(南京航空航天大學(xué) 材料科學(xué)與技術(shù)學(xué)院，南京 210016)
摘 要: 采用雙輝等離子表面滲鉻和后續(xù)多弧離子鍍鋁處理在TC21合金表面制備Al-Cr涂層；同時研究Al-Cr涂層在850 ℃下的高溫氧化行為和850 ℃下25%NaCl+75%Na2SO4(質(zhì)量分?jǐn)?shù))混合鹽中的熱腐蝕行為。結(jié)果表明：Al-Cr復(fù)合涂層包括表面富Al沉積層、中間Al-Cr擴(kuò)散層和內(nèi)側(cè)Cr-Ti互擴(kuò)散層。在850 ℃氧化100 h后，Al-Cr涂層表面生成致密Al2O3膜，對基體有很好的保護(hù)作用；中間Al-Cr擴(kuò)散層中Cr元素的存在促進(jìn)Al的選擇性氧化，有利于涂層的后續(xù)氧化行為。在850 ℃混合熔鹽中腐蝕100 h后，內(nèi)部Cr-Ti擴(kuò)散區(qū)仍保持完整，涂層表現(xiàn)出較好的熱腐蝕抗力。
關(guān)鍵字: TC21合金；Al-Cr涂層；雙輝等離子表面冶金；多弧離子鍍鋁；高溫氧化；熱腐蝕
（School of Material Science and Technology, Nanjing University of Aeronautics and Astronautics,
Nanjing 210016, China）
Abstract:Cr+Al-type(Al-Cr) composite coating was prepared by double glow plasma surface chromizing on TC21 substrate followed by multi-arc ion aluminizing. The oxidation behaviors of Al-Cr coating in air and in mixed salt (25%NaCl+75%Na2SO4, mass fraction) at 850 ℃ were tested, respectively. The results demonstrate that Al-Cr coating consists of an outer layer of Al-rich deposition, an intermediate Al-Cr diffusion layer and an inner Cr-Ti mutual diffusion zone. After oxidation at 850 ℃ for 100 h, a dense Al2O3 oxide layer forms in the external oxide film, which provides protection for the substrate. As for the Al-Cr diffusion layer, the presence of Cr can promote the selective oxidation of Al, which is beneficial for improving the oxidation resistance. After 100 h exposure in mixed salt at 850 ℃, the inner Cr-Ti mutual diffusion zone is still integrated, indicating that Al-Cr coating has relatively good hot corrosion resistance.
Key words: TC21 alloy; Al-Cr coating; double glow plasma surface metallurgy; multi-arc ion aluminizing; oxidation; hot corrosion
