', wherein the upright post is mainly stressed, the service life is longer and can exceed 2 years, the shed plate is greatly influenced by shear stress at high temperature or generates bending deformation and the like under the condition of load, the service life is generally not more than 5 months, the damage mechanism is mainly the final thinning, bending, deformation, cracking and the like of the material caused by oxidation deterioration of a binding phase, the reduction of the breaking strength of the material, particularly the high-temperature breaking strength is shown, and the reliability of the silicon carbide kiln tool in the aspect of maintaining the continuous and stable operation of the kiln is difficult to ensure and the silicon carbide kiln tool is forced to be replaced.

The patent CN 101768003 'a high-performance silicon carbide composite kiln furniture material and a preparation method thereof' discloses a technical scheme that nitrides are used as a binding phase, partial aluminum titanate is introduced to improve the oxidation resistance of the kiln furniture material, and the specific introduction mode of the nitrides is not involved, and the related process of oxide films is not involved.

The patent with the application number of 201510399821.1 discloses a toughened silicon carbide slab and a preparation method thereof, and the technical scheme is that 10-15% of graphene is introduced to achieve toughening, and is obviously different from the technical scheme of the invention.

The patent with the application number of 201510399828.3 discloses a technical scheme of a high-strength silicon carbide slab and a preparation method thereof, which is characterized in that 10-15% of graphene is introduced, the firing temperature is 2100-2300 ℃, and finally, carbon nanotubes are sprayed by plasma to realize high strength, the used raw materials are expensive, the firing temperature is high, and the process is complex.

The patent with the application number of 201510399878.1 discloses an oxidation-resistant silicon carbide deck and a preparation method thereof, and the technical scheme is that 10-15% of graphene is introduced, the firing temperature is 2100-2300 ℃, and finally, molybdenum disulfide is sprayed by plasma to achieve high strength, the used raw materials are expensive, the firing temperature is high, and the process is complex.

The technical scheme disclosed by the patent 'energy-saving kiln furniture and a preparation method thereof' with the application number of '201711289649. X' is that silicon carbide, silicon nitride and silicon oxynitride are used as main components, aluminum titanate and a small amount of boron carbide are introduced, and the sintering temperature is 1380-1750 ℃.

The patent with the application number of '201510402345.4' discloses a technical scheme of an anti-corrosion silicon carbide slab and a preparation method thereof, which is characterized in that 10-15% of graphene is introduced, the firing temperature is 2100-2300 ℃, and finally, high strength is realized by spraying molybdenum disulfide and lubricating grease by using plasma, the used raw materials are expensive, the firing temperature is high, and the process is complex.

Disclosure of Invention

The invention aims to provide a crystal boundary enhanced nitride combined silicon carbide kiln furniture, which improves the oxidation resistance of the key supporting kiln furniture such as columns, shed plates and the like in the industries such as alumina ceramic balls, lining bricks and the like, and finally improves the service life of the kiln furniture.

The invention adopts the following technical scheme for achieving the purpose:

a crystal boundary enhanced nitride combined silicon carbide kiln furniture takes a nitride + oxide film as a combined phase and silicon carbide as a main crystal phase; the crystal boundary enhanced nitride-combined silicon carbide kiln furniture is composed of 10-20% of nitride, 3-10% of oxide film and 70-87% of silicon carbide; wherein the nitride comprises a nitride generated by a nitridation reaction of hydrogenated amorphous silicon at 1400-1550 ℃ in a nitrogen atmosphere and another nitride; the content of nitride generated by the nitridation reaction of hydrogenated amorphous silicon at 1400-1550 ℃ in the crystal boundary enhanced nitride-bonded silicon carbide kiln furniture is 1-10%.

The other nitride is one of silicon nitride, silicon oxynitride or sialon which is directly introduced.

The other nitride is generated by introducing Si powder into an in-situ nitridation reaction.

The oxide film is formed by oxidizing nitride or silicon carbide with SiO₂Is a predominantly one oxidation product.

The critical grain size of the hydrogenated amorphous silicon is less than 100nm, the hydrogenated amorphous silicon contains a plurality of dangling bonds and holes, the potential barrier of a nitridation reaction is reduced in the nitridation firing process, the introduction of hydrogen bonds can play a role in purifying a reaction interface, the nitridation efficiency is high, and the generated nitride crystal is completely developed.

After the nitridation reaction is finished, the oxide film directly uses air to replace nitrogen and is subjected to interface enhancement treatment by heat preservation at 1400-1550 ℃, and a uniform and compact oxide protective film is formed on the surface of a completely developed nitride crystal.

The grain boundary strengthening mechanism of the kiln furniture combining the grain boundary enhanced nitride with the silicon carbide provided by the invention is as follows: 1. the nano-amorphous silicon has physical filling effect on pores of the blank; 2. the removal effect of the suspension hydrogen bond of the hydrogenated amorphous silicon on oxygen-containing impurities introduced by oxygen element, silicon carbide raw material and the like in the nitrogen atmosphere enables the surface of the Si powder participating in the nitridation reaction to be always in a chemical reaction control stage, and the diffusion resistance of nitrogen on the surface of the Si powder is reduced; 3. after the nitridation reaction is finished, the surface of the nitride crystal is subjected to interface enhancement through air replacement of nitrogen gas and preoxidation at 1400-1550 ℃, an oxide film is uniformly and densely distributed to seal air holes, the integrity of the nitride crystal is protected, and finally, a nitride is formed to provide excellent mechanical properties, and the oxide film provides excellent oxidation resistance, so that the crystal boundary enhanced nitride combined silicon carbide kiln furniture is formed. 4. The introduction of the oxide film improves the fracture toughness of the traditional nitride combined silicon carbide kiln furniture and enhances the long-term service stability.

The crystal boundary enhanced nitride combined silicon carbide kiln furniture has the advantages of being high in heat conductivity coefficient, high in high-temperature strength and good in oxidation resistance, facilitating the stability of mechanical properties of relevant kiln furniture materials such as a shed plate and an upright post under long-term use conditions, and finally achieving cost reduction and efficiency improvement of industries such as alumina ceramic balls and lining bricks.

The following table shows the performance of one type of grain boundary enhanced nitride bonded silicon carbide kiln furniture (ZQ) compared to the performance of conventional nitride bonded silicon carbide kiln furniture (PT).

The performance of the grain boundary enhanced nitride bonded silicon carbide kiln furniture (ZQ) is compared with the microstructure of the common nitride bonded silicon carbide kiln furniture (PT) in figures 1-3.

Drawings

FIG. 1 is a schematic view of an oxide film on the inner wall of pores of a grain boundary-enhanced nitride-bonded silicon carbide kiln furniture.

FIG. 2 is a schematic diagram of well-developed nitride bonding to SiC kiln furniture using grain boundary-enhanced nitride.

Fig. 3 is a schematic view of the microstructure of a general nitride bonded silicon carbide kiln furniture (PT).

Detailed Description

Example 1:

the composition of the crystal boundary enhanced nitride combined silicon carbide kiln furniture is as follows: silicon carbide 70%, nitride 20%, oxideThe proportion of the material film is 10 percent; the nitride generated by the nitridation reaction of the hydrogenated amorphous silicon with the critical particle size of 90nm is 10 percent, the nitridation temperature is 1550 ℃, the pre-oxidation temperature is 1550 ℃, the apparent porosity of the product is 6.0 percent, and the volume density is 2.79g/cm³The normal temperature strength is 60.0Mpa, the high temperature strength is 70.0Mpa at 1400 ℃, the delta m% is 0.8% and the delta V% is 0.5% at 1550 ℃ multiplied by 50h (saturated steam oxidation).

Example 2:

the crystal boundary enhanced nitride combined silicon carbide kiln furniture comprises the following components: the proportion of silicon carbide is 87%, the proportion of nitride is 10%, and the proportion of oxide film is 3%. The proportion of nitride generated by the nitridation reaction of hydrogenated amorphous silicon having a critical particle size of 80nm was 1%. The nitriding temperature is 1400 ℃, and the pre-oxidation temperature is 1400 ℃; the apparent porosity of the product was 12.8%, and the bulk density was 2.68g/cm³The normal temperature strength is 50.0Mpa, the high temperature strength is 55.0Mpa at 1000 ℃, the delta m% is 1.8% and the delta V% is 2.0% at 1550 ℃ multiplied by 50h (saturated steam oxidation).

Example 3

The crystal boundary enhanced nitride combined silicon carbide kiln furniture comprises the following components: the proportion of silicon carbide is 78%, the proportion of nitride is 15%, and the proportion of oxide film is 7%. The proportion of nitride generated by nitridation reaction of hydrogenated amorphous silicon having a critical particle size of 50nm was 5%. The nitriding temperature is 1450 ℃, and the pre-oxidation temperature is 1500 ℃. The apparent porosity of the product was 9.0%, and the bulk density was 2.74g/cm³The normal temperature strength is 50.0Mpa, the high temperature strength is 55.0Mpa at 1000 ℃, the delta m% is 1.3% and the delta V% is 1.5% at 1550 ℃ multiplied by 50h (saturated steam oxidation).