共查询到19条相似文献,搜索用时 177 毫秒
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MCrAlY涂层对TiAl金属间化合物抗高温氧化性能的影响 总被引:8,自引:2,他引:8
研究了溅射Co-30Cr-6Al-0.5Y及Ni-30Cr-6Al-0.5Y涂层对TiAl金属间化合物抗高温氧化性能的影响。结果表明,在900℃-1000℃范围内,CoCrAlY,NiCrAlY涂层表面由于可形成粘附性良好的Al2O3膜。大大改善了TiAl金属间化合物的抗氧化性能。 相似文献
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熔融盐热腐蚀的电化学阻抗模型 总被引:6,自引:0,他引:6
研究了Ni3A,FeAl合金及溅射CoCrAlY涂层在熔融盐腐蚀过程中的阻抗谱特征,根据合金在熔融盐腐蚀过程进行了表面氧化膜形成的特点,并结合阻抗实验结果,提出金属材料在熔融盐腐蚀过程中的电化学阻抗模型,当合金表面形成完整,致密的氧化膜时,其阻抗谱呈双容抗弧特征;反之,当氧化膜疏松,多孔时,则表现为受氧化剂扩散控制;当合金表面氧化膜不完整的涂层遭受局部较快腐蚀时,则通常表现为双容抗弧特征。 相似文献
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研究了Na_2SO_4沉积盐引起的Ni_3Al-Fe于700一820℃空气中的腐蚀行为。结果表明,Ni_3Al-Fe遭受自持性的热腐蚀。热腐蚀的发生似可归因于Fe与Na_2SO_4反应的产物Na_2O与Na_2SO_4形成了Na_2O-Na_2SO_4共晶熔融盐,随后合金中Mo的氧化产物MoO_3参与电化学阴极还原反应,从而引发合金快速的热腐蚀。此外,熔盐中Na_2SO_4与MoO_3反应生成的SO_3导致了熔盐的高酸度和合金的内硫化,从而进一步加剧了腐蚀的进程。 相似文献
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研究了溅射Ni-40Cr-10Al-0.5Y涂层对Ni3Al基金属间化合物IC6合金性能的影响。结果表明NiCrAlY涂层可以大大提高IC6合金在1000-1100℃下的抗氧化性能和900℃纯Na2SO4中的抗热腐蚀性能,同时涂层还可使合金的力学性能及冷热疲劳性能得到改善。 相似文献
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研究了含Mo的Ni3Al-Fe基合金在900-1100℃空气中的等温氧化行为,利用光学显微镜、SEM、EPMA、XRD分析了氧化膜的形态和结构.研究表明,含Mo的Ni3Al-Fe基合金由γ和β相组成.对应于γ相的氧化膜由多相组成,合金元素Fe和Mo使得γ相的氧化速率增大,氧化膜的粘附性和内聚力下降,其氧化反应激活能为42.7kJ/mol,Fe穿过Al2O3氧化层的扩散为氧化反应的速率控制步骤.而β相中的Fe和Mo,对其抗氧化性无不利影响,氧化膜仅由Al2O3. 相似文献
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等离子喷涂ZrO2-NiCoCrAlY梯度涂层的界面强化热处理工艺 总被引:6,自引:1,他引:5
在大气条件下经高温长时间保温后,ZrO2NiCoCrAlY 梯度涂层中的NiCoCrAlY 组元发生严重氧化, 形成大量的NiO, Al2O3 和Cr2O3 等氧化物, 导致ZrO2 表面层中产生粗大网状裂纹, 并最终导致ZrO2 表面层碎裂而失效。对梯度涂层进行(900 ℃) 保温(8 h) 的真空热处理后, 涂层完好无损, NiCoCrAlY 底层与TC4 基体发生了冶金化学反应, 在涂层与基体界面形成了含NiTi, NiTi2 和TiAl3 等化合物的反应层, 涂层的抗热震性能得以显著地提高 相似文献
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研究了Na2SO4沉积盐引起的Ni3Al-Fe于700-820℃空气中的腐行为,结果表明,Ni3Al-Fe遭受自持性的热腐蚀,热腐蚀的发生似可归因于Fe与Na2SO4反应的产物Na2O与Na2SO4形成了Na2O-Na2SO4共晶熔融盐,随中金中Mo的氧化产物MoO3参与电化学阴极还原反应,从而引发合金快速的热腐蚀,此外,熔盐中Na2SO4与MoO3反应生成的SO3导致了熔盐的高酸度和合金的内硫化 相似文献
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Ni_3Al基合金的初期氧化速率 总被引:1,自引:0,他引:1
用感量为2μg的Setaram热天平研究了Ni3Al及Ni3Al-Cr基合金700℃~1100℃的初期氧化行为。Ni3Al合金在中温区(7000℃~900℃)的氧化,随温度升高初期氧化速率明显增加(氧化5min),800℃及900℃氧化0.5h后试样的氧化增重低于700℃的。在温度低于900℃时,Ni3Al-Cr基合金的氧化增重明显小于Ni3Al基合金;高于1000℃时,其氧化增重明显大于Ni3Al基合金的。EDS分析表明Ni3Al-Cr基合金表面不出现纯NiO相的氧化物区。加Cr可降低Ni3Al的晶格常数,增加原子密堆度,从而阻碍Ni原子的扩散,降低合金的氧化速率。 相似文献
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1.IntroductionThesputterednanocrystallinecoatingswiththesameconlpositionasthesubstrateweresuccessfullyappliedtoK38G[ll,Kl7F[2]lLDZc5[3]Ni-basetlsuperalloys.Themaincharacterizati0nisthatnan0crystallizati0ncouldimpr0vetheselectiveoxidationofAl,therefore,thetransiti0nfr0minternalt0externaloxidati0nofAlisrealizedandanex-ternalAl2O3scaleisfOrn1ed.Niisthemainingredient0fNi-basedsuperal1oysandtheeffectivenessofthesesuperal1oysdependsgreatly0ntllepresellceofAlorCrtoformaprotectivelayerofAl2O:jo… 相似文献
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The corrosion resistance of 12CrMoV and SS304 steels in contact with a molten mixture of (55–45) mol.% ZnCl2–KCl, similar to that found in waste-incineration plants, has been examined in air at 400 °C by the electrochemical-impedance-spectroscopy (EIS) technique. The initial Nyquist plots of 12CrMoV showed a semicircle at high frequency and a line at low frequency indicating a diffusion-controlled reaction. At a later stage, the Nyquist plots are composed of a small semi-circle at high frequency, a line at medium frequency and a large semi-circle at low frequency, similar to that shown by SS304 during the whole experimental test. The larger impedance of SS304 as compared to 12CrMoV may be attributed to the presence of Ni and to the higher Cr content of SS304. Equivalent circuits representing the features of the corrosion of 12CrMoV and SS304 are proposed to fit the corresponding impedance spectra, and the electrochemical parameters in the equivalent circuits are calculated. 相似文献
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磁控溅射Ni_3(AlCr)微晶涂层的抗氧化性能 总被引:1,自引:0,他引:1
研究了铸态Ni3(AlCr)合金及其微晶溅射涂层在900—1000℃下的高温氧化性能,结果表明:铸态Ni3(AlCr)合金在氧化过程中,开始形成以Al2O3为主含有少量NiAl2O4的氧化膜,但氧化膜的粘附性很差,在冷却时很容易剥落,在继续氧化过程中合金表面将形成NiO膜,由于NiO的保护性较差,合金表现出“失稳氧化”行为。而溅射微晶Ni3(AlCr)涂层表面形成的氧化膜与基体粘附良好,冷却过程中未发生剥落。长时间氧化后表面氧化膜只由Al2O3和NiAl2O4组成,未出现NiO,因此溅射微晶化合金的抗氧化 相似文献
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溅射NiCrAlY渗Al涂层的高温氧化行为 总被引:1,自引:0,他引:1
用SEM、XRD和EPMA等手段,研究了溅射NiCrAlY涂层渗Al前后在1000℃和1100℃的高温氧化行为.结果表明,溅射涂层在1000℃形成了单相的α-Al2O3,具有优异的抗氧化性能;但在1100℃由于Al的过度消耗而失去保护作用.渗Al涂层在1000℃快速增长θ-Al2O3相,使其抗氧化性能稍逊于溅射涂层;在1100℃表面形成了以α-Al2O3为主的保护膜,抗氧化性能优于溅射涂层. 相似文献
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Jiang Chengyang Yang Yingfei Zhang Zhengyi Bao Zebin Zhu Shenglong Wang Fuhui 《金属学报》2018,(4):581-590
Prior to practical service, hot-section components (e.g. airfoils and vanes) of a gas turbine engine are necessarily coated by a protective metallic coating (such as aluminidi diffusion coating, modified aluminide coating and MCrAlY overlay etc.) to resist high temperature oxidation and hot corrosion. Among the modified aluminide coatings, the coating with Pt-modification has attracted great attention and is widely used in applications requiring high reliability and extended service life since it possesses superior oxidation/corrosion resistance at high temperature. The presence of Pt in aluminide coating is favorable for increasing bonding strength of oxide scale, enlarging phase region of beta 3-NiAI and confining detrimental effect of sulphur etc. Although Pt-modification has exhibited visible benefits for acquiring better high-temperature performance, it is far from satisfaction to develop an ideal aluminide diffusion coating. Reactive elements such as Y, Hf, Zr or their oxides have been employed to modify the nickel aluminide coating system, with an aim to further improve scale adhesion and promote exclusive formation of alpha-Al2O3 simultaneously. In this work, a Zr-doped PtAl2+(Ni, Pt)Al dual-phase aluminide coating was prepared on a Ni-based single crystal superalloy by co-deposition of Pt-Zr through electroplating and sub-sequent aluminization treatments The coating was mainly composed of three layers: the outmost layer consisted of double phases with PtAl2 particles dispersed in beta-(Ni, Pt)Al domain, while the interlayer comprised beta-(Ni, Pt)Al with small amount of Cr-precipitates, and the bottom layer was an inter-diffusion zone (IDZ). Zirconium was mainly distributed inside beta-(Ni, Pt)Al solid solution in both the outmost layer and the interlayer. Compared with normal PtAl2+(Ni, Pt)Al dual-phase coating, the hot corrosion behavior of the Zr-doped PtAl2 + (Ni, Pt)Al coating was assessed in a salt mixture of Na2SO4/NaCI (75:25, mass ratio) at 850 degrees C in static air. The results indicated that the Zr-doped PtAl2+(Ni, Pt)Al dual-phase coating exhibited superior hot corrosion resistance since Zr was confirmed able to capture and fix S and CI to diminish their detrimental effects. Meanwhile, a pre-oxidation treatment did not effectively improve the overall hot corrosion resistance of normal PtAl2+(Ni, Pt)Al coating because the thin alumina scale formed during pre-oxidation was unable to prohibit the sustained inward-invasion of the mixed salt. 相似文献
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A two-electrode probe was used for electrochemical impedance studies of hot corrosion kinetics of molybdenum-containing Ni3Al-base alloy IC6 covered with a solid Na2SO4 film at 750 and 800???C in air. The alloy was subject to catastrophic corrosion at both temperatures, forming a thick porous oxide layer, as a result of the formation of Na2MoO4?CMoO3?CNa2SO4 melt. The experimental temperature affected the formation of the melt, the ionic conduction of the corrosion layer, and thus the impedance characteristics. For the corrosion at 800???C the Nyquist plots were composed of two capacitive loops at high-mid frequency and a line at low frequency indicating a diffusion-controlled reaction. At 750???C, however, the plots consisted of a single capacitive loop in the initial stage, followed by the same impedance features as at 800???C. Two equivalent circuits were proposed to fit the impedance spectra at the two temperatures. Based on the precise measurements of diffusion impedance, the diffusion flux of oxygen through the salt layer was calculated, and the main reduction reaction was also discussed. 相似文献
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目的研究NiAl复合涂层在腐蚀环境下的腐蚀行为及其失效机理,为其在工程中的实际应用提供理论依据。方法采用超音速电弧喷涂技术在20#钢基体表面制备了NiAl复合涂层,在此基础上对涂层的组织结构进行了表征,并对涂层与基体在3.5%NaCl溶液中的极化行为和交流阻抗谱行为进行了对比研究。结果 NiAl复合涂层的表层主要由Ni固溶体、NiAl金属间化合物和少量通过孔隙扩散到表层的Al组成。涂层呈典型的层状结构,结合较致密,表层(Ni)的孔隙率为5.3%,底层(Al)的孔隙率为4.4%。NiAl复合涂层的自腐蚀电位低于基体的自腐蚀电位,能起到良好的阴极保护效果。在测试初期,由于涂层厚度高达380μm,腐蚀介质通过涂层中存在的微裂纹和孔隙进入涂层内部,涂层快速消耗,形成较少的不溶性腐蚀产物,涂层阻抗较小,腐蚀速率较快。随腐蚀时间延长,不溶性腐蚀产物逐渐在孔隙内堆积,涂层内的极化电阻迅速增大,起到延缓腐蚀的作用。结论 NiAl复合涂层更好地发挥了Ni的耐蚀作用和Al的钝化保护作用,结合了两者的长处,表现出更好的耐蚀性能。涂层的自封闭作用是涂层阻抗值增加的主要原因。 相似文献