Wet Seal Research Articles

A comparison of two aluminizing methods for corrosion protection in the wet seal of molten carbonate fuel cells

The corrosion behavior of aluminized Type 310S stainless steel (SS) in the wet seal of molten carbonate fuel cells was investigated. Coupons of Type 310S SS were aluminized by two different aluminizing methods: thermal spray and slurry-coating. In both types of samples Fe and Cr diffused readily into the Al layer at 650 °C. At first this interdiffusion is limited to the interfacial area. With time, Fe and Cr aluminides precipitate in the Al layer. The slurry-coated layer contains a higher concentration of FeAl and Fe3Al than does the thermal spray layer. Consequently, the slurry-coated layer also displays a greater degree of corrosion than the thermal spray layer.

腐食防食 イオンプレーティングと酸化拡散処理による溶融炭酸塩型燃料電池セパレータ用耐食コーティングの開発

In order to improve the corrosion resistance of MCFC separator, a new coating was made by combination of ion plating and heat treatment. The corrosion resistance of coating was investigated by electrochemical corrosion tests in a molten carbonate and MCFC single cell tests. The composition of coating was analyzed by means of EPMA and XRD. The characteristics required for the wet seal area of separator such as the flatness of surface were discussed.The results obtained are as follows:(1) Through the plating of Al layer on stainless steel and the heat treatment under a particular condition, the multi-layer coating having aluminum oxide phase at the outer side and Al-Cr-Ni diffusion alloy phase at the inner side is obtained.(2) The morphology of the coating film is affected by the thickness of Al layer plated on stainless steel.(3) Corrosion resistance in a molten carbonate environment is dependent on the composition of the oxide layer.

Development of materials and production technologies for molten carbonate fuel cells

Molten carbonate fuel cell stacks are assembled from nickel-coated stainless steel frames comprising a bipolar plate, the flanges for the wet seal and current transmitting structures and the cell components, namely the anode, electrolyte matrix and cathode which are introduced into the stack in the form of “green foils” or presintered metal sponges and which are transformed into the respective cell components by ex situ or in situ reactive sintering.

Wetting Properties of Molten Carbonate Fuel Cell Electrode Materials

not Available.

Electrolyte Loss and Performance Decay of Molten Carbonate Fuel Cells

Postmortem chemical analysis, gas chromatography, electrode polarization studies, atomic adsorption spectroscopy, and Hg intrusion porosimetry have been employed in studies of the extent of electrolyte loss from cell components and the resultant performance decay. This study has identified electrolyte creep, hardware corrosion, and chrome lithiation as the pivotal electrolyte consumption mechanisms. The principal mechanisms of performance decay are increased cell resistance, increased cathode polarization, and deteriorating gas compositions due to gas crossover and parasitic reactions at the wet seal edges of the cell.

Corrosion of the Wet‐Seal Area in Molten Carbonate Fuel Cells: II . Experimental Results

Experimental results for anode wet‐seal corrosion in molten carbonate fuel cells generally agree with postulated mechanisms that involve corrosion couples acting along or across the seal area. The corrosion rate of Type 316 stainless steel in the anode wet‐seal area under all test conditions is unacceptably high. Substitution of an aluminum containing alloy, such as Kanthai A‐1, reduces the anode wet‐seal corrosion by at least two orders of magnitude. The corrosion rate of Type 316 stainless steel in the cathode wet seal is about two orders of magnitude lower than in the anode wet seal.

Corrosion of the Wet‐Seal Area in Molten Carbonate Fuel Cells: I . Analysis

Severe corrosion can occur in the seal area between the cell housing and the electrolyte tile of a molten carbonate fuel cell even if an optimal selection of the active cell materials has been made. Thermodynamic calculations and an approximate mixed‐potential analysis indicate that several minor corrosion cells are active at open circuit, and a major corrosion cell is established when the cell is under load. Extensive corrosion can be expected on the anode side of the wet seal, although effects at the cathode side are minor.

Corrosion Protection of Molten Carbonate Fuel Cell Gas Seals

not Available.