Amorphous alloy nozzle material and preparation method thereof
阅读说明：本技术 一种非晶态合金喷嘴材料及其制备方法 (Amorphous alloy nozzle material and preparation method thereof ) 是由 苗赫濯 李敏超 于 2021-06-30 设计创作，主要内容包括：本发明公开了一种非晶态合金喷嘴材料及其制备方法,以质量百分比计,其原料组成及配比为：BN：50～70％,ZrO-2：15～30％,SiC：3～10％,Al-2O-3：5～15％,增强增韧剂：5～15％,助烧结剂：1～5％。本发明的制备方法包括将原料进行混合、造粒和干压成型,在温度1700～1850℃和压力15～30MPa下烧结,保温保压1～3小时,得到所述非晶态合金喷嘴材料。本发明通过增强增韧剂和助烧结剂来增加喷嘴材料的耐磨性、抗热冲击性和耐腐蚀性,从而提高其使用寿命。(The invention discloses an amorphous alloy nozzle material and a preparation method thereof, wherein the amorphous alloy nozzle material comprises the following raw materials in percentage by mass: BN: 50 to 70% of ZrO 2 ：15～30％，SiC：3～10％，Al 2 O 3 : 5-15%, reinforcing and toughening agent: 5-15%, sintering aid: 1 to 5 percent. The preparation method comprises the steps of mixing, granulating and dry-pressing raw materials, sintering at 1700-1850 ℃ and 15-30 MPa, and preserving heat and pressure for 1-3 hours to obtain the amorphous alloy nozzle material. The invention increases the wear resistance, thermal shock resistance and corrosion resistance of the nozzle material by reinforcing the toughening agent and the sintering aid, thereby prolonging the service life of the nozzle material.)
1. An amorphous alloy nozzle material is characterized by comprising the following raw materials in percentage by mass:
2. the amorphous alloy nozzle material as claimed in claim 1, wherein the reinforcing and toughening agent is Si3N4Or La2O3。
3. The amorphous alloy nozzle material of claim 1, wherein the sintering aid is MgO and/or CeO2。
4. A method for preparing an amorphous alloy nozzle material, comprising:
weighing the raw materials according to the proportion; mixing, granulating and dry-pressing the raw materials, sintering at 1700-1850 ℃ and 15-30 MPa, and keeping the temperature and pressure for 1-3 hours to obtain the amorphous alloy nozzle material.
5. The method according to claim 4, wherein the mixing and granulating comprise:
the raw materials, the grinding medium and water in a mass ratio of 1: 4-7: 2-4 are put into a grinding machine and ground for 24-72 hours.
6. The method according to claim 5, wherein the grinding medium is grinding balls made of oxide ceramic.
7. The method according to claim 6, wherein the oxide ceramic is Al2O3Or ZrO2The diameter of the grinding ball is 1-4 cm.
8. The production method according to claim 4, wherein the molding pressure of the dry press molding is 30 to 60 MPa.
9. The method of manufacturing according to claim 4, wherein the sintering comprises:
when the temperature in the sintering furnace is increased to 500 ℃ at normal temperature, the sintering furnace is in a vacuum state;
when the temperature in the sintering furnace rises to 500 ℃, introducing inert gas, and continuing to rise the temperature at the temperature rising speed of 600-1200 ℃/h;
when the temperature in the sintering furnace rises to 1400-1600 ℃, gradually pressurizing and continuously raising the temperature,
when the temperature in the sintering furnace rises to 1700-1850 ℃, the temperature is preserved at 1700-1850 ℃ and the pressure is maintained at 15-30 MPa for 1-3 hours.
10. The preparation method according to claim 4, wherein the sintering is performed by using a medium-frequency induction hot-pressing furnace or a graphite heating element resistance type hot-pressing furnace.
Technical Field
The invention belongs to a nozzle material for directly converting molten metal from a liquid state to a solid state, and particularly relates to an amorphous alloy nozzle material and a preparation method thereof.
Technical Field
Directly ejecting molten metal through a nozzle and cooling it to form a desired shape such as a tube, a thin strip, etc., is a new metal material forming technique, and the key component thereof is a nozzle resistant to high temperature, thermal shock, abrasion, workability, and appropriate thermal conductivity and thermal expansion coefficient. The nozzle needs to be cut into a long and thin narrow slit, and molten alloy flows out of the narrow slit under the condition of 1400-1600 ℃, so that the nozzle bears multiple effects of thermal shock, erosion abrasion and melt corrosion. As the nozzle is used, the narrow slit becomes wider to thicken the metal strip, and the nozzle fails when the thickness of the metal strip exceeds a predetermined thickness to end the life. Therefore, how to improve the wear resistance, corrosion resistance and thermal shock fracture resistance of the nozzle material is the focus of research.
A boron nitride-based ceramic nozzle and a preparation method thereof (Chinese patent invention, patent number: ZL201310683025.1) disclose a nozzle made of composite boron nitride-based ceramic material, which takes BN as a matrix and is added with ZrO2、Al2O3、SiC、Y2O3And CaZrO3. Among them, ZrO2 and Al2O3 play roles in improving hardness and wear resistance of the material. Y is2O3And CaZrO3As a stabilizer, ZrO is enhanced2I.e. at high temperatures (. gtoreq.1100 ℃) without phase changes with accompanying volume reduction. In practice this stabilization does not provide a benefit for the application of the nozzle. Because the volume expansion of the particles of the various components takes place after the high temperature is reached, ZrO alone2Due to the volume contraction caused by the phase change, just a part of the expansion is eliminated, thereby reducing the deformation of the nozzle slot. Thus Y is2O3Is added to ZrO2Volume stabilization is not suitable for applications requiring consistent thickness of the alloy strip.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides an amorphous alloy nozzle material and a preparation method thereof. According to the invention, the wear resistance, thermal shock resistance and corrosion resistance of the nozzle material are improved by adding silicon nitride or lanthanum oxide, and magnesium oxide and/or cerium oxide, so that the service life of the nozzle material is prolonged.
In order to achieve the purpose, the invention adopts the following technical scheme:
the amorphous alloy nozzle material provided by the embodiment of the first aspect of the disclosure comprises the following raw materials in parts by mass:
in some embodiments, the reinforcing and toughening agent is Si3N4Or La2O3。
In some embodiments, MgO and/or CeO are selected as the sintering aid2。
The preparation method of the amorphous alloy nozzle material provided by the embodiment of the second aspect of the disclosure comprises the following steps:
weighing the raw materials according to the proportion; mixing, granulating and dry-pressing the raw materials, sintering at 1700-1850 ℃ and 15-30 MPa, and keeping the temperature and pressure for 1-3 hours to obtain the amorphous alloy nozzle material.
In some embodiments, the mixing, granulating comprises:
the raw materials, the grinding medium and water in a mass ratio of 1: 4-7: 2-4 are put into a grinding machine and ground for 24-72 hours.
In some embodiments, the grinding media employ grinding balls made of oxide ceramics.
In some embodiments, the oxide ceramic is Al2O3Or ZrO2And the diameter of the grinding ball is 2-4 cm.
In some embodiments, the forming pressure of the dry pressing is 30-60 MPa.
In some embodiments, the sintering comprises:
when the temperature in the sintering furnace is increased to 500 ℃ at normal temperature, the sintering furnace is in a vacuum state;
when the temperature in the sintering furnace rises to 500 ℃, introducing inert gas, and continuing to rise the temperature at the temperature rising speed of 600-1200 ℃/h;
when the temperature in the sintering furnace rises to 1400-1600 ℃, gradually pressurizing and continuously raising the temperature,
when the temperature in the sintering furnace rises to 1700-1850 ℃, the temperature is preserved at 1700-1850 ℃ and the pressure is maintained at 15-30 MPa for 1-3 hours.
In some embodiments, the sintering is performed in a medium frequency induction autoclave, a graphite heating element resistance autoclave, or an atmospheric pressure oven.
The characteristics and the beneficial effects of the embodiment of the disclosure are as follows:
in the working process of the nozzle, 1400-1600 ℃ molten metal flows through a narrow gap of the nozzle at a high speed and is cooled to form a strip, the nozzle material is subjected to multiple actions such as thermal shock, high-temperature fluid friction corrosion and the like, and the material is cracked due to large thermal stress caused by rapid temperature change. Therefore, the material is required to have not only high wear resistance and corrosion resistance but also excellent thermal shock fracture resistance. Due to Si3N4Has a small thermal expansion coefficient (-3 x 10)-6/. degree. C.), so that it is very good in thermal shock cracking resistance, and at the same time, it is a long columnar crystal grain, and its strength, hardness and toughness are higher, so that Si is3N4Or La2O3The addition of (2) can improve the thermal shock resistance, wear resistance and corrosion resistance of the nozzle base material. But of Si3N4Is a covalent bond material which is difficult to sinter, and MgO and CeO2Can form eutectic point substance with various oxides and can become Si3N4And La2O3The sintering aid.
The non-wetting property and the easy processing property of the BN ceramic and the molten metal are used as the base material of the nozzle, so that the metal is not bonded on the nozzle material; however, since BN is a covalent bond material and is difficult to sinter densely, ZrO is added2、Al2O3Plasma bonding material makes it possible to sinter BN. On the basis, the invention adds Si3N4Or La2O3As a reinforcing and toughening agent, the characteristics of small thermal expansion coefficient and long columnar crystal grains are utilized to improve the thermal shock resistance, strength and wear resistance of the nozzle, thereby prolonging the service life of the amorphous alloy nozzle or the horizontal continuous casting separation ring; meanwhile, in order to further improve the sintering property of the composite BN material; MgO and/or CeO are also added2MgO and/or CeO2Can form eutectic point compound with other oxide impurities, thereby improving sintering of the whole material systemAnd (4) sex.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments.
Example 1
The amorphous alloy nozzle of the embodiment comprises the following components in percentage by mass: BN: 60% of ZrO2：22％，SiC：8％，Al2O3：3％，Si3N4: 6%, MgO: 1 percent. Wherein, Si3N4As reinforcing and toughening agent to improve the strength, toughness and thermal shock resistance of the nozzle material. MgO as Si3N4To facilitate sintering densification of the nozzle material.
The preparation method of the amorphous alloy nozzle in the embodiment comprises the following steps:
1) mixing and grinding granulation
BN and ZrO are weighed according to the mass percentage2、SiC、Al2O3、Si3N4And MgO as a mixture, the mixture, a grinding medium and water in a mass ratio of 1:7:4 are put into a ball mill, and Al with the diameter of 2-4 cm is adopted2O3The balls are used as grinding media, and the mixing and grinding time is 72 hours; then putting the ground mixed slurry into a drying box for drying, wherein the drying temperature is set to be 100 ℃; and (4) sieving and granulating the dried mixture (40-80 mesh sieve) to obtain dried and granulated materials.
2) Dry pressing to form
And (2) putting the dried granulation material obtained in the step 1) into a metal mold of a dry pressing forming machine for dry pressing forming, and adopting unidirectional pressurization with the forming pressure of 40MPa to obtain a blank body, wherein the solid volume relative density of the blank body reaches 50-60%.
3) Hot pressed sintering
And (3) placing the blank formed by dry pressing into a graphite die, placing the graphite die into a medium-frequency induction hot-pressing furnace, and then vacuumizing and heating. The method specifically comprises the following steps: introducing nitrogen gas when the temperature reaches 500 ℃, keeping the temperature, increasing the temperature at 1000 ℃/h, starting pressurizing and gradually increasing the pressure after the temperature reaches 1500 ℃, and when the temperature reaches 1750 ℃, the pressure also reaches the maximum value of 20 MPa. The temperature was maintained at the maximum temperature and maximum pressure for 2 hours, and then the temperature was decreased by cutting off the power. After cooling, the nozzle material for forming amorphous alloy is obtained.
Example 2
The composite boron nitride ceramic material of the embodiment is used for manufacturing the horizontal continuous casting steel separating ring. The composite material comprises the following components in percentage by mass: BN: 58% of ZrO2：23％，SiC：4％，Al2O3：5％，Si3N4：8％，MgO：2％。
The preparation method of the amorphous alloy nozzle material for horizontal continuous casting comprises the following steps:
1) mixing and grinding granulation
BN and ZrO are weighed according to the mass parts2、SiC、Al2O3、Si3N4And MgO as a mixture, the grinding medium and water in a mass ratio of 1:5:3 are put into a ball mill, and Al with the diameter of 1-2 cm is adopted2O3The ball is used as a grinding medium, the mixing and grinding time is 48 hours, and then the ground mixed slurry is put into a drying box to be dried, and the drying temperature is set to be 100 ℃; and sieving and granulating the dried mixture to obtain dried granules.
2) Dry pressing to form
And (2) putting the dried granulation material obtained in the step 1) into a metal mold of a dry pressing forming machine for dry pressing forming, and adopting unidirectional pressurization with the forming pressure of 50MPa to obtain a blank body, wherein the solid volume relative density of the blank body reaches 50-60%.
3) Hot pressed sintering
And (3) putting the blank formed by dry pressing into a graphite die, putting the graphite die into a graphite heating element resistance type hot pressing furnace, and then vacuumizing and heating. The method specifically comprises the following steps: and introducing argon after the temperature reaches 500 ℃, keeping the temperature, raising the temperature at 900 ℃/h, starting pressurizing after the temperature reaches 1500 ℃, and reaching the highest value of 25MPa when the temperature reaches 1800 ℃. The temperature was maintained at the maximum temperature and maximum pressure for 1 hour, and then the temperature was decreased by cutting off the power. After cooling, the excellent horizontal continuous casting separating ring material can be obtained.
Example 3
The amorphous alloy nozzle material of the present example was used to manufacture a thermometric protection tube for molten metal. The composite material comprises the following components in percentage by mass: BN: 55% of ZrO2：20％，Al2O3：5％，SiC：3％，Si3N4：13％，MgO：4％。
The preparation method of the amorphous alloy nozzle material for measuring the temperature of the molten metal comprises the following steps:
1) mixing and grinding granulation
BN and ZrO are weighed according to the mass parts2、SiC、Al2O3、Si3N4And MgO as a mixture, wherein the mass ratio of MgO to MgO is 1:6:4, the mixture, the grinding medium and water are charged into a ball mill, ZrO 1.2cm in diameter is used2The balls are used as grinding media, and the mixing and grinding time is 36 hours; then putting the ground mixed slurry into a drying box for drying, wherein the drying temperature is set to be 110 ℃; and sieving the dried mixture for later use.
2) Isostatic compaction
And (2) forming the dried granulated material obtained in the step 1) into a tubular shape by using an isostatic pressing forming machine, wherein the forming pressure is 150MPa, and a blank body is obtained, and the relative density of the solid volume of the blank body reaches 55-60%.
3) Atmosphere pressure sintering
And (3) putting the blank formed by dry pressing into an atmosphere pressure furnace for pressure sintering, heating to 1780 ℃ within 3 hours under the protection of nitrogen, keeping the temperature for 2 hours at the highest temperature and pressure, and then cutting off the power and reducing the temperature. After cooling, the excellent material of the molten metal temperature measuring tube can be obtained.
Example 4
The amorphous alloy nozzle of the embodiment comprises the following components in percentage by mass: BN: 50% of ZrO2：30％，SiC：7％，Al2O3：4％，La2O3：7％，CeO2:2 percent. Wherein, La2O3As reinforcing and toughening agent for improving nozzleStrength and toughness of the material. CeO (CeO)2As a sintering aid, sintering of the nozzle material can be promoted.
The preparation method of the amorphous alloy nozzle in the embodiment comprises the following steps:
1) mixing and grinding granulation
BN and ZrO are weighed according to the mass percentage2、SiC、Al2O3、La2O3And CeO2As the ingredients, the grinding medium and water in a mass ratio of 1:6:4 are put into a ball mill, and Al with the diameter of 2-3 cm is adopted2O3The balls are used as grinding media, and the mixing and grinding time is 48 hours; then putting the ground mixed slurry into a drying box for drying, wherein the drying temperature is set to be 100 ℃; and (4) sieving and granulating the dried mixture (40-80 mesh sieve) to obtain dried and granulated materials.
2) Dry pressing to form
And (2) putting the dried granulation material obtained in the step 1) into a metal mold of a dry pressing forming machine for dry pressing forming, and adopting unidirectional pressurization with the forming pressure of 50MPa to obtain a blank body, wherein the solid volume relative density of the blank body reaches 50-60%.
3) Hot pressed sintering
And (3) placing the blank formed by dry pressing into a graphite die, placing the graphite die into a medium-frequency hot pressing furnace, and then vacuumizing, heating and boosting. The method specifically comprises the following steps: introducing nitrogen gas after the temperature reaches 500 ℃, keeping the temperature, increasing the temperature at 1000 ℃/h, starting pressurizing and gradually increasing the temperature after the temperature reaches 1500 ℃, and when the temperature reaches 1780 ℃, the pressure also reaches the maximum value of 25 MPa. The temperature was maintained at the maximum temperature and maximum pressure for 2.5 hours, and then the temperature was decreased by cutting off the power. After cooling, the nozzle material for forming amorphous alloy is obtained.
Example 5
The amorphous alloy nozzle of the embodiment comprises the following components in percentage by mass: BN: 67% of ZrO2：15％，SiC：8％，Al2O3：4％，La2O3: 5%, MgO: 1 percent. Wherein, La2O3As a reinforcing and toughening agent to improve the strength and toughness of the nozzle material. MgO as combustion aidThe binder can promote sintering of the nozzle material.
The preparation method of the amorphous alloy nozzle in the embodiment comprises the following steps:
1) mixing and grinding granulation
BN and ZrO are weighed according to the mass percentage2、SiC、Al2O3、La2O3And MgO as a mixture, the grinding medium and water in a mass ratio of 1:5:4 are put into a ball mill, and Al with the diameter of 2-3 cm is adopted2O3The balls are used as grinding media, and the mixing and grinding time is 36 hours; then putting the ground mixed slurry into a drying box for drying, wherein the drying temperature is set to be 100 ℃; and (4) sieving and granulating the dried mixture (40-80 mesh sieve) to obtain dried and granulated materials.
2) Dry pressing to form
And (2) putting the dried granulation material obtained in the step 1) into a metal mold of a dry pressing forming machine for dry pressing forming, and adopting unidirectional pressurization, wherein the forming pressure is 45MPa, so as to obtain a blank body, and the solid volume relative density of the blank body reaches 50% -60%.
3) Hot pressed sintering
And (3) placing the blank formed by dry pressing into a graphite die, placing the graphite die into a medium-frequency hot pressing furnace, and then vacuumizing, heating and boosting. The method specifically comprises the following steps: introducing nitrogen after the temperature reaches 500 ℃, keeping the temperature, increasing the temperature at 1100 ℃/h, starting pressurizing and gradually increasing the temperature after the temperature reaches 1600 ℃, and when the temperature reaches 1850 ℃, the pressure also reaches the maximum value of 30 MPa. The temperature was maintained at the maximum temperature and maximum pressure for 1 hour, and then the temperature was decreased by cutting off the power. After cooling, the nozzle material for forming amorphous alloy is obtained.
The principle of the disclosed embodiments: the composite BN ceramic has no wettability with molten metal, so that when liquid metal flows through the composite BN ceramic, the adhesion phenomenon cannot occur, which is a necessary condition for a nozzle of the molten metal, but the strength and the hardness of the BN are all lower. Since the Si3N4 has small thermal expansion coefficient, long columnar crystal grains and higher strength and hardness, the invention adopts Si3N4 to be added into the nozzle material to form BN, ZrO2，Al2O3SiC, reinforcing and toughening agent and sintering aidThe six-component system of the agent improves the comprehensive performance of the nozzle material.
In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although examples of the present invention have been shown and described above, it should be understood that the above examples are illustrative and not to be construed as limiting the present invention, and that changes, modifications, substitutions and alterations can be made in the above examples by those of ordinary skill in the art without departing from the scope of the present invention.
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