CN115109564A - Surface modified carbonyl iron powder and preparation method and application thereof - Google Patents
Surface modified carbonyl iron powder and preparation method and application thereof Download PDFInfo
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- CN115109564A CN115109564A CN202110298423.6A CN202110298423A CN115109564A CN 115109564 A CN115109564 A CN 115109564A CN 202110298423 A CN202110298423 A CN 202110298423A CN 115109564 A CN115109564 A CN 115109564A
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical class [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 181
- 238000002360 preparation method Methods 0.000 title claims abstract description 22
- 238000006243 chemical reaction Methods 0.000 claims abstract description 42
- 230000004048 modification Effects 0.000 claims abstract description 26
- 238000012986 modification Methods 0.000 claims abstract description 26
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 22
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims abstract description 14
- 239000007800 oxidant agent Substances 0.000 claims abstract description 14
- 230000001590 oxidative effect Effects 0.000 claims abstract description 14
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 4
- 229910052802 copper Inorganic materials 0.000 claims abstract description 4
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 4
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 4
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 4
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims abstract description 4
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 105
- 239000006185 dispersion Substances 0.000 claims description 38
- 239000007788 liquid Substances 0.000 claims description 35
- 239000000243 solution Substances 0.000 claims description 32
- 229910052760 oxygen Inorganic materials 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 20
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical group [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 19
- 239000001301 oxygen Substances 0.000 claims description 19
- 238000003756 stirring Methods 0.000 claims description 19
- 239000006096 absorbing agent Substances 0.000 claims description 14
- 230000007797 corrosion Effects 0.000 claims description 14
- 238000005260 corrosion Methods 0.000 claims description 14
- 239000007789 gas Substances 0.000 claims description 14
- 230000032683 aging Effects 0.000 claims description 10
- 230000008569 process Effects 0.000 claims description 9
- 239000011358 absorbing material Substances 0.000 claims description 7
- 150000002500 ions Chemical class 0.000 claims description 7
- 238000005406 washing Methods 0.000 claims description 7
- 239000007853 buffer solution Substances 0.000 claims description 6
- 239000000460 chlorine Substances 0.000 claims description 4
- 238000001035 drying Methods 0.000 claims description 4
- 238000000926 separation method Methods 0.000 claims description 4
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 3
- 229910052801 chlorine Inorganic materials 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims 3
- 239000002131 composite material Substances 0.000 claims 1
- 239000011159 matrix material Substances 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 16
- 239000002184 metal Substances 0.000 abstract description 11
- 229910052751 metal Inorganic materials 0.000 abstract description 11
- 229910006540 α-FeOOH Inorganic materials 0.000 abstract description 11
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 abstract description 9
- 229910002588 FeOOH Inorganic materials 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 25
- 239000000843 powder Substances 0.000 description 8
- 239000000047 product Substances 0.000 description 8
- 150000001768 cations Chemical class 0.000 description 6
- 239000008367 deionised water Substances 0.000 description 6
- 229910021641 deionized water Inorganic materials 0.000 description 6
- 229910000403 monosodium phosphate Inorganic materials 0.000 description 6
- 235000019799 monosodium phosphate Nutrition 0.000 description 6
- AJPJDKMHJJGVTQ-UHFFFAOYSA-M sodium dihydrogen phosphate Chemical compound [Na+].OP(O)([O-])=O AJPJDKMHJJGVTQ-UHFFFAOYSA-M 0.000 description 6
- 229910000162 sodium phosphate Inorganic materials 0.000 description 6
- 239000001488 sodium phosphate Substances 0.000 description 6
- 235000011008 sodium phosphates Nutrition 0.000 description 6
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 239000011734 sodium Substances 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 239000000872 buffer Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 3
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 239000013067 intermediate product Substances 0.000 description 3
- 239000011241 protective layer Substances 0.000 description 3
- 238000001694 spray drying Methods 0.000 description 3
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000012467 final product Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- UMYVESYOFCWRIW-UHFFFAOYSA-N cobalt;methanone Chemical compound O=C=[Co] UMYVESYOFCWRIW-UHFFFAOYSA-N 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 229960004887 ferric hydroxide Drugs 0.000 description 1
- 239000003574 free electron Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/16—Carbonyls
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention provides surface modified carbonyl iron powder and a preparation method and application thereof. The preparation method comprises the step of introducing an oxidant into a reaction system containing sulfate and carbonyl iron powder to perform oxidation reaction under the alkaline condition so as to form a surface modification layer on the surface of the carbonyl iron powder, wherein the surface modification layer is alpha-M x Fe y OOH, wherein x is 0-1, y is 0-1, M is one or more selected from Cu, Ni, Cr, Mo, V and Nb, and the sulfate includes FeSO 4 And sulfate salts of M. The application coats alpha-M on the surface of carbonyl iron powder x Fe y The OOH (namely the alpha-FeOOH doped with M metal) surface modification layer effectively prevents carbonyl iron powder from contacting with chloride ions, thereby preventing the carbonyl iron powder from being corroded. Meanwhile, FeOOH has higher magnetic loss and lower electrical constant, and the broadband of the carbonyl iron powder is expandedWave absorbing effect.
Description
Technical Field
The invention relates to the technical field of wave-absorbing materials, in particular to surface-modified carbonyl iron powder and a preparation method and application thereof.
Background
Stealth technology has become the important content of the present military technology, and the research of wave absorbing agent is the important link for promoting the development of radar wave absorbing coating, and is the material basis for developing and improving the performance of wave absorbing material. The magnetic metal micro powder such as carbonyl iron, carbonyl nickel, carbonyl cobalt and the like has better wave-absorbing performance because the carbonyl metal powder has free electron wave-absorbing and magnetic loss in the same work. But also has some disadvantages such as poor corrosion resistance, large dielectric constant, and poor spectral characteristics. The application of the carbonyl metal powder in the marine environment is limited due to the defect of poor corrosion resistance, and an inorganic or organic coating method is often adopted to improve the corrosion resistance of the carbonyl metal wave absorber. However, these methods have poor barrier effect against corrosion in marine environments in the presence of chloride ions.
Patent application No. 201711262016.X discloses a carbonyl iron powder wave absorber and a preparation method thereof, and proposes that a resin shell layer is coated on the surface of carbonyl iron powder to improve the dispersibility and oxidation resistance of the carbonyl iron powder. However, the wave absorbing agent adopts organic matter surface coating to make the absorption peak move to high frequency, and the low frequency absorption effect is reduced. The patent application with the application number of 201711195023.2 discloses a modified metal powder wave absorbing agent and a preparation method thereof, and SiO is provided 2 And (3) a coated modified metal powder wave absorbing agent. SiO 2 2 Although the oxidation resistance of the metal powder wave absorber can be improved, the blocking effect on chloride ions in the marine environment is limited, and the corrosion risk still exists after the metal powder wave absorber is used in the marine environment for a long time.
Disclosure of Invention
The invention mainly aims to provide surface modified carbonyl iron powder and a preparation method and application thereof, and aims to solve the problem that in the prior art, the corrosion resistance and high wave-absorbing performance of a wave-absorbing agent in a marine environment cannot be considered at the same time.
In order to achieve the above object, according to one aspect of the present invention, there is provided a method for preparing a surface-modified carbonyl iron powder, the method comprising: under the alkaline condition, introducing an oxidant into a reaction system containing sulfate and carbonyl iron powder for oxidation reaction to form a surface modification layer on the surface of the carbonyl iron powder, wherein the surface modification layer is alpha-M x Fe y OOH, wherein x is 0-1, y is 0-1, M is one or more selected from Cu, Ni, Cr, Mo, V and Nb, and sulfate includes FeSO 4 And sulfate salts of M.
Further, the alkaline condition is a condition of pH 7 to 10, preferably a condition of pH 8 to 10.
Further, the oxidation reaction is carried out at 35 to 40 ℃.
Further, the preparation method comprises the following steps: step S1, mixing the sulfate solution, the buffer solution and carbonyl iron powder at 35-40 ℃ to obtain carbonyl iron powder dispersion liquid, wherein the pH value of the carbonyl iron powder dispersion liquid is 7-10, and the mass concentration of the carbonyl iron powder in the carbonyl iron powder dispersion liquid is preferably 1-3.0 g/mL; and step S2, introducing an oxidant and a NaOH solution into the carbonyl iron powder dispersion liquid for oxidation reaction to obtain the surface modified carbonyl iron powder, wherein the pH value of a reaction system in the oxidation reaction process is 7-10, and the oxidant is preferably oxygen-containing gas.
Further, Fe is contained in the carbonyl iron powder dispersion liquid 2+ The concentration of (b) is 10 to 30g/L, and preferably the concentration of M ions is 0.5 to 3 g/L.
Further, the buffer includes (Na) 3 PO 4 、NaH 2 PO 4 One or two of them, preferably carbonyl iron powder dispersion liquid (Na) 3 PO 4 The concentration of (a) is 5-15 g/L, preferably NaH 2 PO 4 The concentration of (B) is 15-25 g/L, preferably stirring is carried out in the processes of step S1 and step S2, and the stirring speed is preferably 200-700 r/min.
Further, the step S2 includes: heating an oxygen-containing gas and a NaOH solution to 35-40 ℃, and introducing the heated oxygen-containing gas and the heated NaOH solution into the carbonyl iron powder dispersion liquid for reaction; preferably, the concentration of the NaOH solution is 80-200 g/L, the feeding speed is 20-100L/h, the oxygen content in the oxygen-containing gas is 90-99.9%, the feeding speed is 20-200 mL/h, and the time of the oxidation reaction is 10-60 min.
Further, the preparation method further comprises the following steps: and (4) sequentially aging and carrying out solid-liquid separation on the product system containing the surface modified carbonyl iron powder obtained in the step (S2) to obtain the surface modified carbonyl iron powder, washing and drying the surface modified carbonyl iron powder to obtain the surface modified carbonyl iron powder, wherein the aging treatment time is preferably 10-60 min.
According to another aspect of the present invention, there is provided a surface-modified carbonyl iron powder prepared by any one of the above-described preparation methods.
According to another aspect of the invention, a chlorine corrosion resistant wave-absorbing material is provided, which comprises a substrate and a wave-absorbing agent, wherein the wave-absorbing agent is any one of the surface modified carbonyl iron powder described above, or the surface modified carbonyl iron powder prepared by any one of the preparation methods described above.
By applying the technical scheme of the invention, the oxidant is introduced under the alkaline condition to ensure that the sulfate reacts on the surface of the carbonyl iron powder to react Fe 2+ Oxidation to Fe 3+ And M ion and Fe 3+ With OH - And O 2- Combined to form compact and uniform alpha-M attached to the surface of carbonyl iron powder x Fe y The OOH modified layer has cation selectivity, can effectively prevent carbonyl iron powder from contacting with chloride ions, and further prevents the carbonyl iron powder from being corroded. Meanwhile, alpha-FeOOH is used as a low-valence Fe element to be oxidized into Fe 2 O 3 The intermediate product in the process has higher magnetic loss and lower electric constant, so that the protective layer of the carbonyl iron powder does not reduce the wave absorbing performance of the carbonyl iron powder, and the alpha-FeOOH has low dielectric and can be matched with the carbonyl iron with high dielectric, so that the whole body presents a more matched state of dielectric and magnetic conductivity, the dispersion characteristic of the carbonyl iron powder is further improved, the carbonyl iron powder has good wave absorbing effect on low-frequency and high-frequency electromagnetic waves, and the broadband wave absorbing effect of the carbonyl iron powder is further expanded.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail with reference to examples.
According to the description in the background art of the application, the carbonyl iron powder with the coating layer in the prior art cannot simultaneously obtain high wave-absorbing performance and good corrosion resistance in a chloride ion (such as ocean) environment. In order to solve the problems, the application provides surface modified carbonyl iron powder and a preparation method and application thereof.
In an exemplary embodiment of the present application, there is provided a method for preparing a surface-modified carbonyl iron powder, the method comprising: under the alkaline condition, introducing an oxidant into a reaction system containing sulfate and carbonyl iron powder for oxidation reaction to form a surface modification layer on the surface of the carbonyl iron powder, wherein the surface modification layer is alpha-M x Fe y OOH, wherein x is 0-1, y is 0-1, M is one or more selected from Cu, Ni, Cr, Mo, V and Nb, and sulfate includes FeSO 4 And sulfate salts of M.
The preparation method comprises the steps of introducing an oxidant under the alkaline condition to enable sulfate to react on the surface of carbonyl iron powder, and reacting Fe 2+ Oxidation to Fe 3+ And M ion and Fe 3+ With OH - And O 2- Combined to form compact and uniform alpha-M attached to the surface of the carbonyl iron powder x Fe y The OOH modified layer has cation selectivity, can effectively prevent carbonyl iron powder from contacting with chloride ions, and further prevents the carbonyl iron powder from being corroded. Meanwhile, alpha-FeOOH is used as a low-valence Fe element to be oxidized into Fe 2 O 3 The intermediate product in the process has higher magnetic loss and lower electric constant, so that the protective layer of the carbonyl iron powder does not reduce the wave absorbing performance of the carbonyl iron powder, and the alpha-FeOOH has low dielectric and can be matched with the carbonyl iron with high dielectric, so that the whole body presents a more matched state of dielectric and magnetic conductivity, and further the frequency dispersion characteristic of the carbonyl iron powder is improved. In summary, the application attaches alpha-M to the surface of carbonyl iron powder x Fe y OOH modified layer realizes Cl resistance to carbonyl iron powder - The corrosivity is improved, and the broadband wave absorbing effect of the carbonyl iron powder is expanded.
In one embodiment, the alkaline condition is preferably a pH value of 7 to 10, preferably a pH value of 8 to 10, and the oxidation reaction is preferably carried out at 35 to 40 ℃. When the temperature is higher than the upperWhen the temperature range or the pH value is lower than the above range, the thickness of the surface modification layer is large, and the surface modification layer is loose, and the effect of blocking chloride ions is not desirable. When the temperature is lower than the temperature range, the adhesion between the surface modification layer and the carbonyl iron powder is low, the structural stability of the formed product is reduced, and the preparation time is prolonged, so that the preparation efficiency is reduced. When the pH is higher than the above numerical range, Fe is easily formed in the surface modification layer 2 O 3 The impurity phase reduces the purity of the product, and further reduces the wave-absorbing performance and the corrosion resistance of the final product.
The method comprises the following steps of adjusting the pH of a reaction system by using a buffer solution and a sodium hydroxide solution, wherein the buffer solution is weak in alkalinity, and can well control the pH to be 7-10, and preferably the preparation method comprises the following steps: step S1, mixing the sulfate solution, the buffer solution and carbonyl iron powder at 35-40 ℃ to obtain carbonyl iron powder dispersion liquid, wherein the pH value of the carbonyl iron powder dispersion liquid is 7-10, and the mass concentration of the carbonyl iron powder in the carbonyl iron powder dispersion liquid is preferably 0.1-3.0 g/mL; and step S2, introducing an oxidant and a NaOH solution into the carbonyl iron powder dispersion liquid for oxidation reaction to obtain the surface modified carbonyl iron powder, wherein the pH value of a reaction system in the oxidation reaction process is 7-10, and the oxidant is preferably an oxygen-containing gas. The pH value of the formed carbonyl iron powder dispersion liquid is regulated and controlled by using a phosphate solution, and the pH value of a reaction system is controlled by using a sodium hydroxide solution in the reaction process.
In some embodiments, it is preferable that Fe in the carbonyl iron powder dispersion liquid is contained in the carbonyl iron powder dispersion liquid 2+ The concentration of (b) is 10 to 30g/L, and preferably the concentration of M ions is 0.5 to 3 g/L. By controlling the concentration of each metal cation within the numerical range, the mass ratio of the metal ions in the surface modification layer can be adjusted, and the ion selection performance is further improved.
The buffer used in the present application may be a weakly basic buffer commonly used in the art, and it is preferable that the above buffer includes (Na) for cost reduction 3 PO 4 And NaH 2 PO 4 Preferably carbonyl iron powder dispersion (Na) 3 PO 4 The concentration of (a) is 5-15 g/L, NaH 2 PO 4 The concentration of (b) is 15-25 g/L. Use (Na) 3 PO 4 And NaH 2 PO 4 The pH value is adjusted, other impurity cations are not introduced, and the purity of the surface modification layer is further ensured. Preferably, the stirring is performed during the steps S1 and S2, and the stirring speed is preferably 200 to 700 r/min. The stirring can ensure that the carbonyl iron powder and the reaction raw materials of the surface modification layer are more uniformly dispersed in the reaction system, so that not only can the carbonyl iron powder be coated by the surface modification layer as much as possible, but also the structure of the surface modification layer can be further improved, and the corrosion resistance and the wave-absorbing performance of the surface modified carbonyl iron powder are further improved.
As described above, the reaction temperature in the present application affects the morphology of the final product, and in order to reduce the temperature fluctuation and make the surface modification layer more uniform and dense, it is preferable that the step S2 includes: and heating the oxygen-containing gas and the NaOH solution to 35-40 ℃, and introducing the heated oxygen-containing gas and the heated NaOH solution into the carbonyl iron powder dispersion liquid for reaction to obtain the carbonyl iron powder dispersion liquid after reaction. Preferably, the concentration of the NaOH solution is 80-200 g/L, the input speed is 20-100 mL/h, the oxygen content in the oxygen-containing gas is 90-99.9%, and the input speed is 20-200 mL/h. By controlling the concentration and the input speed of NaOH and oxygen-containing gas within the numerical range, the formation speed of ferric iron can be effectively controlled, the ferric iron is prevented from forming ferric hydroxide precipitate in an alkaline environment at an excessively high formation speed, and the alpha-M is ensured to be uniformly formed on the surface of carbonyl iron powder x Fe y And (4) an OOH modified layer. The oxidant is preferably added in an oxygen-containing gas mode, so that oxygen is introduced into the reaction system in a dispersed small bubble mode, the oxygen has better dispersibility in the reaction system, the effect of uniform reaction is further achieved, and the compactness and uniformity of the surface modification layer are further improved. The time of the oxidation reaction is preferably 10-60 min, the time of the oxidation reaction is less than the above range, the surface of the carbonyl iron powder can not be completely coated, and the time of the oxidation reaction is more than the above range, the surface of the carbonyl iron powder can not be completely coatedAnd the wave absorbing performance is reduced to some extent by over-coating.
In one embodiment, it is preferable that the above preparation method further comprises: and (4) sequentially aging and carrying out solid-liquid separation on the product system containing the surface modified carbonyl iron powder obtained in the step (S2) to obtain the surface modified carbonyl iron powder, washing and drying the surface modified carbonyl iron powder to obtain the surface modified carbonyl iron powder, wherein the aging treatment time is preferably 10-60 min. The aging treatment can further grow the crystals in the surface modification layer, reduce the lattice defects, further improve the mechanical property of the crystal, and finally carry out solid-liquid separation, washing and drying to obtain the target product.
In another exemplary embodiment of the present application, there is provided a surface-modified carbonyl iron powder prepared by any of the above-described preparation methods. The application coats alpha-M on the surface of carbonyl iron powder x Fe y The OOH (namely the alpha-FeOOH doped with M metal) surface modification layer effectively prevents carbonyl iron powder from contacting with chloride ions by utilizing the cation selectivity of the surface modification layer, thereby avoiding the corrosion of the carbonyl iron powder. Meanwhile, alpha-FeOOH has higher magnetic loss and lower electrical constant, so that the wave-absorbing performance of the carbonyl iron powder cannot be reduced when the alpha-FeOOH is used as a surface modification layer of the carbonyl iron powder, and the alpha-FeOOH has low dielectric and can be matched with carbonyl iron with high dielectric so that the whole body presents a more matched state of dielectric and magnetic conductivity, the frequency dispersion characteristic of the carbonyl iron powder is further improved, the carbonyl iron powder has good wave-absorbing effect on low-frequency and high-frequency electromagnetic waves, and the broadband wave-absorbing effect of the carbonyl iron powder is further expanded.
In another exemplary embodiment of the present application, there is provided a chlorine corrosion resistant wave-absorbing material, which includes a substrate and a wave-absorbing agent, where the wave-absorbing agent is any one of the surface-modified carbonyl iron powders described above, or is a surface-modified carbonyl iron powder prepared by any one of the preparation methods described above.
The wave-absorbing material adopting the surface modified carbonyl iron powder has stronger corrosion resistance, improves the dispersion characteristic of the carbonyl iron, has good wave-absorbing effect on low-frequency and high-frequency electromagnetic waves, and further expands the broadband wave-absorbing effect of the wave-absorbing material.
The following examples and comparative examples are provided to further illustrate the advantageous effects of the present application.
Example 1
Step (1)
0.5g of sodium phosphate, 1g of sodium dihydrogen phosphate and 30mL of deionized water were added to a 100mL reaction vessel, and the temperature was raised to 38 ℃. Followed by the continuous addition of 10mL FeSO 4 (0.2g/mL)、2.5mL Cr 2 (SO 4 ) 3 (0.1g/mL) solution, adding carbonyl iron powder after the solution is uniformly mixed and stirred, and adding 56g of carbonyl iron powder and keeping the reaction kettle in a stirring state (the stirring speed is 500r/min) all the time to obtain carbonyl iron powder dispersion liquid, wherein the pH value of the carbonyl iron powder dispersion liquid is 8-8.5.
Step (2)
Stirring continuously (the stirring speed is 500r/min), and simultaneously opening NaOH and O on two sides of the reaction kettle 2 The input device, set up the constant temperature bath between input device and the reation kettle, the constant temperature bath temperature is 38 ℃, the material of input to the reation kettle is through the preheating of constant temperature bath 3min to reaction temperature, and then the rethread reactor. The concentration of NaOH is 120g/L, the input speed is 60mL/h, O 2 Input rate of 100mL/h, NaOH and O 2 Continuously feeding for 10min, wherein O 2 Blowing into the reaction kettle in the form of highly dispersed tiny bubbles, and controlling the pH value of the reaction system to be 8.4 in the whole process.
Step (3)
Aging for 10min after the reaction is finished, filtering, washing, and spray drying to obtain the product with alpha-Cr 0.2 Fe 0.8 Carbonyl iron powder of OOH.
Example 2
Step (1)
0.5g of sodium phosphate, 1g of sodium dihydrogen phosphate and 30mL of deionized water were added to a 100mL reaction vessel, and the temperature was raised to 40 ℃. Followed by the continuous addition of 9mL of FeSO 4 (0.2g/mL)、2mL CuSO 4 (0.1g/mL) solution, adding carbonyl iron powder after the solution is uniformly mixed and stirred, and adding 106g of carbonyl iron powder and keeping the reaction kettle in a stirring state (the stirring speed is 500r/min) all the time to obtain carbonyl iron powder dispersion liquid, wherein the pH value of the carbonyl iron powder dispersion liquid is 8-8.5.
Step (2)
Continuously stirring (the stirring speed is 500r/min), and simultaneously opening NaOH and O on two sides of the reaction kettle 2 The input device, set up the constant temperature bath between input device and the reation kettle, the constant temperature bath temperature is 40 ℃, and the material of input to the reation kettle is through the preheating of constant temperature bath 3min to reaction temperature after the rethread reactor. The concentration of NaOH is 120g/L, the input speed is 58mL/h, O 2 The input speed of (2) is 98mL/h, NaOH and O 2 Continuously feeding for 10min, wherein O 2 Blown into the reaction kettle in the form of highly dispersed very small bubbles.
Step (3)
Aging for 10min after the reaction is finished, filtering, washing, and spray drying to obtain the product with alpha-Cu 0.1 Fe 0.9 Carbonyl iron powder of OOH.
Example 3
Step (1)
0.5g of sodium phosphate, 1g of sodium dihydrogen phosphate and 30mL of deionized water were added to a 100mL reaction vessel, and the temperature was raised to 40 ℃. Followed by continuous addition of 9mLFeSO 4 (0.2g/mL)、2.5mLNiSO 4 (0.1g/mL) solution, adding carbonyl iron powder after the solution is uniformly mixed and stirred, adding 56g of carbonyl iron powder, and keeping the reaction kettle in a stirring state (the stirring speed is 500r/min)) to obtain carbonyl iron powder dispersion liquid, wherein the pH value of the carbonyl iron powder dispersion liquid is 8-8.5.
Step (2)
Continuously stirring (the stirring speed is 500r/min), and simultaneously opening NaOH and O on two sides of the reaction kettle 2 The input device, set up the constant temperature bath between input device and the reation kettle, the constant temperature bath temperature is 40 ℃, and the material of input to the reation kettle is through the preheating of constant temperature bath 3min to reaction temperature after the rethread reactor. The concentration of NaOH is 120g/L, the input speed is 60mL/h, O 2 The input speed of (2) is 100mL/h, NaOH and O 2 Continuously feeding for 12min, wherein O 2 Blown into the reaction kettle in the form of highly dispersed very small bubbles.
Step (3)
Aging for 10min after the reaction is finished, filtering, washing, and spray drying to obtain the product with a-Ni attached 0.2 Fe 0.8 Carbonyl iron powder of OOH.
Example 4
The difference from example 1 is that the temperature of the thermostat in step (2) was 40 ℃.
Example 5
The difference from example 1 is that the temperature of the thermostat in step (2) was 35 ℃.
Example 6
The difference from example 1 is that the temperature of the thermostat in step (2) was 45 ℃.
Example 7
The difference from example 1 is that the temperature of the thermostat in step (2) was 30 ℃.
Example 8
The difference from the example 1 is that in the step (1), 0.5g of sodium phosphate, 2.2g of sodium dihydrogen phosphate and 30mL of deionized water are added into a 100mL reaction kettle, the temperature is raised to 38 ℃, and the pH value of the carbonyl iron powder dispersion liquid is controlled to be 7-7.5.
Example 9
The difference from the example 1 is that in the step (1), 0.82g of sodium phosphate, 1.3g of sodium dihydrogen phosphate and 30mL of deionized water are added into a 100mL reaction kettle, the temperature is raised to 38 ℃, and the pH value of the carbonyl iron powder dispersion liquid is controlled to be 9.5-10.
Example 10
The difference from the example 1 is that in the step (1), 1.8g of sodium phosphate, 0.6g of sodium dihydrogen phosphate and 30mL of deionized water are added into a 100mL reaction kettle, the temperature is raised to 38 ℃, and the pH value of the carbonyl iron powder dispersion liquid is controlled to be 6-6.5.
Example 11
The difference from example 1 is that the concentration of the NaOH solution in step (2) was 80 g/L.
Example 12
The difference from example 1 is that the concentration of the NaOH solution in step (2) was 200 g/L.
Example 13
The difference from example 1 is that the concentration of the NaOH solution in step (2) was 50 g/L.
Example 14
The difference from example 1 is that the concentration of the NaOH solution in step (2) was 230 g/L.
Example 15
The difference from example 1 is that the NaOH solution was introduced at a rate of 20L/h in step (2).
Example 16
The difference from example 1 is that the rate of introduction of the NaOH solution in step (2) was 100L/h.
Example 17
The difference from example 1 is that the rate of introduction of the NaOH solution in step (2) was 10L/h.
Example 18
The difference from example 1 is that the rate of introduction of the NaOH solution in step (2) was 120L/h.
Example 19
The difference from example 1 is that O in step (2) 2 The input rate of (2) was 20 mL/h.
Example 20
The difference from example 1 is that O in step (2) 2 The input rate of (2) is 10 mL/h.
Example 21
The difference from example 1 is that O in step (2) 2 The input rate of (2) is 120 mL/h.
Example 22
The difference from example 1 is that NaOH and O are present in step (2) 2 Continuously inputting for 60 min.
Example 23
The difference from example 1 is that NaOH and O are present in step (2) 2 Continuously inputting for 5 min.
Example 24
The difference from example 1 is that NaOH and O are present in step (2) 2 Continuously inputting for 80 min.
Comparative example 1
Shaanxi is the Xinghua T-P carbonyl iron powder (the particle size is 3-5 mu m).
Performance testing
The surface-modified carbonyl iron powder obtained in the example was mixed with paraffin (mass ratio 85:15), coaxial rings (outer diameter 7mm, inner diameter 3mm) were produced, electromagnetic parameters (real permittivity part e ', imaginary permittivity part e ", real permeability part u ' and imaginary permeability part u ') before and after the coaxial rings were soaked in 5% NaCl brine were measured, and the same test as described above was carried out for comparative example 1 to obtain corresponding electromagnetic parameters. In addition, the color of the coaxial rings before and after the saline soak was compared. The results are shown in Table 1.
TABLE 1
From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:
the preparation method leads sulfate to react on the surface of carbonyl iron powder by introducing an oxidant under the alkaline condition, and leads Fe 2+ Is oxidized into Fe 3+ And M ion and Fe 3+ With OH - And O 2- Combined to form compact and uniform alpha-M attached to the surface of carbonyl iron powder x Fe y The OOH modified layer has cation selectivity, can effectively prevent carbonyl iron powder from contacting with chloride ions, and further prevents the carbonyl iron powder from being corroded. Meanwhile, alpha-FeOOH is used as a low-valence Fe element to be oxidized into Fe 2 O 3 The intermediate product in the process has higher magnetic loss and lower electric constant, so that the protective layer of the carbonyl iron powder does not reduce the wave absorbing performance of the carbonyl iron powder, and the alpha-FeOOH has low dielectric and can be matched with the carbonyl iron with high dielectric, so that the whole body presents a more matched state of dielectric and magnetic conductivity, the dispersion characteristic of the carbonyl iron powder is further improved, the carbonyl iron powder has good wave absorbing effect on low-frequency and high-frequency electromagnetic waves, and the broadband wave absorbing effect of the carbonyl iron powder is further expanded.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A preparation method of surface modified carbonyl iron powder is characterized by comprising the following steps:
under the alkaline condition, introducing an oxidant into a reaction system containing sulfate and carbonyl iron powder for oxidation reaction to form a surface modification layer on the surface of the carbonyl iron powder, wherein the surface modification layer is alpha-M x Fe y OOH, wherein x is 0-1, y is 0-1, M is one or more selected from Cu, Ni, Cr, Mo, V, Nb,
the sulfate comprises FeSO 4 And sulfate salts of M.
2. The method according to claim 1, wherein the alkaline condition is a condition of pH 7 to 10, preferably a condition of pH 8 to 10.
3. The method according to claim 1, wherein the oxidation reaction is carried out at 35 to 40 ℃.
4. The method of manufacturing according to claim 2, comprising:
step S1, mixing a sulfate solution, a buffer solution and carbonyl iron powder at 35-40 ℃ to obtain carbonyl iron powder dispersion liquid, wherein the pH value of the carbonyl iron powder dispersion liquid is 7-10, and the mass concentration of the carbonyl iron powder in the carbonyl iron powder dispersion liquid is preferably 1-3.0 g/mL;
and step S2, introducing an oxidant and a NaOH solution into the carbonyl iron powder dispersion liquid for oxidation reaction to obtain the surface modified carbonyl iron powder, wherein the pH value of a reaction system in the oxidation reaction process is 7-10, and preferably, the oxidant is an oxygen-containing gas.
5. The method according to claim 4, wherein the dispersion of carbonyl iron powder contains Fe 2+ Has a concentration of 10 to 30g/L, preferably the concentration of the M ions is 0.5-3 g/L.
6. The method according to claim 4, wherein the buffer solution comprises (Na) 3 PO 4 、NaH 2 PO 4 Preferably the (Na) in the carbonyl iron powder dispersion liquid 3 PO 4 The concentration of (a) is 5-15 g/L, and the NaH is preferably selected 2 PO 4 Preferably, the concentration of (A) is 15 to 25g/L, and the stirring is performed in the processes of the step S1 and the step S2, and the stirring speed is preferably 200 to 700 r/min.
7. The method for preparing a composite material according to claim 4, wherein the step S2 includes:
heating the oxygen-containing gas and the NaOH solution to 35-40 ℃, and then introducing the heated oxygen-containing gas and the heated NaOH solution into the carbonyl iron powder dispersion liquid for reaction; preferably, the concentration of the NaOH solution is 80-200 g/L, the feeding speed is 20-100L/h, the oxygen content in the oxygen-containing gas is 90-99.9%, the feeding speed is 20-200 mL/h, and the time of the oxidation reaction is 10-60 min.
8. The method of manufacturing according to claim 4, further comprising:
and (3) sequentially aging and carrying out solid-liquid separation on the product system containing the surface modified carbonyl iron powder obtained in the step (S2) to obtain the surface modified carbonyl iron powder, washing and drying the surface modified carbonyl iron powder to obtain the surface modified carbonyl iron powder, wherein the aging treatment time is preferably 10-60 min.
9. A surface-modified carbonyl iron powder, characterized in that it is produced by the production method according to any one of claims 1 to 8.
10. A chlorine corrosion resistant wave absorbing material, which comprises a matrix and a wave absorbing agent, and is characterized in that the surface modified carbonyl iron powder in claim 9 is adopted.
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