燃煤MHD发电Cr_（25）Al_5电极材料的腐蚀行为研究

The Corrosion Behavior of Cr_(25)Al_5 Metallic Electrode Material Uscd for MHD Power Generation

采用Ｃｒ＿（２５）Ａｌ＿５合金进行煤渣／种子条件下静态腐蚀试验（温度１３７３－１５７３ｋ，时间５０－１５０ｈｒ），试验后得出三种温度下腐蚀重量变化与腐蚀时间的关系，并借助金相显微镜、扫描电镜和俄歇分析进行有关形貌及成份分析，试验表明，温度是材料腐蚀的主要因素，在１４７３ｋ条件下材料的抗蚀性最好，Ａｌ、Ｓｉ元素在腐蚀过渡层中富集，Ｃｒ元素变化不大，但有从基体向外扩散的趋势。由此，这一材料若能进一步改进，可望在控制壁面温度的半热壁型通道中进行试验研究。

Metallic electrode material is important to coal-fired M HD generator.Anal loy with properties similarto platinum or its alloys is being sought.The alternative method is to find new metallic n1aterial or toimprove conventional alloy. In this paper the second method is discussed.Cr_(25)Al_5 alloy is selected for thestatic coal slag corrosion test.The results are analyzed and three statistical models for different temfperatureare built bv means of mathematic method of TRID,Mean while surfare morphology and composition aretested by use of optical microscope ,SEM and Auger.The experimcntal resul ts indicate that temperature isthe main factor that affects the corrosion degree of the alloy. In the transition layer Al and Si are rich,whi le the variation of Cr is not remarkable,But the diffusion tendenev of element Cr from interior to surfaceis apparent.Besides,under the condition of the biggest viscosity of liquid slag the alloy has good corrosionresistance. Therefore ,if the properties of the alloy are improved and the experimental temperature of coalfired semihot MHD generator channel wall is controlled ,the further experiment on the alloy might bepossible.