Method for testing thermophysical property of rare earth aluminate glass melt

Abstract

The invention discloses a method for testing the thermophysical property of a rare earth aluminate glass melt. The density, the viscosity and the surface tension of the high-temperature melt of La2O3-Al2O3-ZrO2 series glass are tested by adopting a container-free air suspension technology. The method has the remarkable advantages that a small amount of raw materials can be used and rapid heating and cooling can be realized by the container-free air suspension technology, crucible pollution and devitrification are avoided, and the measurement precision is ensured; the temperature control range of laser heating is from 200 DEG C to 3200 DEG C, and the physical property data of the La2O3-Al2O3-ZrO2 glass in a deep supercooling interval can be accurately measured; the doping amount of ZrO2 has obvious influence on the viscosity and the surface tension of the glass, and important reference is provided for component design and process optimization of the high-performance glass of the system; experimental results show that along with the increase of the ZrO2 content, the glass is easy to crystallize in the cooling process, and the physical property data of a low-temperature interval cannot be measured, but the measurable range can be effectively extended by adopting the method disclosed by the invention, and a reliable testing means is provided for the physical property research of the rare earth aluminate glass and the preparation of high-performance glass.

Description

Technical Field

[0001] The invention relates to the field of thermal property testing, in particular to a method for testing the thermal properties of a rare earth aluminate glass melt. Background Art

[0002] In the process of glass preparation and crystal growth research, high-temperature thermophysical parameters such as melt viscosity, surface tension and density have important guiding significance for glass forming, crystallization control and new material design. Traditional testing methods (such as crucible method and rotation method) are easily affected by factors such as container contamination, high-temperature environment instability and crystallization during cooling, making it difficult to accurately collect data in a wider temperature range.

[0003] Since La2O3-Al2O3-ZrO2 glass does not contain traditional glass network formers (such as SiO2, B2O3, P2O5, etc.), its forming ability is poor and it is easy to crystallize when cooled to near the melting point, resulting in the inability to measure the physical property data in the deep supercooled temperature range below the melting point. Therefore, how to obtain its complete thermophysical property curves such as viscosity, surface tension and density in a deep supercooled state has become a technical problem that needs to be solved in this field.

[0004] In recent years, with the application of containerless gas suspension technology, this technology can avoid crucible contamination, achieve rapid temperature rise and fall, and provide a wider measurement range, and has gradually been introduced into high-temperature material research. However, for La2O3-Al2O3-ZrO2 system glass, since its heating and melting temperature exceeds 2000℃, traditional containerless technology is difficult to stably suspend samples, and it is difficult to measure its thermophysical property data in high temperature and deep supercooling ranges, and there is still a lack of mature processes and measurement methods.

[0005] To this end, the present invention proposes a method for testing the thermal properties of rare earth aluminate glass. By combining laser heating, gas suspension technology and oscillation attenuation measurement, the viscosity, surface tension and density data in a wide temperature range (including deep supercooling range) are obtained under the conditions of small sample size and rapid cooling, providing a scientific basis for the research and development of high-performance rare earth aluminate glass materials. Summary of the invention

[0006] The purpose of the present invention is to provide a rare earth aluminate glass thermal property testing method to solve the difficulties faced by the prior art in obtaining the physical property data of La2O3-Al2O3-ZrO2 glass in the deep supercooling range, reduce raw material requirements, avoid container contamination and other problems.

[0007] The present invention achieves the above-mentioned purpose through the following technical scheme: A method for testing the thermal properties of rare earth aluminate glass melt, comprising the following steps:

[0008] Step 1, preparation of rare earth aluminate glass: select La2O3 25%-32% rare earth oxide, mix with Al2O3 45%-75% mol, ZrO2 0%-23% mol powder, and make glass balls through pre-sintering and laser melting-solidification treatment. The diameter of the sphere of rare earth aluminate glass is 1.8mm-2.3mm, avoiding impurity pollution caused by traditional crucibles;

[0009] Step 2: Air suspension + laser heating test: The air suspension technology is used to achieve stable suspension without a container in the high temperature range, and multiple laser beams are used to heat from different directions, and the temperature is quickly heated to 2000-2600°C. The infrared thermometer is used to record the temperature in real time, and the speaker oscillation frequency (0Hz-2000Hz) is adjusted to a suitable value to make the melt produce second-order oscillation. The viscosity camera is used to collect the melt oscillation attenuation process, and then the viscosity and surface tension of the melt are calculated;

[0010] Step 3: Deep supercooling density test: After the laser is turned off, the density camera is used to collect the change in the radius of the glass ball during the solidification process, and the density change of the glass in the low temperature range below the melting point is calculated to provide a basis for studying the glass forming ability;

[0011] Step 4: Data analysis: Compare the test results of glasses with different ZrO2 doping amounts (0%-23% mol) to analyze the effect of ZrO2 on viscosity, surface tension, density, and the improvement or reduction of glass forming ability.

[0012] Preferably, the method for preparing the rare earth aluminate glass in step 1 specifically comprises:

[0013] S1. Weigh ZrO2 powder, Al2O3 powder and La2O3 powder according to the composition of rare earth aluminate glass and mix them to obtain a mixed powder;

[0014] S2, pressing the obtained mixed powder into a glass raw material block, and then pre-burning it in a muffle furnace, and performing a melting-solidification process to obtain a rare earth aluminate glass;

[0015] S21, the melting-solidification process is specifically as follows: after the glass raw material block is stably suspended, it is heated to a molten state by laser, and then cooled to obtain rare earth aluminate glass.

[0016] Preferably, the suspension method is not limited to pneumatic suspension, and the gas used in pneumatic suspension is preferably any one of oxygen and argon.

[0017] Preferably, the laser heating uses three 60W CO2 lasers with a beam angle of 120°.

[0018] Preferably, the temperature measurement range of the infrared thermometer is 200°C - 3200°C, and the working wavelength is 1.95μm - 2.6μm.

[0019] Preferably, in step two, the method for finding the second-order oscillation is to calculate the resonance frequency through Fourier transform.

[0020] Preferably, in step two, when collecting the oscillation decay process of the melt, the oscillation decay curve of the melt is fitted by the least square method to calculate the viscosity and surface tension of the melt at the current temperature.

[0021] Preferably, the field of view of the density camera is 1300 - 200μm, the frame rate is 200fps, and the resolution is 1.3MP; the field of view of the viscosity camera is 640 - 750μm, the frame rate is 2500fps, and the resolution is 0.3MP.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. The containerless air suspension technology adopted by the present invention uses less material during the test, can quickly heat up and cool down, avoids crucible contamination and crystallization interference, and has high measurement accuracy;

[0024] 2. The laser heating range is wide, and accurate temperature measurement from 200°C to 3200°C can be achieved, enabling accurate acquisition of the physical property data of La2O3 - Al2O3 - ZrO2 glass in the deep undercooling range;

[0025] 3. The incorporation amount of ZrO2 has a significant impact on the viscosity and surface tension of the glass, providing an important reference for the composition design and process optimization of high-performance glass in this system;

[0026] 4. Through proportional verification, as the content of incorporated Zr02 increases, the glass is prone to crystallization during the cooling process, and the physical property data in the low-temperature range cannot be measured; adopting the method of the present invention can effectively extend the measurable temperature range, which is of great significance for studying the glass-forming ability of rare earth aluminosilicate glass. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings without creative efforts based on these drawings.

[0028] Figure 1 : Results of the viscosity and surface tension of rare earth aluminosilicate glass in the present invention varying with temperature;

[0029] Figure 2 : Density test results of Example 1, Example 2 and Comparative Example 1;

[0030] Figure 3 : Viscosity test results of Examples 1 and 2 and Comparative Example 1;

[0031] Figure 4 : Surface tension test results of Examples 1 and 2 and Comparative Example 1. Detailed implementation manners

[0032] To make the objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0033] The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation manners.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, specific orientation structure, or operation. Therefore, it should not be construed as a limitation of the present invention.

[0035] Please refer to Figures 1-4 As shown, the present invention provides a method for testing the thermal physical properties of rare earth aluminate glass melt, including the following steps:

[0036] Step 1: Preparation of rare earth aluminate glass: Select rare earth oxides of 25%-32% La2O3, mix them with powders of 45%-75% mol Al2O3 and 0%-23% mol ZrO2, and prepare glass spheres through pre-firing and laser melting-solidification treatment. The sphere diameter of the rare earth aluminate glass is 1.8 mm - 2.3 mm, avoiding the impurity contamination that may be brought by traditional crucibles;

[0037] The specific preparation method is as follows:

[0038] S1. Weigh ZrO2 powder, Al2O3 powder, and La2O3 powder according to the composition of the rare earth aluminate glass and mix them to obtain a mixed powder;

[0039] S2. Press the mixed powder into a glass raw material block, put it into a muffle furnace for pre-firing treatment, and then perform melting-solidification treatment to obtain the rare earth aluminate glass;

[0040] S21. The specific steps of the melting-solidification treatment are as follows: After stably suspending the glass raw material blocks, they are heated to the molten state by laser and then cooled to obtain rare earth aluminate glass.

[0041] Step 2. Gas suspension + laser heating test: Achieve containerless stable suspension in the high-temperature range through gas suspension technology, and use multiple laser beams to heat from different directions, quickly heating to 2000 - 2600 °C. Combine with an infrared thermometer to record the temperature in real time. Turn on the speaker with an oscillation frequency of 0 Hz - 2000 Hz to find the appropriate oscillation frequency to make the melt generate second-order oscillation. Turn on the viscosity camera to collect the oscillation decay process of the melt, so as to calculate the viscosity and surface tension.

[0042] Further, the method for finding the second-order oscillation: Calculate the resonance frequency through Fourier transform.

[0043] Further, during the process of collecting the oscillation decay of the melt, fit the oscillation decay curve of the melt by the least square method to calculate the viscosity and surface tension of the melt at the current temperature.

[0044] Further, 3 60W CO2 lasers are used for laser heating, the beam angle is 120°, and the temperature is measured in real time by an infrared thermometer. The infrared thermometer has a working range of 200 °C - 3200 °C and a working wavelength of 1.95 um - 2.6 um.

[0045] Step 3. Deep undercooling density test: After the laser is turned off, use a density camera to collect the change in the radius of the glass sphere during the solidification process, and deduce the density change of the glass in a lower temperature range below the melting point, providing a basis for studying its glass-forming ability.

[0046] Step 4. Data analysis: Compare the test results of glasses with different ZrO2 0% - 23% mol, and analyze the effects of ZrO2 on viscosity, surface tension, density, and the improvement or weakening of the glass-forming ability.

[0047] Further, the method of suspension is not limited to pneumatic suspension only. The gas preferably used for pneumatic suspension is any one of oxygen and argon.

[0048] Further, the density camera has a range of 1300 - 200 um, a frame rate of 200 fps, and a resolution of 1.3 MP.

[0049] Further, the viscosity camera has a range of 640 - 750 um, a frame rate of 2500 fps, and a resolution of 0.3 MP.

[0050] Next, with reference to Table 1 and Table 2, and through specific examples and control examples, the technical solution of the present invention will be further described.

[0051] The general process of the following examples is as follows:

[0052] Process 1: Raw material preparation and powder mixing: Weigh the corresponding powders according to the target chemical composition of rare earth aluminosilicate glass, where La2O3 is 32 mol%, Al2O3 is 45%-75% mol, and ZrO2 is 0%-23% mol. After mixing evenly, press them into a block and place it in a muffle furnace for appropriate pre-sintering to remove impurities;

[0053] Process 2: Preparation of glass by laser melting-solidification: Place the pre-sintered block sample in a pneumatic suspension device. By adjusting the gas flow rate and direction, make the block in a stable suspension state. Use 3 60W CO2 lasers (beam angle 120°) for heating, so that the sample is completely melted and then rapidly cooled to obtain rare earth aluminosilicate glass balls with a diameter of 1.8 mm - 2.3 mm;

[0054] Process 3: Thermal property testing, specifically as follows:

[0055] Step A: Density testing: Continue heating to 2300°C and then turn off the laser. Use a high-speed camera to record the radius change of the glass ball during the process from the molten state to deep undercooled solidification, and deduce the density-temperature curve;

[0056] Step B: Viscosity and surface tension testing: Heat the glass ball to 2200°C again. By changing the oscillation frequency (0 Hz - 2000 Hz) and observing the resonance frequency, collect the second-order oscillation decay process of the melt. Use the least squares method to fit the oscillation curve and calculate the viscosity and surface tension at the current temperature;

[0057] Process 4: Data analysis: Compare the test results of glasses with different ZrO2 contents (0 - 15 mol%), and analyze the effects of ZrO2 on viscosity, surface tension, density, and the improvement or weakening of the glass-forming ability.

[0058] Example 1

[0059] ● Formula: 32 mol% La2O3, 58 mol% Al2O3, 10 mol% ZrO2;

[0060] ● Process: As in the aforementioned general process, obtain glass balls by laser melting-solidification; Test the viscosity and surface tension at 2200°C, and turn off the laser at 2300°C to record the radius change of the sphere to obtain density data;

[0061] ● Result: Compared with the control example without ZrO2, the viscosity has decreased overall and the surface tension has increased.

[0062] Example 2

[0063] ● Formula: 32 mol% La2O3, 53 mol% Al2O3, 15 mol% ZrO2;

[0064] ● The same testing process as in Example 1;

[0065] ● Result: When the ZrO2 content continues to increase to 15 mol%, the viscosity further decreases compared to Example 1, and the surface tension is greater than that of Example 1.

[0066] Comparative Example 1

[0067] ● Formula: 32 mol% La2O3, 68 mol% Al2O3, 0 mol% ZrO2;

[0068] ● The remaining processes are the same;

[0069] ● Result: The viscosity is the highest, the surface tension is the lowest, the comparative example has a certain tendency to crystallize, and the supercooling range of the melt is relatively narrow.

[0070] Table 1 shows the chemical composition of the rare earth-aluminate glass in the present invention:

[0071] <![CDATA[La2O3 / mol%]]> <![CDATA[Al2O3 / mol%]]> <![CDATA[ZrO2 / mol%]]> Status Example 1 32 58 10 Glass Example 2 32 53 15 Glass Comparative Example 1 32 68 0 Glass

[0072] Table 2 shows the results of the viscosity and surface tension of the rare earth-aluminate glass in the present invention changing with temperature:

[0073]

[0074] The conversion between the temperature units K and °C is 273. Taking 2023 K as an example, 2023 K = 1750 °C

[0075] Comparing Example 1 with Comparative Example 1, the difference is that 10% mol ZrO2 is incorporated in Example 1. The viscosity of the glass decreases as a whole in the temperature range of 2023 K - 2473 K, and the surface tension increases as a whole, indicating that the incorporation of ZrO2 reduces the polymerization degree of the La2O3 - Al2O3 glass, resulting in a decrease in the overall viscosity and a decline in the glass-forming ability.

[0076] Comparing Example 2 with Example 1 and Comparative Example 1, the difference is that the ZrO2 content in Example 2 increases to 15% mol, and the viscosity further decreases compared to Example 1, and the surface tension is greater than that of Example 1 as a whole.

[0077] Conclusions and beneficial effects:

[0078] 1. The containerless gas suspension technology adopted in the present invention uses less raw materials and can quickly raise and lower the temperature during the testing process, avoiding crucible contamination and crystallization interference, and having high measurement accuracy;

[0079] 2. The laser has a wide heating range and can measure temperatures from 200°C to 3200°C, enabling the accurate acquisition of physical property data of La2O3-Al2O3-ZrO2 glass in the deep undercooling range;

[0080] 3. The amount of ZrO2 incorporated has a significant impact on the viscosity and surface tension of the glass, providing important references for the composition design and preparation process of high-performance glass in this system;

[0081] 4. Through comparative verification, as the content of incorporated ZrO2 increases, the glass is more prone to crystallization during the cooling process, and physical property data in the lower temperature range cannot be measured; while the method of the present invention can effectively extend the measurable range, which is of great significance for studying the glass-forming ability of rare earth aluminosilicate glass.

[0082] Those skilled in the art can understand that the specific embodiments of this specification are only used to illustrate the technical solutions of the present invention, rather than limiting the present invention. Without departing from the spirit and scope of the present invention, various equivalent substitutions or modifications can be made to it, and these equivalent modifications or substitutions should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for testing the thermal properties of rare earth aluminate glass melt, characterized in that: It includes the following steps: Step 1, preparation of rare earth aluminate glass: La2O3 25%-32% rare earth oxide is mixed with Al2O3 45%-75% mol, ZrO2 0%-23% mol powder, and glass balls are obtained through pre-sintering and laser melting-solidification treatment. The diameter of the sphere of rare earth aluminate glass is 1.8mm-2.3mm, avoiding impurity pollution caused by traditional crucibles; Step 2: Air suspension + laser heating test: The air suspension technology is used to achieve stable suspension without a container in the high temperature range, and multiple laser beams are used to heat from different directions, and the temperature is quickly heated to 2000-2600°C. The infrared thermometer is used to record the temperature in real time, and the speaker oscillation frequency (0Hz-2000Hz) is adjusted to a suitable value to make the melt produce second-order oscillation. The viscosity camera is used to collect the melt oscillation attenuation process, and then the viscosity and surface tension of the melt are calculated; Step 3: Deep supercooling density test: After the laser is turned off, the density camera is used to collect the change in the radius of the glass ball during the solidification process, and the density change of the glass in the low temperature range below the melting point is calculated to provide a basis for studying the glass forming ability; Step 4: Data analysis: Compare the test results of glasses with different ZrO2 doping amounts (0%-23% mol) to analyze the effect of ZrO2 on viscosity, surface tension, density, and the improvement or reduction of glass forming ability.

2. The method for testing thermal properties of rare earth aluminate glass melt according to claim 1, characterized in that: The method for preparing the rare earth aluminate glass in step 1 specifically comprises: S1. Weigh ZrO2 powder, Al2O3 powder and La2O3 powder according to the composition of rare earth aluminate glass and mix them to obtain a mixed powder; S2, pressing the obtained mixed powder into a glass raw material block, and then pre-burning it in a muffle furnace, and performing a melting-solidification process to obtain a rare earth aluminate glass; S21, the melting-solidification treatment specifically comprises: after the glass raw material block is stably suspended, it is heated to a molten state by laser, and then cooled to obtain the rare earth aluminate glass.

3. The method for testing thermal properties of rare earth aluminate glass melt according to claim 1, characterized in that: The suspension method is not limited to pneumatic suspension, and the preferred gas for pneumatic suspension is either oxygen or argon.

4. The method for testing thermal properties of rare earth aluminate glass melt according to claim 1, characterized in that: The laser heating uses three 60W CO2 lasers with a beam angle of 120°.

5. The method for testing thermal properties of rare earth aluminate glass melt according to claim 1, characterized in that: The infrared thermometer has a working range of 200°C-3200°C and a working wavelength of 1.95 μm-2.6 μm.

6. The method for testing thermal properties of rare earth aluminate glass melt according to claim 1, characterized in that: In step 2, the second-order oscillation is found by calculating the resonant frequency through Fourier transform.

7. The method for testing thermal properties of rare earth aluminate glass melt according to claim 1, characterized in that: In step 2, when collecting the melt oscillation decay process, the oscillation decay curve of the melt is fitted by the least square method, so as to calculate the viscosity and surface tension of the melt at the current temperature.

8. The method for testing thermal properties of rare earth aluminate glass melt according to claim 1, characterized in that: The field of view of the density camera is 1300-200 μm, the frame rate is 60-200 fps, and the resolution is 1.3 MP; the field of view of the viscosity camera is 640-750 μm, the frame rate is 1500-2500 fps, and the resolution is 0.3 MP.

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