Atmospheric Corrosion Behavior of Mg-alloys AZ31B and AZ91D in Simulated Low Temperature Environments
The atmospheric corrosion behavior of Mg-alloys AZ31B and AZ91D at alternating low temperatures was investigated via laboratory simulation i.e.a high/low temperature dry-humid alternating test chamber.The corrosion rate of the two alloys was positively correlated with temperature as the re-sults acquired by the mass loss measurement.The morphology analysis showed that the two alloys ex-hibited obvious localized corrosion in the low temperature environment.Combined with corrosion rate and morphology observation(SEM,CLSM),it was found that AZ31B Mg-alloy was more seriously corrod-ed than AZ91D Mg-alloy at the same temperature,but AZ91D Mg-alloy showed obvious pitting character-istics.The average pitting density and depth of AZ91D Mg-alloy were larger than that of AZ31B Mg-alloy,but the corresponding average pitting volume was smaller.FTIR and EDS analysis showed that Mg(OH)2,MgO and carbonates were the main components of the corrosion products formed at 15-25℃,while the content of MgO in the corrosion products was higher at lower alternating temperatures(from-5℃ to-15℃ and-5℃ to-25℃).EDS results suggested that Aland Cl were present in the area where AZ91D Mg-alloy pitting was serious.It was considered that the destruction of the oxide scale by Cl-had an important influ-ence on the pitting corrosion of AZ91D Mg-alloy.
Mg-alloylocation corrosioncorrosion morphologycorrosion productlow temperature corrosion
NETL
NSTL
万方数据
