自反应喷射成形过程中复合粉金属成分的氧化问题探讨
Discussion on Oxidation of Metallic Components in Composite Powders During Self-reactive Spray Forming Process
刘宏伟1, 马世宁1, 孙晓峰1, 王建江2
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作者单位：(1. 装甲兵工程学院 装备再制造工程系, 北京 100072; 2. 军械工程学院 先进材料研究所, 河北 石家庄 050003)
中文关键字：自反应喷射成形； 复合粉； 金属组元； 氧化规律
英文关键字：self-reactive spray forming; composite powders; metallic composition; oxidation rule
中文摘要：针对利用Ti-B4C-C体系复合粉制备Ti(C，N)-TiB2陶瓷坯件时，复合粉中金属组元易被氧化，使喷射沉积坯件内含有有害相TiO2的问题，利用综合热分析仪研究分析了该复合粉中金属组元Ti的氧化规律，探讨了向喷射体系中加入5wt% Al对复合粉氧化规律及喷射沉积坯件组织结构的影响。结果表明：在自反应喷射成形过程中，喷射体系中金属组元Ti的氧化机理遵从抛物线-线性氧化规律；复合粉体系中引入活性组元Al后，由于Al的选择氧化，在金属表面形成具有保护性作用的致密氧化膜Al2O3，有效抑制了Ti的氧化；金属的氧化机理转变为Ti-Al二元金属的线性-抛物线规律；喷射沉积坯件的致密度、硬度、弯曲强度和断裂韧性等性能也由97.2 %、17.3 GPa、387 MPa、6.0 MPa·m1/2分别提高到97.7%、20.6 GPa、425 MPa、7.3 MPa·m1/2。
英文摘要：During forming Ti(C, N)-TiB2 by self-reactive spray, metallic components are easy to be oxidized ,which make the preforms contain the undesirable phase TiO2. To dissolve the problems, the rule of the metallic oxidation of the composite powders was studied by synthetic thermal analyzer, and the influences of 5wt% additive of Al on the rule of metallic oxidation and the structure and properties of the spray-formed preforms were discussed. The results show that during self-reactive forming process, the oxidation of the metallic components in the Ti-B4C-C system accords with parabola-linearity rule. After adding 5wt%Al into the spraying system, the oxidation rule of the metallic components changes into linearity-parabola because the compact oxide film of Al2O3 forms on the surface by the selective oxidation of Al and effectively restrains the oxidation of Ti. The relative density, hardness, flexural strength and fracture toughness of the preforms increases from 97.2%, 17.3 GPa, 387 MPa, 6.0 MPa·m1/2, to 97.7%, 20.6 GPa, 425 MPa，7.3 MPa·m1/2 , respectively.