CN103193476B

CN103193476B - Wet chemical method for preparing pure phase BiFeO3 ceramics

Info

Publication number: CN103193476B
Application number: CN201310160017.9A
Authority: CN
Inventors: 缪菊红; 徐林华; 苏静; 陈玉林
Original assignee: Nanjing University of Information Science and Technology
Current assignee: Nanjing University of Information Science and Technology
Priority date: 2013-05-03
Filing date: 2013-05-03
Publication date: 2014-11-26
Anticipated expiration: 2033-05-03
Also published as: CN103193476A

Abstract

The invention provides a wet chemical method for preparing pure phase BiFeO3 ceramics, and relates to the field of inorganic non-metal materials. The method comprises the steps that Fe(NO3)3.9H2O and Bi(NO3)3.5H2O are dissolved in water; tartaric acid is added, then stirred continuously at 90-150 DEG C till a solution is viscous, dried, presintered at 380-420 DEG C for 3-5 hours, and ground to form precursor powder; the precursor powder is presintered at 500-600 DEG C for 2-4 hours to form BiFeO3 powder; the BiFeO3 powder is ground and subjected to sheet pressing to form a BiFeO3 ceramic body; the BiFeO3 ceramic body is sintered in a sealing manner at 700-800 DEG C for 1-2 hours; and the pure phase BiFeO3 ceramics are obtained. The method is simple in technology; the obtained pure phase BiFeO3 ceramics are densified; and sizes of particles of the pure phase BiFeO3 ceramics can be adjusted and controlled through a sintering temperature.

Description

One is prepared pure phase BiFeO 3the wet chemical method of pottery

Technical field

The present invention relates to field of inorganic nonmetallic material, be specifically related to one and prepare pure phase BiFeO ₃the wet chemical method of pottery.

Background technology

Multi-ferroic material, make it can be widely used in the high-tech sectors such as transverter, sensor, multiple-state storage because there is ferroelectricity, ferromegnetism and ferroelasticity (having wherein two kinds of performances at least) and consequent coupling effect simultaneously, cause scientists broad interest, and become the study hotspot in Materials Science and Engineering field.

BiFeO ₃that one has the triangle distorted perovskite structure typical multi-ferroic material of (belonging to R3C space group).Under room temperature, have simultaneously ferroelectric order ( t _c=1103 K) and G type antiferromagnetic order ( t _n=643 K), be under minority room temperature, to there is one of ferroelectricity and ferromagnetic monophase materials simultaneously.Although find very early BiFeO ₃in the ferroelectricity and the ferromegnetism that coexist, but due to large leakage conductance makes its ferroelectricity cannot Measurement accuracy, simultaneously room temperature magnetic a little less than, these features have limited its application greatly.

Due to BiFeO ₃stable warm area narrower, adopt traditional solid reaction process to be difficult to avoid other dephasign as Bi ₂fe ₄o ₉, Bi _2.5feO ₄₀generation.Meanwhile, the synthetic BiFeO of solid phase method ₃temperature higher, Bi is volatile, can cause the skew of stoichiometric ratio.Thereby, pure phase BiFeO ₃the preparation of pottery is very difficult.In early days, the people such as M.Mahesh (M.Mahesh Kumar, et al., Applied Physics Letters 76,2764 (2004)) first adopt traditional solid reaction process to prepare the BiFeO that contains dephasign ₃pottery, then cleans dephasign wherein with rare nitric acid, thereby obtains single-phase BiFeO ₃pottery.(Chinese patent, the publication number CN 1686932A) BiFeO to sintering such as the Zhang Shantao of Nanjing University ₃pottery carries out quick cooling process, adopts quench method to prepare single-phase BiFeO ₃pottery.Aspect the preparation of ceramic powder, conventional solid-state method need obtain powder through the ball milling of long period, has increased the input of processing step and equipment, and cost is higher.

Wet chemical methods has that low, the each component of temperature of reaction is mixed on molecular level, product good uniformity, purity are high, easy control of reaction system and the advantage such as energy-efficient, is widely used in the preparation of high-quality electronic ceramics powder.Prepare BiFeO with wet chemistry method ₃the correlative study report of pottery is few.Cao Chuanbao etc. (Chinese patent, publication number CN 102225865A) first obtain BiFeO by sol-gel method ₃xerogel, then carries out twice preheating, after last compressing tablet, at 450-550 DEG C of sintering, obtains the single-phase BiFeO that particle diameter is less than 62nm ₃pottery, has saturated magnetic hysteresis loop.But because the ceramic particle of preparation is less, hole is many, fine and close not, the leakage current of system is larger.

Summary of the invention

The object of the present invention is to provide one to prepare pure phase BiFeO ₃the wet chemical method of pottery, technique is simple, the pure phase BiFeO obtaining ₃ceramic dense, the size of particle can regulate and control by sintering temperature.

In order to realize above-mentioned aspect object, the present invention adopts following technical scheme:

One is prepared pure phase BiFeO ₃the wet chemical method of pottery, comprises the following steps:

(1) by Fe (NO ₃) ₃9H ₂o and Bi (NO ₃) ₃5H ₂o is water-soluble, obtains mixing solutions;

(2) tartrate is dissolved in the described mixing solutions of step (1), then continues to stir at 90-150 DEG C, until solution is thick, stop stirring, dry, at 380-420 DEG C of pre-burning 3-5h, after grinding, obtain precursor powder;

(3) described step (2) precursor powder is obtained to BiFeO at 500-600 DEG C of pre-burning 2-4h ₃powder; By described BiFeO ₃after powder grinding, compressing tablet, obtain BiFeO ₃pottery idiosome; By described BiFeO ₃pottery idiosome, at 700-800 DEG C of sealed sintering 1-2h, obtains pure phase BiFeO ₃pottery.

Fe (NO in step (1) ₃) ₃9H ₂o and Bi (NO ₃) ₃5H ₂the mol ratio of O is 1:1.

Fe in step (2) unresolvable tartaric acid and the described mixing solutions of step (1) ³⁺and Bi ³⁺the mol ratio of summation is 1:1.

Pressure when the middle compressing tablet of step (3) is 10 ~ 12 Mpa.

In step (3) by described BiFeO ₃pottery idiosome is embedded in BiFeO ₃in powder, then just carry out sealed sintering.

After sealed sintering, grind off described pure phase BiFeO ₃the dirt settling of ceramic surface; Described surface attachments is by BiFeO ₃powder forms in sealed sintering process.

Beneficial effect: the present invention prepares pure phase BiFeO ₃the wet chemical method of pottery, technique is simple, the pure phase BiFeO obtaining ₃ceramic dense, the size of particle can regulate and control by sintering temperature.

Brief description of the drawings

Fig. 1 is the X-ray diffractogram (XRD) of sample 1.

Fig. 2 is the field emission scanning electron microscope figure (SEM) of sample 1.

Fig. 3 is the field emission scanning electron microscope figure (SEM) of sample 2

Fig. 4 is the field emission scanning electron microscope figure (SEM) of sample 3.

Embodiment

Embodiment 1

Preparation pure phase BiFeO ₃the wet chemical method of pottery, comprises the following steps:

(1) use analytically pure Fe (NO ₃) ₃9H ₂o and Bi (NO ₃) ₃5H ₂o, as raw material, mixes according to mol ratio 1:1, adds deionized water, by magnetic agitation, raw material is dissolved completely, becomes uniform mixing solutions;

(2) take analytically pure tartrate, Fe in the described mixing solutions of tartrate and step (1) ³⁺with Bi ³⁺the mol ratio of ion summation is 1:1.Tartrate is added in the described mixing solutions of step (1), stir and make tartrate dissolve completely and mix; Then continue to stir at 100 DEG C, until that solution becomes is thick, stop stirring, at 100 DEG C, dry, then reaction vessel is transferred in retort furnace, at 400 DEG C of pre-burning 4h, remove organism, then, through grinding, obtain precursor powder;

(3) by obtain precursor powder transfer to alumina crucible, at 500 DEG C of pre-burning 2h, obtain BiFeO ₃powder.By gained BiFeO ₃powder obtains BiFeO at the pressure lower sheeting of 10 Mpa after grinding ₃pottery idiosome _.in alumina crucible, put into BiFeO ₃powder, by BiFeO ₃pottery idiosome is imbedded BiFeO ₃in powder, cover lid is sealed sintering 1h in the time of 700 DEG C, finally grinds off the dirt settling of ceramic surface, obtains sample 1.Surface attachments is by BiFeO ₃powder forms in sealed sintering process, and they can be bonded in ceramic surface, is easy to grind off.

In sealed sintering process, by BiFeO ₃pottery idiosome is imbedded BiFeO ₃powder, is because Bi easily volatilizees, in sealed sintering process, and BiFeO ₃bi in powder can first volatilize, and forms the atmosphere of Bi element relative saturation in closed environment, thereby stops BiFeO ₃bi volatilization in pottery idiosome, reduces ceramic defect.

The X-ray diffractogram (XRD) of sample 1 as shown in Figure 1, the diffraction peak that can observe and the BiFeO of standard ₃, there is not other impurity peaks in (JCPDS No. 21-0169) unanimously.The BiFeO that this illustrative material 1 is pure phase ₃pottery.Fig. 2 is the field emission scanning electron microscope figure (SEM) of sample 1.As can be seen from the figure, ceramic dense, tight, greatly about 2-3 μ m, there are some little crystal grain in its particle size.

Embodiment 2

(1) use analytically pure Fe (NO ₃) ₃9H ₂o and Bi (NO ₃) ₃5H ₂o, as raw material, after mixing, adds deionized water according to mol ratio 1:1, by magnetic agitation, raw material is dissolved completely, becomes uniform mixing solutions;

(2) take analytically pure tartrate, Fe in the described mixing solutions of tartrate and step (1) ³⁺with Bi ³⁺ion summation mol ratio be 1:1.Tartrate is added in the described mixing solutions of step (1), stir and make tartrate dissolve completely and mix; Then continue to stir at 120 DEG C, until that solution becomes is thick, stop stirring, dry 120 DEG C of conditions, then reaction vessel is transferred in retort furnace, at 380 DEG C of pre-burning 3h, remove organism, then grinding, obtains precursor powder;

(3) by obtain precursor powder transfer to alumina crucible, at 600 DEG C of pre-burning 2h, obtain BiFeO ₃powder.By BiFeO ₃powder obtains BiFeO at the pressure lower sheeting of 12 Mpa after grinding ₃pottery idiosome _.in alumina crucible, put into BiFeO ₃powder, at BiFeO ₃in powder, imbed BiFeO ₃pottery idiosome, cover lid is sealed sintering 1.5h in the time of 750 DEG C, finally grinds off the dirt settling of ceramic surface, obtains sample 2.Surface attachments is by BiFeO ₃powder forms in sealed sintering process, and they can be bonded in ceramic surface, is easy to grind off.

Sample 2 is carried out to X-ray diffraction, find out the BiFeO of diffraction peak and standard ₃, there is not other impurity peaks in (JCPDS No. 21-0169) unanimously.The BiFeO that this interpret sample 2 is pure phase ₃pottery.

Fig. 3 is the field emission scanning electron microscope figure (SEM) of sample 2.As can be seen from the figure, ceramic dense, tight, its particle size is greatly about 2 ~ 4 μ m.

Embodiment 3

(1) use analytically pure Fe (NO ₃) ₃9H ₂o and Bi (NO ₃) ₃5H ₂o, as raw material, after being 1:1 weighing, adds deionized water according to mol ratio, by magnetic agitation, raw material is dissolved completely, becomes uniform mixing solutions;

(2) take analytically pure tartrate, Fe in the described mixing solutions of tartrate and step (1) ³⁺with Bi ³⁺ion summation mol ratio be 1:1.Tartrate is added in the described mixing solutions of step (1), stir and make tartrate dissolve completely and mix; Then continue to stir at 150 DEG C, until that solution becomes is thick, stop stirring, under 150 DEG C of conditions, dry, then reaction vessel is transferred in retort furnace, at 420 DEG C of pre-burning 4.5h, remove organism, then, through grinding, obtain precursor powder;

(3) by obtain precursor powder transfer to alumina crucible, at 550 DEG C of pre-burning 2.5h, obtain BiFeO ₃powder.By BiFeO ₃powder obtains BiFeO at the pressure lower sheeting of 11 Mpa after grinding ₃pottery idiosome.In alumina crucible, put into BiFeO ₃powder, at BiFeO ₃in powder, imbed BiFeO ₃pottery idiosome, cover lid is sealed sintering 1h in the time of 800 DEG C, finally grinds off the dirt settling of ceramic surface, obtains sample 3.Surface attachments is by BiFeO ₃powder forms in sealed sintering process, and they can be bonded in ceramic surface, is easy to grind off.

Sample 3 is carried out to X-ray diffraction, find out the BiFeO of diffraction peak and standard ₃, there is not other impurity peaks in (JCPDS No. 21-0169) unanimously.The BiFeO that this illustrative material 3 is pure phase ₃pottery.

Fig. 4 is the field emission scanning electron microscope figure (SEM) of sample 3.As can be seen from the figure, ceramic dense, tight, its particle size is greatly about 4 ~ 5 μ m.

Claims

1. prepare pure phase BiFeO for one kind ₃the wet chemical method of pottery, is characterized in that comprising the following steps:

(1) by Fe (NO ₃) ₃9H ₂o and Bi (NO ₃) ₃5H ₂o is water-soluble, obtains mixing solutions; Wherein Fe (NO ₃) ₃9H ₂o and Bi (NO ₃) ₃5H ₂the mol ratio of O is 1:1;

(2) tartrate is dissolved in the described mixing solutions of step (1), then continues to stir at 90-150 DEG C, until solution is thick, stop stirring, dry, at 380-420 DEG C of pre-burning 3-5h, after grinding, obtain precursor powder; Fe in the described mixing solutions of its unresolvable tartaric acid and step (1) ³⁺and Bi ³⁺the mol ratio of summation is 1:1;

2. prepare according to claim 1 pure phase BiFeO ₃the wet chemical method of pottery, is characterized in that: pressure when the middle compressing tablet of step (3) is 10 ~ 12 Mpa.

3. prepare according to claim 1 pure phase BiFeO ₃pottery wet chemical method, it is characterized in that: in step (3) by described BiFeO ₃pottery idiosome is embedded in BiFeO ₃in powder, then just carry out sealed sintering.

4. preparation pure phase BiFeO according to claim 3 ₃the wet chemical method of pottery, is characterized in that: after sealed sintering, grind off described pure phase BiFeO ₃the dirt settling of ceramic surface; Described surface attachments is by BiFeO ₃powder forms in sealed sintering process.