TY - JOUR
T1 - Conversion-coating treatment for magnesium alloys by a permanganate-phosphate solution
AU - Chong, Kwo Zong
AU - Shih, Teng Shih
PY - 2003/4/29
Y1 - 2003/4/29
N2 - A chrome-free conversion coating treatment, a mainly permanganate-phosphate solution, was developed in this study for magnesium and its alloys. The morphology of the conversion-coated layer was observed using SEM; the crystal structure and the composition was analysed and determined by using XRD and XPS. The XRD results indicated that amorphous structures existed that covered the coated specimen. The solution treated specimen showed a greater intensity of Mg17Al12 than the as-received. The XPS results indicated that the coated layer contained products of MgO, Mg(OH)2, MgAl2O4, Al2O3, Al(OH)3, MnO2 or Mn2O3 and amorphous oxy-hydroxides for Mg-Al-Zn alloys, but MgO, Mg(OH)2, MnO2, amorphous oxy-hydroxides and MgMn2O8 for pure Mg. The electrochemical polarisation test results demonstrated that the presented conversion treatment for the series of AZ alloys had an equivalent corrosion protection potential as the JIS H 8651 MX-1 (similar to Dow No. 1) chrome-based method.
AB - A chrome-free conversion coating treatment, a mainly permanganate-phosphate solution, was developed in this study for magnesium and its alloys. The morphology of the conversion-coated layer was observed using SEM; the crystal structure and the composition was analysed and determined by using XRD and XPS. The XRD results indicated that amorphous structures existed that covered the coated specimen. The solution treated specimen showed a greater intensity of Mg17Al12 than the as-received. The XPS results indicated that the coated layer contained products of MgO, Mg(OH)2, MgAl2O4, Al2O3, Al(OH)3, MnO2 or Mn2O3 and amorphous oxy-hydroxides for Mg-Al-Zn alloys, but MgO, Mg(OH)2, MnO2, amorphous oxy-hydroxides and MgMn2O8 for pure Mg. The electrochemical polarisation test results demonstrated that the presented conversion treatment for the series of AZ alloys had an equivalent corrosion protection potential as the JIS H 8651 MX-1 (similar to Dow No. 1) chrome-based method.
KW - Conversion coating
KW - Corrosion
KW - Magnesium alloys
KW - Non-chrome chemical conversion
UR - http://www.scopus.com/inward/record.url?scp=0037472171&partnerID=8YFLogxK
U2 - 10.1016/S0254-0584(02)00481-9
DO - 10.1016/S0254-0584(02)00481-9
M3 - 期刊論文
AN - SCOPUS:0037472171
SN - 0254-0584
VL - 80
SP - 191
EP - 200
JO - Materials Chemistry and Physics
JF - Materials Chemistry and Physics
IS - 1
ER -