Corrosion Commentary

The effect of tin, copper, nickel and molybdenum on the mechanical properties and corrosion resistance of sintered stainless steel (AISI304L). The industrial use of sintered stainless steel is restricted by the poor corrosion resistance of the materials in comparison with the wrought counterpart. It has been shown in the literature that the addition of tin and copper can bring about improvements in the corrosion performance of certain alloys and this paper reports a systematic study of the use of these and other alloying additions. In this work, elemental additions of Sn, Cu, Ni and Mo singly and in combinations were made to 304L stainless steel powder. The mechanical properties and corrosion resistance to salt spray and immersion in saline solution of the sintered compacts have been measured and compared with samples made from 316L powder and wrought stainless steel. It was found that 304L containing additions of either 2% Sn or 2% Ni + 2% Cu + 1% Sn had the most improved corrosion resistance but with some loss of strength following sintering under conditions suitable for 304L powder. Increasing' the sintering time of the alloys with elemental additions from 45 minutes to two hours at 1180°C increased the strengths of the compacts to the same level as 304L and 316L while retaining the improved resistance to corrosion. ITRI Publication No. 650, is by S. K. Chatterjee, M. E. Warwick, and D. J. Maykuth, and is available from ITRI, Fraser Road, Perivale, Greenford, Middx UB6 7AQ.