Incone1690超合金在600～900℃含硫氣氛之腐蝕研究

The High Temperature Sulfidation of Inconel 690 at 600~900℃ in Various S2-Containing Environments

本研究在探討Inconel 690超合金（In-690）在600～900℃，純硫氣氛（硫分壓Ps2 = 104Pa）及於H2/H2S/H2O混合氣氛下之腐蝕行為。研究結果顯示，In-690在上述兩種含硫氣氛之腐蝕動力學皆遵守拋物線型定律，且其腐蝕反應速率隨著溫度上升而加快，且In-690在H2/H2S/H2O混合氣氛下的腐蝕速率均較同溫度下的硫化腐蝕速率為快。由X-光繞射及顯微分析得知，純硫壓之腐蝕生成物可分為內、外兩層，其中，外層為硫化鎳（Ni3S2），內層是硫化鉻（Cr2S3/Cr3S4）及硫化鎳鉻（NiCr2S4）；而在混合氣氛下亦生成內、外兩層硫化物，包括外層的硫化鎳含Ni3S2及（Ni1-xS）及少量的硫化鐵鎳（Fe,Ni）9S8，而內層則為硫化鉻（Cr2S3/Cr3S4）、硫化鎳鉻（NiCr2S4）及硫化鐵鉻（FeCr2S4）。

The purpose of this research is to study the high temperature corrosion of Inconel 690(In-690) in a pure sulfur vapor of Ps2= 104 Pa and in a H2/H2S/H2O gas mixture at 600~900℃. The results showed that the corrosion kinetics followed the parabolic rate law, and the corrosion rates increased with increasing temperature. The parabolic rate constants observed in mixed gases are much faster than those of sulfidation at the same temperature studied. Based on XRD and microstructure analyses, the scales formed on In-690 in both environments were duplex. The outer scales formed consisted of nickel sulfieds(Ni3S2) and the inner scales consisted of Cr2S3/Cr3S4 and NiCr2S4 (in the pure sulfur vapor), while the outer scales formed in H2/H2S/H2O mixed gases consisted of Nickel sulfides (Ni3S2 and Ni1-xS)and minor (Fe,Ni)9S8 and the inner scales consisted of Cr2S3/Cr3S4 , NiCr2S4 , and FeCr2S4.