Hf+Cr共改性(Ni,Pt)Al涂层在1100℃下的氧化行为

Oxidation Behavior of Hf+Cr Co-modified(Ni,Pt)Al Coatings at 1100℃

通过复合电镀的方法在N5单晶合金上先后沉积了Ni-Cr复合镀层和Pt-Hf复合镀层,随后通过气相渗铝的方法,制备了一种Hf+Cr共改性的(Ni,Pt)Al涂层。在1100℃静态空气中对该涂层进行了500 h的氧化试验,并以普通(Ni,Pt)Al涂层和Hf改性(Ni,Pt)Al涂层为对比样。通过三种涂层的氧化动力学、氧化后物相组成和形貌的对比分析,研究了Hf、Cr元素对(Ni,Pt)Al涂层抗氧化性能的影响。结果表明:在三种涂层中,Hf+Cr共改性(Ni,Pt)Al涂层具有最低的氧化速率、最强的黏附性能以及最低的表面起伏;相比于单一Hf改性,Hf+Cr共改性具有协同作用,使Al_(2)O_(3)的生长速率及涂层内部应力降低;同时,Ni-Cr层可以作为(Ni,Pt)Al涂层与基体之间的缓冲层,抑制涂层与基体之间的互扩散。

A Hf+Cr co-modified(Ni,Pt)Al coating on single crystal alloy N5 was prepared successively via composite electroplating of Ni-Cr and Pt-Hf and then aluminizing treatment.The oxidation test of the coating was carried out at 1100℃in static air for 500 h in comparison with the ordinary(Ni,Pt)Al coating and Hf modified(Ni,Pt)Al coating.The effects of Hf and Cr elements on the oxidation resistance of the(Ni,Pt)Al coatings were studied in terms of comparison of the oxidation kinetics,phase composition and morphology after oxidation of three coatings.The results show that the Hf+Cr co-modified(Ni,Pt)Al coating had the lowest oxidation rate,the strongest oxide scale adhesion and the lightest surface rumpling in three coatings.Compared with the single Hf modified coating,the addition of Cr could synergize with Hf to reduce the growth rate of Al_(2)O_(3)and internal stress of coating.Moreover,the Ni-Cr layer acted as a buffer layer between the(Ni,Pt)Al coating and the substrate,inhibiting the inter-diffusion behavior between the(Ni,Pt)Al coating and the substrate.