(1. 廣西大學(xué) 材料科學(xué)與工程學(xué)院，南寧 530004；
2. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
3. SEG-CEMUC-Department of Mechanical Engineering, University of Coimbra,
Rua Luís Reis Santos, P-3030 788 Coimbra, Portugal)
摘 要: 由磁控濺射技術(shù)沉積Nb-Cr、Nb-Cr-Al和Al/Nb-Cr 3種涂層，對涂層的微觀結(jié)構(gòu)和初期抗氧化性進行研究。結(jié)果表明：Nb-Cr涂層呈柱狀結(jié)構(gòu)，含Cr2Nb相；Nb-Cr-Al涂層為含非晶組織的柱狀結(jié)構(gòu)；Al/Nb-Cr復(fù)合涂層的內(nèi)層保留了Nb-Cr的柱狀結(jié)構(gòu)，外層無明顯特征，涂層包含面心立方(FCC) Al、Cr2Nb和NbAl3等相。在1 200 ℃氧化60 min后，3種涂層顯示出不同的氧化增質(zhì)方式及生成了性質(zhì)各異的氧化產(chǎn)物：Nb-Cr涂層呈拋物線方式增質(zhì)，表面產(chǎn)物為Cr2O3和CrNbO4多孔混合氧化物；Nb-Cr-Al涂層表現(xiàn)出近線性的氧化增質(zhì)，表面生成以Cr2O3和CrNbO4為外層、Al2O3為內(nèi)層的復(fù)合氧化物層，氧化膜中有裂紋和脫落，涂層主體呈多孔結(jié)構(gòu)；Al/Nb-Cr復(fù)合涂層氧化增質(zhì)輕微，表面膜以Al2O3為主、連續(xù)且致密，涂層中保持高Cr含量，Al/Nb-Cr涂層有較強的抗氧化能力。
關(guān)鍵字: Nb-Cr基涂層；微觀結(jié)構(gòu)；高溫氧化；表面氧化膜
（1. School of Materials Science and Engineering, Guangxi University, Nanning 530004, China;
2. School of Material Science and Engineering, Central South University, Changsha 410083, China;
3. SEG-CEMUC-Department of Mechanical Engineering, University of Coimbra,
Rua Luís Reis Santos, P-3030 788 Coimbra, Portugal）
Abstract:Nb-Cr, Nb-Cr-Al and Al/Nb-Cr coatings were deposited by DC reactive magnetron sputtering and the microstructures and initial oxidation resistance of the three coatings were studied. The results show that the as-deposited Nb-Cr coating is composed of Cr2Nb phase and exhibits columnar structure. The Nb-Cr-Al coating is columnar with amorphous phases. The structure of Al/Nb-Cr duplex coatings is a combination of columnar structure in the Nb-Cr and featureless in the Al overlayer. The main phases in the Al/Nb-Cr duplex coatings include FCC Al, Cr2Nb and NbAl3. During thermal exposure at 1 200 ℃ in air for 60 min, the Nb-Cr coating exhibits a parabolic mass gain vs time and the mixture of Cr2O3 and CrNbO4 is formed on the surface. The Nb-Cr-Al coating presents a linear increase in mass gain and the oxidation products are Cr2O3and CrNbO4 on the surface and Al2O3 in the sub-layer. The mass gain is slight and the Cr content remains high in the Al/Nb-Cr coating after exposure. Continuous, dense and mainly Al2O3 scales are formed on the surface. It can be concluded that the Al/Nb-Cr coating possesses strong high temperature oxidation resistance.
Key words: Nb-Cr based coating; microstructures; high temperature oxidation; surface scales
