CN111606710A - Wear-resistant high-purity rare earth gadolinium oxide ceramic ball for preparing gadolinium-containing compound and preparation and use methods thereof - Google Patents
Wear-resistant high-purity rare earth gadolinium oxide ceramic ball for preparing gadolinium-containing compound and preparation and use methods thereof Download PDFInfo
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Abstract
The invention belongs to the field of new materials, and particularly relates to a wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing a gadolinium compound, and a preparation method and a use method thereof. The gadolinium oxide ceramic ball is prepared by the steps of material preparation, blank making, cold forming and the like, primary rounding, pre-sintering, secondary rounding, secondary sintering, screening and the like. The gadolinium oxide ceramic ball provided by the invention has high purity and good wear resistance, and can be used as a ball milling medium for preparing gadolinium-containing compounds. The gadolinium-containing compound prepared by using the gadolinium oxide ceramic ball provided by the invention as a ball milling medium has high purity and outstanding photoelectric properties. In addition, the invention also provides a preparation method of the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing the gadolinium compound; the method is simple in process and suitable for batch production, and the prepared gadolinium oxide spheres are adjustable in size, good in stability and high in yield.
Description
Technical Field
The invention belongs to the field of new materials, and particularly relates to a wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing a gadolinium compound, and a preparation method and a use method thereof.
Background
The rare earth elements have special magnetic, optical and electric properties, and play an important role in the fields of national defense, supersonic weapons and aerospace. In particular, gadolinium has a very high atomic number (64) and a large absorption cross section of high-energy radiation, and compounds composed of gadolinium are widely used in fluorescent materials, single crystal materials, optical glasses, magnetic bubbles, electronic industry, manufacturing capacitors, x-ray intensifying screens, and the like. Film materials such as gadolinium oxysulfide powder are widely used for chest X-ray DR; the lutetium-gadolinium solid solution transparent ceramic and the gadolinium-gallium multicomponent garnet scintillation ceramic are key elements in a medical CT detector; the gadolinium-iron garnet crystal is a core material in the fields of optical fiber communication and magneto-optical switches. These compounds are typically mixed together by gadolinium oxide and other anionic compounds, with heating or pressure to form another compound. In the mixing process, the mixed media mainly comprise materials such as alumina, zirconia, agate and the like, and the mixed media and the raw materials are repeatedly rubbed and impacted, so that certain impurities are introduced into the raw materials, and the photoelectric properties of the materials are seriously influenced. In the field of photoelectric materials, trace impurities can introduce defect energy levels and light absorption centers into the materials, thereby having a fatal influence on photoelectric properties.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing a gadolinium compound. According to the invention, the wear-resistant high-purity rare earth gadolinium oxide ceramic ball with high strength and large size is prepared by combining a cold isostatic pressing technology and a high-temperature calcination process, and the prepared gadolinium oxide ceramic ball is used for replacing mixed media such as alumina, agate and zirconia used in the process of preparing a gadolinium-containing compound, so that the problem of pollution of the mixed media to raw materials is effectively solved, and the photoelectric property of the prepared gadolinium-containing compound is remarkably improved.
In order to achieve the purpose, the invention is realized by the following technical scheme: a preparation method for preparing wear-resistant high-purity rare earth gadolinium oxide ceramic balls containing gadolinium compounds comprises the following steps:
(S1) batching: putting commercial high-purity gadolinium oxide into an oven for drying, and weighing the required commercial high-purity gadolinium oxide according to the size of gadolinium oxide spheres;
(S2) blank making: preparing the dried commercial high-purity gadolinium oxide into a spherical blank;
(S3) cold-forming: pressing and molding the spherical blank by using a cold isostatic press;
(S4) primary rounding: placing the cold-formed blank on sand paper for rounding;
(S5) burn-in: laying a layer of gadolinium oxide powder at the bottom of the crucible, placing the rounded blank, covering a layer of gadolinium oxide powder, and stacking the rounded blank in the crucible in a manner of one layer of blank and one layer of gadolinium oxide powder; then placing the crucible in a muffle furnace, and heating to 1200 ℃ for pre-sintering; cooling to room temperature;
(S6) secondary rounding: rolling the pre-sintered ball on sand paper for the second time;
(S7) secondary sintering: vacuum sintering the spheres subjected to the secondary rounding by using a high-temperature carbon tube furnace, wherein the sintering pressure is less than or equal to 20Pa, and the sintering temperature is 1500-1900 ℃;
(S8) screening: and removing the defective products with irregular shapes to obtain the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing the gadolinium compound.
Further, in the above preparation method for preparing the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing gadolinium compound, in the step (S3), the pressure of the cold isostatic press is set to be 30-300Mpa, and the pressure maintaining time is 1-30 min;
preferably, in the above preparation method for preparing the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing gadolinium compound, in the step (S4), the specification of the selected sand paper is 500-.
Preferably, in the above preparation method for preparing the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing a gadolinium compound, in the step (S5), the temperature control program of the muffle furnace is set as follows: from room temperature, heating to 300 ℃ at a speed of 1-5 ℃/min, and keeping the temperature for 10min-120min, heating to 600 ℃ at a speed of 2-6 ℃/min, and keeping the temperature for 10min-60min, and heating to 1200 ℃ at a speed of 5-8 ℃/min, and keeping the temperature for 60min-240 min; cooling to 300 deg.C at 1-2 deg.C/min, and naturally cooling to room temperature.
Further, the above preparation method for preparing the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing gadolinium compound comprises the following steps (S7): placing the sphere subjected to secondary rounding in a boron nitride crucible, covering a cover, placing the crucible in a high-temperature carbon tube furnace, arranging a graphite cushion block below the crucible, adjusting the height to enable the central position of the crucible to be located at the measuring position of a thermocouple, covering the furnace cover, and screwing nuts on the periphery; starting process cooling water, starting a mechanical pump to reduce the pressure to be within 20Pa, starting a diffusion pump, preheating for 40min, then starting a vacuum switch, heating, raising the temperature to 1200 ℃ at 10 ℃/min, raising the temperature to 1900 ℃ at 1-5 ℃/min, and preserving the temperature for 120-480 min; cooling to room temperature at the speed of 2 ℃/min.
Preferably, the preparation method for preparing the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing the gadolinium compound comprises the following steps:
(S1) batching: putting commercial high-purity gadolinium oxide into an open container, then putting the container into an oven for drying, and heating the container to 30-200 ℃ at a speed of 1-5 ℃/min from room temperature and preserving heat for 2-10 h; weighing the dried commercial high-purity gadolinium oxide according to the size of the gadolinium oxide spheres, wherein the amount of the dried commercial high-purity gadolinium oxide can be increased by 2% due to loss in the material preparation and the subsequent steps;
(S2) blank making: assembling a plastic funnel with the diameter of 3mm-10mm and a plastic bag together, filling the weighed gadolinium oxide into the funnel by using a medicine spoon, then pressing down the gadolinium oxide to the bottom of the plastic bag by using a carbon fiber rod, compacting the powder and then knotting to obtain a blank; repeating the charging steps to obtain a plurality of blanks; one plastic bag contains 2-6 blanks;
(S3) cold-forming: placing the plastic bag containing the blank prepared in the step (S2) in a steel hollow mold, then placing the plastic bag in a cavity of a cold isostatic press, covering an upper cover, boosting the pressure to 30-300MPa at 1-10MPa/min, maintaining the pressure for 1-30min, naturally releasing the pressure, opening the upper cover of the cold isostatic press, taking out the plastic bag, drying the water stain on the outer surface of the plastic bag by using a blower, and then peeling the plastic bag;
(S4) primary rounding: placing the cold-formed blank on sand paper for rounding; the specification of the selected sand paper is 500-;
(S5) burn-in: laying a layer of gadolinium oxide powder at the bottom of the crucible, placing the rounded blank, covering a layer of gadolinium oxide powder, and stacking the rounded blank in the crucible in a manner of one layer of blank and one layer of gadolinium oxide powder; then the crucible is arranged in a muffle furnace, and the temperature control program of the muffle furnace is set as follows: from room temperature, heating to 300 ℃ at a speed of 1-5 ℃/min, and keeping the temperature for 10min-120min, heating to 600 ℃ at a speed of 2-6 ℃/min, and keeping the temperature for 10min-60min, and heating to 1200 ℃ at a speed of 5-8 ℃/min, and keeping the temperature for 60min-240 min; cooling to 300 ℃ at a speed of 1-2 ℃/min and then naturally cooling to room temperature;
(S6) secondary rounding: rounding the pre-burned ball body on sand paper for the second time, and polishing off corners and particles adhered to the surface;
(S7) secondary sintering: placing the sphere subjected to secondary rounding in a boron nitride crucible, covering a cover, placing the crucible in a high-temperature carbon tube furnace, arranging a graphite cushion block below the crucible, adjusting the height to enable the central position of the crucible to be located at the measuring position of a thermocouple, covering the furnace cover, and screwing nuts on the periphery; starting process cooling water, starting a mechanical pump to reduce the pressure to be within 20Pa, starting a diffusion pump, preheating for 40min, then starting a vacuum switch, heating, raising the temperature to 1200 ℃ at 10 ℃/min, raising the temperature to 1900 ℃ at 1-5 ℃/min, and preserving the temperature for 120-480 min; cooling to room temperature at the speed of 2 ℃/min;
(S8) screening: randomly selecting 6 diameters in different directions, measuring by using a vernier caliper, dividing the value obtained by subtracting the minimum value from the maximum value by the average value to define uniformity, and removing defective products with the uniformity of more than 8% to obtain the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing the gadolinium compound.
Further, the use method of the wear-resistant high-purity rare earth gadolinium oxide ceramic ball for preparing the gadolinium-containing compound is used for preparing the gadolinium-containing compoundThe wear-resistant high-purity rare earth gadolinium oxide ceramic balls used for preparing gadolinium-containing compounds are used as ball milling media, and the mixed materials are mixed. According to the method, the gadolinium oxide ceramic balls are used as ball milling media, no other impurities are introduced into the mixed material except gadolinium oxide in the mixing process, and gadolinium oxide is one of raw materials for preparing a gadolinium-containing compound, so that trace impurities in the prepared gadolinium-containing compound can be effectively reduced. In addition, the method has wide applicability, and is suitable for preparing various gadolinium-containing compounds, including but not limited to (AGd)2O3、Gd2O2S、Gd3(GaAl)5O12、Gd3Fe5O12、GdF3And the like, wherein A is selected from Y, Lu, Tb, Pr, Ce, Y, Sc, La and the like.
Preferably, in the using method for preparing the wear-resistant high-purity rare earth gadolinium oxide ceramic balls containing gadolinium compounds, the mass ratio of the gadolinium oxide balls to the mixed materials is 3-1:1, the mixing speed is 60-240r/min, and the mixing time is 6-20 h.
Preferably, in the above method for preparing wear-resistant high-purity rare earth gadolinium oxide ceramic balls containing gadolinium compounds, the mixture comprises gadolinium oxide and raw materials capable of forming compounds with gadolinium elements, wherein the raw materials capable of forming compounds with gadolinium elements include but are not limited to europium oxide, lutetium oxide, yttrium oxide, scandium oxide, lanthanum oxide, iron oxide, aluminum oxide and gallium oxide.
Has the advantages that: compared with the prior art, the wear-resistant high-purity rare earth gadolinium oxide ceramic ball for preparing the gadolinium-containing compound provided by the invention has high purity and good wear resistance, and can be used as a ball-milling medium for preparing the gadolinium-containing compound. The gadolinium-containing compound prepared by using the gadolinium oxide ceramic ball provided by the invention as a ball milling medium has high purity and outstanding photoelectric properties. In addition, the invention also provides a preparation method of the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing the gadolinium compound; the method is simple in process and suitable for batch production, and the prepared gadolinium oxide spherical particles are adjustable in diameter, good in stability and high in yield.
Drawings
FIG. 1 is a pictorial view of sample 1;
FIG. 2 is a pictorial view of sample 2;
FIG. 3 is a graph of relative light output measurements for sample 1;
FIG. 4 is a graph of relative light output measurements for sample 2;
FIG. 5 is a graph showing the results of afterglow performance tests of samples 3 and 4.
Detailed Description
The invention will be further illustrated by the following specific examples, which are given for the purpose of illustration only and are not intended to be limiting.
Example 1
A wear-resistant high-purity rare earth gadolinium oxide ceramic ball for preparing a gadolinium-containing compound is prepared by the following steps:
(S1) batching: weighing 500g of gadolinium oxide with the purity of 99.999 percent, placing the gadolinium oxide in a tray, and drying the whole in an oven for 6 hours at the temperature of 150 ℃; according to the mass m of the ball, which is rho multiplied by 4/3 pi r 3, 13.07g of gadolinium oxide raw material is needed for the ball with the diameter of 1.5cm, and 13.07 multiplied by 1.02 which is actually weighed is 13.33g, and 20 parts are weighed for standby.
(S2) blank making: the method comprises the steps of assembling a 10mm plastic funnel and a plastic bag together, gradually adding weighed raw materials into the funnel by using a medicine spoon, filling the raw materials to the bottommost part by using a carbon fiber rod to form a round drum shape, tying and screwing a knot on the round drum shape, finishing the preparation of a first green body ball, and preparing 5 green body balls in the strip-shaped plastic bag in the same step, wherein four green body balls are prepared in total.
(S3) cold-forming: the four plastic ball bags are respectively arranged on 1-3 layers of the steel hollow mould, can not be mutually extruded and are laid in parallel. Supplementing the liquid level in the cavity of the cold isostatic press to the highest liquid level and completely submerging the steel hollow mold, covering the upper cover of the cold isostatic press, boosting the pressure to 250MPa at 5MPa/min, maintaining the pressure for 3min, opening the upper cover of the cold isostatic press after naturally relieving the pressure, wearing rubber gloves, taking out the plastic bag, putting the plastic bag integrally in a basin for dewatering for 10min, removing water stains on the outer surface of the plastic bag one by one, blowing the plastic bag open by using a blower, and peeling the cold ball and the plastic film.
(S4) primary rounding: due to the extrusion effect of cold isostatic pressing, powder is extruded at the knotting gap of the spherical blank and the plastic bag to form a certain shape, the powder needs to be disposed, 1000# abrasive paper is selected, the upper and lower convex parts of the ball are rubbed off and trimmed into an arc shape, and the smooth surface is ensured in the process.
(S5) burn-in: cleaning and drying an alumina crucible with the diameter of 5cm, laying a layer of gadolinium oxide powder at the bottom, placing a flat gadolinium oxide ball on the flat gadolinium oxide ball, then continuously laying a layer of gadolinium oxide powder on the flat gadolinium oxide ball, continuously placing gadolinium oxide balls on the flat gadolinium oxide ball, namely stacking the gadolinium oxide powder layer by layer in sequence, covering an alumina crucible cover after the flat gadolinium oxide ball is placed, integrally moving the alumina crucible cover into a muffle furnace, heating to 300 ℃ at the speed of 2 ℃/min, keeping the temperature for 90min, heating to 600 ℃ at the speed of 4 ℃/min, keeping the temperature for 60min, heating to 1200 ℃ at the speed of 5 ℃/min, keeping the temperature for 120min, cooling to 300 ℃ at the speed of 2 ℃/min after the heat preservation.
(S6) secondary rounding: and opening an alumina crucible cover, separating the gadolinium oxide powder from the gadolinium oxide spheres, polishing and removing the powder adhered to the upper surfaces of the gadolinium oxide spheres by using sand paper, and picking out the gadolinium oxide pre-sintered spheres with obvious deformation.
(S7) secondary sintering: placing the secondary rounded ball in a boron nitride crucible with the diameter of 9cm, covering a cover, integrally placing the secondary rounded ball on a graphite cushion block, adjusting the height to enable the center position of the crucible to be located at the measuring position of a thermocouple, covering the furnace cover, and screwing the peripheral nuts. Starting process cooling water, starting a mechanical pump, slowly opening a valve of the mechanical pump until the maximum amplitude is reached, starting a diffusion pump after pumping to be within 20Pa, preheating for 40min, starting a vacuum switch, then starting heating, heating to 1200 ℃ at the speed of 10 ℃/min, and keeping the temperature for 180min at the speed of 3 ℃/min to 1650 ℃. Cooling to room temperature at the speed of 2 ℃/min.
(S8) screening: the uniformity values of the prepared ceramic balls are defined as: d is (Dmax-Dmin)/Dave. Opening the furnace door, taking out a sample, randomly selecting 6 diameters in different directions for each ceramic ball, measuring by using a vernier caliper, and then calculating the uniformity value of the ball, wherein the value within 8% is a qualified product.
Example 2
A wear-resistant high-purity rare earth gadolinium oxide ceramic ball for preparing a gadolinium-containing compound is prepared by the following steps:
(S1) batching: weighing 300g of gadolinium oxide with the purity of 99.999 percent, putting the gadolinium oxide in a tray, and drying the whole in an oven for 10 hours at the temperature of 200 ℃; according to the mass m of the ball, which is rho multiplied by 4/3 pi r 3, the ball with the diameter of 1cm needs 3.94g (2% excess) of raw gadolinium oxide, and 60 parts are weighed for standby.
(S2) blank making: the method comprises the steps of assembling an 8mm plastic funnel and a plastic bag together, gradually adding weighed raw materials into the funnel by using a medicinal peony root, filling the raw materials to the bottommost part by using a carbon fiber rod to form a round drum shape, tying and screwing a knot on the round drum shape, finishing the preparation of a first green body ball, and preparing 5 green body balls in a strip-shaped plastic bag in the same step. A total of 12 strips were prepared.
(S3) cold-forming: the 12 plastic ball bags are respectively placed on 1-3 layers of the steel hollow mould, can not be mutually extruded and are laid in parallel. Supplementing the liquid level in the cavity of the cold isostatic press to the highest liquid level and completely submerging the steel hollow mold, covering the upper cover of the cold isostatic press, boosting the pressure to 300MPa at 8MPa/min, maintaining the pressure for 6min, opening the upper cover of the cold isostatic press after naturally relieving the pressure, wearing rubber gloves, taking out the plastic bag, putting the plastic bag integrally in a basin for dewatering for 20min, removing water stains on the outer surface of the plastic bag one by one, blowing the plastic bag open by using a blower, and peeling the cold ball and the plastic film.
(S4) primary rounding: due to the extrusion effect of cold isostatic pressing, powder is extruded at the knotting gap of the spherical blank and the plastic bag to form a certain shape, the powder needs to be disposed, 800# abrasive paper is selected, the upper and lower protruding parts of the ball are rubbed off and trimmed into an arc shape, and the smooth trimming surface is ensured in the process.
(S5) burn-in: cleaning and drying an alumina crucible with the diameter of 10cm, laying a layer of gadolinium oxide powder at the bottom, placing a flat gadolinium oxide ball on the flat gadolinium oxide ball, then continuously laying a layer of gadolinium oxide powder on the flat gadolinium oxide ball, continuously placing gadolinium oxide balls on the flat gadolinium oxide ball, namely stacking the gadolinium oxide ball layer by layer and the gadolinium oxide powder layer in sequence, covering an alumina crucible cover after the flat gadolinium oxide ball is placed, integrally moving the alumina crucible cover into a muffle furnace, heating to 300 ℃ at 3 ℃/min, keeping the temperature for 120min, heating to 800 ℃ at 4 ℃/min, keeping the temperature for 90min, heating to 1200 ℃ at 5 ℃/min, keeping the temperature for 120min, cooling to 300 ℃ at 1 ℃/min after the heat preservation is finished, and then naturally.
(S6) secondary rounding: and opening an alumina crucible cover, separating the gadolinium oxide powder from the gadolinium oxide spheres, polishing and removing the powder adhered to the upper surfaces of the gadolinium oxide spheres by using sand paper, and picking out the gadolinium oxide pre-sintered spheres with obvious deformation.
(S7) secondary sintering: placing the secondary rounded ball in a boron nitride crucible with the diameter of 10cm, covering a cover, integrally placing the secondary rounded ball on a graphite cushion block, adjusting the height to enable the center position of the crucible to be located at the measuring position of a thermocouple, covering the furnace cover, and screwing the peripheral nuts. Starting process cooling water, starting a mechanical pump, slowly opening a valve of the mechanical pump until the maximum amplitude is reached, starting a diffusion pump after pumping to be within 20Pa, preheating for 40min, starting a vacuum switch, then starting heating, heating to 1200 ℃ at the speed of 10 ℃/min, and keeping the temperature for 380min at the temperature of 1650 ℃ at the speed of 5 ℃/min. Cooling to room temperature at the speed of 2 ℃/min.
(S8) screening: the uniformity values of the prepared ceramic balls are defined as: d is (Dmax-Dmin)/Dave. Opening the furnace door, taking out a sample, randomly selecting 6 diameters in different directions for each ceramic ball, measuring by using a vernier caliper, and then calculating the uniformity value of the ball, wherein the value within 8% is a qualified product.
Performance testing
20 gadolinium oxide ceramic balls prepared in example 1 were washed twice with ethanol and dried, the weighed weight was 261.202g, the balls were placed in a clean ball mill, 120mL of ethanol was added, ball milling was performed at 120r/min for 24h, the gadolinium oxide ceramic balls were taken out and dried, and the weighed weight was 261.198g, and the wear rate was calculated, i.e., the wear rate was mass loss/surface area (261.202-261.201)/(20 × 4 × pi × 7.5.5 7.5 × 7.5.5) was 0.708 × 10-7g/mm2。
15 gadolinium oxide ceramic balls prepared in example 2 were taken, washed twice with ethanol and dried, the weighed weight was 58.048g, then the balls were placed in a clean ball mill, 60mL of ethanol was added, ball milling was carried out at 120r/min for 24h, the gadolinium oxide ceramic balls were taken out and dried, and the weighed weight was 58.046g, and the wear rate was calculated, where the wear rate is mass loss/surface area (58.048-58.046)/(15 × 4 × pi × 5 × 5) is 0.424 × 10-7g/mm2。
Taking two identical 500ml mixing tanks, adding 0.001g of 5N europium oxide, 30g of 5N lutetium oxide, 30g of 5N gadolinium oxide, 180g of ball milling medium and 60ml of ethanol into each mixing tank, then mixing for 12h at a speed of 120r/min, drying and sieving to obtain the mixed powder for preparing the gadolinium-containing compound. Wherein, the gadolinium oxide ceramic balls prepared in the embodiment 1 are added into a first mixing tank as a ball milling medium, and the prepared mixed powder is marked as mixed powder 1; and adding steel balls as ball milling media into the second mixing tank, and marking the prepared mixed powder as mixed powder 2. The content of the original in mixed powder 1 and mixed powder 2 was measured by glow discharge mass spectrometry using VG9000, and the results are shown in table 1. As can be seen from Table 1, the steel ball-mixed raw material introduced Fe impurity of about 400ppm, while the gadolinium oxide ball-mixed raw material contained less Fe impurity.
TABLE 1
Respectively dry-pressing and molding the mixed powder 1 and the mixed powder 2, and then sintering the mixture in vacuum at 1700 ℃ for 12h to prepare (LuGd)2O3Eu scintillating ceramic sample, sample 1 made of mixed powder 1, and sample 2 made of mixed powder 2. FIG. 1 shows a physical diagram of sample 1, and FIG. 2 shows a physical diagram of sample 2. The relative light output measurements for sample 1 and sample 2 were performed using plate 1417, with the results for sample 1 shown in fig. 3 and sample 2 shown in fig. 4. The results show that the relative light output of the samples prepared from gadolinium spheres is 3.81 times that of steel spheres under the test condition of 90 kV. Gadolinium element and Lu which are ground by gadolinium balls form a solid solution, Fe element introduced by the steel balls is used as impurity ions and exists in a ceramic matrix in the form of a second phase, and strong light absorption centers are generated, so that a sample is black.
Further, two identical 500ml mixing tanks are taken, 0.001g of 5N europium oxide, 30g of 5N lutetium oxide, 30g of 5N gadolinium oxide, 120g of ball milling medium and 60ml of ethanol are added into each mixing tank, then the materials are mixed for 15 hours at a speed of 240r/min, and the mixture is dried and sieved to obtain the mixed powder for preparing the gadolinium-containing compound. Wherein, one mixing pot is added with the gadolinium oxide ceramic prepared in example 2The ball is used as a ball milling medium, and the prepared mixed powder is marked as mixed powder 3; and adding agate balls as a ball milling medium into the other mixing tank, and marking the prepared mixed powder as mixed powder 4. Respectively dry-pressing and molding the mixed powder 3 and the mixed powder 4, and then sintering the mixture in vacuum at 1700 ℃ for 12h to prepare (LuGd)2O3Eu scintillating ceramic sample, sample 3 made of mixed powder 3 is designated as sample 3, and sample 4 made of mixed powder 4 is designated as sample 4. The afterglow test was carried out on samples 3 and 4, and the results are shown in FIG. 5. The results show that the afterglow of the agate ball mixed sample is significantly larger than that of the gadolinium oxide ball mixed sample. The trace impurities introduce defect energy levels in the band gap of the scintillation material, which can trap carriers, thereby affecting the light output, and when the scintillation material is disturbed thermally, the carriers are released and are trapped by activated ions to emit light, thereby causing afterglow.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that modifications can be made by those skilled in the art without departing from the principle of the present invention, and these modifications should also be construed as the protection scope of the present invention.
Claims (10)
1. A preparation method for preparing wear-resistant high-purity rare earth gadolinium oxide ceramic balls containing gadolinium compounds is characterized by comprising the following steps: the method comprises the following steps:
(S1) batching: putting commercial high-purity gadolinium oxide into an oven for drying, and weighing the required commercial high-purity gadolinium oxide according to the size of gadolinium oxide spheres;
(S2) blank making: preparing the dried commercial high-purity gadolinium oxide into a spherical blank;
(S3) cold-forming: pressing and molding the spherical blank by using a cold isostatic press;
(S4) primary rounding: placing the cold-formed blank on sand paper for rounding;
(S5) burn-in: laying a layer of gadolinium oxide powder at the bottom of the crucible, placing the rounded blank, covering a layer of gadolinium oxide powder, and stacking the rounded blank in the crucible in a manner of one layer of blank and one layer of gadolinium oxide powder; then placing the crucible in a muffle furnace, and heating to 1200 ℃ for pre-sintering; cooling to room temperature;
(S6) secondary rounding: rolling the pre-sintered ball on sand paper for the second time;
(S7) secondary sintering: vacuum sintering the spheres subjected to the secondary rounding by using a high-temperature carbon tube furnace, wherein the pressure is less than or equal to 20Pa, and the sintering temperature is 1500-1900 ℃;
(S8) screening: and removing the defective products with irregular shapes to obtain the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing the gadolinium compound.
2. The preparation method of the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing gadolinium compound according to claim 1, wherein: in the step (S3), the pressure of the cold isostatic press is set to be 30-300Mpa, and the pressure maintaining time is set to be 1-30 min.
3. The preparation method of the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing gadolinium compound according to claim 1, wherein: in the step (S4), the specification of the selected sand paper is 500-.
4. The preparation method of the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing gadolinium compound according to claim 1, wherein: in the step (S5), the temperature control program of the muffle furnace is set as follows: from room temperature, heating to 300 ℃ at a speed of 1-5 ℃/min, and keeping the temperature for 10min-120min, heating to 600 ℃ at a speed of 2-6 ℃/min, and keeping the temperature for 10min-60min, and heating to 1200 ℃ at a speed of 5-8 ℃/min, and keeping the temperature for 60min-240 min; cooling to 300 deg.C at 1-2 deg.C/min, and naturally cooling to room temperature.
5. The preparation method of the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing gadolinium compound according to claim 1, wherein: the step (S7) is: placing the sphere subjected to secondary rounding in a boron nitride crucible, covering a cover, placing the crucible in a high-temperature carbon tube furnace, arranging a graphite cushion block below the crucible, adjusting the height to enable the central position of the crucible to be located at the measuring position of a thermocouple, covering the furnace cover, and screwing nuts on the periphery; starting process cooling water, starting a mechanical pump to reduce the pressure in the furnace chamber to be within 20Pa, starting a diffusion pump, preheating for 40min, then starting a vacuum switch, heating, raising the temperature to 1200 ℃ at 10 ℃/min, raising the temperature to 1900 ℃ at 1-5 ℃/min, and keeping the temperature for 120-480 min; cooling to room temperature at the speed of 2 ℃/min.
6. The preparation method of the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing gadolinium compound according to claim 1, wherein: the method comprises the following steps:
(S1) batching: putting commercial high-purity gadolinium oxide into an open container, then putting the container into an oven for drying, and heating the container to 30-200 ℃ at a speed of 1-5 ℃/min from room temperature and preserving heat for 2-10 h; weighing dried commercial high-purity gadolinium oxide according to the size of gadolinium oxide spheres, and weighing 2% more;
(S2) blank making: assembling a plastic funnel with the diameter of 3mm-10mm and a plastic bag together, filling the weighed gadolinium oxide into the funnel by using a medicine spoon, then pressing down the gadolinium oxide to the bottom of the plastic bag by using a carbon fiber rod, compacting the powder and then knotting to obtain a blank; repeating the charging steps to obtain a plurality of blanks; one plastic bag contains 2-6 blanks;
(S3) cold-forming: placing the plastic bag containing the blank prepared in the step (S2) in a steel hollow mold, then placing the plastic bag in a cavity of a cold isostatic press, covering an upper cover, boosting the pressure to 30-300MPa at 1-10MPa/min, maintaining the pressure for 1-30min, naturally releasing the pressure, opening the upper cover of the cold isostatic press, taking out the plastic bag, drying the water stain on the outer surface of the plastic bag by using a blower, and then peeling the plastic bag;
(S4) primary rounding: placing the cold-formed blank on sand paper for rounding; the specification of the selected sand paper is 500-;
(S5) burn-in: laying a layer of gadolinium oxide powder at the bottom of the crucible, placing the rounded blank, covering a layer of gadolinium oxide powder, and stacking the rounded blank in the crucible in a manner of one layer of blank and one layer of gadolinium oxide powder; then the crucible is arranged in a muffle furnace, and the temperature control program of the muffle furnace is set as follows: from room temperature, heating to 300 ℃ at a speed of 1-5 ℃/min, and keeping the temperature for 10min-120min, heating to 600 ℃ at a speed of 2-6 ℃/min, and keeping the temperature for 10min-60min, and heating to 1200 ℃ at a speed of 5-8 ℃/min, and keeping the temperature for 60min-240 min; cooling to 300 ℃ at a speed of 1-2 ℃/min and then naturally cooling to room temperature;
(S6) secondary rounding: rolling the pre-sintered ball on sand paper for the second time;
(S7) secondary sintering: placing the sphere subjected to secondary rounding in a boron nitride crucible, covering a cover, placing the crucible in a high-temperature carbon tube furnace, arranging a graphite cushion block below the crucible, adjusting the height to enable the central position of the crucible to be located at the measuring position of a thermocouple, covering the furnace cover, and screwing nuts on the periphery; starting process cooling water, starting a mechanical pump to reduce the pressure to be within 20Pa, starting a diffusion pump, preheating for 40min, then starting a vacuum switch, heating, raising the temperature to 1200 ℃ at 10 ℃/min, raising the temperature to 1900 ℃ at 1-5 ℃/min, and preserving the temperature for 120-480 min; cooling to room temperature at the speed of 2 ℃/min;
(S8) screening: randomly selecting 6 diameters in different directions, measuring by using a vernier caliper, dividing the value obtained by subtracting the minimum value from the maximum value by the average value to define uniformity, and removing defective products with the uniformity of more than 8% to obtain the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing the gadolinium compound.
7. A wear-resistant high-purity rare earth gadolinium oxide ceramic ball for preparing gadolinium-containing compounds is characterized in that: the preparation method of the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing gadolinium compound according to any one of claims 1 to 6.
8. The use method of the wear-resistant high-purity rare earth gadolinium oxide ceramic ball for preparing the gadolinium-containing compound is characterized by comprising the following steps of: when the gadolinium-containing compound is prepared, the wear-resistant high-purity rare earth gadolinium oxide ceramic balls for preparing the gadolinium-containing compound are used as ball milling media, and the mixed materials are mixed.
9. The use method of the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing gadolinium compound according to claim 8, wherein: the mass ratio of the gadolinium oxide spheres to the mixed material is 3-1:1, the mixing speed is 60-240r/min, and the mixing time is 6-20 h.
10. The use method of the wear-resistant high-purity rare earth gadolinium oxide ceramic ball containing gadolinium compound according to claim 8, wherein: the mixed material comprises gadolinium oxide and raw materials capable of forming a compound with gadolinium, wherein the raw materials capable of forming the compound with gadolinium comprise europium oxide, lutetium oxide, yttrium oxide, scandium oxide, lanthanum oxide, iron oxide, aluminum oxide and gallium oxide.
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