Induction vacuum furnace observation window material

Abstract

The invention discloses a material for an observation window of an induction vacuum furnace. The material comprises 70-74wt% of aluminum oxide and 26-28wt% of magnesium oxide as base materials, the raw materials comprise, by weight, 0.05%-0.15% of yttrium oxide fine powder, 0.1%-0.7% of titanium oxide fine powder and 0.05%-0.15% of lanthanum oxide fine powder; 0.1 wt%-1wt% of strontium carbonate fine powder is used as an additive; molding the obtained raw material powder into a blank, and calcining and primarily sintering; and carrying out hot isostatic pressing high-temperature sintering on the pre-sintered green body to obtain the induction vacuum furnace observation window material. The invention relates to the technical field of induction vacuum furnaces, and provides an induction vacuum furnace observation window material which improves the optical transmittance of visible light and infrared light compared with the prior art due to addition of lanthanum oxide and strontium carbonate, and particularly has more excellent high-temperature performance.

Description

Technical Field

[0001] The invention relates to the technical field of induction vacuum furnaces, in particular to an observation window material for an induction vacuum furnace. Background Art

[0002] Induction vacuum furnace is a high-temperature smelting equipment commonly used in the smelting industry, especially in the non-ferrous metal, special metal, precious metal and rare earth industries. It has the characteristics of high smelting purity, no material oxidation, no pollution and high efficiency and energy saving. The observation window for induction vacuum furnace is one of the components of vacuum furnace smelting equipment. It is used to observe the smelting status and the infrared thermometer to measure the temperature of the molten liquid through the observation window. Under vacuum state, the negative pressure in the furnace will reach 10 -5 MPa, so the observation window is required to have strong mechanical properties, crack resistance, and high visible light and infrared light transmittance, and the quality of the observation window directly affects the safety and reliability of production.

[0003] At present, the observation windows for induction vacuum furnaces are generally made of glass. Due to the lack of mechanical strength of the material and low temperature resistance, they often age quickly, crack and have a short lifespan, increasing risks and production costs. Summary of the Invention

[0004] In order to overcome the deficiencies in the background technology, the present invention discloses an observation window material for an induction vacuum furnace.

[0005] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions: An induction vacuum furnace observation window material comprises: 70% to 74% by weight of aluminum oxide and 26% to 28% by weight of magnesium oxide as a base material; 0.05% to 0.15% by weight of yttrium oxide fine powder, 0.1% to 0.7% by weight of titanium oxide fine powder, and 0.05% to 0.15% by weight of lanthanum oxide fine powder as sintering aids; and 0.1% to 1% by weight of strontium carbonate fine powder as an additive. The preparation method is: (1) Weighing and mixing ingredients: weigh and mix the above base material, sintering aid, and additives, grind and stir; (2) Primary calcination: The ground and stirred materials are kept at 600-900°C in an air atmosphere for 4-10 hours, and then naturally cooled to room temperature; (3) Pressing: dry pressing the material after primary calcination at a pressure of 4-30 MPa for 2-4 minutes, and then isostatic pressing at a pressure of 100-300 MPa for 5-15 minutes. (4) Primary sintering: The formed material is sintered in an argon atmosphere at a temperature of 1200°C to 1400°C for 6 to 10 hours, and then naturally cooled to room temperature; (5) Secondary sintering: The material after the primary sintering is subjected to secondary sintering in an argon atmosphere. At a pressure of 100-250 MPa, the temperature is raised from room temperature to 1400°C at a heating rate of 10-20°C / min and kept at this temperature for 4-6 hours. The temperature is then raised to 1800°C at a heating rate of 5-10°C / min and kept at this temperature for 8-12 hours. The material is then naturally cooled to room temperature to obtain the product.

[0006] Preferably, when the thickness is ≥4 mm, the linear transmittance in the wavelength range of 380 to 2500 nm is ≥83%.

[0007] Preferably, the purity of the strontium carbonate powder is ≥99.99% and the particle size is 50 nm to 100 nm.

[0008] Preferably, the purity of the base material is ≥99.8%, and the particle size is 10 nm to 150 nm; the purity of the sintering aid is ≥99.7%, and the particle size is 10 nm to 2000 nm.

[0009] Due to the adoption of the above-mentioned technical solution, the present invention has the following beneficial effects: The induction vacuum furnace observation window material made by the present invention has the performance characteristics of good strength, good toughness, good wear resistance, good light transmittance and high temperature resistance due to the addition of yttrium oxide, strontium carbonate and titanium oxide in specific proportions, especially the addition of lanthanum oxide and strontium carbonate elements. This is of great significance for reducing production costs and improving safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Linear transmittance curves of the observation window materials prepared in Examples 1-3. DETAILED DESCRIPTION

[0011] The present invention can be explained in detail by the following examples, the purpose of which is to disclose the present invention and to protect all technical improvements within the scope of the present invention. Example 1

[0012] An induction vacuum furnace observation window material, comprising: 73 wt% aluminum oxide and 26.7 wt% magnesium oxide as a base material; 0.05 wt% yttrium oxide fine powder, 0.1 wt% titanium oxide fine powder, and 0.05 wt% lanthanum oxide fine powder as sintering aids; and 0.1 wt% strontium carbonate fine powder as an additive; The preparation method is: (1) Weighing and mixing ingredients: weigh and mix the above base material, sintering aid, and additives, grind and stir; (2) Primary calcination: calcine the ground and stirred materials at 600-900°C in air atmosphere for 4 hours and then cool naturally to room temperature; (3) Pressing: dry pressing the material after primary calcination at a pressure of 4-30 MPa for 2 minutes, and then isostatic pressing at a pressure of 100-300 MPa for 5 minutes. (4) Primary sintering: The formed material is sintered in an argon atmosphere at a temperature of 1200°C to 1400°C for 6 hours, and then naturally cooled to room temperature; (5) Secondary sintering: The material after the primary sintering is subjected to secondary sintering in an argon atmosphere. At a pressure of 100 MPa, the temperature is raised from room temperature to 1400°C at a heating rate of 10°C / min and kept at that temperature for 4 h. The temperature is then raised to 1800°C at a heating rate of 5°C / min and kept at that temperature for 8 h. The product is then naturally cooled to obtain the product. Example 2

[0013] An induction vacuum furnace observation window material, comprising: 73 wt% aluminum oxide and 26 wt% magnesium oxide as base materials; 0.1 wt% yttrium oxide fine powder, 0.32 wt% titanium oxide fine powder, and 0.08 wt% lanthanum oxide fine powder as sintering aids; and 0.5 wt% strontium carbonate fine powder as an additive; The preparation method is: (1) Weighing and mixing ingredients: weigh and mix the above base material, sintering aid, and additives, grind and stir; (2) Primary calcination: calcine the ground and stirred materials at 600-900°C in air atmosphere for 7 hours, and then cool naturally to room temperature; (3) Pressing: dry pressing the material after primary calcination at a pressure of 4-30 MPa for 3 minutes, and then isostatic pressing at a pressure of 100-300 MPa for 10 minutes. (4) Primary sintering: The formed material is sintered in an argon atmosphere at a temperature of 1300°C to 1600°C for 8 hours, and then naturally cooled to room temperature; (5) Secondary sintering: The material after the primary sintering was subjected to secondary sintering in an argon atmosphere. At a pressure of 170 MPa, the temperature was raised from room temperature to 1400 °C at a heating rate of 15 °C / min and kept at that temperature for 5 h. The temperature was then raised to 1800 °C at a heating rate of 7 °C / min and kept at that temperature for 10 h. The product was then naturally cooled to obtain the product. Example 3

[0014] An induction vacuum furnace observation window material, comprising: 70.05 wt% aluminum oxide and 28 wt% magnesium oxide as base materials; 0.15 wt% yttrium oxide fine powder, 0.7 wt% titanium oxide fine powder, and 0.1 wt% lanthanum oxide fine powder as sintering aids; and 1 wt% strontium carbonate fine powder as an additive; The preparation method is: (1) Weighing and mixing ingredients: weigh and mix the above base material, sintering aid, and additives, grind and stir; (2) Primary calcination: calcine the ground and stirred materials at 600-900°C in air atmosphere for 10 hours, and then cool naturally to room temperature; (3) Pressing: dry pressing the material after primary calcination at a pressure of 4-30 MPa for 4 minutes, and then isostatic pressing at a pressure of 100-300 MPa for 15 minutes. (4) Primary sintering: The formed material is sintered in an argon atmosphere at a temperature of 1200°C to 1400°C for 10 hours, and then naturally cooled to room temperature; (5) Secondary sintering: The material after the primary sintering was subjected to secondary sintering in an argon atmosphere. At a pressure of 250 MPa, the temperature was raised from room temperature to 1400 °C at a heating rate of 20 °C / min and kept at that temperature for 6 h. The temperature was then raised to 1800 °C at a heating rate of 10 °C / min and kept at that temperature for 12 h. The product was then naturally cooled to obtain the product.

[0015] Comparative Example 1 Existing induction vacuum furnace observation window.

[0016] Table 1 Performance comparison of an observation window material for an induction vacuum furnace and its preparation method

[0017] Table 1 shows the test performance of Examples 1 to 3. Compared with the prior art, it can be seen that compared with Comparative Example 1, Examples 1 to 3 not only have better mechanical properties, but also have better optical properties than traditional materials.

[0018] pass Figure 1 It can be seen that, because the present invention adopts a specific ratio of lanthanum oxide and strontium carbonate, the product has excellent light transmittance.

[0019] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present invention.

Claims

1. An induction vacuum furnace observation window material, characterized by comprising: 70% to 74wt% alumina and 26% to 28wt% magnesia as the base material; 0.05wt% to 0.15wt% of yttrium oxide fine powder, 0.1wt% to 0.7wt% of titanium oxide fine powder, and 0.05wt% to 0.15wt% of lanthanum oxide fine powder as sintering aids; 0.1wt% to 1wt% of strontium carbonate fine powder as an additive; The preparation method is: (1) Weighing and mixing ingredients: weigh and mix the above base material, sintering aid, and additives, grind and stir; (2) Primary calcination: calcine the ground and stirred materials at 600-900°C in air atmosphere for 4-10 hours, and then cool naturally to room temperature; (3) Pressing: dry pressing the material after primary calcination at a pressure of 4-30 MPa for 2-4 minutes, and then isostatic pressing at a pressure of 100-300 MPa for 5-15 minutes. (4) Primary sintering: The formed material is sintered in an argon atmosphere at a temperature of 1200°C to 1400°C for 6 to 10 hours, and then naturally cooled to room temperature; (5) Secondary sintering: The material after the primary sintering is subjected to secondary sintering in an argon atmosphere. At a pressure of 100-250 MPa, the temperature is raised from room temperature to 1400°C at a heating rate of 10-20°C / min and kept at this temperature for 4-6 hours. The temperature is then raised to 1800°C at a heating rate of 5-10°C / min and kept at this temperature for 8-12 hours. The material is then naturally cooled to room temperature to obtain the product.

2. The induction vacuum furnace observation window material according to claim 1, characterized in that: When the thickness is ≥4mm, the linear transmittance in the wavelength range of 380~2500nm is ≥83%.

3. The induction vacuum furnace observation window material according to claim 1, characterized in that: The purity of the strontium carbonate fine powder is ≥99.99%, and the particle size is 50nm to 100nm.

4. The induction vacuum furnace observation window material according to claim 1, wherein: The purity of the base material is ≥99.8%, and the particle size is 10nm-150nm; the purity of the sintering aid is ≥99.7%, and the particle size is 10nm-2000nm.

5. The induction vacuum furnace observation window material according to claim 1, wherein: include: 73wt% alumina and 26.7wt% magnesia as the base material; 0.05wt% of yttrium oxide fine powder, 0.1wt% of titanium oxide fine powder, and 0.05wt% of lanthanum oxide fine powder are used as sintering aids; and 0.1wt% of strontium carbonate fine powder is used as an additive.

6. The induction vacuum furnace observation window material according to claim 1, wherein: 73wt% alumina and 26wt% magnesium oxide are used as base materials; 0.1wt% yttrium oxide fine powder, 0.32wt% titanium oxide fine powder, and 0.08wt% lanthanum oxide fine powder are used as sintering aids; and 0.5wt% strontium carbonate fine powder is used as an additive.

7. The induction vacuum furnace observation window material according to claim 1, characterized in that it comprises: 70.05wt% alumina and 28wt% magnesia as the base material; 0.15wt% of yttrium oxide fine powder, 0.7wt% of titanium oxide fine powder, and 0.1wt% of lanthanum oxide fine powder are used as sintering aids; and 1wt% of strontium carbonate fine powder is used as an additive.

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