DD3单晶高温合金的热腐蚀行为

HOT CORROSION OF SINGLE-CRYSTAL SUPERALLOY DD3

用涂９０Ｎａ２ＳＯ４（ｗｔ％）和１０ＮａＣｌ（ｗｔ％）的混合盐膜法研究了单晶高温合金ＤＤ３在９００℃空气中的热腐蚀行为。结果表明，ＤＤ３单晶合金的高温热腐蚀是灾难性的；其动力学曲线无明显孕育期，但有明显的阶段性。文中对各阶段的腐蚀机理进行了简要的讨论。

Hot corrosion behavior of singlecrystal superalloy DD3 in air at 900℃ was studied using specimens coated with po(wt.)Na2SO4+10(wt.%)NaCl.The kinetic processes consisted of three stages.The basic fluxing of metal/oxide predominated in stage Ⅰ.Stage Ⅱ was a transitional process form basic fluxing to acidic fluxing.The presence of W and Mo oxidex at corrosion front during stage Ⅲ showed acidic fluxing reaction.Optical microscopy,electron scanning microscopy and EPMAwere employed for the micro-morphology study of hot corrosion.After corrosion test for an hour,some bubbles were observed on the surface of the superalloy.The corrosion product was in the form of loose scale thickening with time.A specimen of 3mm thickness crumbled seriously into powder after 100 hours hot corrosion. These results indicated that the hot corrosion of single-crystal supperalloy DD3 was catastrophic.