S.M.Morsy (Metallurgy Dept. Nuclear Research Center
,
Atomic Energy Authority
,
Cairo
,
Egypt) I.Z.Selim (Physical Chemistry Dept.
,
National Research Center
,
Dokki
,
Cairo
,
Egypt)S. H. Tantawi (Building Research Institute
,
Dokki
,
Cairo
,
Egypt)
材料科学技术（英文）
Electrochemical techniques of the corrosion measurements of reinforcing steeI in concrete have been evaluated. These techniques include half-cell potential measurements, impressed voltage method, impressed current method and potentiostatic polarization technique. The results of corrosion behaviour of the steel in both 5%NaCl and 5%MgSO4 show that each electrochemical technique provides some information about the condition of the steel bar or the corrosivity of the environment being evaluated, yet none provides a complete data regarding the corrosion resistance of reinforcing steel in aggressive media
关键词:
A.F.Waheed and H.M.Soliman(Dept. of Metallurgy
,
Nuclear Research Center
,
Atomic Energy Authority
,
Cairo
,
Egypt)
材料科学技术（英文）
The beginning of failure of a (ZrO2-7%Y2O3)/(Ni-22%Co-17%Cr-12.5%Al-0.6%Y) duplex andgraded coating systems on lnconel 617 and IN738LC in burner rig tests has been characterized.The test conditions are 40 s heating up to 75O℃ substrate temperature followed by 80 s aircooling. Failure is considered at the appearance of the first bright spot during heating period.Stresses due to thermal expansion mismatch strains on cooling are the probable cause of life-limiting in this conditions of testing.
关键词:
H.M.Soliman
,
K.E.Mohamed
,
M.E.Abd El-Azim and F.H.Hammad(Metallurgy Dept.
,
Atomic Energy Authority
,
Cairo
,
Egypt)
材料科学技术（英文）
Low and medium carbon steels were aluminized by the pack aluminizing technique using halideactivated pure-Al and Fe-Al packs. The effect of mixture composition, aluminizing temperatureand time and C content of the steel substrate on the structure and thickness of the aluminidelayer, and on the oxidation resistance was investigated. The optimum oxidation resistance canbe achieved with a low carbon steel substrate when the intermetallic phases Fe3Al and FeAlform the surface of the aluminide layer. In this case, the Al concentration at the surface of thealuminide coating is at least ≥15 wt pct. Formation of high Al concentration phases (FeAl3 andFe2Al5) during aluminizing should be avoided as they tend to embrittle the aluminide layer andreduce its oxidation resistance.
关键词:
