【摘要】 目的提高钼合金表面红外辐射性能与高温抗氧化性能。方法将40%Si、20%Cr、5%Ti、5%SiC、30%Mn O₂五种粉末与酒精、粘结剂按比例混合,经高能球磨6 h后制得均匀悬浮的料浆。采用浸涂工艺对预处理的钼合金试样进行料浆涂覆,在1450℃真空烧结0.5 h后制得黑色涂层试样。通过1550℃高温静态氧化试验和高温粒子薄片红外光谱综合实验系统,分别评价涂层抗氧化性能和红外辐射性能,并通过扫描电镜（SEM）、能谱分析（EDS）、X射线衍射仪（XRD）对涂层氧化前后的形貌与组织结构进行分析。结果钼合金Si-Cr-Ti-SiC-Mn O₂涂层在700、900℃的法向发射率分别达0.85、0.88,在1550℃高温有氧环境下的静态抗氧化寿命达7 h。原始涂层呈四层复合梯度结构,由外到内分别为SiO₂+Mn3O₄+M5Si3（M指Mo、Cr、Ti）、M5Si3+Mo Si2+SiC+Mn3O₄、Mo Si2、Mo5Si3。高温氧化后,涂层四层复合结构由外到内转变为SiO₂+（Cr,Ti）5Si3+Mn Cr2O₄+Mn3O₄、M5Si3+SiC+Mn Cr2O₄+Mn3O₄、Mo Si2、M5Si3。高温氧化过程中,MSi2高硅化物层逐渐转变为M5Si3低硅化物层,涂层表面形成含Mn Cr2O₄尖晶石相和复合硅化物的致密SiO₂玻璃膜。结论 Si-Cr-Ti-SiC-Mn O₂涂层可有效提高钼合金基体的红外辐射性能和高温抗氧化性能,复合硅化物与硅锰复杂氧化物具有良好的抗氧化性能、高辐射性能和自愈合性能。更多还原

【Abstract】 The work aims to improve infrared emissivity property and high temperature oxidation resistance of molybdenum alloy surface. Uniform suspension slurry was obtained after the slurry made of 40wt% Si, 20wt% Cr, 5wt% Ti, 5wt% Si C and 30wt% Mn O₂ powders as well as ethyl alcohol and bonder in proportion were milled with high energy ball for 6 h. Then the slurry was dip coated on the pretreated molybdenum alloy surface. Finally, the silicide coatings were synthesized at 1450 in ℃vacuum atmosphere for 0.5 h and furnace-cooled down to room temperature. Oxidation resistance and infrared radiation properties of the silicide coatings were evaluated by performing high-temperature static oxidation test 1550 and high℃-temperature particle slice infrared spectroscopy integrated experimental system. Morphology and organizational structure of the unoxidized and oxidized coatings were analyzed by using SEM, EDS, and XRD. Normal infrared emissivity of the Si-Cr-Ti-Si C-Mn O₂ coating at 700 ℃and 900 was ℃0.85 and 0.88, respectively. Static oxidization resistance life at 1550 ℃in aerobic environment was 7 h. The original coating exhibited a four-layer composite gradient structure consisting of Si O₂+Mn3O₄+M5Si3, M5Si3+Mo Si2+Si C+Mn3O₄, Mo Si2 layer and Mo5Si3 diffusion layer（outside-in）. After oxidation at 1550 for 4 h, composition ℃of the four-layer structure changed into Si O₂+（Cr,Ti）5Si3+Mn Cr2O₄+Mn3O₄ layer, M5Si3+Si C+Mn Cr2O₄+Mn3O₄ layer, MSi2 layer and M5Si3 diffusion layer（outside-in）. During the high-temperature oxidation process, the MSi2 high silicide layer gradually transformed into M5Si3 low silicide layer, and a dense Si O₂ glass film containing Mn Cr2O₄ spinel phase and composite silicide took shape on the coatings. The Si-Cr-Ti-Si C-Mn O₂ coating can effectively improve the infrared emissivity performance and high temperature oxidation resistance of the molybdenum alloy substrate. Composite silicide and silicon-manganese complex oxide exhibit excellent oxidization resistance, high radiation property and self-healing property.更多还原