TY - JOUR
T1 - Microstructure and high temperature oxidation resistance of Si-Y2O3 co-deposition coatings prepared on Nb-silicide-based ultrahigh temperature alloy by pack cementation process
AU - Qi, Tao
AU - Guo, Xi Ping
PY - 2009/11
Y1 - 2009/11
N2 - Si-Y2O3 co-deposition coatings on Nb-silicide-based ultrahigh temperature alloy were prepared by pack cementation processes. The co-deposition holding temperatures were 1050°C, 1150°C and 1250°C, and the holding times were 5, 10, 15 and 20h, respectively. The microstructure and isothermal oxidation resistance of the coatings were studied. The results show that all Si-Y2O3 co-deposition coatings are composed of a (Nb,X)Si2 (X represents Ti, Hf and Cr elements) outer layer and a (Nb,X)5Si3 transitional layer. Some thin discontinuous (Cr,Al)2(Nb,Ti) laves phase precipitates exist between the substrate and (Nb,X)5Si3 transitional layer. EDS analyses reveal that the distribution of Y on the coatings is not uniform. The content of Y in (Nb,X)Si2 and (Nb,X)5Si3 phases is about 0.46at%-0.57at% while that in (Cr,Al)2(Nb,Ti) is about 0.94at%. After oxidation at 1250°C for 5, 10, 20, 50 and 100h respectively, the retained Si-Y2O3 co-deposition coatings still possess double layers structure with their original constituent phases and combine tightly with both scale and substrate. The dense scale developed on Si-Y2O3 co-deposition coatings during oxidation at 1250°C is composed of TiO2, SiO2 and Cr2O3. Si-Y2O3 co-deposition coatings possess better oxidation resistance than simple Si deposition coatings.
AB - Si-Y2O3 co-deposition coatings on Nb-silicide-based ultrahigh temperature alloy were prepared by pack cementation processes. The co-deposition holding temperatures were 1050°C, 1150°C and 1250°C, and the holding times were 5, 10, 15 and 20h, respectively. The microstructure and isothermal oxidation resistance of the coatings were studied. The results show that all Si-Y2O3 co-deposition coatings are composed of a (Nb,X)Si2 (X represents Ti, Hf and Cr elements) outer layer and a (Nb,X)5Si3 transitional layer. Some thin discontinuous (Cr,Al)2(Nb,Ti) laves phase precipitates exist between the substrate and (Nb,X)5Si3 transitional layer. EDS analyses reveal that the distribution of Y on the coatings is not uniform. The content of Y in (Nb,X)Si2 and (Nb,X)5Si3 phases is about 0.46at%-0.57at% while that in (Cr,Al)2(Nb,Ti) is about 0.94at%. After oxidation at 1250°C for 5, 10, 20, 50 and 100h respectively, the retained Si-Y2O3 co-deposition coatings still possess double layers structure with their original constituent phases and combine tightly with both scale and substrate. The dense scale developed on Si-Y2O3 co-deposition coatings during oxidation at 1250°C is composed of TiO2, SiO2 and Cr2O3. Si-Y2O3 co-deposition coatings possess better oxidation resistance than simple Si deposition coatings.
KW - Coating structure
KW - High temperature oxidation resistance
KW - Nb-silicide-based ultrahigh temperature alloy
KW - Si-YO co-deposition coatings
UR - http://www.scopus.com/inward/record.url?scp=71049154071&partnerID=8YFLogxK
U2 - 10.3724/SP.J.1077.2009.01219
DO - 10.3724/SP.J.1077.2009.01219
M3 - 文章
AN - SCOPUS:71049154071
SN - 1000-324X
VL - 24
SP - 1219
EP - 1225
JO - Wuji Cailiao Xuebao/Journal of Inorganic Materials
JF - Wuji Cailiao Xuebao/Journal of Inorganic Materials
IS - 6
ER -