Summary of the invention
The object of the present invention is to provide a kind of preparation method of Mn ferrite nano-powder, the method has the advantages that preparation process is simple, chemical time is short.
The technical solution adopted in the present invention is, a kind of preparation method of Mn ferrite nano-powder, specifically implements according to following steps:
Step 1, by MnCl
24H
2o and Fe (NO
3)
39H
2o is dissolved in deionized water and is configured to mixing solutions, wherein, and Mn in this mixed solution
2+concentration be 0.12mol/L;
Add surface-modifying agent Sodium dodecylbenzene sulfonate in step 2, the mixing solutions that obtains in step 1 to dissolve, and mix;
Step 3, ammoniacal liquor is slowly added in the mixing solutions of step 2 gained, regulate the pH value of microwave hydrothermal reaction system; Add in micro-wave diminishing pot by the solution mixing up pH value again, sealing is placed on microwave dissolver, carries out microwave hydrothermal reaction;
After step 4, reaction terminate, stop heating, take out solution, filter, precipitation distilled water and dehydrated alcohol are repeatedly washed rear drying, obtains microwave hydrothermal product, be Mn ferrite nano-powder.
Feature of the present invention is also,
Mn in step 1 in mixing solutions
2+with Fe
3+mol ratio is 1:1.9-1:2.1.
Sodium dodecylbenzene sulfonate and MnCl in step 2
24H
2o and Fe (NO
3)
39H
2the mass ratio of O total amount is 1:100-1:10.
In step 3, the concentration of ammoniacal liquor is 10wt%; The pH value of described microwave hydrothermal reaction system is 9 ~ 13.
The condition of microwave hydrothermal reaction is: temperature is 100 DEG C ~ 145 DEG C; Time is 8min-12min.
In step 4, drying conditions is: drying temperature is 65 DEG C-75 DEG C; Time of drying is 1.5h-2.5h.
The invention has the beneficial effects as follows: traditional hydrothermal synthesis method combines with microwave field by the present invention, utilize the dielectric effect of microwave to water to carry out transmission ofenergy, and heat-processed is from material is inner, can produce the thermograde contrary with conventional heat transfer process.The present invention have rate of heating fast, be quick on the draw, be heated evenly, a lot of reaction system had to the advantage accelerating chemical reaction, in preparation evenly, there is unique advantage in the nano-powder of narrow particle size distribution.The present invention adopts microwave-hydrothermal method to synthesize Mn ferrite, shortens the microwave reaction time, avoids calcination process, simplify experimental procedure, finally obtains the Mn ferrite that degree of crystallinity is good, saturation magnetization is higher, coercive force is little.
Embodiment
Below in conjunction with embodiment, the present invention is described in detail.
The invention provides a kind of preparation method of Mn ferrite nano-powder, specifically implement according to following steps:
Step 1, by Mn
2+with Fe
3+mol ratio is 1:1.9-1:2.1, by MnCl
24H
2o and Fe (NO
3)
39H
2o is dissolved in deionized water and is configured to mixing solutions, wherein, and Mn in this mixed solution
2+concentration be 0.12mol/L;
Step 2, in above-mentioned solution, add surface-modifying agent Sodium dodecylbenzene sulfonate, wherein, Sodium dodecylbenzene sulfonate and MnCl
24H
2o and Fe (NO
3)
39H
2the mass ratio of O total amount is 1:100-1:10, dissolves and mixes;
Step 3, be that the ammoniacal liquor of 10wt% slowly adds in the mixing solutions of step 2 gained by concentration, regulate the pH value of microwave hydrothermal reaction system to 9-13; Add in micro-wave diminishing pot by the solution mixing up pH value again, sealing is placed on microwave dissolver, and be warming up to 100 DEG C ~ 145 DEG C and carry out microwave hydrothermal reaction, the reaction times is 8min-12min;
After step 4, reaction terminate, stop heating, take out solution, filter, precipitation distilled water and dehydrated alcohol are repeatedly washed rear drying, obtains microwave hydrothermal product, be Mn ferrite nano-powder, wherein, drying temperature is 65 DEG C-75 DEG C; Time of drying is 1.5h-2.5h.
Adopt microwave heating than conventional hydrothermal method rate of heating faster evenly, efficiency is higher, the reaction times only needs 8-12min, and microwave hydrothermal product is target product Mn ferrite, without the need to high-temperature calcination, simplifies experimental procedure and decreases energy consumption; Microwave hydrothermal reaction environment is a kind of supercritical state, in this condition, raw molecule, ion be Quick Casting under microwave heating action, is conducive to forming a large amount of nucleus instantaneously, thus reduce the granularity of product, finally obtain the little and nano particle of better crystallinity degree of granularity.
MnCl in the present invention
24H
2o, Fe (NO
3)
39H
2o is respectively microwave hydrothermal product MnFe
2o
4mn is provided
2+with Fe
3+; Ammoniacal liquor one side and Mn
2+and Fe
3+reaction generates the intermediate product of Mn ferrite, on the one hand in order to regulate the pH value of microwave reaction system; Sodium dodecylbenzene sulfonate is a kind of surface-modifying agent, and its effect is the MnFe to generating in microwave hydrothermal reaction system
2o
4particle carries out surface modification, stops or weakens the reunion between particle.
Adopt microwave hydrothermal reaction method all can generate ZnO product 80 DEG C ~ 150 DEG C temperature ranges, the product particle size wherein during lesser temps is larger.When microwave hydrothermal reaction system pH value lower than 10 time, the MnFe that degree of crystallinity is good can not be obtained
2o
4nano-powder, as the MnFe of preparation
2o
4the pH value of reaction system too high time, microwave hydrothermal product MnFe can be made
2o
4grain fineness number become large.
The beneficial effect of the Mn ferrite nano-powder that the present invention prepares is described below in conjunction with experimental result:
D/max – RB II type X-ray diffractometer (XRD) is adopted to analyze the thing phase of microwave hydrothermal product; Zeiss, Germany ULTRA55 type field emission scanning electron microscope (SEM) is adopted to observe the pattern of microwave product; The magnetic hysteresis loop of microwave hydrothermal product measured by BKT-4500Z type vibrating sample magnetometer (VSM).
By the grain fineness number of Scherrer formulae discovery microwave hydrothermal product.
1, microwave hydrothermal pH value of reaction system is on the impact of its product property
Microwave hydrothermal temperature be 130 DEG C, soaking time be 10min time, change the XRD spectra of pH value of reaction system gained microwave hydrothermal product and experimental result data as shown in figure 1 and table 1.
When microwave hydrothermal temperature be 130 DEG C, microwave soaking time be 10min time, change the magnetic hysteresis loop of pH value of reaction system gained microwave hydrothermal product and experimental result data as shown in Fig. 2 and table 2.
The grain fineness number of gained microwave hydrothermal product and material phase analysis result during table 1 different pH value
From Fig. 1, table 1, microwave hydrothermal temperature is 130 DEG C, soaking time is under 10min condition, and when microwave hydrothermal pH value of reaction system equals 9, products therefrom is amorphous substance.When pH value of reaction system is at 10-13, microwave hydrothermal product is the Mn ferrite MnFe of Spinel
2o
4, and X-ray diffraction peak shape is sharp-pointed, better crystallinity degree.Through Scherrer formulae discovery, when microwave hydrothermal pH value of reaction system is 10-13, the grain fineness number of gained Spinel Mn ferrite is between 17.4nm-25.7nm.
It can thus be appreciated that, can the Mn ferrite of one-step synthesis Spinel under suitable experiment condition by microwave-hydrothermal method, eliminate general wet chemistry method and first obtain the step that Mn ferrite precursor needs calcining.And the time of microwave-hydrothermal method one-step synthesis Spinel Mn ferrite is short, degree of crystallinity good, grain-size is nano level.
The magnetic parameter of microwave hydrothermal product under table 2 different PH
From Fig. 2, table 2, microwave hydrothermal temperature is 130 DEG C, soaking time is under 10min condition, when microwave hydrothermal pH value of reaction system equals 9, because products therefrom is amorphous substance, so its saturation magnetization is very low, only has 3.34emu.g
-1.When pH value of reaction system is at 10-13, the saturation magnetization of the Mn ferrite product of Spinel is greatly improved, and their remanent magnetism and coercive force are also very little.Wherein, as pH=12, the saturation magnetization of Mn ferrite product reaches maximum value 53.56441emu.g
-1.
2, microwave hydrothermal temperature of reaction is on the impact of its product property
When microwave hydrothermal pH value of reaction system be 12, soaking time be 10min time, change the XRD spectra of microwave hydrothermal temperature of reaction products therefrom and experimental result data as shown in Fig. 3 and table 3.
When microwave hydrothermal pH value of reaction system be 12, soaking time be 10min time, change the magnetic hysteresis loop of microwave hydrothermal temperature of reaction products therefrom and experimental result data as shown in Fig. 4 and table 4.
Table 3 microwave hydrothermal temperature of reaction is on the impact of product property
From Fig. 3, table 3, microwave hydrothermal pH value of reaction system is 12, soaking time is under 10min condition, and microwave hydrothermal temperature of reaction all a step can generate the Mn ferrite MnFe of Spinel between 100 DEG C-145 DEG C
2o
4, its grain fineness number is between 17.4nm-31nm.Wherein the degree of crystallinity of microwave hydrothermal temperature of reaction gained Spinel Mn ferrite product between 115 DEG C-145 DEG C is good.
The magnetic parameter of gained Mn ferrite under the different microwave hydrothermal temperature of reaction of table 4
From Fig. 4, table 4, microwave hydrothermal pH value of reaction system is 12, soaking time is under 10min condition, microwave hydrothermal temperature of reaction is that the saturation magnetization of gained Mn ferrite between 100 DEG C-145 DEG C is in falling " V " shape, occurring maximum value when microwave hydrothermal temperature of reaction is 130 DEG C, is 53.56441emug
-1.Their remanent magnetism and coercive force are also very little.
Embodiment 1
A preparation method for Mn ferrite nano-powder, specifically implements according to following steps:
Step 1, take 1.1875gMnCl
24H
2o, 4.8480gFe (NO
3)
39H
2o is placed in same beaker, the two kinds of salt taken with deionized water dissolving, makes the total amount of solution be 50ml.
Step 2, take 0.2414g Sodium dodecylbenzene sulfonate, be dissolved in the solution configured in step 1.
Step 3, be the ammoniacal liquor instillation step 2 gained solution of 10wt% by concentration under rapid mixing conditions, and regulate its pH value to be 12 with the ammoniacal liquor of this concentration, obtain suspension.
Step 4, step 3 gained suspension load microwave dissolver reaction vessels-micro-wave diminishing pot in, microwave dissolver is put into after sealing, arrange that microwave hydrothermal temperature of reaction is 130 DEG C, the reaction times is 10min, microwave hydrothermal reaction product deionized water and dehydrated alcohol respectively wash twice, filter, then put into baking oven at 70 DEG C of dry 2h, products therefrom is Mn ferrite powder.
Gained MnFe under this reaction conditions
2o
4as shown in Figure 5, the grain fineness number of obtained Mn ferrite powder is 17.4nm to scanning electron photomicrograph, and saturation magnetization is 53.56441emu.g
-1, remanent magnetism is 0.73913emu.g
-1, coercive force is 6.81553Oe.
Embodiment 2
A preparation method for Mn ferrite nano-powder, specifically implements according to following steps:
Step 1, take 1.1875gMnCl
24H
2o, 4.6056gFe (NO
3)
39H
2o is placed in same beaker, the two kinds of salt taken with deionized water dissolving, makes the total amount of solution be 50ml.
Step 2, take 0.057931g Sodium dodecylbenzene sulfonate, be dissolved in the solution configured in step 1.
Step 3, be the ammoniacal liquor instillation step 2 gained solution of 10wt% by concentration under rapid mixing conditions, and regulate its pH value to be 9 with the ammoniacal liquor of this concentration, obtain suspension.
Step 4, step 3 gained suspension load microwave dissolver reaction vessels-micro-wave diminishing pot in, microwave dissolver is put into after sealing, arrange that microwave hydrothermal temperature of reaction is 100 DEG C, the reaction times is 8min, microwave hydrothermal reaction product deionized water and dehydrated alcohol respectively wash twice, filter, then baking oven is put at 65 DEG C of dry 1.5h, products therefrom is Mn ferrite powder, belongs to amorphous substance.
Embodiment 3
A preparation method for Mn ferrite nano-powder, specifically implements according to following steps:
Step 1, take 1.1875gMnCl
24H
2o, 5.0904gFe (NO
3)
39H
2o is placed in same beaker, the two kinds of salt taken with deionized water dissolving, makes the total amount of solution be 50ml.
Step 2, take 0.6278g Sodium dodecylbenzene sulfonate, be dissolved in the solution configured in step 1.
Step 3, be the ammoniacal liquor instillation step 2 gained solution of 10wt% by concentration under rapid mixing conditions, and regulate its pH value to be 13 with the ammoniacal liquor of this concentration, obtain suspension.
Step 4, step 3 gained suspension load microwave dissolver reaction vessels-micro-wave diminishing pot in, microwave dissolver is put into after sealing, arrange that microwave hydrothermal temperature of reaction is 145 DEG C, the reaction times is 12min, microwave hydrothermal reaction product deionized water and dehydrated alcohol respectively wash twice, filter, then put into baking oven at 75 DEG C of dry 2.5h, products therefrom is Mn ferrite powder.