Pt+Hf改性的γ-Ni+γ′-Ni_3Al涂层结构及其抗氧化性能研究  

Investigation of Microstructures of Pt+Hf Modified γ-Ni+γ′-Ni_3Al Coatings and Their Oxidation Resistance

作　　者：姚培培[1] 付超[1] 操光辉[1] 

机构地区：[1]上海大学,上海200072

出　　处：《稀有金属材料与工程》2014年第1期224-228,共5页Rare Metal Materials and Engineering

基　　金：上海市科学技术委员会(10JC1405100;11520701200);国家自然科学基金(51271107)

摘　　要：通过包埋Al-Hf共渗在高温合金DZ417G表面制备出Pt+Hf共同改性的γ-Ni+γ′-Ni3Al涂层。Al-Hf共渗过程中,Hf含量不同,涂层表面形成的相结构也不同。当渗剂中Hf含量为2%时(质量分数,下同),涂层呈γ-Ni+γ′-Ni3Al结构;渗剂中Hf含量为6%时,涂层相结构为?-NiAl+Al16Hf6Ni7;而当Hf含量达到12%时,涂层相结构为Al16Hf6Ni7。随着后续热处理的进行,β-NiAl+Al16Hf6Ni7涂层的相结构转变为γ-Ni+γ′-Ni3Al;Al16Hf6Ni7涂层转变为γ-Ni+γ′-Ni3Al+Al3HfNi12结构。1100℃的等温氧化实验表明,经过10 h氧化,高温合金基体表面已经出现了脱落;而渗剂中Hf含量为2%时形成的Pt+Hf改性的γ-Ni+γ′-Ni3Al涂层经过30 h氧化后,其表面依然完整。与单纯的Pt改性的γ-Ni+γ′-Ni3Al涂层相比,Pt+Hf共同改性的γ-Ni+γ′-Ni3Al涂层由于适量活性元素Hf的加入,其抗氧化性能得到了提高。The Pt and Hf modified γ-Ni＋γ′-Ni3Al coatings were fabricated on the DZ417G superalloy substrates by combined aluminizing and hafnizing using a pack cementation. During the co-deposition process, the phase structure formed on the coating surface changes with the increasing of hafnium contents in packs. When the hafnium contents are 2 wt%, 6 wt% and 12 wt% the coatings consist of the γ-Ni＋γ′-Ni3Al, β-NiAI＋Al16Hf6NiT, and Al16Hf6Ni7, respectively. During post heat treatment the β-NiAl＋A116Hf6Ni7 and Al16Hf6Ni7 coatings are transformed to γ-Ni＋γ′-Ni3Al and γ-Ni＋γ＇-Ni3AI＋A13HfNil2. Isothermal oxidation tests at 1100 ℃ for 10 h show that there are a lot of spallation on the surface of the substrate without coating, while the Pt and Hf modifiedγ-Ni＋γ′-Ni3Al coating formed in the packs with 2 wt% Hf remains to be integrated after being oxidized for 30 h. The addition of the reactive element hafnium makes a further improvement on the oxidation resistance of the Pt＋γ-Ni＋γ′-Ni3Al coatings.

关 键 词：高温合金 涂层 包埋渗 HF 抗氧化性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]