Luminescent ceramic for high temperature warning and preparation method thereof

Abstract

This invention discloses a luminescent ceramic for high-temperature warning and its preparation method. The chemical formula of the luminescent ceramic is Ba. 1‑x‑y Eu x Dy y Si 2‑z Ge z O5, where 0.01≤x≤0.05, 0.01≤y≤0.06, 0.2≤z≤0.5. It is obtained by grinding, drying, secondary grinding, and reduction sintering using Ba2CO3, SiO2, GeO2, Eu2O3, and Dy2O3 as raw materials. The luminescent ceramic prepared by this invention exhibits only weak light at low temperatures of 60℃ and below, but its brightness significantly increases as the temperature rises to the range of 60–120℃, thus achieving a warning function within a specific temperature range. It also exhibits good weather resistance; after continuous cycling at temperatures from room temperature to 180℃ for 2160 hours in a high and low temperature cycling test chamber, its brightness still retains more than 90% of its original brightness.

Description

Technical Field

[0001] This invention relates to the field of luminescent ceramic preparation technology, specifically to a luminescent ceramic for high-temperature warning and its preparation method. Background Technology

[0002] High-temperature warning signs for ordinary instruments and equipment mainly use high-temperature warning paint. These high-temperature warning paints have a relatively high VOC content, which can easily cause environmental pollution; in addition, these high-temperature warning paints have poor weather resistance, which can cause serious corrosion to instruments and equipment under high temperatures, and the service life of these paints is also relatively short.

[0003] High-temperature warning luminescent ceramics are mainly used on the outer surfaces of instruments and equipment that require long-term production operations at high temperatures. These ceramics can change their luminescence from dim to bright within a certain temperature range, thus achieving a warning effect within that specific temperature range. Compared to traditional high-temperature warning coatings, high-temperature warning luminescent ceramics do not contain VOCs, will not corrode instruments and equipment, and have excellent weather resistance, significantly extending their service life. However, there are currently no reports on luminescent ceramics suitable for high-temperature warning applications. Summary of the Invention

[0004] The purpose of this invention is to provide a luminescent ceramic for high-temperature warning.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned luminescent ceramic for high temperature warning.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] On one hand, the present invention provides a luminescent ceramic for high-temperature warning, the chemical formula of which is

[0008] Ba 1-x-y Eu x Dy y Si 2-z Ge z O5,

[0009] Where 0.01≤x≤0.05, 0.01≤y≤0.06, and 0.2≤z≤0.5.

[0010] On the other hand, the present invention also provides a method for preparing the above-mentioned luminescent ceramic for high-temperature warning, comprising the following steps:

[0011] (1) Weighing: according to Ba 1-x-y Eu x Dy y Si 2-z Ge zThe stoichiometric ratios of each element in O5, 0.01≤x≤0.05, 0.01≤y≤0.06, 0.2≤z≤0.5 are respectively measured using Ba2CO3, SiO2, GeO2, Eu2O3 and Dy2O3 with a purity greater than 99.99% as raw materials;

[0012] (2) Grinding: Place the weighed raw material powder in an agate mortar, and add sintering aid and anhydrous ethanol at the same time to grind and mix, so that the powder is fine and mixed evenly.

[0013] (3) Drying: Dry the ground slurry;

[0014] (4) Secondary grinding: The dried mixed powder and the curing agent are ground and mixed evenly in a secondary grinding process;

[0015] (5) Sintering: The mixture after secondary grinding is placed in an alumina crucible and placed in a vacuum atmosphere furnace and kept at a reducing atmosphere of 1200-1500℃ for 8-12 hours. Then it is cooled to room temperature with the furnace to obtain the luminescent ceramic.

[0016] Preferably, in step (2), the sintering aids are NH4Cl and H3BO3, wherein the amount of NH4Cl added is 2-5% of the total mass of the reaction raw materials, and the amount of H3BO3 added is 2-10% of the total mass of the reaction raw materials.

[0017] Preferably, in step (2), the mass ratio of the raw material powder to anhydrous ethanol is 1:(0.5-1.0).

[0018] Preferably, in step (2), the grinding and mixing time is 30 to 60 minutes.

[0019] Preferably, in step (3), the drying temperature is 50-80°C and the drying time is 24-36 hours.

[0020] Preferably, in step (4), the curing agent is glass powder, and the amount of curing agent added is 10-20% of the total mass of the reaction raw materials.

[0021] Preferably, in step (4), the grinding and mixing time is 20 to 30 minutes.

[0022] Preferably, in step (5), the heating rate during sintering is 3 to 5 °C / min.

[0023] Preferably, in step (5), the reducing atmosphere is a mixture of 5 vol% H2 and 95 vol% N2.

[0024] This invention prepares the luminescent ceramic using a high-temperature solid-state method. When irradiated by an external light source during the day, the luminescent ceramic stores the energy gained in defects within the matrix lattice. Due to the deep traps in this ceramic material, the charge carriers inside the traps are difficult to release at room temperature, resulting in weak luminescence. However, as the temperature increases, the release rate of charge carriers inside the traps accelerates, and the ceramic brightness significantly increases. Therefore, it can serve as a warning within a specific temperature range.

[0025] Compared with the prior art, the present invention has the following beneficial effects.

[0026] 1. The luminescent ceramic prepared by this invention only exhibits weak light at low temperatures of 60°C and below, but the brightness of the ceramic will be significantly enhanced as the temperature rises to the range of 60-120°C, thereby achieving the function of warning within a specific temperature range.

[0027] 2. The luminescent ceramic prepared by this invention has good weather resistance. On the one hand, it effectively avoids the corrosion of instruments and equipment by traditional high temperature warning coatings. On the other hand, after being continuously cycled in a high and low temperature cycling test chamber at temperatures ranging from room temperature to 180°C for 2160 hours, its brightness can still maintain more than 90% of the original brightness. Attached Figure Description

[0028] Figure 1 The XRD patterns of the luminescent ceramics prepared in Examples 1-4 of this invention are shown below.

[0029] Figure 2 Luminescent ceramics were prepared in Example 1 of this invention at different temperatures: (a) 30℃ and (b) 60℃.

[0030] (c) Actual photos of 90℃, (d) 120℃, (e) 150℃, and (f) 180℃;

[0031] Figure 3 This is a comparison chart of the brightness of the luminescent ceramic prepared in Example 1 of the present invention before and after high and low temperature cycling tests, measured at different temperatures. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0033] Example 1: Ba 0.94 Eu 0.03 Dy 0.03 Si 1.6 Ge 0.4 O5

[0034] (1) Weighing: according to Ba 0.94 Eu 0.03 Dy 0.03 Si 1.6 Ge0.4 The stoichiometric ratio of each element in O5 was determined by weighing Ba2CO3, SiO2, GeO2, Eu2O3 and Dy2O3 with a purity greater than 99.99% as raw materials.

[0035] (2) Grinding: Place the weighed 60g of raw material powder in an agate mortar, and add 2.4g of NH4Cl, 3.0g of H3BO3 and 50g of anhydrous ethanol. Grind and mix for 40min to refine the powder and mix it evenly.

[0036] (3) Drying: Place the ground slurry in a slurry cup and dry it in an 80℃ electric constant temperature drying oven for 24 hours;

[0037] (4) Secondary grinding: Place the dried mixed powder and 10g of glass powder in an agate mortar and grind for 30 minutes to make them evenly mixed;

[0038] (5) Sintering: The ground mixture is placed in a square alumina crucible and placed in a vacuum atmosphere furnace and kept at 1300℃ in a reducing atmosphere of 5% H2 + 95% N2 for 9 hours. Then it is cooled to room temperature with the furnace to obtain the luminescent ceramic.

[0039] The XRD pattern of the luminescent ceramic prepared in this embodiment is shown below. Figure 1 As shown, the luminescent ceramic is a pure phase.

[0040] Figure 2 The images show actual photos of the luminescent ceramic prepared in Example 1 of this invention at different temperatures: (a) 30℃, (b) 60℃, (c) 90℃, (d) 120℃, (e) 150℃, and (f) 180℃. As can be seen from the images, the brightness of the ceramic sample in the temperature range of 60 to 120℃ is significantly higher than that in the temperature range below 60℃ or above 120℃, thus serving as a warning within a specific temperature range.

[0041] Figure 3 This is a comparison chart of the brightness of the luminescent ceramic prepared in Example 1 of the present invention before and after high and low temperature cycling tests, measured at different temperatures. The chart shows that the ceramic sample exhibits high brightness, reaching 12 cd / m², within a temperature range of 60–120°C. 2 However, when the temperature is below 60℃ or above 120℃, the ceramic has very low brightness, less than 2 cd / m². 2 the following.

[0042] Example 2: Ba 0.98 Eu 0.01 Dy 0.01 Si 1.8 Ge 0.2 O5

[0043] (1) Weighing: according to Ba0.98 Eu 0.01 Dy 0.01 Si 1.8 Ge 0.2 The stoichiometric ratio of each element in O5 was determined by weighing Ba2CO3, SiO2, GeO2, Eu2O3 and Dy2O3 with a purity greater than 99.99% as raw materials.

[0044] (2) Grinding: Place the weighed 60g of raw material powder in an agate mortar, and add 1.2g of NH4Cl, 1.2g of H3BO3 and 30g of anhydrous ethanol. Grind and mix for 30min to refine the powder and mix it evenly.

[0045] (3) Drying: Place the ground slurry in a slurry cup and dry it in a 50℃ electric constant temperature drying oven for 36 hours;

[0046] (4) Secondary grinding: Place the dried mixed powder and 6g of glass powder in an agate mortar and grind for 30 minutes to make them evenly mixed;

[0047] (5) Sintering: The ground mixture is placed in a square alumina crucible and placed in a vacuum atmosphere furnace and kept at 1200℃ in a reducing atmosphere of 5% H2 + 95% N2 for 8 hours. Then it is cooled to room temperature with the furnace to obtain the luminescent ceramic.

[0048] The XRD pattern of the luminescent ceramic prepared in this embodiment is shown below. Figure 1 As shown, the luminescent ceramic is a pure phase.

[0049] The actual images of the luminescent ceramic prepared in this embodiment at different temperatures (a) 30℃ (b) 60℃ (c) 90℃ (d) 120℃ (e) 150℃ (f) 180℃, and the brightness comparison images measured at different temperatures before and after high and low temperature cycling tests, are similar to those in Example 1.

[0050] Example 3: Ba 0.94 Eu 0.02 Dy 0.04 Si 1.7 Ge 0.3 O5

[0051] (1) Weighing: according to Ba 0.94 Eu 0.02 Dy 0.04 Si 1.7 Ge 0.3 The stoichiometric ratio of each element in O5 was determined by weighing Ba2CO3, SiO2, GeO2, Eu2O3 and Dy2O3 with a purity greater than 99.99% as raw materials.

[0052] (2) Grinding: Place the weighed 60g of raw material powder in an agate mortar, and add 1.8g of NH4Cl, 4.8g of H3BO3 and 40g of anhydrous ethanol. Grind and mix for 50min to refine the powder and mix it evenly.

[0053] (3) Drying: Place the ground slurry in a slurry cup and dry it in a 60℃ electric constant temperature drying oven for 32 hours;

[0054] (4) Secondary grinding: Place the dried mixed powder and 12g of glass powder in an agate mortar and grind for 20 minutes to make them evenly mixed;

[0055] (5) Sintering: The ground mixture is placed in a square alumina crucible and placed in a vacuum atmosphere furnace and kept at 1400℃ in a reducing atmosphere of 5% H2 + 95% N2 for 11 hours. Then it is cooled to room temperature with the furnace to obtain the luminescent ceramic.

[0056] The XRD pattern of the luminescent ceramic prepared in this embodiment is shown below. Figure 1 As shown, the luminescent ceramic is a pure phase.

[0057] The actual images of the luminescent ceramic prepared in this embodiment at different temperatures (a) 30℃ (b) 60℃ (c) 90℃ (d) 120℃ (e) 150℃ (f) 180℃, and the brightness comparison images measured at different temperatures before and after high and low temperature cycling tests, are similar to those in Example 1.

[0058] Example 4: Ba 0.89 Eu 0.05 Dy 0.06 Si 1.5 Ge 0.5 O5

[0059] (1) Weighing: according to Ba 0.89 Eu 0.05 Dy 0.06 Si 1.5 Ge 0.5 The stoichiometric ratio of each element in O5 was determined by weighing Ba2CO3, SiO2, GeO2, Eu2O3 and Dy2O3 with a purity greater than 99.99% as raw materials.

[0060] (2) Grinding: Place the weighed 60g of raw material powder in an agate mortar, and add 3.0g of NH4Cl, 6.0g of H3BO3 and 60g of anhydrous ethanol. Grind and mix for 60min to refine the powder and mix it evenly.

[0061] (3) Drying: Place the ground slurry in a slurry cup and dry it in a 70℃ electric constant temperature drying oven for 28 hours;

[0062] (4) Secondary grinding: Place the dried mixed powder and 12g of glass powder in an agate mortar and grind for 20 minutes to make them evenly mixed;

[0063] (5) Sintering: The ground mixture is placed in a square alumina crucible and placed in a vacuum atmosphere furnace and kept at 1500℃ in a reducing atmosphere of 5% H2 + 95N2 for 12 hours. Then it is cooled to room temperature with the furnace to obtain the luminescent ceramic.

[0064] The XRD pattern of the luminescent ceramic prepared in this embodiment is shown below. Figure 1 As shown, the luminescent ceramic is a pure phase.

[0065] The actual images of the luminescent ceramic prepared in this embodiment at different temperatures (a) 30℃ (b) 60℃ (c) 90℃ (d) 120℃ (e) 150℃ (f) 180℃, and the brightness comparison images measured at different temperatures before and after high and low temperature cycling tests, are similar to those in Example 1.

[0066] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A luminescent ceramic for high-temperature warning, characterized in that, The chemical formula of the luminescent ceramic is Ba. 1-x- y Eu x Dy y Si 2-z Ge z O5, where 0.01 ≤ x ≤ 0.05, 0.01 ≤ y ≤ 0.06, 0.2 ≤ z ≤ 0.5; the luminescent ceramic is prepared by the following steps: (1) Weighing: according to Ba 1-x-y Eu x Dy y Si 2-z Ge z The stoichiometric ratios of each element in O5, 0.01≤x≤0.05, 0.01≤y≤0.06, 0.2≤z≤0.5 are respectively weighed as raw materials with a purity greater than 99.99%; (2) Grinding: Place the weighed raw material powder in an agate mortar, and add sintering aid and anhydrous ethanol at the same time to grind and mix, so that the powder is fine and mixed evenly. (3) Drying: Dry the ground slurry; (4) Secondary grinding: The dried mixed powder and the curing agent are ground and mixed evenly in a secondary grinding process. The curing agent is glass powder. (5) Sintering: The mixture after secondary grinding is placed in an alumina crucible and placed in a vacuum atmosphere furnace and kept at a reducing atmosphere of 1200~1500℃ for 8~12h. Then it is cooled to room temperature with the furnace to obtain the luminescent ceramic.

2. The luminescent ceramic for high-temperature warning according to claim 1, characterized in that, In step (2), the sintering aids are NH4Cl and H3BO3. The amount of NH4Cl added is 2-5% of the total mass of the reaction raw materials, and the amount of H3BO3 added is 2-10% of the total mass of the reaction raw materials.

3. The luminescent ceramic for high-temperature warning according to claim 1, characterized in that, In step (2), the mass ratio of the raw material powder to anhydrous ethanol is 1:(0.5~1.0).

4. The luminescent ceramic for high-temperature warning according to claim 1, characterized in that, In step (2), the grinding and mixing time is 30~60 min.

5. The luminescent ceramic for high-temperature warning according to claim 1, characterized in that, In step (3), the drying temperature is 50~80℃ and the drying time is 24~36h.

6. The luminescent ceramic for high-temperature warning according to claim 1, characterized in that, In step (4), the amount of curing agent added is 10-20% of the total mass of the reaction raw materials.

7. The luminescent ceramic for high-temperature warning according to claim 1, characterized in that, In step (4), the grinding and mixing time is 20~30 min.

8. The luminescent ceramic for high-temperature warning according to claim 1, characterized in that, In step (5), the heating rate during sintering is 3~5℃ / min.

9. The luminescent ceramic for high-temperature warning according to claim 1, characterized in that, In step (5), the reducing atmosphere is a mixture of 5 vol% H2 and 95 vol% N2.

Images