(西北工業(yè)大學(xué) 凝固技術(shù)國家重點實驗室，西安 710072)
摘 要: 通過1 000~1 150 ℃ Si-Al包埋共滲8 h的方法在鈮基超高溫合金表面制備Al改性硅化物抗氧化涂層，結(jié)果表明：實驗溫度下制備的涂層均具有多層復(fù)合結(jié)構(gòu)；不同溫度下共滲涂層外層的相組成不同，但最內(nèi)層均由(Nb, Ti)Al3和(Cr, Al)2(Nb, Ti)組成。1 050 ℃、8 h Si-Al共滲在合金表面形成了Al改性的硅化物涂層，其最外層主要為Nb3Si5Al2，依次往內(nèi)為(Nb, X)(Si, Al)2(X代表Ti, Cr和Hf元素)層、(Nb, X)5Si3層以及最內(nèi)層；而在1 000 ℃、8 h條件下Si-Al共滲形成的涂層以(Nb, Ti)Al3為主，其中含有少量的(Nb, X)5Si3，沒有形成以硅化物為主的涂層；在1 100 ℃、8 h和1 150 ℃、8 h條件下Si-Al共滲形成的涂層外層以(Nb, X)(Si, Al)2為主，但其中Al含量(摩爾分?jǐn)?shù))僅為2.35%，沒有形成Nb-Si-Al三元化合物層。
關(guān)鍵字: 鈮基超高溫合金；包埋滲；Al改性硅化物涂層
（State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:Al-modified silicide coatings on an advanced Nb-based ultrahigh temperature alloy were prepared by co-depositing Si and Al at 1 000, 1 050, 1 100 and 1 150 ℃ for 8 h, respectively. The results show that the coatings obtained by these processes have a multiple layer structure. The outer layers of the coatings have the different phase constituents at different coating temperature, but all the innermost layers of the coatings are constitutive of (Nb, Ti)Al3 and (Cr, Al)2(Nb, Ti). Al-modified (Nb, X)Si2(X represents Ti, Cr and Hf) coatings with an Nb3Si5Al2 outermost layer are obtained by co-depositing Si and Al at 1 050 ℃ for 8 h. The coatings prepared at 1 000 ℃ for 8 h are mainly constitutive of (Nb, Ti)Al3, and the coatings prepared at 1 100 ℃ for 8 h and 1 150 ℃ for 8 h are mainly constitutive of (Nb, X)- (Si, Al)2 with 2.35%Al (mole fraction).
Key words: Nb-based ultrahigh temperature alloy; pack cementation; Al-modified silicide coating
