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

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-...

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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"

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