熱循環(huán)氧化行為
( 1. 北京航空材料研究院 第五研究室， 北京 100095；
2. 沈陽航空工業(yè)學(xué)院材料系， 沈陽 110031)
摘 要: 采用電子束物理氣相沉積方法（EB-PVD）在NiCoCrAlYHf粘結(jié)層上沉積YSZ熱障層， 研究了該熱障涂層1 100 ℃的循環(huán)氧化行為(每個(gè)循環(huán)為： 1 100 ℃保溫30 min、 空冷5 min), 分析了粘結(jié)層和熱生長氧化物的演化過程。結(jié)果表明： NiCoCrAlYHf 粘結(jié)層氧化初期由β-NiAl和γ固溶體組成， 186次循環(huán)氧化后β相/完全轉(zhuǎn)變?yōu)?I>γ固溶體。 NiCoCrAlYHf/EB-PVD熱障涂層中的熱生長氧化物包含Al2O3層和靠近熱障層的尖晶石薄層。該熱生長氧化物生長速度較快， 在粘結(jié)層的一些富Hf區(qū)域優(yōu)先生長而呈現(xiàn)出明顯的不均勻性；但其具有較大的失效臨界熱生長氧化物厚度， 失效時(shí)熱生長氧化物均勻處的厚度約為10 μm。
關(guān)鍵字: 熱障涂層； 熱生長；氧化物； 循環(huán)氧化
TANG Jian-xin2
（ 1. Laboratory 5, Beijing Institute of Aeronautical Materials, Beijing 100095, China;
2. Department of Materials Science and Engineering,
Shenyang Institute of Aeronautical Engineering， Shenyang 110031, China）
Abstract: The cyclic oxidation(30 min hold at 1 100 ℃, 5 min cooled in air) of electron beam physical vapor deposition(EB-PVD) yttria stabilized zirconia thermal barrier coatings(TBCs) on NiCoCrAlYHf bond coat at 1 100 ℃ was investigated. Attention was focused on the development of bond coat and thermally grown oxide(TGO). The result shows that the bond coat is composed of β -NiAl and γ solid solution at the initial stage of cyclic oxidation. The β phase is completely transferred to γ solid solution after 186 cycles. The TGO consists of an Al2O3 layer and a thin spinel layer in NiCoCrAlYHf/EB-PVD TBCs. This TGO has a big growth rate and grows irregularly because of selective growth at Hf-riched areas in the bond coat. But the TBCs has a larger critical thickness of TGO for failure. The thickness of TGO at uniform place is about 10 μm when the TBCs fails.
Key words: thermal barrier coating; thermally grown; oxide; cyclic oxidation
