Yanjun XI
,
Fuhui WANG
,
Lianlong HE
材料科学技术（英）
The effect of a sputtered Ti-48Al-8Cr-2Ag (at. pct) coating on the oxidation resistance of the cast Ti-46.5Al-5Nb (at. pct) alloy was investigated in air at 1000~1100℃. Hot corrosion in molten 75 wt pct Na¬2SO¬4+25 wt pct K¬2SO¬4 was investigated at 900℃. The scale on the cast TiAlNb tends to spall in air, while the scale on coating is very adherent. The sputtered Ti-48Al-8Cr-2Ag coating remarkably improved high temperature oxidation resistance of the cast Ti-46.5Al-5Nb alloy because of the formation of an adherent Al¬2O¬3 scale. Due to the inward diffusion of Cr, Kirkendall voids were found at the coating/substrate interface. TiAlCrAg coating provided excellent hot corrosion resistance for TiAlNb alloy in molten 75 wt pct Na¬2SO¬4+25 wt pct K¬2SO¬4 at 900℃ due to the formation of a continuous Al¬2O¬3 scale.
关键词:
High temperature oxidation
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Mengjin LI
,
Xiaofeng SUN
,
Hengrong GUAN
,
Xiaoxia JIANG
,
Zhuangqi HU
材料科学技术（英）
(Ni,Pd)Al coating, prepared by low pressure pack cementation on the Ni-base superalloy M38 where Pd-20 wt pct Ni alloy was predeposited, consists of a single β-(Ni,Pd)Al phase. The initial isothermal oxidation behavior of (Ni,Pd)Al coating was investigated by TGA, XRD, SEM/EDS at 800-1100℃. Results show that oxidation kinetics accord preferably with parabolic law at 800, 900 and 1100℃, but not at 1000℃. β-Al2O3 was observed at 800-1100℃. It is found that Pd plays an important role in accelerating the diffusion of Ti from the substrate to the coating surface in the aluminide coating.
关键词:
(Ni
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