A high-alumina phosphate glass and a method of making the same

Abstract

The application discloses a high-alumina phosphate glass and a preparation method thereof. In terms of oxides, the composition of the high-alumina phosphate glass raw material comprises P2O5 34 mol%, Al2O3 36-46 mol% and Na2O 20-30 mol%. The high-alumina phosphate glass disclosed by the application successfully prepares the transparent and uniform phosphate glass without bubbles by strictly controlling the specific content of the raw material composition, and significantly improves the hardness and elastic modulus of the phosphate glass. The nano-hardness of the prepared phosphate glass is as high as more than 5 GPa, and the elastic modulus is as high as more than 60 GPa.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of phosphate glass, and in particular to a high-aluminum phosphate glass and a preparation method thereof. BACKGROUND

[0002] Phosphate glass has been widely studied due to its low scattering and high refractive index, as well as its large capacity for containing rare earth elements, and has broad application prospects in basic scientific research, industrial production, national defense and military industry, etc. For example, in the field of optical components, rare earth-doped phosphate glass has become an important solid-state luminescent material due to its large rare earth excitation cross-section and low thermal-optical coefficient, and can be applied to the fields of lasers, broadband amplifiers, light-emitting devices, display screens, optical data storage devices and optical communication systems. Phosphate glass has the characteristic of large capacity for containing rare earth elements, and has obvious advantages over borosilicate glass, which has been industrialized and operated internationally, in terms of components of high-rare earth content nuclear waste liquid, thus having good application prospects in the field of glass solidification of high-rare earth content nuclear waste liquid. In the field of biomedicine, bioactive phosphate glass not only has good biocompatibility and bioabsorbability, but also can adjust the composition to control the dissolution rate of the glass, thereby completing directional drug delivery and achieving targeted tissue repair.

[0003] The connection between phosphorus and oxygen in phosphate glass is complex and varied. Due to the difference between P-O and P=O bonds in the network structure, the phosphorus-oxygen tetrahedral structure in the glass is unstable, and therefore the chemical stability and mechanical properties of phosphate glass are poor, which limits its application in the industrial field.

[0004] Studies have shown that increasing the content of aluminum helps to change the layered structure of phosphate glass into a framework structure, and the network structure of the glass is more compact, thereby improving the thermal stability and chemical stability of phosphate glass and enhancing the hardness and other mechanical properties of phosphate glass. However, due to the high melting point of alumina of 2050℃, the viscosity of the glass will significantly increase with the increase of the content of alumina. According to the ternary phase diagram of the P2O5-Al2O3-Na2O glass system proposed by A. Kishioka et al. after research, when the content of Al2O3 is greater than 35mol%, glass cannot be formed (A. Kishioka, M. Hayashi, M. Kinoshita, Bull. Chem. Soc. Jpn. 49 (1976) 3032-3036), and this view has been recognized and cited by many scholars.

[0005] Therefore, current scholars around the world focus on the low content of alumina in the study of the influence of alumina on the mechanical properties of phosphate glass, which is very limited for improving the mechanical properties of the glass. SUMMARY

[0006] In view of the deficiencies of the prior art, the application discloses a high-aluminum phosphate glass, by strictly controlling the specific content of raw material composition, not only transparent and uniform, bubble-free phosphate glass is successfully prepared, and the hardness and elastic modulus of the phosphate glass are significantly improved. The nano-hardness of the prepared phosphate glass is as high as 5GPa or more, and the elastic modulus is as high as 60GPa or more.

[0007] The specific technical solutions are as follows:

[0008] A high-aluminum phosphate glass, in terms of oxides, the composition of the raw material includes:

[0009] P2O5 34mol%;

[0010] Al2O3 36~46mol%;

[0011] Na2O 20~30mol%.

[0012] The high-aluminum phosphate glass disclosed by the application has an aluminum oxide content of not less than 36mol% (36-46mol%) in the raw material. Such a high content of Al2O3 theoretically leads to a very high melting temperature of the glass and a too large viscosity, which cannot be applied to actual production, and according to the ternary phase diagram of the P2O5-Al2O3-Na2O glass system, the content cannot form a glass. However, after a large number of experiments in the application, it is unexpectedly found that the raw material with the above specific content proposed in the application not only successfully prepares a transparent and uniform, bubble-free phosphate glass, but also significantly improves the hardness and elastic modulus of the phosphate glass.

[0013] In the preparation process of the phosphate glass, on the one hand, Na2O can reduce the thermal stability, chemical stability and mechanical strength of the glass, and on the other hand, too high Na2O content will make it difficult to form a glass; therefore, the content of sodium oxide is generally not too high. P2O5 as a network former of phosphate glass, if the content is too low, the network former in the glass is not enough, which leads to poor glass forming ability; therefore, the content of P2O5 is generally not too low.

[0014] The high-aluminum phosphate glass disclosed by the application has a sodium oxide content of greater than or equal to 20mol% (20-30mol%) and a phosphorus pentoxide content of less than 35mol% (34mol%). It is found through experiments that both of them are blended with high content of Al2O3 at very unconventional contents, not only successfully preparing a phosphate glass, but also unexpectedly solving the problem of too large viscosity and greatly increasing the melting temperature caused by too high content of aluminum oxide. The possible reason is that:

[0015] The raw material formula of the present application contains more Al2O3, and high content of Na2O can provide sufficient free oxygen to make a part of Al2O3 form aluminum oxygen tetrahedron, which is connected with phosphorus oxygen tetrahedron to make the glass network structure more compact; in addition, both the phosphorus oxygen tetrahedron and the aluminum oxygen tetrahedron have negative charge, and the sodium ion also plays a role of balancing the charge in the network structure; high content of Na2O, as the network outer body, can also play a role of breaking the bond in the glass network structure, which can reduce the viscosity and melting temperature of the glass and play a fluxing role. P2O5 has a large cation field strength, which is easy to accumulate in the network structure, leading to glass crystallization, therefore, the content of P2O5 in the raw material formula disclosed in the present application is controlled to be low (34 mol %), but too low content will lead to poor glass forming ability, and in the present application, a large amount of aluminum oxygen tetrahedron is connected to the glass network structure as another network former, which solves this problem, and at the same time, improves the connection degree of the network structure, and further reduces the crystallization tendency of the glass.

[0016] It can be seen that in the present application, the three raw materials with specific contents exist in mutual synergy, so that the phosphate glass is successfully prepared outside the glass forming region, and a series of problems caused by too high content of aluminum oxide are successfully solved, and the phosphate glass prepared has a nano-hardness of 5 GPa or more, and the highest can reach 5.82 GPa; the elastic modulus is 60 GPa or more, and the highest can reach 72.13 GPa.

[0017] Preferably, the composition of the raw material, in the form of oxides, comprises:

[0018] P2O5 34 mol %;

[0019] Al2O3 36-40 mol %;

[0020] Na2O 26-30 mol %;

[0021] or is:

[0022] P2O5 34 mol %;

[0023] Al2O3 44-46 mol %;

[0024] Na2O 20-22 mol %.

[0025] Further preferably, the composition of the raw material, in the form of oxides, comprises:

[0026] P2O5 34 mol %;

[0027] Al2O3 36 mol %;

[0028] Na2O 30 mol %;

[0029] or:

[0030] P2O5 34mol%;

[0031] Al2O3 46mol%;

[0032] Na2O 20mol%.

[0033] More preferably, the composition of the raw materials, in terms of oxides, comprises:

[0034] P2O5 34mol%;

[0035] Al2O3 36mol%;

[0036] Na2O 30mol%.

[0037] With the continuous optimization of the above raw material composition, the hardness and elastic modulus of the high-alumina phosphate glass prepared also continuously increase.

[0038] The application also discloses a preparation method of the high-alumina phosphate glass.

[0039] 1) The raw materials are weighed according to the mole percentage, uniformly mixed, heated and melted, and then quenched to obtain quenched glass;

[0040] 2) The quenched glass is subjected to annealing treatment to obtain the high-alumina phosphate glass.

[0041] In step 1):

[0042] The raw materials are weighed according to the mole percentage of oxides, wherein P2O5 and Na2O are introduced in the form of ammonium dihydrogen phosphate and sodium carbonate respectively.

[0043] Preferably:

[0044] The heating and melting temperature is 1600-1670℃, the temperature rising rate is 4-8℃ / min, and the holding time is 2-5h.

[0045] The quenching is specifically that the raw material liquid after heating and melting is poured on a copper plate or a graphite plate and cooled to room temperature.

[0046] Preferably:

[0047] The copper plate or the graphite plate is preheated to a temperature of 350-500℃.

[0048] In step 2):

[0049] The annealing treatment is carried out at 585-610℃ for 1-3h, and the temperature rising rate is 3-8℃ / min.

[0050] Compared with the prior art, the present application has the following beneficial effects:

[0051] The present application discloses a high-aluminum phosphate glass, which is successfully prepared to be transparent and uniform and bubble-free under the conditions of high alumina, high sodium oxide and low phosphorus pentoxide, and significantly improves the nano-hardness and elastic modulus of the phosphate glass. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 XRD pattern of the high-aluminum phosphate glass prepared for Example 1;

[0053] Figure 2 Visible light transmittance curve of the high-aluminum phosphate glass prepared for Examples 1-6, respectively; Figure 3 Nano-hardness and elastic modulus data of the high-aluminum phosphate glass prepared for Examples 1-6, respectively. DETAILED DESCRIPTION

[0054] The present application will be further described in detail below in combination with examples and comparative examples, but the embodiments of the present application are not limited thereto.

[0055] Nano-hardness: based on the nano-indentation technology, the nano-hardness of the material is obtained by using the Oliver-Pharr method. The nano-indentation technology is a micro-scale mechanical measurement technology, which has the characteristics of simple operation, high sensitivity and good repeatability, and can measure the mechanical properties of the material at the micro-nano scale.

[0056] Example 1

[0057] 1) The glass raw materials were weighed according to the molar percentage of each component: P2O5 34mol%, Al2O3 36mol%, Na2O 30mol%, wherein P2O5 and Na2O were introduced by ammonium dihydrogen phosphate and sodium carbonate, respectively, and the weighed raw materials were put into an agate mortar, mixed uniformly, and then poured into a 100mL crucible;

[0058] 2) The crucible of step 1) was placed in a high-temperature furnace, and the temperature was raised to 1600℃ at a rate of 6℃ / min, and the molten glass liquid was poured on a preheated copper plate at 350℃ and cooled to room temperature to obtain a quenched glass;

[0059] 3) The quenched glass was placed in a muffle furnace, and the temperature was raised to 585℃ at a rate of 5℃ / min and kept for 2h to obtain a high-aluminum phosphate glass, which is denoted as 36A.

[0060] Figure 1 XRD pattern of the high-aluminum phosphate glass prepared for this example, from which it can be confirmed that the sample is amorphous.

[0061] The glass sample prepared in this example is transparent and uniform, and has no bubbles. According to the visible light transmittance curve of the high-aluminum phosphate glass prepared for Examples 1-6, respectively, the visible light transmittance of the glass sample prepared in this example is 90%.Figure 2 The visible light transmittance curve shows that the highest transmittance of the high-alumina phosphate glass prepared in this embodiment is 93%.

[0062] According to Figure 3 It can be seen that the nano-hardness of the high-alumina phosphate glass prepared in this embodiment is 5.82 GPa, and the elastic modulus is 72.13 GPa.

[0063] Example 2

[0064] 1) The glass raw materials were weighed according to the molar percentage of each component: P2O5 34 mol%, Al2O3 38 mol%, Na2O 28 mol%, and the weighed raw materials were put into an agate mortar, mixed uniformly, and then poured into a 100 mL crucible;

[0065] 2) The crucible of step 1) was placed in a high-temperature furnace, and the temperature was raised to 1650°C at a rate of 6°C / min, and the molten glass liquid was poured onto a copper plate preheated to 400°C and cooled to room temperature to obtain a quenched glass;

[0066] 3) The quenched glass was placed in a muffle furnace, and the temperature was raised to 590°C at a rate of 5°C / min and kept for 2h to obtain a high-alumina phosphate glass, denoted as 38A.

[0067] The glass sample prepared in this embodiment is transparent and uniform without bubbles. According to Figure 2 The visible light transmittance curve shows that the highest transmittance of the high-alumina phosphate glass prepared in this embodiment is 92%.

[0068] According to Figure 3 It can be seen that the nano-hardness of the high-alumina phosphate glass prepared in this embodiment is 5.3 GPa, and the elastic modulus is 67.00 GPa.

[0069] Example 3

[0070] 1) The glass raw materials were weighed according to the molar percentage of each component: P2O5 34 mol%, Al2O3 40 mol%, Na2O 26 mol%, and the weighed raw materials were put into an agate mortar, mixed uniformly, and then poured into a 100 mL crucible;

[0071] 2) The crucible of step 1) was placed in a high-temperature furnace, and the temperature was raised to 1650°C at a rate of 6°C / min, and the molten glass liquid was poured onto a copper plate preheated to 450°C and cooled to room temperature to obtain a quenched glass;

[0072] 3) The quenched glass was placed in a muffle furnace, and the temperature was raised to 595°C at a rate of 5°C / min and kept for 2h to obtain a high-alumina phosphate glass, denoted as 40A.

[0073] The glass sample prepared in this embodiment is transparent and uniform without bubbles. According toFigure 2 The visible light transmittance curve shows that the highest transmittance of the high-aluminum phosphate glass prepared in this embodiment is 94%.

[0074] According to Figure 3 It can be seen that the nano-hardness of the high-aluminum phosphate glass prepared in this embodiment is 5.14 GPa, and the elastic modulus is 64.23 GPa.

[0075] Example 4

[0076] 1) The glass raw materials were weighed according to the molar percentage of each component: P2O5 34mol%, Al2O342mol%, Na2O24mol%, and the weighed raw materials were put into an agate mortar, mixed uniformly, and then poured into a 100mL crucible;

[0077] 2) The crucible of step 1) was placed in a high-temperature furnace, and the temperature was raised to 1670℃ at a rate of 6℃ / min, and the temperature was kept for 3h, and the molten glass liquid was poured on a preheated copper plate to room temperature to obtain a quenched glass;

[0078] 3) Then the quenched glass was placed in a muffle furnace, and the temperature was raised to 600℃ at a rate of 5℃ / min, and kept for 2h to obtain a high-aluminum phosphate glass, marked as 42A.

[0079] The glass sample prepared in this embodiment is transparent and uniform, and has no bubbles. According to Figure 2 The visible light transmittance curve shows that the highest transmittance of the high-aluminum phosphate glass prepared in this embodiment is 94%.

[0080] According to Figure 3 It can be seen that the nano-hardness of the high-aluminum phosphate glass prepared in this embodiment is 4.77 GPa, and the elastic modulus is 61.10 GPa.

[0081] Example 5

[0082] 1) The glass raw materials were weighed according to the molar percentage of each component: P2O5 34mol%, Al2O344mol%, Na2O22mol%, and the weighed raw materials were put into an agate mortar, mixed uniformly, and then poured into a 100mL crucible;

[0083] 2) The crucible of step 1) was placed in a high-temperature furnace, and the temperature was raised to 1670℃ at a rate of 6℃ / min, and the temperature was kept for 3h, and the molten glass liquid was poured on a preheated copper plate to room temperature to obtain a quenched glass;

[0084] 3) The quenched glass was placed in a muffle furnace, and the temperature was raised to 605℃ at a rate of 5℃ / min, and kept for 2h to obtain a high-aluminum phosphate glass, marked as 44A.

[0085] The glass sample prepared in the embodiment is transparent and uniform without bubbles. According to the visible light transmittance curve in the Figure 2 It can be seen from the visible light transmittance curve that the highest transmittance of the high-aluminum phosphate glass prepared in the embodiment is 95%.

[0086] According to the visible light transmittance curve in the Figure 3 It can be seen that the nano-hardness of the high-aluminum phosphate glass prepared in the embodiment is 5.15 GPa, and the elastic modulus is 63.93 GPa.

[0087] Example 6

[0088] 1) Glass raw materials were weighed according to the molar percentage of each component: P2O5 34mol%, Al2O3 46mol%, Na2O 20mol%, the weighed raw materials were put into an agate mortar, mixed uniformly, and then poured into a 100mL crucible;

[0089] 2) The crucible in step 1) was placed in a high-temperature furnace and heated to 1670℃ at a heating rate of 6℃ / min, and kept for 3h, and the molten glass liquid was poured onto a preheated copper plate at 500℃ and cooled to room temperature to obtain a quenched glass;

[0090] 3) Then the quenched glass was placed in a muffle furnace and heated to 610℃ at a heating rate of 5℃ / min and kept for 2h to obtain a high-aluminum phosphate glass, which is denoted as 46A.

[0091] The glass sample prepared in the embodiment is transparent and uniform without bubbles. According to the visible light transmittance curve in the Figure 2 It can be seen from the visible light transmittance curve that the highest transmittance of the high-aluminum phosphate glass prepared in the embodiment is 95%.

[0092] According to the visible light transmittance curve in the Figure 3 It can be seen that the nano-hardness of the high-aluminum phosphate glass prepared in the embodiment is 5.66 GPa, and the elastic modulus is 69.53 GPa.

[0093] Comparative Example 1

[0094] 1) Glass raw materials were weighed according to the molar percentage of each component: P2O5 34mol%, Al2O3 46mol%, Na2O 20mol%, the weighed raw materials were put into an agate mortar, mixed uniformly, and then poured into a 100mL crucible;

[0095] 2) The crucible in step 1) was placed in a high-temperature furnace and heated to 1670℃ at a heating rate of 6℃ / min, and kept for 3h, and the molten glass liquid was poured onto a preheated copper plate at 500℃ and cooled to room temperature to obtain a quenched glass;

[0096] 3) The crucible in step 2) was directly placed in distilled water for quenching, and the obtained sample was largely crystallized and was milky white.

[0097] Comparative Example 2

[0098] 1) Glass raw materials were weighed according to the molar percentage of each component: P2O5 32mol%, Al2O3 46mol%, Na2O 22mol%, wherein P2O5 and Na2O were introduced by ammonium dihydrogen phosphate and sodium carbonate, and the weighed raw materials were put into an agate mortar, mixed uniformly, and then poured into a 100mL crucible;

[0099] 2) The crucible of step 1) was placed in a high-temperature furnace and heated to 1670℃ at a heating rate of 6℃ / min, and kept for 3h. The crucible was taken out of the high-temperature furnace, wherein the raw materials were agglomerated and no melting phenomenon occurred. After quenching with distilled water, it showed a white block structure.

[0100] Comparative Example 3

[0101] 1) Glass raw materials were weighed according to the molar percentage of each component: P2O5 36mol%, Al2O3 46mol%, Na2O 18mol%, wherein P2O5 and Na2O were introduced by ammonium dihydrogen phosphate and sodium carbonate, and the weighed raw materials were put into an agate mortar, mixed uniformly, and then poured into a 100mL crucible;

[0102] 2) The crucible of step 1) was placed in a high-temperature furnace and heated to 1670℃ at a heating rate of 6℃ / min, and kept for 3h. The crucible was taken out of the high-temperature furnace, wherein the raw materials were agglomerated and no melting phenomenon occurred. After quenching with distilled water, it showed a white block structure.

[0103] The applicant declares that the present application is illustrated by the above-mentioned embodiments to explain the detailed method of the present application, but the present application is not limited to the above-mentioned detailed method.

Claims

1. A high-alumina phosphate glass, characterized in that, In oxide form, the raw material consists of: P2O5 34 mol% Al2O3 36~46 mol% Na₂O 20~30 mol%.

2. The high-alumina phosphate glass according to claim 1, characterized in that, In oxide form, the raw material consists of: P2O5 34 mol% Al2O3 36~40 mol% Na₂O 26~30 mol% Or: P2O5 34 mol% Al2O3 44~46 mol% Na₂O 20~22 mol%.

3. The high-alumina phosphate glass according to claim 1, characterized in that, In oxide form, the raw material consists of: P2O5 34 mol% Al2O3 36 mol% Na₂O 30 mol% Or: P2O5 34 mol% Al2O3 46 mol% Na₂O 20 mol%.

4. A method for preparing high-alumina phosphate glass according to any one of claims 1 to 3, characterized in that, Includes the following steps: 1) Weigh each raw material according to the molar percentage, mix them evenly, heat and melt them, and then quench them to obtain quenched glass; 2) The quenched glass is subjected to heat preservation annealing treatment to obtain the high alumina phosphate glass.

5. The method for preparing high-alumina phosphate glass according to claim 4, characterized in that, In step 1): The heating and melting temperature is 1600~1670℃, the heating rate is 4~8℃ / min, and the holding time is 2~5 h.

6. The method for preparing high-alumina phosphate glass according to claim 4, characterized in that, In step 1): The quenching process specifically involves pouring the heated and molten raw material liquid onto a copper plate or graphite plate and cooling it to room temperature.

7. The method for preparing high-alumina phosphate glass according to claim 6, characterized in that, The copper or graphite plate is preheated to a temperature of 350~500℃.

8. The method for preparing high-alumina phosphate glass according to claim 4, characterized in that, In step 2): The annealing process involves holding the temperature at 585~610℃ for 1~3 h, with a heating rate of 3~8℃ / min.

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