论文部分内容阅读
研究了在900℃的90Na_2SO_4-10K_2SO_4(克分子％)熔盐中,电极电位对镍基高温合金腐蚀行为的影响。在正电位条件下可发生酸性熔融(Acidic Fluxing),而在较负电位下则发生碱性熔融(Basic Fluxing)腐蚀。在中间(中性)电位区,含铬较高的合金如IN738,IN 939,IN597和IN657等可生成保护性氧化膜。合金成份将影响发生酸性和碱性熔融腐蚀的临界电位值。含铬低的合金如IN 100和IN 713LC在任何电位下均不能生成稳定的保护性氧化膜。鉴定了腐蚀产物层中的多种硫化物相,它们的生成与电极电位,腐蚀程度和合金的成份有关。只有在碱性熔融腐蚀条件下才能生成硫化物相NaCrS_2,它的出现可作为发生碱性熔融的标志。
The effect of electrode potential on the corrosion behavior of Ni-based superalloy was investigated in 90Na_2SO_4-10K_2SO_4 (mol%) molten salt at 900 ℃. Acidic Fluxing can occur at positive potentials and Basic Fluxing at relatively negative potentials. In the neutral (neutral) potential region, higher chromium alloys such as IN738, IN939, IN597 and IN657 generate protective oxide films. Alloy composition will affect the occurrence of acidic and alkaline molten corrosion of the critical potential value. Low chromium containing alloys such as IN 100 and IN 713LC do not generate stable protective oxide films at any potential. Various sulfide phases in the corrosion product layer were identified and their formation was related to the electrode potential, the degree of corrosion, and the composition of the alloy. Sulfide phase NaCrS 2 can be formed only under basic molten corrosion conditions, and its appearance can be used as a marker of alkaline melting.