K17F高温合金溅射微晶层的抗高温氧化行为

OXIDATION BEHAVIOUR OF SPUTTERED MICRO-GRAINED SUPERALLOY K17F AT HIGH TEMPERATURES

研究了铸态高温合金Ｋｌ７Ｆ及其溅射微晶（小于０．ｌμｍ）层的高温氧化行为．结果表明，微晶层为均匀的γ相组织，它大幅度提高铸态合金的９００至１０００℃的抗氧化性能，甚至比渗Ａｌ涂层还好在高温下，Ｋ１７Ｆ生成以Ａｌ２Ｏ３为主，含有Ｎｉ，Ｃｒ，Ｔｉ氧化物的氧化膜，它在氧化过程中易剥落，而溅射微晶层表面只生成单一的α－Ａｌ２Ｏ３膜，具有优异的防护性和粘附性，在５００ｈ的氧化过程中未见剥落．

The microcrystalline layer of superalloy K17F was produced by planar magnetron sputtering technique.Themicrocrystalline layer has homogeneous structure and very fine grain size (less than 0.1μm) consisting of only γ-phase,while the cast alloy is composed of γ, γ' and carbides.The oxidation resistance of the microcrystalline layer was much better than that of the cast K17F alloy, and was even superior to that of the aluminized alloy.At first, the oxide scales formed on the cast K17F alloy was composed of mainly Al2O3 with small amounts of Cr, Ti and Ni oxides. However, after 500 h oxidation, the content of Al2O3 in the oxide scales reduced because of its spallation during exposure, and the oxide scale was mainly composed of Cr2O3 and TiO2. On the contrary, the oxide scale formed on the microcrystalline layer of alloy K17F was found to consist of only a-Al2O3 which had excellent adhesion and did not spall in the duration of exposure. The beneficial effects of microcrystallization on the oxidation resistance of the superalloy were briefly discussed.