CN107162591A - Nb5+The monoclinic phase VO of doping2Metal insulator Phase transformation ceramics and preparation method thereof - Google Patents

Nb5+The monoclinic phase VO of doping2Metal insulator Phase transformation ceramics and preparation method thereof Download PDF

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CN107162591A
CN107162591A CN201710191616.5A CN201710191616A CN107162591A CN 107162591 A CN107162591 A CN 107162591A CN 201710191616 A CN201710191616 A CN 201710191616A CN 107162591 A CN107162591 A CN 107162591A
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phase transition
doping
temperature
metal
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袁松柳
张润
尹重阳
符青山
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Huazhong University of Science and Technology
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Abstract

The present invention relates to Nb5+The monoclinic phase VO of doping2Metal insulator Phase transformation ceramics and preparation method thereof.This method uses hydro-thermal method to reduce V with citric acid2O5, monoclinic phase VO is obtained through high-temperature heat treatment2Powder material, Nb is mixed by different doping ratios5+Mixed grinding, through tabletting high temperature, repeatedly sintering obtains the VO that metal insulator phase transition temperature is significantly reduced to room temperature or even lower temperature2Block body ceramic material.Present invention process is simple, and preparation efficiency is high, and sintering temperature is low, and energy consumption is small, and cost is low, environment-protecting and non-poisonous pollution-free, and the ceramic phase transition performance being made is good, and Stability Analysis of Structures is uniform, VO2Block ceramic phase transition temperature is greatly reduced near 25 DEG C of room temperature.There is huge value in actual production.

Description

Nb5+The monoclinic phase VO of doping2Metal-insulator phase transition ceramics and preparation method thereof
Technical field
The present invention relates to Phase transformation ceramics field of material technology, and in particular to a kind of Nb5+The monoclinic phase VO of doping2Metal-absolutely Edge body Phase transformation ceramics and preparation method thereof.
Background technology
Conductor is different from idioelectric band structure, the situation that the conductance of conductor is depended mainly near Fermi surface, if Band structure or fermi level can be had influence on by changing external condition, then can just be caused between metallic conductor and insulator Transformation.Vanadium dioxide (VO2) there is metal-insulator phase transition (MIT) characteristic, it is a kind of intelligent thermochromic material.At 68 DEG C Neighbouring VO2It is high temperature quadratic metal phase by low temperature monocline semiconductor phase in version, its photoelectricity and magnetic performance there occurs very big therewith Reversible change so that as a kind of photoelectric conversion material having wide application prospects, optical storage, laser radiation and intelligent window material Material, very high value is above respectively provided with theoretical research and application.VO2Film in low temperature with higher infrared transmittivity, Infrared transmittivity is but very low during high temperature, and using this characteristic, the vanadium dioxide of the different orientations of growth can be deposited on a glass substrate Film, by its change at different temperatures to infrared light transmittance, realizes that the amount of incident of Intelligent adjustment infra-red radiation is played Keep the purpose of room temperature.Therefore, in actual applications, it is necessary to by VO2Phase transition temperature be reduced to room temperature or even lower from 68 DEG C Temperature.
For expand material application, how controllable reduction VO2Phase transition temperature turn into study hotspot.It is reported that logical Overdoping, stress, change crystallite dimension etc. can adjust VO2Phase transition temperature, however from the dimension of material be VO2Film considers, mixes Miscellaneous ratio is unable to Effective Regulation, can not then realize controllable adjustment phase transition temperature；On the other hand, the preparation technology cost of film is high High, program is complicated, it is difficult to carry out industrialization production.In addition, changing VO by changing stress and grain size2Phase transition temperature, Adjust space smaller, poor repeatability, it is impossible to realize that controllable continuous is adjusted.
The content of the invention
The technical problems to be solved by the invention are to provide a kind of Nb5+The monoclinic phase VO of doping2Metal-insulator phase transition is made pottery Porcelain and preparation method thereof, the VO prepared with this method2Block materials phase transition temperature can be reduced to 25 DEG C of room temperature or even lower, its work Skill process is few, and materials are simple, and energy consumption is low, and the Ceramic Material Physics Performance of preparation is superior.
In order to solve the above technical problems, Nb proposed by the present invention5+The monoclinic phase VO of doping2Metal-insulator phase transition ceramics Preparation method, comprise the following steps：
(1) at room temperature, first, load weighted citric acid is put into beaker, deionized water is added, it is molten under magnetic stirring Solution, forms clear solution；Then weigh analytically pure vanadic anhydride to be put into beaker, in the lump magnetic agitation, form uniform molten Liquid；Wherein the amount ratio of the material of vanadic anhydride and citric acid is 1:1.5~2.5, the oxidation of citric acid-five two of mixed solution Vanadium concentration is 0.025 ± 5%g/mL；
(2) mixed solution stirred is poured into closed high temperature and high pressure containers, then by container be put into baking oven with 170 DEG C~190 DEG C heating, it is ensured that HTHP hydro-thermal reaction is carried out inside container；Reaction time is 5~10h；
(3) after question response terminates, then separation of solid and liquid is carried out to reaction solution：Precipitation is subjected to eccentric cleaning；It is again that precipitation is outstanding Turbid liquid is poured into beaker, is finally putting into 80 DEG C~100 DEG C dryings in baking oven, is obtained orthorhombic phase VO2Powder；
(4) by orthorhombic phase VO2500 DEG C under vacuum conditions~600 DEG C 1~2h of heat treatment of powder, organics removal, and very Undergone phase transition in empty heat treatment process, obtain monoclinic phase VO2Powder；
(5) according to the doping ratio of niobium, the stoichiometric proportion that calculating is obtained weighs the monocline prepared by above-mentioned steps respectively Phase VO2Powder and Nb2O5Powder, grinding, tabletting sintering, sintering temperature is 1000~1100 DEG C, and sintering time is 10~12h, Obtain sheet sinter；Above-mentioned niobium doping ratio is that the atomic quantity ratio of vanadium and niobium in sinter is 99%:1%~97%： 3%；
(6) sheet sinter obtained above is smashed to pieces and is fully ground tabletting after 2h, be put into clean quartzy Noah's ark, then It is put into tube furnace；Rinsed with general pure argon 300sccm in tubular type hearthstone English pipe after gaseous environment 15min, then with pumping suction pipe Formula stove, until intraductal pressure≤0.1Pa, then diamond heating is carried out, 1000-1100 DEG C is warming up to 5 DEG C/min, 5-6h is incubated After cool to room temperature with the furnace, obtain mixing Nb5+Monoclinic phase VO2Metal-insulator phase transition ceramic block.
The separation of solid and liquid is using centrifuging, and centrifugal rotational speed is 5000r/min~6000r/min, and centrifugation time is 3~ 5min。
It is preferred that, the vacuum heat uses quartz tube type resistance wire furnace, and general pure argon, argon gas gas are first passed through before heating Rate of flow of fluid is that 300sccm~400sccm rinses quartz ampoule 10-20min.
It is preferred that, before heat treatment, pressure≤0.1Pa in quartz ampoule.
It is preferred that, the sintering uses quartz tube type resistance wire furnace before quartz tube type resistance wire furnace, sintering to be passed through general straight argon Gas, argon gas flow velocity is that 300sccm~400sccm rinses quartz ampoule 10-20min, then with pumping tube furnace, until in pipe Pressure≤0.1Pa.
The Nb that the preparation method is obtained5+The monoclinic phase VO of doping2Metal-insulator phase transition ceramics, with structural mutation, Resistivity be mutated and magnetic mutation characteristic, its phase transition temperature is controllable to 20 DEG C~25 DEG C of room temperature.
The present invention has advantages below：
(1) ceramics that the present invention is prepared are the multifunctional ceramic materials that a class has broad prospect of application, with list Phase structure and abundant physical property transformation.
(2)V2O5Hydro-thermal reaction with citric acid is thorough, and preparation efficiency is high, greatly shortens preparation time.
(3) Nb of incorporation 1%~3%5+So that VO2Block ceramic phase transition temperature is greatly reduced near 25 DEG C of room temperature.
(4) Nb is passed through5+The change of doping can continuously reduce phase transition temperature.
(5) preparation technology is repeated, it is adaptable to a large amount of productions.
Brief description of the drawings
Technical scheme is further described in detail with reference to the accompanying drawings and detailed description.
Fig. 1 is the Nb into embodiment 4 of embodiment 15+VO under different dopings2Metal-insulator phase transition block ceramic sample XRD refine collection of illustrative plates；
(a) is the Nb into embodiment 4 of embodiment 1 in Fig. 25+VO under different dopings2The magnetic temperature change of block ceramic sample Curve；(b) it is the Nb into embodiment 4 of embodiment 15+VO under different dopings2Metal-insulator phase transition block ceramic sample The warm change curve of resistance.
Fig. 3 is the VO into embodiment 4 of embodiment 12The phase transition temperature of metal-insulator phase transition block ceramic sample is with Nb5+ Doping changes scatter diagram.
The crystal parameterses abc and volume V under each doping ratio are listed according to refine result in table 1.
Table 1
Embodiment
Nb proposed by the present invention5+The monoclinic phase VO of doping2The preparation method of metal-insulator phase transition ceramics, including it is following Step：
(1) at room temperature, first, load weighted citric acid is put into beaker, deionized water is added, it is molten under magnetic stirring Solution, forms clear solution；Then weigh analytically pure vanadic anhydride to be put into beaker, in the lump magnetic agitation, form uniform molten Liquid；Wherein the amount ratio of the material of vanadic anhydride and citric acid is 1:1.5~2.5, the oxidation of citric acid-five two of mixed solution Vanadium concentration is 0.025 ± 5%g/mL；
(2) mixed solution stirred is poured into closed high temperature and high pressure containers, then by container be put into baking oven with 170 DEG C~190 DEG C heating, it is ensured that HTHP hydro-thermal reaction is carried out inside container；Reaction time is 5~10h；
(3) after question response terminates, then separation of solid and liquid is carried out to reaction solution；Separation of solid and liquid is using centrifugation, centrifugal rotational speed For 5000r/min~6000r/min, centrifugation time is 3~5min.Precipitation is subjected to eccentric cleaning；Precipitation suspension is fallen again Enter in beaker, be finally putting into 80 DEG C~100 DEG C dryings in baking oven, obtain orthorhombic phase VO2Powder；
(4) by orthorhombic phase VO2500 DEG C under vacuum conditions~600 DEG C 1~2h of heat treatment of powder, organics removal, and very Undergone phase transition in empty heat treatment process, obtain monoclinic phase VO2Powder；Vacuum heat can use quartz tube type resistance wire furnace.Plus Before heat, it is passed through general pure argon 10-20min and rinses quartz ampoule, argon gas flow velocity is 300sccm~400sccm；Vacuumize again, Make pressure≤0.1Pa in quartz ampoule；
(5) according to the doping ratio of niobium, the stoichiometric proportion that calculating is obtained weighs the monocline prepared by above-mentioned steps respectively Phase VO2Powder and Nb2O5Powder, grinding, tabletting sintering, sintering temperature is 1000~1100 DEG C, and sintering time is 10~12h, Obtain sheet sinter；Above-mentioned niobium doping ratio is that the atomic quantity ratio of vanadium and niobium in sinter is 99%:1%~97%： 3%；Sintering uses quartz tube type resistance wire furnace before quartz tube type resistance wire furnace, sintering to be passed through general pure argon, argon gas flow velocity Quartz ampoule 10-20min is rinsed for 300sccm~400sccm, then with pumping tube furnace, until intraductal pressure≤0.1Pa.
(6) sheet sinter obtained above is smashed to pieces and is fully ground tabletting after 2h, be put into clean quartzy Noah's ark, then It is put into tube furnace；Rinsed with general pure argon 300sccm~400sccm in tubular type hearthstone English pipe after gaseous environment 10-20min, Again with pumping tube furnace, until intraductal pressure≤0.1Pa, then diamond heating is carried out, 1000- is warming up to 5 DEG C/min 1100 DEG C, cool to room temperature with the furnace after being incubated 5-6h, obtain mixing Nb5+Monoclinic phase VO2Metal-insulator phase transition ceramic block.
The Nb that this preparation method is obtained5+The monoclinic phase VO of doping2Metal-insulator phase transition ceramics, with structural mutation, electricity Resistance rate be mutated and magnetic mutation characteristic, its phase transition temperature is controllable to 20 DEG C~25 DEG C of room temperature.
Embodiment 1
1. using citric acid-V2O5Hydro-thermal reaction prepares monoclinic phase VO2Powder material：
(1) 0.00375mol citric acids are measured to be put into 50mL beaker, deionized water 20mL are added, under magnetic stirring Dissolving, forms clear solution, then weighs 0.0025molV2O5Solid powder, is added in above-mentioned citric acid solution, in the lump magnetic force Homogeneous yellow solution is formed after stir about 30min, citric acid-vanadic anhydride concentration of mixed solution is 0.025 ± 5%g/ mL；
(2) above-mentioned yellow solution is poured into 50mL stainless steel water thermal synthesis reactors, and point measure several times 10mL go from Residual medicine in sub- water rinsing step (1), is added in reactor, end reaction solution is about 50mL, then by reactor in the lump It is put into baking oven, is heated to 180 DEG C, sustained response 5h；
(3) after the above-mentioned reaction time terminates, separation of solid and liquid is carried out to reaction solution, upper strata about 35mL settled solutions are sucked, Black precipitate and surplus solution formation precipitation suspension are stirred with glass bar, then sucked suspension in centrifuge tube with sebific duct, if Centrifugal rotational speed 6000r/min, centrifugation time 3min are put, Acceleration and deceleration time is respectively 1min；After centrifugation terminates, suck in centrifuge tube Layer settled solution, then centrifuge tube is cleaned with ethanol or distilled water, accompany by glass bar and stir to form precipitation suspension, then carry out above-mentioned Centrifugally operated；After separation of solid and liquid so at least three times, final precipitation suspension is rinsed and poured into beaker, then beaker is put into The dry 15h of 90 DEG C of baking oven；
(4) the orthorhombic phase VO obtained after aforesaid operations is collected2Powder, puts it into clean quartz boat, places into tubular type In stove；Gaseous environment 10-20min in tubular type hearthstone English pipe is rinsed with general pure argon 300sccm, tube furnace is aspirated with mechanical pump, Until intraductal pressure≤0.1Pa, then diamond heating is carried out, cooled to the furnace after being warming up to 550 DEG C, insulation 2h with 5 DEG C/min Room temperature, obtains monoclinic phase VO2Powder material；
2. high temperature sintering prepares non-impurity-doped monoclinic phase VO2Metal-insulator phase transition ceramics：
(1) the monoclinic phase VO that aforesaid operations are obtained is collected2Powder material, is fully ground after 2h, weighs about 0.6g powder Tabletting；
(2) the sheet VO for obtaining aforesaid operations2It is put into clean quartzy Noah's ark, places into tube furnace；With general straight argon Gas 300sccm rinses gaseous environment 15min in tubular type hearthstone English pipe, and tube furnace is aspirated with mechanical pump, until intraductal pressure≤ 0.1Pa, then diamond heating is carried out, cool to room temperature with the furnace after being warming up to~1000 DEG C, insulation~10h with 5 DEG C/min, obtain Sheet sinter；
(3) sheet sinter obtained above is smashed to pieces and is fully ground tabletting after 2h, be put into clean quartzy Noah's ark, then It is put into tube furnace；Gaseous environment 15min in tubular type hearthstone English pipe is rinsed with general pure argon 300sccm, with mechanical pump suction tube Formula stove, until intraductal pressure≤0.1Pa, then diamond heating is carried out, it is warming up to 5 DEG C/min after~1000 DEG C, insulation~5h Cool to room temperature with the furnace, obtain undoped monoclinic phase VO2Metal-insulator phase transition ceramic block.
The non-impurity-doped monoclinic phase VO prepared using embodiment 12The XRD of metal-insulator phase transition ceramics sample is as schemed Shown in 1 (a), observe that all characteristic peaks coincide with standard PDF cards from Fig. 1 (a), single-phase the second phase of nothing diffraction maximum occurs, table 1 In when listing x=0, lattice parameter abc and volume V.Fig. 2 (a) (b) sets forth VO2Magnetic temperature curve, resistance-temperature curve. Wherein, example 1 is expressed as curve x=0 in Fig. 1,2 (a) (b).
Embodiment 2
1. using citric acid-V2O5Hydro-thermal reaction prepares monoclinic phase VO2Powder material：
Prepared using the method in embodiment 1.
2. high temperature sintering prepares Nb5+The VO of doping 1%2Vanadium in metal-insulator phase transition ceramic block, i.e. Phase transformation ceramics Atomic quantity ratio with niobium is 99%:1%, including procedure below：
(1) 99% is compared according to the atomic quantity of vanadium and niobium:1% calculating weighs the monoclinic phase VO that aforesaid operations are obtained2Powder 0.5747g, with the 0.0050g Nb measured2O5Powder is mixed, and is fully ground after 2h, tabletting；
(2) Nb is mixed by what aforesaid operations were obtained2O5Sheet VO2It is put into clean quartzy Noah's ark, places into tube furnace；With General pure argon 400sccm rinses gaseous environment 10min in tubular type hearthstone English pipe, mechanical pump suction tube furnace, until intraductal pressure ≤ 0.1Pa, then diamond heating is carried out, cool to room temperature with the furnace after being warming up to 1100 DEG C, 10~12h of insulation with 5 DEG C/min, obtain To sheet sinter；
(3) sheet sinter obtained above is smashed to pieces and is fully ground tabletting after 2h, be put into clean quartzy Noah's ark, then It is put into tube furnace；Gaseous environment 15min in tubular type hearthstone English pipe is rinsed with general pure argon 300sccm, with mechanical pump suction tube Formula stove, until intraductal pressure≤0.1Pa, then carries out diamond heating, with 5 DEG C/min be warming up to after 1000 DEG C, insulation~5h with Stove is cooled to room temperature, obtains Nb5+Doping is 1% monoclinic phase VO2Metal-insulator phase transition ceramic block.
Nb is prepared using embodiment 25+The monoclinic phase VO of doping 1%2Metal-insulator phase transition ceramic block sample XRD such as Fig. 1 (b) shown in, observe that all characteristic peaks and standard PDF cards coincide from Fig. 1 (a), single-phase the second phase of nothing diffraction Peak occurs, when listing x=1% in table 1, lattice parameter abc and volume V.Fig. 2 (a) (b) sets forth VO2Magnetic Wen Qu Line, resistance-temperature curve.Wherein, example 1 is expressed as curve x=1% in Fig. 1,2 (a) (b).
Embodiment 3
1. using citric acid-V2O5Hydro-thermal reaction prepares monoclinic phase VO2Powder material：
Prepared using the method in embodiment 1.
2. high temperature sintering prepares Nb5+The VO of doping 2%2Vanadium in metal-insulator phase transition ceramic block, i.e. Phase transformation ceramics Atomic quantity ratio with niobium is 98%:2%, including procedure below：
(1) 98% is compared according to the atomic quantity of vanadium and niobium:2% calculating weighs the monoclinic phase VO that aforesaid operations are obtained2Powder 0.5689g, with the 0.0100g Nb measured2O5Powder is mixed, and is fully ground after 2h, tabletting；
(2) Nb is mixed by what aforesaid operations were obtained2O5Sheet VO2It is put into clean quartzy Noah's ark, places into tube furnace；With General pure argon 400sccm rinses gaseous environment 10min in tubular type hearthstone English pipe, mechanical pump suction tube furnace, until intraductal pressure ≤ 0.1Pa, then diamond heating is carried out, cool to room temperature with the furnace after being warming up to 1000 DEG C, 10~12h of insulation with 5 DEG C/min, obtain To sheet sinter；
(3) sheet sinter obtained above is smashed to pieces and is fully ground tabletting after 2h, be put into clean quartzy Noah's ark, then It is put into tube furnace；Gaseous environment 15min in tubular type hearthstone English pipe is rinsed with general pure argon 300sccm, with mechanical pump suction tube Formula stove, until intraductal pressure≤0.1Pa, then diamond heating is carried out, it is warming up to 5 DEG C/min after~1000 DEG C, insulation~5h Cool to room temperature with the furnace, obtain Nb5+Doping is 2% monoclinic phase VO2Metal-insulator phase transition ceramic block.
Nb is prepared using embodiment 35+The monoclinic phase VO of doping 2%2Metal-insulator phase transition ceramic block sample XRD such as Fig. 1 (c) shown in, observe that all characteristic peaks and standard PDF cards coincide from Fig. 1 (c), single-phase the second phase of nothing diffraction Peak occurs, when listing x=2% in table 1, lattice parameter abc and volume V.Fig. 2 (a) (b) sets forth VO2Resistance Wen Qu Line, magnetic temperature curve.Wherein, example 1 is expressed as curve x=2% in Fig. 1,2 (a) (b).
Embodiment 4
1. using citric acid-V2O5Hydro-thermal reaction prepares monoclinic phase VO2Powder material：
Prepared using the method in embodiment 1.
2. high temperature sintering prepares Nb5+The VO of doping 3%2Vanadium in metal-insulator phase transition ceramic block, i.e. Phase transformation ceramics Atomic quantity ratio with niobium is 97%:3%, including procedure below：
(1) 97% is compared according to the atomic quantity of vanadium and niobium:3% calculating weighs the monoclinic phase VO that aforesaid operations are obtained2Powder 0.5631g, with the 0.0151g Nb measured2O5Powder is mixed, and is fully ground after 2h, tabletting；
(2) Nb is mixed by what aforesaid operations were obtained2O5Sheet VO2It is put into clean quartzy Noah's ark, places into tube furnace；With General pure argon 400sccm rinses gaseous environment 10min in tubular type hearthstone English pipe, mechanical pump suction tube furnace, until intraductal pressure ≤ 0.1Pa, then diamond heating is carried out, cool to room temperature with the furnace after being warming up to 1020 DEG C, 10~12h of insulation with 5 DEG C/min, obtain To sheet sinter；
(3) sheet sinter obtained above is smashed to pieces and is fully ground tabletting after 2h, be put into clean quartzy Noah's ark, then It is put into tube furnace；Gaseous environment 15min in tubular type hearthstone English pipe is rinsed with general pure argon 300sccm, with mechanical pump suction tube Formula stove, until intraductal pressure≤0.1Pa, then diamond heating is carried out, it is warming up to 5 DEG C/min after~1000 DEG C, insulation~5h Cool to room temperature with the furnace, obtain Nb5+Doping is 3% monoclinic phase VO2Metal-insulator phase transition ceramic block.
Nb is prepared using embodiment 45+The monoclinic phase VO of doping 3%2Metal-insulator phase transition ceramic block sample XRD such as Fig. 1 (d) shown in, observe that all characteristic peaks and standard PDF cards coincide from Fig. 1 (d), single-phase the second phase of nothing diffraction Peak occurs, when listing x=3% in table 1, lattice parameter abc and volume V.Fig. 2 (a) (b) sets forth VO2Magnetic Wen Qu Line, resistance-temperature curve.Wherein, example 4 is expressed as curve x=3% in Fig. 1,2 (a) (b)..
The Nb prepared using above method5+VO after doping2It is special that ceramics possess the single-phase superior metal of structure-insulator transformation Property, its transition temperature is controllable to arrive room temperature, is a kind of functional material with broad prospect of application.X-ray diffraction is employed herein Instrument (XRD) is to its material phase analysis；Using the comprehensive property test system (PPMS) of Quantum Design companies to sample Magnetic warm nature, which and can hinder warm nature, to be measured.
As shown in figure 1, giving incorporation Nb5+Ratio is respectively 0,1%, 2% and 3% rear monoclinic phase VO2Ceramic block The XRD refine collection of illustrative plates of sample, it is observed from fig. 1 that all characteristic peaks are identical with standard PDF cards, this demonstrate through solid VO prepared by phase reaction method2, the sample purity that is obtained after high-temperature heat treatment is high, and structure is single without dephasign.From the refine In XRD, Nb in table 1 is obtained5+Lattice parameter abc and volume V under different doping ratios, it is clear that with the raising of doping ratio, Lattice parameter becomes big, and this is also to promote VO2The influence factor of phase transition temperature reduction.
Fig. 2 (a) gives incorporation different proportion Nb5+Monoclinic phase VO afterwards2Ceramic block sample is in externally-applied magnetic field H=10kOe Under intensity, magnetic susceptibility varies with temperature measurement result.It can be seen that with the rise of doping ratio, the magnetization of sample Rate is being mutated near 340K, 313K, 302K, 293K respectively, and transition temperature is reduced as doping ratio is raised.From Find out in XRD spectrum with Nb5+The rise of doping ratio, the crystal parameterses of ceramics sample gradually increase, and unit cell volume becomes Greatly, while which increases V4+-V4+Between distance, be unfavorable in VO2Middle formation V4+-V4+Dimer pair, in other words, adulterate band Come crystal expansion cause it is Dimerized formed in lower temperature so that sample has lower magnetic transition temperature.
Fig. 2 (b) provides the Nb of incorporation different proportion5+VO afterwards2Resistivity measurement of the ceramic block sample in temperature-rise period As a result, it can be seen that with Nb from the warm measure of the change of resistance5+Doping ratio is improved, and the bust transition temperature of resistivity is also difference Be consistent with magnetic transition, show as insulating properties to the transformation of metallicity, the change of resistivity is above 1 magnitude, especially when Nb5+During doping ratio x=3%, resistivity is undergone mutation close at room temperature 300K.This is substantially reducing the premise of transition temperature Under, it is ensured that the material property of metal-insulator transition.Test result indicates that, by being scaled up Nb5+Doping, can be with Near-linear reduces the metal-insulator body resistivity transition temperature of sample.
Fig. 3 is intuitively provided with Nb5+The raising of doping ratio, VO2The phase transition temperature of ceramic block sample constantly controllable drop It is low, the often doping of lifting 1%, 13 DEG C or so of transition temperature reduction, and when doping reaches 3%, its phase transition temperature is It is reduced near 25 DEG C of room temperature.As a result show, pass through Nb5+Doping, controllable reduction VO2The phase transition temperature of ceramic block sample, makes Metal-insulator transition is obtained closer to room temperature, effectiveness of this ceramic material in actual production is potentially greatly promoted.
It should be noted last that, above embodiment is merely illustrative of the technical solution of the present invention and unrestricted, Although the present invention is described in detail with reference to preferred embodiment, it will be understood by those within the art that, can be right Technical scheme is modified or equivalent substitution, and without departing from the spirit and scope of technical solution of the present invention, its is equal It should cover among scope of the presently claimed invention.

Claims (6)

1. a kind of Nb5+The monoclinic phase VO of doping2The preparation method of metal-insulator phase transition ceramics, it is characterised in that including following Step：
(1) at room temperature, first, load weighted citric acid is put into beaker, deionized water is added, dissolves under magnetic stirring, Form clear solution；Then weigh analytically pure vanadic anhydride to be put into beaker, in the lump magnetic agitation, form homogeneous solution； Wherein the amount ratio of the material of vanadic anhydride and citric acid is 1:1.5~2.5, citric acid-vanadic anhydride of mixed solution is dense Spend for 0.025 ± 5%g/mL；
(2) mixed solution stirred is poured into closed high temperature and high pressure containers, then container is put into baking oven with 170 DEG C ~190 DEG C of heating, it is ensured that HTHP hydro-thermal reaction is carried out inside container；Reaction time is 5~10h；
(3) after question response terminates, then separation of solid and liquid is carried out to reaction solution：Precipitation is subjected to eccentric cleaning；Suspension will be precipitated again Pour into beaker, be finally putting into 80 DEG C~100 DEG C dryings in baking oven, obtain orthorhombic phase VO2Powder；
(4) by orthorhombic phase VO2500 DEG C under vacuum conditions~600 DEG C 1~2h of heat treatment of powder, organics removal, and Vacuum Heat Undergone phase transition in processing procedure, obtain monoclinic phase VO2Powder；
(5) according to the doping ratio of niobium, the stoichiometric proportion that calculating is obtained weighs the monoclinic phase VO prepared by above-mentioned steps respectively2 Powder and Nb2O5Powder, grinding, tabletting sintering, sintering temperature is 1000~1100 DEG C, and sintering time is 10~12h, obtains piece Shape sinter；Above-mentioned niobium doping ratio is that the atomic quantity ratio of vanadium and niobium in sinter is 99%:1%~97%：3%；
(6) sheet sinter obtained above is smashed to pieces and is fully ground tabletting after 2h, be put into clean quartzy Noah's ark, place into In tube furnace；Rinsed with general pure argon 300sccm in tubular type hearthstone English pipe after gaseous environment 15min, then with pumping tube furnace, Until intraductal pressure≤0.1Pa, then carry out diamond heating, with 5 DEG C/min be warming up to after 1000-1100 DEG C, insulation 5-6h with Stove is cooled to room temperature, obtains mixing Nb5+Monoclinic phase VO2Metal-insulator phase transition ceramic block.
2. Nb according to claim 15+The monoclinic phase VO of doping2The preparation method of metal-insulator phase transition ceramics, it is special To levy and be, the separation of solid and liquid is using centrifuging, and centrifugal rotational speed is 5000r/min~6000r/min, centrifugation time is 3~ 5min。
3. Nb according to claim 15+The monoclinic phase VO of doping2The preparation method of metal-insulator phase transition ceramics, it is special Levy and be, the vacuum heat is used before quartz tube type resistance wire furnace, heating in vacuum, is passed through general pure argon, argon gas stream Speed rinses quartz ampoule 10-20min for 300sccm~400sccm.
4. Nb according to claim 35+The monoclinic phase VO of doping2The preparation method of metal-insulator phase transition ceramics, it is special Levy and be, before vacuum heat, make pressure≤0.1Pa in quartz ampoule.
5. Nb according to claim 15+The monoclinic phase VO of doping2The preparation method of metal-insulator phase transition ceramics, it is special Levy and be, the sintering uses quartz tube type resistance wire furnace before quartz tube type resistance wire furnace, sintering to be passed through general pure argon, argon gas gas Rate of flow of fluid is that 300sccm~400sccm rinses quartz ampoule 10-20min, then with pumping tube furnace, until intraductal pressure≤ 0.1Pa。
6. the Nb that preparation method described in a kind of claim 1 is obtained5+The monoclinic phase VO of doping2Metal-insulator phase transition ceramics, its It is characterised by, the VO2Characteristic of the metal-insulator phase transition ceramics with structural mutation, resistivity mutation and magnetic mutation, its Phase transition temperature is controllable to 20 DEG C~25 DEG C of room temperature.
CN201710191616.5A 2017-03-28 2017-03-28 Nb5+The monoclinic phase VO of doping2Metal insulator Phase transformation ceramics and preparation method thereof Pending CN107162591A (en)

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CN114538925A (en) * 2022-01-25 2022-05-27 北京科技大学 Preparation method of high-strength high-stability vanadium oxide electronic phase change composite ceramic
CN114538924A (en) * 2022-01-25 2022-05-27 北京科技大学 Method for preparing electronic phase-change ceramic material by doping transition metal oxide with vanadium oxide
CN115745605A (en) * 2022-10-24 2023-03-07 四川大学 Method for preparing niobium zirconate potassium sodium bismuth iron by using pretreated niobium pentoxide

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114538925A (en) * 2022-01-25 2022-05-27 北京科技大学 Preparation method of high-strength high-stability vanadium oxide electronic phase change composite ceramic
CN114538924A (en) * 2022-01-25 2022-05-27 北京科技大学 Method for preparing electronic phase-change ceramic material by doping transition metal oxide with vanadium oxide
CN114538925B (en) * 2022-01-25 2023-01-31 北京科技大学 Preparation method of high-strength high-stability vanadium oxide electronic phase change composite ceramic
CN115745605A (en) * 2022-10-24 2023-03-07 四川大学 Method for preparing niobium zirconate potassium sodium bismuth iron by using pretreated niobium pentoxide
CN115745605B (en) * 2022-10-24 2023-12-22 四川大学 Method for preparing potassium sodium bismuth iron niobate zirconate by pretreated niobium pentoxide

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