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Method for preparing ZrN-Al2O3-ZrO2 multiphase ceramic material by Al-ZrO2-N2 reactive sintering

A composite ceramic and reaction technology, applied in the field of high-temperature ceramic materials, can solve problems such as large volume effect of crystal transformation, interrupted continuous casting process, and short service life of zirconia nozzles.

Inactive Publication Date: 2014-05-14
NORTH CHINA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] As a high-temperature structural material, although ZrO 2 The material has been widely used, but because of ZrO 2 The volume effect of crystal transformation is large, and the thermal conductivity is small (about 0.36-1.27W m -1 ·K -1 ), high coefficient of thermal expansion (α=8~11×10 -6 / °C), its poor thermal shock resistance is still an urgent problem to be solved.
For example, during metallurgical continuous casting and pouring steel, the zirconia sizing nozzle undergoes a high-temperature sudden change from 800°C (preheating temperature) to about 1650°C (molten steel temperature). Such harsh thermal shock conditions can easily cause the zirconia sizing nozzle to Thermal shock cracking occurs, which deteriorates the erosion resistance of the sizing nozzle to molten steel, and greatly reduces the service life of the zirconia sizing nozzle, and even interrupts the continuous casting process due to abnormal changes in the hole diameter, resulting in excessive flow of molten steel, or steel breakout , or damage the key continuous casting equipment "mold"
For this reason, Shandong Laiwu Iron and Steel Co., Ltd. has developed a domestically initiated and internationally leading continuous casting tundish pouring sizing nozzle quick replacement device, and proposed a continuous casting tundish sizing nozzle rapid replacement technology for continuous flow, which is used to solve the problem of oxidation. The service life of zirconium nozzle is short, the tundish is replaced frequently, there is a large amount of molten steel injection, the loss of cutting head and tail of continuous casting blank is large, and the casting speed is too fast due to the erosion of nozzle in the later stage of casting, which is not good for the quality of casting blank and may cause leakage. Problems such as steel accidents
Although this measure relieved the impediment brought by the short life of the zirconia nozzle to the rapid development of high-efficiency continuous casting technology, it did not fundamentally solve the inapplicability of the current sizing nozzle material to the existing high-efficiency rapid continuous casting process The problem

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Ingredients composition: 90% monoclinic zirconia with particle size ≤0.1μm, median particle size d 50 = 5% of metallic aluminum with a diameter of 7.5μm, 1.5% of molybdenum disilicide with a particle size of ≤10μm (extra).

[0019] First, mix monoclinic zirconia fine powder, metal aluminum fine powder, and fine molybdenum disilicide powder according to the metering ratio. After dry mixing for 2 minutes, add an appropriate amount of absolute ethanol to form a flowable viscous slurry. Mix for 5 hours; filter the wet-mixed slurry to remove ethanol, and gradually add 10% by mass rosin ethanol solution to the mixed powder under constant stirring, about 12% (mass percentage, extra), continue After stirring and mixing for 15 minutes, the material is trapped in a sealed condition, and a blank for pressure forming is obtained after 3 hours of trapping. The uniformly mixed and trapped blank is formed into a blank using a hydraulic press, and the forming pressure of the blank is 150 ...

Embodiment 2

[0023] Ingredients: 85% of monoclinic zirconia with particle size ≤0.1μm, median particle size d 50 = 7.5μm metal aluminum 10%, particle size≤10μm calcium fluoride 1.5% (additional).

[0024] First, mix the monoclinic zirconia powder, metal aluminum powder, and calcium fluoride powder according to the metering ratio. After dry mixing for 2 minutes, add an appropriate amount of absolute ethanol to form a flowable viscous slurry. Mix for 5 hours; filter the wet-mixed slurry to remove ethanol, then gradually add 10% by mass rosin ethanol solution about 12% (mass percentage, extra) to the mixed powder under constant stirring, continue After stirring and mixing for 15 minutes, the material is trapped in a sealed condition, and a blank for pressure forming is obtained after 3 hours of trapping. The uniformly mixed and trapped blank is formed into a blank using a hydraulic press, and the forming pressure of the blank is 150 MPa. The molded body is dried at 60° C. for 5 hours to obtain ...

Embodiment 3

[0028] Ingredients: 80% monoclinic zirconia with particle size ≤0.1μm, median particle size d 50 = 20% metallic aluminum with a diameter of 7.5μm, 1.5% zirconium diboride with a particle size of ≤10μm (extra).

[0029] First, mix the monoclinic zirconia fine powder, the metal aluminum fine powder, and the zirconium diboride fine powder according to the metering ratio. After dry mixing for 2 minutes, add an appropriate amount of absolute ethanol to form a flowable viscous slurry. Method mixing for 5 hours; filter the wet mixed slurry to remove ethanol, and then gradually add 10% by mass rosin ethanol solution about 12% (mass percentage, extra) to the mixed powder under constant stirring. Continue to stir and mix for 15 minutes and then trap the material under sealed conditions. After 3 hours of trapping, a billet for pressure forming is obtained. The uniformly mixed and trapped blank is formed into a blank using a hydraulic press, and the forming pressure of the blank is 150MPa. ...

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Abstract

The invention relates to a method for preparing a ZrN-Al2O3-ZrO2 multiphase ceramic material by Al-ZrO2-N2 reactive sintering, belonging to the field of high-temperature ceramic materials. The multiphase material is prepared from the following raw materials in percentage by mass: 5-30% of metal aluminum fine powder, 70-95% of monoclinic zirconium dioxide fine powder, and 1-1.5% of sintering accelerator (CaF2 or ZrB2 or MoSi2) fine powder (additional). The method comprises the following steps: dryly mixing the raw materials, adding anhydrous ethanol, and wetly mixing; removing ethanol from the slurry, adding a rosin ethanol solution, stirring, and standing in a sealed environment to obtain a blank; and molding the blank, drying, and keeping the temperature at 1400 DEG C for 6-8 hours in a dynamic nitrogen atmosphere to obtain the ZrN-Al2O3-ZrO2 multiphase ceramic material. The multiphase material has the advantages of high soaking capacity, small thermal expansion coefficient and favorable thermal shock resistance, and can provide a novel high-temperature ceramic material for the fields of steel and non-ferrous metallurgy, construction materials, electronics and the like.

Description

Technical field [0001] The invention belongs to the field of high-temperature ceramic materials, and specifically relates to an Al-ZrO 2 -N 2 Preparation of ZrN-Al by reaction sintering 2 O 3 -ZrO 2 Multiphase ceramic material method. Background technique [0002] ZrO 2 It has many excellent characteristics such as high melting point (2700℃), good chemical stability, high hardness, and resistance to being wetted and corroded by metal solutions. It is a high-temperature material that has attracted much attention. But because of ZrO 2 There are three crystal types with different densities (cubic zirconia c-ZrO 2 6.27g / cm 3 , Tetragonal zirconia t-ZrO 2 6.10g / cm 3 And monoclinic zirconia m-ZrO 2 5.68g / cm 3 ), in the temperature range of room temperature to 2700℃, ZrO 2 M-ZrO 2 →t-ZrO 2 →c-ZrO 2 Crystal transformation, temperature reduction ZrO 2 Reverse transformation occurs, and in ZrO 2 The crystal form transition is accompanied by a larger volume effect, so monoclinic zirconia (m-...

Claims

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Application Information

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IPC IPC(8): C04B35/48C04B35/622
Inventor 王榕林卜景龙张利芳王志发蔡艳张健
Owner NORTH CHINA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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