CN110361313A - A kind of electrochemical test method of quantitative assessment phosphatization membrane porosity - Google Patents
A kind of electrochemical test method of quantitative assessment phosphatization membrane porosity Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 45
- 239000012528 membrane Substances 0.000 title claims abstract description 32
- 238000000840 electrochemical analysis Methods 0.000 title claims abstract description 20
- 238000012360 testing method Methods 0.000 claims abstract description 55
- 229910052751 metal Inorganic materials 0.000 claims abstract description 42
- 239000002184 metal Substances 0.000 claims abstract description 42
- 229910001209 Low-carbon steel Inorganic materials 0.000 claims abstract description 27
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 23
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 23
- 239000003792 electrolyte Substances 0.000 claims abstract description 22
- 238000002847 impedance measurement Methods 0.000 claims abstract description 14
- 239000008151 electrolyte solution Substances 0.000 claims abstract description 12
- 239000000243 solution Substances 0.000 claims description 30
- 238000002474 experimental method Methods 0.000 claims description 23
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 20
- 229910021607 Silver chloride Inorganic materials 0.000 claims description 15
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 15
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 claims description 15
- 239000011780 sodium chloride Substances 0.000 claims description 10
- 239000007864 aqueous solution Substances 0.000 claims description 4
- 238000004364 calculation method Methods 0.000 claims description 4
- 238000005868 electrolysis reaction Methods 0.000 claims description 2
- 238000009738 saturating Methods 0.000 claims 2
- 239000000523 sample Substances 0.000 description 83
- 230000007797 corrosion Effects 0.000 description 32
- 238000005260 corrosion Methods 0.000 description 32
- 239000011701 zinc Substances 0.000 description 28
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 description 26
- 238000000576 coating method Methods 0.000 description 18
- 229910019142 PO4 Inorganic materials 0.000 description 16
- 238000001453 impedance spectrum Methods 0.000 description 16
- ODPUKHWKHYKMRK-UHFFFAOYSA-N cerium;nitric acid Chemical compound [Ce].O[N+]([O-])=O ODPUKHWKHYKMRK-UHFFFAOYSA-N 0.000 description 15
- 239000010410 layer Substances 0.000 description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 15
- 229910002651 NO3 Inorganic materials 0.000 description 14
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 14
- 230000005611 electricity Effects 0.000 description 14
- 229910052725 zinc Inorganic materials 0.000 description 14
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 description 13
- MFXMOUUKFMDYLM-UHFFFAOYSA-L zinc;dihydrogen phosphate Chemical compound [Zn+2].OP(O)([O-])=O.OP(O)([O-])=O MFXMOUUKFMDYLM-UHFFFAOYSA-L 0.000 description 13
- GTKRFUAGOKINCA-UHFFFAOYSA-M chlorosilver;silver Chemical compound [Ag].[Ag]Cl GTKRFUAGOKINCA-UHFFFAOYSA-M 0.000 description 12
- 239000011248 coating agent Substances 0.000 description 12
- 230000005518 electrochemistry Effects 0.000 description 10
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 9
- 239000010452 phosphate Substances 0.000 description 9
- 230000008569 process Effects 0.000 description 8
- 238000001228 spectrum Methods 0.000 description 8
- 238000004140 cleaning Methods 0.000 description 7
- 238000005259 measurement Methods 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 7
- 230000000149 penetrating effect Effects 0.000 description 7
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 7
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 239000003153 chemical reaction reagent Substances 0.000 description 6
- 238000003682 fluorination reaction Methods 0.000 description 6
- 238000013178 mathematical model Methods 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 239000011734 sodium Substances 0.000 description 6
- 229910052708 sodium Inorganic materials 0.000 description 6
- 238000002425 crystallisation Methods 0.000 description 5
- 230000008025 crystallization Effects 0.000 description 5
- 238000003756 stirring Methods 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 3
- UGWKCNDTYUOTQZ-UHFFFAOYSA-N copper;sulfuric acid Chemical compound [Cu].OS(O)(=O)=O UGWKCNDTYUOTQZ-UHFFFAOYSA-N 0.000 description 3
- 238000002848 electrochemical method Methods 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 230000010287 polarization Effects 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000010998 test method Methods 0.000 description 3
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 239000012085 test solution Substances 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 241000208340 Araliaceae Species 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 235000005035 Panax pseudoginseng ssp. pseudoginseng Nutrition 0.000 description 1
- 235000003140 Panax quinquefolius Nutrition 0.000 description 1
- 208000037656 Respiratory Sounds Diseases 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- ZYDVNTYVDVZMKF-UHFFFAOYSA-N [Cl].[Ag] Chemical compound [Cl].[Ag] ZYDVNTYVDVZMKF-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 229910052927 chalcanthite Inorganic materials 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 238000000157 electrochemical-induced impedance spectroscopy Methods 0.000 description 1
- 235000008434 ginseng Nutrition 0.000 description 1
- CPSYWNLKRDURMG-UHFFFAOYSA-L hydron;manganese(2+);phosphate Chemical compound [Mn+2].OP([O-])([O-])=O CPSYWNLKRDURMG-UHFFFAOYSA-L 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- -1 kirsite Inorganic materials 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- WJZHMLNIAZSFDO-UHFFFAOYSA-N manganese zinc Chemical compound [Mn].[Zn] WJZHMLNIAZSFDO-UHFFFAOYSA-N 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
Landscapes
- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
Abstract
The present invention relates to a kind of electrochemical test methods of quantitative assessment phosphatization membrane porosity, the specific steps are as follows: (1) phosphating coat sample is placed in progress electrochemical AC impedance test in electrolyte, obtains Nyquist figure and Bode figure；(2) parent metal low carbon mild steel sample is fitted in the electrolyte solution using the Nyquist figure that step (1) obtainsAnd the interface differential capacitance C of phosphating coat sample in the electrolytic solutiondl；(3) the Bode figure obtained by step (1) fit phosphating coat in ac impedance measurement frequency range from high frequency to penetrate test frequency points N corresponding to phase or pentration frequency '；(4) porosity is calculated according to step (2) and (3) parameters obtained.Compared with prior art, the porosity of quantitative assessment phosphating coat of the present invention is easy to carry out, fast and convenient, and accuracy is high.
Description
Technical field
The present invention relates to a kind of measuring methods of phosphatization membrane porosity, more particularly, to a kind of quantitative assessment phosphatization membrane pores
The electrochemical test method of rate.
Background technique
Carbon steel, aluminium alloy, kirsite, cadmium and other metal materials phosphatization be the method being widely used in surface treatment
One of, the purpose of metal surface phosphating is mainly manifested in two aspects, first is that applying the pretreatment procedure in coating, increases coating
Adhesive force, second is that obtaining the functional phosphating film of corrosion-resistant, lubrication, electrical isolation, furthermore phosphating coat has decorative effect, phosphorus
Post-processing of the metal parts of change as combined oil or paraffin, can provide temporary protection effect[1].In these characteristics of phosphating coat
In the middle, corrosion resisting property is one important property data of phosphating coat, is evaluated at present about the test of phosphating coat corrosion resisting property
Method is divided into conventional methods and electrochemical test method, and routine experimentation mainly has copper sulphate pitting test, salt water test,
Both test methods can more directly evaluate the corrosion resistance of phosphating coat, but can only provide qualitatively as a result, and working as film layer
It needs to be readily incorporated biggish human error by micro-judgment test endpoint when thicker, testing result has biggish subjectivity
Property.The corrosion proof electrochemical test method of phosphating coat is mainly potentiodynamic method and electrochemical AC impedance method, both sides
Method is covered with corrosion potential, corrosion current and the polarization resistance of corrosion of the sample of phosphating coat in electrolyte by test, from
And quantitatively evaluate the corrosion resisting property of phosphating coat[2,3]。
The corrosion proof Electrochemical method of phosphating coat has the advantages that accuracy is high.In fact, in addition to corrosion potential, corruption
Other than the corrosion resisting property for losing the polarization resistance energy quantitative assessment phosphating coat of electric current and corrosion, the porosity of phosphating coat and film layer it is resistance to
Corrosion can also have good corresponding relationship, be the key property of phosphating coat, measure the porosity of phosphorization membrane, can also quantitatively comment
The corrosion resisting property of valence phosphating coat.
The quantitative assessment of phosphatization membrane porosity can be calculated by image analysis software[4], principle is from phosphating coat
It is darker at the defects of sample SEM pattern can be seen that hole, crackle, by Photoshop software with color range at hole
Threshold values appropriate is set, white is presented in the region higher than this value, and black is presented in the region lower than this value, thus generates in sharp contrast
Gray scale pictures, percentage shared by black area in gray scale pictures is then calculated by image analysis software, calculates phosphorus
Change the porosity of film.In addition, Notter etc.[5]Using the method for dynamic potential scanning electrochemistry experiment, Weng and Lendvay etc.[1,6]
Using the method quantitative assessment porosity of phosphating coat of electrochemical AC impedance experiment.In fact Notter, Weng etc. are used
The mathematical model that electrochemical method evaluates phosphatization membrane porosity is derived from A.T.A.Jenkins, R.D.Armstrong[7]Report
Mathematical model (as shown in Figs. 1-2) about coating porosity.Model is thought carrying out porosity electrochemical AC impedance in Fig. 1
In test, film is insulation, after electrolyte penetrates into metal surface by membrane pores, area and hole that parent metal corrodes
The calculation formula of area equation, porosity can be indicated with following equations:
Wherein, AdPorosity, bath resistance rate (Ω cm) in ρ-hole, d- coating layer thickness (cm), RpoMatrix gold
Belong to polarization resistance (Ω cm in the electrolytic solution2)。
Mathematical model in Fig. 2 thinks in electrochemical AC impedance test that film is insulation, and electrolyte passes through membrane pores
After penetrating into metal surface, the area of the area and film surface hole of parent metal corrosion is unequal, and the area of corrosion is greater than film table
The calculation formula of the area of face gap, porosity can be indicated with following equations:
Wherein, AdPorosity,The differential capacitance (μ F) of parent metal in the electrolytic solution, CdlFilm is in the electrolytic solution
Differential capacitance (μ F).
Notter etc. is using the porosity of the method test phosphating coat of dynamic potential scanning electrochemistry experiment and Weng etc.[1]
The mathematical model using electrochemical AC impedance experimental method quantitative assessment phosphatization membrane porosity of report thinks that phosphating coat is
Insulation, phosphating coat is not involved in electrochemical dissolution in electrochemical test process.
Although the test method of these above-mentioned evaluation phosphatization membrane porosities has certain theoretical basis, but they only consider
The micromorphology of phosphating coat, does not touch the internal structure situation of phosphatization membrane crystallization, does not account for phosphating coat yet
Influence of the thickness to porosity test, the porosity data being calculated by these methods inevitably deviate phosphatization fenestra
The truth of gap rate.
Bibliography:
[1]Weng D,Jokiel P,Uebleis A,et a1.Corrosion and characteristics of
zinc and manganese phosphate coatings[J].Surface and Coatings Technology,
1996,88:147-156.
[2] He Deliang, Wang Minghao, Cui Zhengdan wait research and the phosphatization membrane electrochemical point of high corrosion-resistant zinc-manganese based phosphatization liquid
Analyse [J] Hunan University journal, 2009,36 (4): 65-69.
[3] Lin Bilan, Lu Jintang, Kong Gang wait On Electrochemical Measurement Technique For Phosphate Coatings progress [J] corrosion science and prevent
Shield technology, 2006,18 (6), 429-432.
[4] Shao Honghong, Chen Tingting, Qi Changyang wait Seal treatment to the shadow of phosphatization film properties under 316L stainless steel ultrasonic field
Ring [J] China Surface Engineering, 2017,30 (1): 63-69.
[5]Notter I M,Gabe D R.Polarisation resistance methods for
measurement of the porosity of thin metal coatings[J].Corrosion Science,1993,
34(5):851.
[6]Lendvay-gyorik G,Meszaros G,Lengyel B.A simple testing method for
quality control of phosphate coatings based on impedance measurements[J]
.Journal of Applied Electrochemistry,2002,32(8):891.
[7]A.T.A.Jenkins,R.D.Armstrong.Comments on the article“Use of
electrochemical impedance spectroscopy for the study of corrosion protection
by polymer coatings”by F.Mansfeld[J].Journal of Applied Electrochemistry,
1995,25:1143-1144.
Summary of the invention
It is an object of the present invention to overcome the above-mentioned drawbacks of the prior art and provide a kind of quantitative assessment phosphatizations
The electrochemical test method of membrane porosity.
The purpose of the present invention can be achieved through the following technical solutions:
A kind of electrochemical test method of quantitative assessment phosphatization membrane porosity, the specific steps are as follows:
(1) phosphating coat sample is placed in progress electrochemical AC impedance test in electrolyte, obtains Nyquist figure and Bode
Figure；
(2) parent metal low carbon mild steel sample is fitted in the electrolyte solution using the Nyquist figure that step (1) obtains
InAnd the interface differential capacitance C of phosphating coat sample in the electrolytic solutiondl；
(3) phosphating coat is fitted in ac impedance measurement frequency range from high frequency by the Bode figure that step (1) obtains
(10kHz) to penetrate test frequency points N corresponding to phase or pentration frequency '；
(4) porosity is calculated according to step (2) and (3) parameters obtained, the calculation formula for evaluating porosity is as follows:
Wherein, AdPorosity,The differential capacitance (μ F) of parent metal in the electrolytic solution, CdlPhosphating coat is in electrolyte
In differential capacitance (μ F), K- proportionality coefficientWherein N' is in phosphating coat ac impedance measurement frequency range from high frequency
It counts to test frequency corresponding to phase or pentration frequency is penetrated, NoIt is total in phosphating coat ac impedance measurement frequency range
Test frequency points.
Preferably, in step (1): electrochemical AC impedance experiment uses three-electrode system, and phosphating coat sample is put into three
In electrode electrolytic pool, tested using electrochemical workstation.
It is furthermore preferred that in three-electrode system, after working electrode is respectively parent metal low-Carbon steel specimen and phosphorating treatment
Mild steel phosphating coat sample, auxiliary electrode are platinum black electrode, and reference electrode is Ag/AgCl/KCl aqueous solution electrode.
It is furthermore preferred that the area of working electrode is 1cm2。
It is furthermore preferred that the concentration of KCl aqueous solution is 3mol/L in reference electrode.
Preferably, AC signal amplitude is ± 10mV in electrochemical workstation.
Preferably, electrolyte is the NaCl solution of 3.5wt.%.
Preferably, electrolysis temperature is 20 DEG C.
Preferably, range of scanned frequencies is 10KHz-0.01Hz in electrochemical workstation.
Parent metal sample uses low carbon mild steel, having a size of 30mm × 50mm × 0.5mm.Parent metal sample material is soaked
Stain phosphatization 10min time into middle temperature phosphating solution, it is prepared into phosphating coat sample.
Medium temperature Zinc phosphating solution composition and operating parameter are as follows: zinc dihydrogen phosphate (Zn (H2PO4)2) 33g/L, zinc nitrate (Zn
(NO3)2·6H2O) 95g/L, nickel nitrate (Ni (NO3)2·6H2O) 1g/L, sodium fluoride (NaF) 1.2g/L, cerous nitrate (Ce
(NO)3·6H2O) 0-100mg/L, 65 DEG C of temperature, pure water is used in the preparation of phosphating solution and the cleaning of sample.
The obvious riser portions of capacitive reactance arc phase are allocated as tangent line and being basically unchanged of high frequency treatment phase part at low frequency in Bode figure
Make corresponding phase and frequency at tangent line crosspoint and obtains ΦτAnd logfτTwo parameters, they show respectively electrochemical ac
Impedance is tested from the test process of high frequency tremendously low frequency, and electrolyte arrives at matrix gold from the hole of phosphatization film surface infiltration phosphating coat
Metal surface penetrates phase and corresponding pentration frequency, the thickness of the compactness extent of the two parameters and phosphating coat, phosphating coat
It spends closely related.AC impedance experiment is tested since high frequency to ΦτOr logfτWhen corresponding test frequency total number be
N'。
Compared with prior art, the invention has the following advantages:
1, the structure situation inside energy reflected well phosphatization membrane crystallization, such as crystalline particle size, the shape of crystallization, crystalline substance
Superposition and fine and close gas porosity, hole, crack between grain etc., and consider the influence of phosphatization film thickness device to hole gap rate.
2, it can be well reflected out the truth of phosphatization membrane porosity, and can be opposite with the corrosion resistance of phosphating coat
It answers.
3, it is easy to carry out using the porosity of electrochemical AC impedance experimental method quantitative assessment phosphating coat, it is fast and convenient,
Accuracy is high.
Detailed description of the invention
Fig. 1 is A.T.A.Jenkins, the signal of the mathematical model about coating porosity of R.D.Armstrong report
Figure；
Fig. 2 is A.T.A.Jenkins, the signal of the mathematical model about coating porosity of R.D.Armstrong report
Figure；
Fig. 3 is the schematic diagram of phosphatization membrane porosity in the present invention；
Fig. 4 is phosphating coat sample AC impedance Nyquist figure in embodiment 1；
Fig. 5 is phosphating coat sample AC impedance Bode figure in embodiment 1；
Fig. 6 is phosphating coat sample AC impedance Nyquist figure in embodiment 2；
Fig. 7 is phosphating coat sample AC impedance Bode figure in embodiment 2；
Fig. 8 is phosphating coat sample AC impedance Nyquist figure in embodiment 3；
Fig. 9 is phosphating coat sample AC impedance Bode figure in embodiment 3；
Figure 10 is phosphating coat sample AC impedance Nyquist figure in embodiment 4；
Figure 11 is phosphating coat sample AC impedance Bode figure in embodiment 4；
Figure 12 is phosphating coat sample AC impedance Nyquist figure in embodiment 5；
Figure 13 is phosphating coat sample AC impedance Bode figure in embodiment 5；
Figure 14 is phosphating coat sample AC impedance Nyquist figure in embodiment 6；
Figure 15 is phosphating coat sample AC impedance Bode figure in embodiment 6.
Specific embodiment
The present invention is described in detail with specific embodiment below in conjunction with the accompanying drawings.
Test equipment used in following embodiment:
Low carbon mild steel (30mm × 50mm × 0.5mm), 250mL three-electrode system electrolytic cell, 260 type platinum black electrodes, silver-chlorine
Change silver electrode [Ag/AgCl, KCl (3.0mol/L)], AutolabPGST302/FRA electrochemical workstation, QCC-A type magnetism is surveyed
Thick instrument.Phosphate coating thickness is measured using QCC-A type magnetic thickness tester, after instrumental correction, specimen surface surveys 3 points, is averaged
Obtain the thickness of phosphorization membrane.
Embodiment 1
Medium temperature Zinc phosphating solution composition and operating parameter are as follows: zinc dihydrogen phosphate (Zn (H2PO4)2) 33g/L, zinc nitrate (Zn
(NO3)2·6H2O) 95g/L, nickel nitrate (Ni (NO3)2·6H2O) 1g/L, sodium fluoride (NaF) 1.2g/L, cerous nitrate (Ce
(NO)3·6H2O) 0mg/L, 65 DEG C of temperature.33g zinc dihydrogen phosphate, 95g zinc nitrate, 1g nickel nitrate, 1.2g fluorination are weighed respectively
Load weighted above-mentioned chemical reagent is dissolved into the pure water of 500mL by sodium under stiring, it is to be dissolved completely after be diluted to
1000mL is stirred evenly, is heated and is maintained at 65 DEG C to get medium temperature Zinc phosphating solution is arrived.
By parent metal low carbon mild steel sample (30mm × 50mm × 0.5mm) with 1#~5#Abrasive paper for metallograph is successively polished, pure
It is impregnated into middle temperature phosphating solution in phosphatization 10min after water cleaning, is prepared into phosphating coat sample.QCC- is used to phosphating coat sample
A type magnetic thickness tester measures phosphate coating thickness, then implements electrochemical alternate impedance spectrum measurement, and specific operation process is as follows:
The NaCl solution 200mL that prepared 3.5wt% is measured with graduated cylinder, is poured onto the three-electrode cell of 250mL,
It is then placed in constant temperature in 20 DEG C of water-baths.It is 1cm by geometric area2Phosphating coat sample be placed on three electrodes as working electrode
In electrolytic cell, 260 type platinum black electrodes are auxiliary electrode, and silver-silver chloride electrode [Ag/AgCl, KCl (3.0mol/L)] is reference electricity
Pole, test equipment are AutolabPGST302/FRA electrochemical workstation, and the amplitude of ac voltage signal is ± 10mV, exchange letter
Number 10 KHz-0.01 Hz of frequency range, under the conditions of open circuit potential, atmosphere containing dissolved oxygen carry out impedance spectrum experiment, experiment
Total frequency spectrum number NoIt is 61.Obtain the electrochemical AC impedance Nyquist figure (Fig. 4) and Bode figure (Fig. 5) of phosphating coat sample.By
Electrochemical analysis software is fitted Nyquist figure, obtains differential capacitance C of the phosphating coat sample in the electrolytedl, according to electrochemistry
Impedance spectrum Bode figure obtains phosphating coat sample in ac impedance measurement frequency range from high frequency to penetrating phase or pentration frequency
Corresponding test frequency points N '.
It is 1cm by geometric area2Parent metal low carbon mild steel sample be placed on three-electrode cell as working electrode
In, 260 type platinum black electrodes are auxiliary electrode, and silver-silver chloride electrode [Ag/AgCl, KCl (3.0mol/L)] is reference electrode, with
Above-mentioned identical test equipment and test condition carry out electrochemical AC impedance test, obtain the Nyquist of parent metal sample
Figure obtains differential electricity of the parent metal low carbon mild steel sample in the electrolyte by electrochemical analysis software fitting Nyquist figure
HoldFurther by formulaCalculate the porosity of phosphating coat.Each parameter and porosity calculated result such as table 1
It is shown.
Table 1
Embodiment 2
Medium temperature Zinc phosphating solution composition and operating parameter are as follows: zinc dihydrogen phosphate (Zn (H2PO4)2) 33g/L, zinc nitrate (Zn
(NO3)2·6H2O) 95g/L, nickel nitrate (Ni (NO3)2·6H2O) 1g/L, sodium fluoride (NaF) 1.2g/L, cerous nitrate (Ce
(NO)3·6H2O) 20mg/L, 65 DEG C of temperature.33g zinc dihydrogen phosphate, 95g zinc nitrate, 1g nickel nitrate, 1.2g fluorination are weighed respectively
Load weighted above-mentioned chemical reagent is dissolved into the pure water of 500mL by sodium, 20mg cerous nitrate under stiring, to be dissolved complete
After be diluted to 1000mL, stir evenly, heat and be maintained at 65 DEG C to get to medium temperature Zinc phosphating solution.
By parent metal low carbon mild steel sample (30mm × 50mm × 0.5mm) with 1#~5#Abrasive paper for metallograph is successively polished, pure
It is impregnated into middle temperature phosphating solution in phosphatization 10min after water cleaning, is prepared into phosphating coat sample.QCC- is used to phosphating coat sample
A type magnetic thickness tester measures phosphate coating thickness, then implements electrochemical alternate impedance spectrum measurement, and specific operation process is as follows:
The NaCl solution 200mL that prepared 3.5wt% is measured with graduated cylinder, is poured onto the three-electrode cell of 250mL,
It is then placed in constant temperature in 20 DEG C of water-baths.It is 1cm by geometric area2Phosphating coat sample be placed on three electrodes as working electrode
In electrolytic cell, 260 type platinum black electrodes are auxiliary electrode, and silver-silver chloride electrode [Ag/AgCl, KCl (3.0mol/L)] is reference electricity
Pole, test equipment are AutolabPGST302/FRA electrochemical workstation, and the amplitude of ac voltage signal is ± 10mV, exchange letter
Number frequency range 10KHz-0.01Hz, the experiment of impedance spectrum is carried out under the conditions of open circuit potential, atmosphere containing dissolved oxygen, experiment is total
Spectrum number NoIt is 61.Obtain the electrochemical AC impedance Nyquist figure (Fig. 6) and Bode figure (Fig. 7) of phosphating coat sample.By electricity
Chemical analysis software is fitted Nyquist figure, obtains differential capacitance C of the phosphating coat sample in the electrolytedl, hindered according to electrochemistry
Anti- spectrum Bode figure obtains phosphating coat sample in ac impedance measurement frequency range from high frequency to penetrating phase or pentration frequency institute
Corresponding test frequency points N '.
It is 1cm by geometric area2Parent metal low carbon mild steel sample be placed on three-electrode cell as working electrode
In, 260 type platinum black electrodes are auxiliary electrode, and silver-silver chloride electrode [Ag/AgCl, KCl (3.0mol/L)] is reference electrode, with
Above-mentioned identical test equipment and test condition carry out electrochemical AC impedance test, obtain the Nyquist of parent metal sample
Figure obtains differential electricity of the parent metal low carbon mild steel sample in the electrolyte by electrochemical analysis software fitting Nyquist figure
HoldFurther by formulaCalculate the porosity of phosphating coat.Each parameter and porosity calculated result such as table 2
It is shown.
Table 2
Embodiment 3
Medium temperature Zinc phosphating solution composition and operating parameter are as follows: zinc dihydrogen phosphate (Zn (H2PO4)2) 33g/L, zinc nitrate (Zn
(NO3)2·6H2O) 95g/L, nickel nitrate (Ni (NO3)2·6H2O) 1g/L, sodium fluoride (NaF) 1.2g/L, cerous nitrate (Ce
(NO)3·6H2O) 40mg/L, 65 DEG C of temperature.33g zinc dihydrogen phosphate, 95g zinc nitrate, 1g nickel nitrate, 1.2g fluorination are weighed respectively
Load weighted above-mentioned chemical reagent is dissolved into the pure water of 500mL by sodium, 40mg cerous nitrate under stiring, to be dissolved complete
After be diluted to 1000mL, stir evenly, heat and be maintained at 65 DEG C to get to medium temperature Zinc phosphating solution.
By parent metal low carbon mild steel sample (30mm × 50mm × 0.5mm) with 1#~5#Abrasive paper for metallograph is successively polished, pure
It is impregnated into middle temperature phosphating solution in phosphatization 10min after water cleaning, is prepared into phosphating coat sample.QCC- is used to phosphating coat sample
A type magnetic thickness tester measures phosphate coating thickness, then implements electrochemical alternate impedance spectrum measurement, and specific operation process is as follows:
The NaCl solution 200mL that prepared 3.5wt% is measured with graduated cylinder, is poured onto the three-electrode cell of 250mL,
It is then placed in constant temperature in 20 DEG C of water-baths.It is 1cm by geometric area2Phosphating coat sample be placed on three electrodes as working electrode
In electrolytic cell, 260 type platinum black electrodes are auxiliary electrode, and silver-silver chloride electrode [Ag/AgCl, KCl (3.0mol/L)] is reference electricity
Pole, test equipment are AutolabPGST302/FRA electrochemical workstation, and the amplitude of ac voltage signal is ± 10mV, exchange letter
Number frequency range 10KHz-0.01Hz, the experiment of impedance spectrum is carried out under the conditions of open circuit potential, atmosphere containing dissolved oxygen, experiment is total
Spectrum number NoIt is 61.Obtain the electrochemical AC impedance Nyquist figure (Fig. 8) and Bode figure (Fig. 9) of phosphating coat sample.By electricity
Chemical analysis software is fitted Nyquist figure, obtains differential capacitance C of the phosphating coat sample in the electrolytedl, hindered according to electrochemistry
Anti- spectrum Bode figure obtains phosphating coat sample in ac impedance measurement frequency range from high frequency to penetrating phase or pentration frequency institute
Corresponding test frequency points N '.
It is 1cm by geometric area2Parent metal low carbon mild steel sample be placed on three-electrode cell as working electrode
In, 260 type platinum black electrodes are auxiliary electrode, and silver-silver chloride electrode [Ag/AgCl, KCl (3.0mol/L)] is reference electrode, with
Above-mentioned identical test equipment and test condition carry out electrochemical AC impedance test, obtain the Nyquist of parent metal sample
Figure obtains differential electricity of the parent metal low carbon mild steel sample in the electrolyte by electrochemical analysis software fitting Nyquist figure
HoldFurther by formulaCalculate the porosity of phosphating coat.Each parameter and porosity calculated result such as table 3
It is shown.
Table 3
Embodiment 4
Medium temperature Zinc phosphating solution composition and operating parameter are as follows: zinc dihydrogen phosphate (Zn (H2PO4)2) 33g/L, zinc nitrate (Zn
(NO3)2·6H2O) 95g/L, nickel nitrate (Ni (NO3)2·6H2O) 1g/L, sodium fluoride (NaF) 1.2g/L, cerous nitrate (Ce
(NO)3·6H2O) 60mg/L, 65 DEG C of temperature.33g zinc dihydrogen phosphate, 95g zinc nitrate, 1g nickel nitrate, 1.2g fluorination are weighed respectively
Load weighted above-mentioned chemical reagent is dissolved into the pure water of 500mL by sodium, 60mg cerous nitrate under stiring, to be dissolved complete
After be diluted to 1000mL, stir evenly, heat and be maintained at 65 DEG C to get to medium temperature Zinc phosphating solution.
By parent metal low carbon mild steel sample (30mm × 50mm × 0.5mm) with 1#~5#Abrasive paper for metallograph is successively polished, pure
It is impregnated into middle temperature phosphating solution in phosphatization 10min after water cleaning, is prepared into phosphating coat sample.QCC- is used to phosphating coat sample
A type magnetic thickness tester measures phosphate coating thickness, then implements electrochemical alternate impedance spectrum measurement, and specific operation process is as follows:
The NaCl solution 200mL that prepared 3.5wt% is measured with graduated cylinder, is poured onto the three-electrode cell of 250mL,
It is then placed in constant temperature in 20 DEG C of water-baths.It is 1cm by geometric area2Phosphating coat sample be placed on three electrodes as working electrode
In electrolytic cell, 260 type platinum black electrodes are auxiliary electrode, and silver-silver chloride electrode [Ag/AgCl, KCl (3.0mol/L)] is reference electricity
Pole, test equipment are AutolabPGST302/FRA electrochemical workstation, and the amplitude of ac voltage signal is ± 10mV, exchange letter
Number frequency range 10KHz-0.01Hz, the experiment of impedance spectrum is carried out under the conditions of open circuit potential, atmosphere containing dissolved oxygen, experiment is total
Spectrum number NoIt is 61.Obtain the electrochemical AC impedance Nyquist figure (Figure 10) and Bode figure (Figure 11) of phosphating coat sample.By
Electrochemical analysis software is fitted Nyquist figure, obtains differential capacitance C of the phosphating coat sample in the electrolytedl, according to electrochemistry
Impedance spectrum Bode figure obtains phosphating coat sample in ac impedance measurement frequency range from high frequency to penetrating phase or pentration frequency
Corresponding test frequency points N '.
It is 1cm by geometric area2Parent metal low carbon mild steel sample be placed on three-electrode cell as working electrode
In, 260 type platinum black electrodes are auxiliary electrode, and silver-silver chloride electrode [Ag/AgCl, KCl (3.0mol/L)] is reference electrode, with
Above-mentioned identical test equipment and test condition carry out electrochemical AC impedance test, obtain the Nyquist of parent metal sample
Figure obtains differential electricity of the parent metal low carbon mild steel sample in the electrolyte by electrochemical analysis software fitting Nyquist figure
HoldFurther by formulaCalculate the porosity of phosphating coat.Each parameter and porosity calculated result such as table 4
It is shown.
Table 4
Embodiment 5
Medium temperature Zinc phosphating solution composition and operating parameter are as follows: zinc dihydrogen phosphate (Zn (H2PO4)2) 33g/L, zinc nitrate (Zn
(NO3)2·6H2O) 95g/L, nickel nitrate (Ni (NO3)2·6H2O) 1g/L, sodium fluoride (NaF) 1.2g/L, cerous nitrate (Ce
(NO)3·6H2O) 80mg/L, 65 DEG C of temperature.33g zinc dihydrogen phosphate, 95g zinc nitrate, 1g nickel nitrate, 1.2g fluorination are weighed respectively
Load weighted above-mentioned chemical reagent is dissolved into the pure water of 500mL by sodium, 80mg cerous nitrate under stiring, to be dissolved complete
After be diluted to 1000mL, stir evenly, heat and be maintained at 65 DEG C to get to medium temperature Zinc phosphating solution.
By parent metal low carbon mild steel sample (30mm × 50mm × 0.5mm) with 1#~5#Abrasive paper for metallograph is successively polished, pure
It is impregnated into middle temperature phosphating solution in phosphatization 10min after water cleaning, is prepared into phosphating coat sample.QCC- is used to phosphating coat sample
A type magnetic thickness tester measures phosphate coating thickness, then implements electrochemical alternate impedance spectrum measurement, and specific operation process is as follows:
The NaCl solution 200mL that prepared 3.5wt% is measured with graduated cylinder, is poured onto the three-electrode cell of 250mL,
It is then placed in constant temperature in 20 DEG C of water-baths.It is 1cm by geometric area2Phosphating coat sample be placed on three electrodes as working electrode
In electrolytic cell, 260 type platinum black electrodes are auxiliary electrode, and silver-silver chloride electrode [Ag/AgCl, KCl (3.0mol/L)] is reference electricity
Pole, test equipment are AutolabPGST302/FRA electrochemical workstation, and the amplitude of ac voltage signal is ± 10mV, exchange letter
Number frequency range 10KHz-0.01Hz, the experiment of impedance spectrum is carried out under the conditions of open circuit potential, atmosphere containing dissolved oxygen, experiment is total
Spectrum number NoIt is 61.Obtain the electrochemical AC impedance Nyquist figure (Figure 12) and Bode figure (Figure 13) of phosphating coat sample.By
Electrochemical analysis software is fitted Nyquist figure, obtains differential capacitance C of the phosphating coat sample in the electrolytedl, according to electrochemistry
Impedance spectrum Bode figure obtains phosphating coat sample in ac impedance measurement frequency range from high frequency to penetrating phase or pentration frequency
Corresponding test frequency points N '.
It is 1cm by geometric area2Parent metal low carbon mild steel sample be placed on three-electrode cell as working electrode
In, 260 type platinum black electrodes are auxiliary electrode, and silver-silver chloride electrode [Ag/AgCl, KCl (3.0mol/L)] is reference electrode, with
Above-mentioned identical test equipment and test condition carry out electrochemical AC impedance test, obtain the Nyquist of parent metal sample
Figure obtains differential electricity of the parent metal low carbon mild steel sample in the electrolyte by electrochemical analysis software fitting Nyquist figure
HoldFurther by formulaCalculate the porosity of phosphating coat.Each parameter and porosity calculated result such as table 5
It is shown.
Table 5
Embodiment 6
Medium temperature Zinc phosphating solution composition and operating parameter are as follows: zinc dihydrogen phosphate (Zn (H2PO4)2) 33g/L, zinc nitrate (Zn
(NO3)2·6H2O) 95g/L, nickel nitrate (Ni (NO3)2·6H2O) 1g/L, sodium fluoride (NaF) 1.2g/L, cerous nitrate (Ce
(NO)3·6H2O) 100mg/L, 65 DEG C of temperature.33g zinc dihydrogen phosphate, 95g zinc nitrate, 1g nickel nitrate, 1.2g fluorination are weighed respectively
Load weighted above-mentioned chemical reagent is dissolved into the pure water of 500mL by sodium, 100mg cerous nitrate under stiring, to be dissolved complete
After be diluted to 1000mL, stir evenly, heat and be maintained at 65 DEG C to get to medium temperature Zinc phosphating solution.
By parent metal low carbon mild steel sample (30mm × 50mm × 0.5mm) with 1#~5#Abrasive paper for metallograph is successively polished, pure
It is impregnated into middle temperature phosphating solution in phosphatization 10min after water cleaning, is prepared into phosphating coat sample.QCC- is used to phosphating coat sample
A type magnetic thickness tester measures phosphate coating thickness, then implements electrochemical alternate impedance spectrum measurement, and specific operation process is as follows:
The NaCl solution 200mL that prepared 3.5wt% is measured with graduated cylinder, is poured onto the three-electrode cell of 250mL,
It is then placed in constant temperature in 20 DEG C of water-baths.It is 1cm by geometric area2Phosphating coat sample be placed on three electrodes as working electrode
In electrolytic cell, 260 type platinum black electrodes are auxiliary electrode, and silver-silver chloride electrode [Ag/AgCl, KCl (3.0mol/L)] is reference electricity
Pole, test equipment are AutolabPGST302/FRA electrochemical workstation, and the amplitude of ac voltage signal is ± 10mV, exchange letter
Number frequency range 10KHz-0.01Hz, the experiment of impedance spectrum is carried out under the conditions of open circuit potential, atmosphere containing dissolved oxygen, experiment is total
Spectrum number NoIt is 61.Obtain the electrochemical AC impedance Nyquist figure (Figure 14) and Bode figure (Figure 15) of phosphating coat sample.By
Electrochemical analysis software is fitted Nyquist figure, obtains differential capacitance C of the phosphating coat sample in the electrolytedl, according to electrochemistry
Impedance spectrum Bode figure obtains phosphating coat sample in ac impedance measurement frequency range from high frequency to penetrating phase or pentration frequency
Corresponding test frequency points N '.
It is 1cm by geometric area2Parent metal low carbon mild steel sample be placed on three-electrode cell as working electrode
In, 260 type platinum black electrodes are auxiliary electrode, and silver-silver chloride electrode [Ag/AgCl, KCl (3.0mol/L)] is reference electrode, with
Above-mentioned identical test equipment and test condition carry out electrochemical AC impedance test, obtain the Nyquist of parent metal sample
Figure obtains differential electricity of the parent metal low carbon mild steel sample in the electrolyte by electrochemical analysis software fitting Nyquist figure
HoldFurther by formulaCalculate the porosity of phosphating coat.Each parameter and porosity calculated result such as table 6
It is shown.
Table 6
It can be seen that phosphorization film layer thickness pair from embodiment 1 to 6 thicknesses of layers parameter of embodiment and porosity conclusion
Porosity has an impact, as embodiment 2, embodiment 3, embodiment 4 and 6 film layer porosity of embodiment have significantly with the increase of film thickness
Downward trend, when this is primarily due to film thickness increase, the superposition between crystal grain is obvious, cause phosphating coat gas porosity, hole,
Reduce porosity decline in crack.But the porosity of film layer is other than the superposition between crystal grain is related, also and phosphatization
Structure situation inside membrane crystallization, if crystalline particle size, the shape of crystallization are related, this results in thicknesses of layers increase and hole
Rate declines uninevitable relevance, the ginseng obtained such as embodiment 2 and embodiment 1, embodiment 4, embodiment 5 and embodiment 6
Number shows that porosity will not necessarily decline when thicknesses of layers increase.
The various concentration of cerous nitrate is primarily to control thicknesses of layers, nitric acid cerium concentration are being less than 40mg/L in embodiment
The thickness of film layer can be improved in range, the thickness of nitric acid cerium concentration film when being greater than 40mg/L is slightly fluctuated, be can be considered substantially
It is constant.
Comparative example
The corrosion resisting property of phosphating coat is its important feature, and the routine experimentation of evaluation film layer corrosion resisting property mainly has sulfuric acid
Copper droplet test method, the ingredient of copper sulphate drop method detection film layer corrosion resistance test solution, content are respectively as follows: copper sulphate
(CuSO4·5H2O)41g/L；Sodium chloride (NaCl) 35g/L；Hydrochloric acid (HCl) 13mL/L of 0.1mol/L, remaining is distilled water.?
At 15-23 DEG C, test solution is dripped on phosphatization surface, while pressing manual time-keeping.When dropping liquid is in phosphatization film surface, by day
When blue becomes light yellow or pale red, the time is recorded.This method can more directly evaluate the corrosion resistance of phosphating coat.And phosphating coat
Porosity and the corrosion resistance of film layer have preferable corresponding relationship, porosity is bigger, and membranous layer corrosion resistance is poorer, so evaluation phosphatization
The corrosion resisting property of film can determine by measuring its porosity, conventional sulfuric acid copper drop experimental method and this patent quantitative assessment
The electrochemical test method result of phosphatization membrane porosity is as shown in the table.
Table 7
The conventional sulfuric acid copper droplet test time is longer, shows that the corrosion resistance of phosphating coat is better, but this method can only give
Out qualitatively as a result, and needing to be readily incorporated biggish human error by micro-judgment test endpoint when film layer is thicker.
As can be seen from the data in the table, the electrochemical test method result of this patent quantitative assessment phosphatization membrane porosity and routine experiment knot
Fruit compares can correspond to the corrosion resistance of film very well, there is better accuracy.
The above description of the embodiments is intended to facilitate ordinary skill in the art to understand and use the invention.
Person skilled in the art obviously easily can make various modifications to these embodiments, and described herein general
Principle is applied in other embodiments without having to go through creative labor.Therefore, the present invention is not limited to the above embodiments, ability
Field technique personnel announcement according to the present invention, improvement and modification made without departing from the scope of the present invention all should be of the invention
Within protection scope.
Claims (9)
1. a kind of electrochemical test method of quantitative assessment phosphatization membrane porosity, which is characterized in that specific step is as follows:
(1) phosphating coat sample is placed in progress electrochemical AC impedance test in electrolyte, obtains Nyquist figure and Bode figure；
(2) parent metal low carbon mild steel sample is fitted in the electrolyte solution using the Nyquist figure that step (1) obtainsAnd the interface differential capacitance C of phosphating coat sample in the electrolytic solutiondl；
(3) the Bode figure obtained by step (1) fits phosphating coat in ac impedance measurement frequency range from high frequency to wearing
Test frequency points N corresponding to saturating phase or pentration frequency '；
(4) porosity is calculated according to step (2) and (3) parameters obtained, the calculation formula for evaluating porosity is as follows:
Wherein, AdPorosity,The differential capacitance (μ F) of parent metal in the electrolytic solution, CdlPhosphating coat is in the electrolytic solution
Differential capacitance (μ F), K- proportionality coefficientWherein N' is in phosphating coat ac impedance measurement frequency range from high frequency to wearing
Test frequency points, N corresponding to saturating phase or pentration frequencyoIt is experiment total in phosphating coat ac impedance measurement frequency range
Frequency points.
2. a kind of electrochemical test method of quantitative assessment phosphatization membrane porosity according to claim 1, which is characterized in that
In step (1): electrochemical AC impedance experiment uses three-electrode system, and phosphating coat sample is put into three-electrode cell, is adopted
It is tested with electrochemical workstation.
3. a kind of electrochemical test method of quantitative assessment phosphatization membrane porosity according to claim 2, which is characterized in that
In three-electrode system, working electrode is respectively the mild steel phosphating coat sample after parent metal low-Carbon steel specimen and phosphorating treatment,
Auxiliary electrode is platinum black electrode, and reference electrode is Ag/AgCl/KCl aqueous solution electrode.
4. a kind of electrochemical test method of quantitative assessment phosphatization membrane porosity according to claim 3, which is characterized in that
The area of working electrode is 1cm2。
5. a kind of electrochemical test method of quantitative assessment phosphatization membrane porosity according to claim 3, which is characterized in that
The concentration of KCl aqueous solution is 3mol/L in reference electrode.
6. a kind of electrochemical test method of quantitative assessment phosphatization membrane porosity according to claim 2, which is characterized in that
AC signal amplitude is ± 10mV in electrochemical workstation.
7. a kind of electrochemical test method of quantitative assessment phosphatization membrane porosity according to claim 2, which is characterized in that
Electrolyte is the NaCl solution of 3.5wt.%.
8. a kind of electrochemical test method of quantitative assessment phosphatization membrane porosity according to claim 2, which is characterized in that
Electrolysis temperature is 20 DEG C.
9. a kind of electrochemical test method of quantitative assessment phosphatization membrane porosity according to claim 2, which is characterized in that
Range of scanned frequencies is 10KHz-0.01Hz in electrochemical workstation.
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| CN113340945A (en) * | 2021-04-30 | 2021-09-03 | 武汉工程大学 | Electrochemical detection method for structure and performance of extraction membrane and pervaporation membrane |
| CN113376072A (en) * | 2021-05-14 | 2021-09-10 | 唐山钢铁集团有限责任公司 | Method for measuring porosity of phosphating film of steel plate |
| CN115112544A (en) * | 2022-08-29 | 2022-09-27 | 江苏时代新能源科技有限公司 | Method for detecting porosity of substance to be detected |
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