鎂合金表面LDH改性MAO復(fù)合材料涂層的表征及其緩蝕性能研究

鎂合金表面LDH改性MAO復(fù)合材料涂層的表征及其緩蝕性能研究鎂合金表面LDH改性MAO復(fù)合材料涂層的表征及其緩蝕性能研究

摘要：

鎂合金由于其低密度、高強(qiáng)度及易加工性等優(yōu)點(diǎn)，在航空、汽車、電子、醫(yī)療等領(lǐng)域得到廣泛應(yīng)用。然而，其在濕潤(rùn)和鹽霧環(huán)境下易發(fā)生腐蝕，從而影響其使用壽命和性能，限制了其廣泛應(yīng)用。本文通過(guò)LDH改性MAO復(fù)合材料涂層對(duì)鎂合金表面進(jìn)行了改性，并對(duì)其表征和緩蝕性能進(jìn)行了研究。結(jié)果表明，LDH改性MAO復(fù)合材料涂層不僅可以改善鎂合金表面的耐蝕性能，還可以提高其表面硬度和耐磨性能，顯著改善鎂合金的綜合性能。該研究為鎂合金表面的涂層改性以及表面緩蝕性能的提升提供了一種新的思路和方法。

關(guān)鍵詞：鎂合金，LDH，MAO，復(fù)合材料涂層，緩蝕性能

1.引言

鎂合金由于其獨(dú)特的優(yōu)點(diǎn)，在各領(lǐng)域得到廣泛應(yīng)用。然而在濕潤(rùn)和鹽霧環(huán)境下，鎂合金易發(fā)生腐蝕，從而限制了其應(yīng)用。為了改善鎂合金表面的耐蝕性能，目前研究重點(diǎn)在于表面涂層改性。

2.實(shí)驗(yàn)方法

采用LDH改性MAO復(fù)合材料涂層對(duì)鎂合金表面進(jìn)行改性，并對(duì)其進(jìn)行表征和緩蝕性能研究。首先，在氣相MAO處理后的鎂合金表面，利用電泳沉積法進(jìn)行LDH改性MAO復(fù)合材料涂層的制備。然后，采用掃描電鏡、X射線衍射儀、拉曼光譜儀、電化學(xué)測(cè)試等手段對(duì)其進(jìn)行表征和緩蝕性能研究。

3.結(jié)果和討論

結(jié)果表明，LDH改性MAO復(fù)合材料涂層可以顯著提高鎂合金表面的硬度和耐磨性能。同時(shí)，研究發(fā)現(xiàn)LDH在MAO復(fù)合材料中的添加，可以顯著改善鎂合金的耐蝕性能，降低其腐蝕速率。進(jìn)一步研究發(fā)現(xiàn)，該復(fù)合材料涂層能夠形成一種保護(hù)膜層，防止鎂合金與外界介質(zhì)發(fā)生反應(yīng)，從而顯著提高了其緩蝕性能。

4.結(jié)論

本研究通過(guò)LDH改性MAO復(fù)合材料涂層對(duì)鎂合金表面進(jìn)行改性，并對(duì)其進(jìn)行了表征和緩蝕性能研究。結(jié)果表明，LDH改性MAO復(fù)合材料涂層可以顯著提高鎂合金表面的硬度、耐磨性和緩蝕性能。該研究為鎂合金表面的涂層改性以及表面緩蝕性能的提升提供了一種新的思路和方法。

關(guān)鍵詞：鎂合金，LDH，MAO，復(fù)合材料涂層，緩蝕性能5.討論

5.1LDH在MAO復(fù)合材料中的作用

研究表明，LDH在MAO復(fù)合材料中的添加可以顯著改善鎂合金的耐蝕性能。這是因?yàn)長(zhǎng)DH具有層狀結(jié)構(gòu)，在表面涂層中形成了一定的屏障作用，防止鎂合金表面與外界介質(zhì)發(fā)生反應(yīng)。同時(shí)，LDH中的陽(yáng)離子可以與陰離子形成離子交換復(fù)合物，并將其固定在表面涂層中，形成一種保護(hù)膜。這種保護(hù)膜可以有效地防止鎂合金表面被侵蝕，從而顯著提高了其緩蝕性能。

5.2復(fù)合材料涂層的優(yōu)勢(shì)

采用LDH改性MAO復(fù)合材料涂層可以顯著提高鎂合金表面的硬度、耐磨性和緩蝕性能。這是因?yàn)閺?fù)合材料具有天生的優(yōu)勢(shì)，可以在不同材料的優(yōu)點(diǎn)中取長(zhǎng)補(bǔ)短，形成一種性能優(yōu)異的材料。對(duì)于鎂合金表面涂層來(lái)說(shuō)，復(fù)合材料可以起到多重作用，如防蝕、抗磨、提高機(jī)械強(qiáng)度等。

5.3未來(lái)研究方向

雖然LDH改性MAO復(fù)合材料涂層能夠顯著提高鎂合金表面的硬度、耐磨性和緩蝕性能，但是這種涂層仍存在一些問(wèn)題。例如，考慮到LDH的制備成本和工藝條件，需要進(jìn)一步探索更為經(jīng)濟(jì)、環(huán)保的LDH改性MAO復(fù)合材料涂層制備方法。另外，還需深入研究該涂層在不同環(huán)境下的緩蝕性能變化規(guī)律，以提高其實(shí)際應(yīng)用效果。

6.結(jié)論

本研究利用LDH改性MAO復(fù)合材料涂層對(duì)鎂合金表面進(jìn)行改性，并對(duì)其進(jìn)行了表征和緩蝕性能研究。結(jié)果表明，LDH改性MAO復(fù)合材料涂層可以顯著提高鎂合金表面的硬度、耐磨性和緩蝕性能。LDH在MAO復(fù)合材料中的添加可以形成一種保護(hù)膜，防止鎂合金表面被腐蝕，從而顯著提高了其緩蝕性能。該研究為鎂合金表面的涂層改性以及表面緩蝕性能的提升提供了一種新的思路和方法。7.參考文獻(xiàn)

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Severalsurfacemodificationtechniqueshavebeendevelopedtoenhancethewearresistanceofmagnesiumalloys,includingsurfacecoatings,surfacetreatments,andsurfacemodifications.Amongthesetechniques,surfacecoatingshavebeenextensivelyinvestigatedduetotheircapabilitytoprovideaprotectivelayeronthesurfaceofmagnesiumalloys.Variouscoatingssuchasorganiccoatings,ceramiccoatings,andmetalcoatingshavebeenexploredforimprovingthewearresistanceofmagnesiumalloys.

Ceramiccoatings,especiallyplasmaelectrolyticoxidation(PEO)coatings,havebeenwidelyinvestigatedforimprovingthewearresistanceofmagnesiumalloys.PEOcoatingisanelectrolyticprocessthatcanproduceceramiccoatingsbyanodicoxidationofmetalsubstratesinanaqueouselectrolytecontainingsolublesalts.PEOcoatingshavebeenreportedtoimprovethewearresistance,corrosionresistance,andfatigueresistanceofmagnesiumalloys.ThePEOcoatingsareusuallycomposedofseveralceramicphasessuchasMgO,MgAl2O4,andMgSiO3,andthecompositionandmicrostructureofthecoatingscanbecontrolledbyadjustingtheelectrolytecomposition,appliedvoltage,andprocessingtime.

Anothereffectivesurfacemodificationtechniqueforimprovingthewearresistanceofmagnesiumalloysismicro-arcoxidation(MAO),whichisasimilarprocesstoPEO.MAOprocesscanproduceceramiccoatingscontainingvariousceramicphasessuchasMgO,MgAl2O4,andMgSiO3onthesurfaceofmagnesiumalloys.TheMAOcoatingshavebeenreportedtoimprovethewearresistance,corrosionresistance,andbiocompatibilityofmagnesiumalloys.

Inadditiontosurfacecoatings,surfacetreatmentssuchasanodizingandshotpeeninghavebeendemonstratedtoenhancethewearresistanceofmagnesiumalloys.Anodizingisanelectrochemicalprocessthatcanproduceadenseandhardoxidelayeronthesurfaceofmagnesiumalloys,whichimprovesthewearresistanceandcorrosionresistance.Shotpeeningisamechanicalprocessthatcaninducecompressiveresidualstressesonthesurfaceofmagnesiumalloys,whichenhancesthefatigueresistanceandwearresistance.

Inconclusion,thedevelopmentofsurfacemodificationtechniqueshassignificantlyimprovedthewearresistanceofmagnesiumalloys,whichhasexpandedtheirpotentialapplications.Differentsurfacemodificationtechniquescanprovidevarioustypesofprotectivelayersonthesurfaceofmagnesiumalloys,whichcanimprovethewearresistance,corrosionresistance,andbiocompatibility.However,theselectionofsuitablesurfacemodificationtechniquesshouldbebasedonthespecificapplicationrequirementsandthepropertiesofthemagnesiumalloysubstrates.Inrecentyears,magnesiumalloyshavegainedincreasingattentioninvariousindustrialsectorsduetotheirlightweight,highstrength,andexcellentbiocompatibility.However,thepoorwearresistanceofmagnesiumalloyslimitstheirwideapplicationsinwear-criticalenvironments.Therefore,itiscrucialtoimprovethewearresistanceofmagnesiumalloystoexpandtheirpotentialapplications.

Manysurfacemodificationtechniqueshavebeendevelopedtoimprovethewearresistanceofmagnesiumalloys.Thesetechniquescanbecategorizedintotwomaingroups:surfacecoatingsandsurfacetreatments.

Surfacecoatingsinvolvedepositingathinlayerofprotectivematerialontothesurfaceofthemagnesiumalloy.Differentcoatingtechniquescanbeused,includingphysicalvapordeposition(PVD),chemicalvapordeposition(CVD),electroplating,andelectrolessplating.Coatingscanimprovewearresistance,corrosionresistance,andbiocompatibility,dependingonthecoatingmaterial.

Forexample,diamond-likecarbon(DLC)coatingshavebeenshowntosignificantlyimprovethewearresistanceofmagnesiumalloys.DLCcoatingscanincreasethesurfacehardnessandreducethefrictioncoefficientofmagnesiumalloysbyprovidingasmoothsurfacewithlowsurfaceenergy.Additionally,DLCcoatingscanalsoimprovethecorrosionresistanceofmagnesiumalloys.

Anothercoatingmaterialthathasbeenusedtoimprovethewearresistanceofmagnesiumalloysishydroxyapatite(HA).HAisabiocompatibleceramicmaterialthatiswidelyusedinorthopedicanddentalimplants.HAcoatingscanimprovethewearresistanceandbiocompatibilityofmagnesiumalloys,makingthemsuitableforbiomedicalapplications.

Surfacetreatmentsinvolvemodifyingthesurfaceofthemagnesiumalloywithoutdepositingaseparateprotectivelayer.Surfacetreatmentscanbemechanical,thermal,orchemicalinnature.Commonsurfacetreatmentsformagnesiumalloysincludeshotpeening,lasersurfacetreatment,andionimplantation.

Shotpeeningisamechanicalsurfacetreatmentthatinvolvesbombardingthesurfaceofmagnesiumalloyswithhigh-velocitysphericalbeadsorshots.Shotpeeninginducescompressiveresidualstressesinthesurfacelayerofthemagnesiumalloy,whichcanimprovethefatiguestrengthandwearresistanceofthematerial.

Lasersurfacetreatmentisathermalsurfacetreatmentthatinvolvesusingalaserbeamtoheatandmeltthesurfaceofthemagnesiumalloy.Themoltensurfacelayersolidifiestoformathinlayerofmicrostructurewithimprovedwearresistance.Lasersurfacetreatmentcanalsoinducecompressiveresidualstressesinthesurfacelayerofmagnesiumalloys,whichcanfurtherimprovethewearresistance.

Ionimplantationisachemicalsurfacetreatmentthatinvolvesbombardingthesurfaceofmagnesiumalloyswithhigh-energyions.Theionbombardmentcanmodifythesurfacechemistryandmicrostructureofthemagnesiumalloy,leadingtoimprovementsinwearresistanceandcorrosionresistance.

Inconclusion,varioussurfacemodificationtechniquescanimprovethewearresistanceofmagnesiumalloys,enhancingtheirpotentialapplicationsinwear-criticalenvironments.Theselectionofsuitablesurfacemodificationtechniquesshouldconsiderthespecificapplicationrequirementsandthepropertiesofthemagnesiumalloysubstrates.Moreover,itisessentialtoexplorenovelsurfacemodificationtechniquestofurtherenhancethewearresistanceofmagnesiumalloys.Inadditiontosurfacemodificationtechniques,otherstrategiescanalsobeemployedtoimprovethewearresistanceofmagnesiumalloys.Oneapproachistoalloymagnesiumwithotherelementsthatcanenhanceitsmechanicalproperties.Forexample,theadditionofsmallamountsofrareearthelementscanimprovethetoughnessandwearresistanceofmagnesiumalloys(Lietal.,2020).

Anotherstrategyistoapplycoatingstothesurfaceofmagnesiumalloys.Coatingscanprovideabarrieragainstwearandcorrosion,aswellasalterthesurfacechemistrytoimproveadhesionandreducefriction.Varioustypesofcoatings,suchasmetallic,ceramic,andorganiccoatings,havebeeninvestigatedformagnesiumalloys(Wangetal.,2019).Onerecentstudyreportedthatadiamond-likecarboncoatingcansignificantlyimprovethewearresistanceofmagnesiumalloys(Kuangetal.,2021).

Furthermore,thedevelopmentofnewprocessingmethodscanalsoenhancethewearresistanceofmagnesiumalloys.Forexample,severeplasticdeformation(SPD)hasbeendemonstratedtoimprovethemechanicalpropertiesofmagnesiumalloys,includingwearresistance(Wangetal.,2021).SPDinvolvessubjectingthematerialtoahighstrainratethroughtechniquessuchasequalchannelangularpressingorhigh-pressuretorsion.Thiscanresultinafine-grainedmicrostructurethatcanimprovethemechanicalpropertiesofthematerial.

Insummary,improvingthewearresistanceofmagnesiumalloysiscrucialfortheirpotentialapplicationsinwear-criticalenvironments.Surfacemodificationtechniques,suchasplasmaelectrolyticoxidationandlasersurfacemodification,canbeeffectiveinenhancingthewearresistanceofmagnesiumalloys.However,otherstrategies,includingalloying,coatings,andprocessingmethods,canalsobeemployedtoimprovetheirmechanicalproperties.Futurestudiesshouldfocusonexploringnewapproachesanddevelopingmoreeffectivesurfacemodificationtechniquestoenhancethewearresistanceofmagnesiumalloys.Inadditiontosurfacemodificationtechniques,thereareseveralotherstrategiesthatcanbeusedtoimprovethemechanicalpropertiesofmagnesiumalloys,includingalloying,coatings,andprocessingmethods.

Alloyingisoneofthemostcommonmethodsusedtoenhancethemechanicalpropertiesofmagnesiumalloys.Theadditionofelementssuchasaluminum,zinc,andmanganesecanimprovethestrength,ductility,andcorrosionresistanceofmagnesiumalloys.Forexample,theadditionofaluminumtomagnesiumcanformtheMg-Alalloy,whichexhibitsexcellentmechanicalandthermalproperties.Similarly,theZn-Mgalloycanimprovethecorrosionresistanceandhardnessofmagnesiumalloys.

Coatingsareanothereffectivewaytoenhancethewearresistanceofmagnesiumalloys.Varioustypesofcoatings,suchasplasma-sprayedcoatings,electrolessplating,andanodizedcoatings,havebeendevelopedtoimprovethetribologicalpropertiesofmagnesiumalloys.Thesecoatingscanformaprotectivelayeronthesurfaceofmagnesiumalloys,whichcanpreventwearandcorrosion.

Processing