資源描述:
《電鍍鋅磷化工藝對磷化膜性能影響》由會員上傳分享,免費在線閱讀,更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫。
1、哈爾濱工業(yè)大學(xué)工學(xué)碩士學(xué)位論文摘要隨著汽車廠對轎車用電鍍鋅鋼板的表面形貌以及耐蝕性的要求越來越高,以前一些不作要求的表面物理性質(zhì),比如粗糙度,現(xiàn)在都進(jìn)行了嚴(yán)格的要求。為此本文就電鍍鋅鋼板磷化工藝對磷化膜的各種性能的影響進(jìn)行了系統(tǒng)的研究。本文通過磷化膜的電化學(xué)阻抗曲線、Tafel極化曲線、SEM,XRD、電勢時間變化曲線、膜厚時間變化曲線等研究了Nit+,Mn2+,NaF,N03-、總酸度、游離酸度、溫度、時間、鋼板走速等因素對磷化膜的影響。研究發(fā)現(xiàn),鎳離子濃度在0.5g/L時磷化結(jié)晶顯得最為均勻致密。鎳離子濃度對膜厚度的影響正好與耐蝕性的影響相一致。錳離子的增加在最開始的時候有利于膜的增長,得
2、到的膜耐蝕性好。隨NaF濃度的增大,磷化膜的厚度先平緩增加,當(dāng)大于lg/L時其厚度急劇增加。膜耐蝕性先平緩下降后急劇上升。隨N03一離子濃度增加磷化膜的粗糙度緩慢下降,添加N03一后磷化膜相對致密。磷化膜的粗糙度隨著磷化液的總酸度的升高而增大,隨游離酸度的上升而下降。隨溫度的增加先下降后上升,隨著磷化時間的增加先平穩(wěn)上升,后下降。磷化膜的耐蝕性隨著游離酸度增加先上升后下降,隨溫度上升而增加,隨磷化時間延長而增加。通過磷化過程中時間電勢研究,提出了鍍鋅磷化前期的三階段磷化反應(yīng)過程:鋅在酸性磷化液中發(fā)生電化學(xué)陽極溶解過程,鋅的磷化膜底層生成過程,膜生長過程。在磷化液中添加Ni2+后產(chǎn)生了置換反應(yīng)改
3、變了磷化過程。關(guān)鍵詞電鍍鋅;磷化;粗糙度;電化學(xué)阻抗哈爾濱工業(yè)大學(xué)工學(xué)碩士學(xué)位論文AbstractWiththestricterandstricterdemandsofautomobilefactoryonsurfacemorphologyandcorrosionresistanceofcar-usedsteelgalvanizedwithzinc,somephysicalcharacteristicswhichwereneglectedinthepast,suchasroughnessandsoon,areclaimedstrictlynow.Asaresult,influenceofpho
4、sphatingofgalvanizedzincsteelondiverseperformanceofphosphatelayersystemicallystudiedinthispaper.Diversemethods,suchaselectrochemicalimpedancespectroscopy(EIS),electrochemicalpolarization,scanningelectronmicroscope(SEM),X-raydiffraction(XRD),relationshipbetweenpotentialandtime,relationshipbetweenphos
5、phatecoatingmassandtimechangeandsoon,werecarriedouttostudyinfluenceoffactorsincludingNit+,Mn2',NaF,N03-,totalacidity,freeacidity,temperature,time,andspeedofsteel,onphosphatelayer.Itwasfoundthatphosphatecrystalwouldbethemostequalanddenseatthe0.5g/LofNit+.TheinfluenceofNit'onthethicknessofphosphatelay
6、erwasthesameasthatonthecorrosionresistance.TheincreaseofMn2+wasgoodtothegrowthofcoatinginthebeginning,gaininggoodcorrosionresistancecoatingWiththeincreaseofconcentrationofNaF,thethicknessofphosphatecoatingshowedeven-increaseatfirst,andsharprisewhentheconcentrationwasmorethanIg/L,meanwhile,thecorrosi
7、onresistanceofphosphatecoatinghadthesamevariety,evenlyincreasedfirst,andthensharplyrose.WhilewiththeincreaseofN03-,theroughnessofphosphatecoatinggraduallydeclined,andthedensificationofthecoatingwascom