Stainless steel separator for fuel cells, method for making the same, and solid polymer fuel cell including the same

摘要

A stainless steel separator having gas channels including grooves and projections for fuel cells. The separator has a composition including about 0.03 mass percent or less of carbon; about 0.03 mass percent or less of nitrogen, the total content of carbon and nitrogen being about 0.03 mass percent or less; about 16 mass percent to about 45 mass percent chromium; about 0.5 mass percent to about 3.0 mass percent molybdenum; and the balance being iron and incidental impurities. The separator has a contact resistance of about 100 mOMEGA.cm2 or less. Preferably, the projections have an arithmetic average surface roughness Ra in the range of about 0.01 to about 1.0 mum and a maximum height Ry in the range of about 0.01 to about 20 mum. The stainless steel separator preferably further includes about 0.001 to about 0.1 mass percent silver. A fuel cell including this separator exhibits a stable output voltage for a long period of time.