摘要
研究TiAl合金表面等离子喷涂NiCoCrAl-Y2O3涂层在850℃下对75%Na2SO4+25%NaCl熔盐的热腐蚀行为,及对TiAl金属间化合物抗高温热腐蚀性能的影响。研究表明,在850℃,等离子喷涂NiCoCrAl-Y2O3涂层由于生成Cr2O3,NiO和NiCr2O4等各种氧化物组成的氧化层,显著提高了TiAl基体的抗热腐蚀性能。在热腐蚀过程中,S元素以Ni元素为载体,逐步渗入涂层中,生成过渡产物Ni3S2。随着O分压的升高,反应进入了氧化阶段,生成Cr2O3、NiO等氧化物,随着两种物质含量的增加,最后发生固相反应,生成尖晶石结构的NiCr2O4化合物。过渡产物Ni3S2与腐蚀介质中的Cl-离子形成微电池,可以加快热腐蚀反应速度。
The hot corrosion behavior of plasma-sprayed NiCoCrAl-Y2O3 coating on TiAl alloy surface in the mixed melted salt of 75%Na2SO4＋25%NaCl at 850 oC for 100 h and the influence of the coating on the anti-corrosion properties of TiAl intermetallics were investigated.The results show that the plasma-sprayed NiCoCrAl-Y2O3 coating could remarkably improve the hot corrosion resistance of TiAl matrix by generating a compound oxide layer of Cr2O3,NiO and NiCr2O4.In the course of hot corrosion,S,carried by Ni,gradually infiltrated into the composite coating and generated a transition product of Ni3S2.Then the partial pressure of the oxygen increased,followed by oxidation which produced oxides including Cr2O3 and NiO.As the amount of the both oxides increasing,the solid-state reaction took place and generated the NiCr2O4 compounds of spinel structure.The transition product of Ni3S2 and the chloridion contained in corrosion media jointly constituted micro-cell,thus accelerating hot corrosion.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2010年第8期1439-1442,共4页
Rare Metal Materials and Engineering
基金
国家自然科学基金(59975046
50305010)
江苏省自然科学基金重点项目(BK2004005)
