摘要
研究了镁合金微弧氧化膜层的组织分布情况。在碱性电解液(NaH2PO4/Na2SiO3/NaAlO2:5～20g/L,NaOH:1～5g/L,KF:5～8g/L,Na3C6H5O7:0.5～2g/L,EDTA:0.5～2g/L)中,以AZ91镁合金为基体制备出微弧氧化陶瓷薄膜,制备时采用恒电流控制模式,电流密度为20A/dm2;采用扫描电镜(SEM)、光学显微镜和X-ray衍射仪(XRD)研究了氧化薄膜的微观组织结构。发现:(1)在所研究的3种电解液体系中,选用硅酸盐电解液制备的膜层具有较好的组织形貌;(2)氧化膜的两层结构中,致密层占整个膜层厚度的绝大部分,大约在75%～85%之间;(3)电解液中的成膜元素如Si、Al、P主要分布在膜层的表面层中,致密层则主要由Mg、O两种元素构成;相应的物相构成中,MgSiO3、MgAl2O4或Mg3(PO4)2主要分布在表面层中,致密层则主要由MgO构成。
An extensive study was made of the microstructure distribution of the ceramic coating formed on AZ91 magnesium alloy substrate by micro-arc oxidation（MAO）.The coating was prepared in an alkaline electrolytic solution composed of 5-20g/L of NaH2PO4/Na2SiO3/NaAlO2,1-5g/L of NaOH,5-8g/L of KF;0.5-2g/L of Na3C6H5O7 and 0.5-2g/L of EDTA,employing a constant-current controlled AC power supply with a current density of 20A/dm2;and the microstructure of the coatings was characterized using scanning electron microscopy（SEM）,optical microscopy and X-ray diffraction instrument（XRD）.It was found that：（1）The microstructure prepared in an alkaline electrolytic solution was best than in aluminate or phosphate electrolytic solution;（2）The ceramic coating had both structures,and the dense inner sublayer made of most of the thickness,about 75%-85%;（3）The elements made of coatings,such as Si,Al or P,distributed in the outer sublayer,and the compositions of the dense inner sublayer were Mg and O;the phase compositions corresponding to the three electrolytic solutions,such as MgSiO3,MgAl2O4 or Mg3（PO4）2 distributed in the outer sublayer,and it was MgO in the dense inner sublayer.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2010年第12期2075-2079,共5页
Journal of Functional Materials
基金
广东省科技工业攻关资助项目(2003C103013)
关键词
镁合金
微弧氧化
微观组织
膜层
物相
magnesium alloy
micro-arc oxidation
microstructure
coating
phase
