Effect of Chromium on Mechanical and Corrosion Behaviour of Ferrous Metal Matrix Composites by Using Powder Metallurgy Route

In this present research work effect of chromium in ferrous material by using the powder metallurgy technique is been studied in detail. Chromium is added to iron matrix in various proportions of 2%Cr, 4%Cr, 6%Cr, and 8%Cr and the remaining is Fe powder. First challenge was to produce these metal matrix composites by using the powder metallurgy technique, we also added zinc stearate as a binder and die releasing agent. The compaction load is optimized to 160KN by trial-and-error method to get a healthy specimen and the required density is achieved (Mahajan et al. in Indian J Sci Technol 8:101–105, 2015). These compacted green specimens were sintered at 12,000 C to make them hard and useable shape. Once this Fe–Cr metal matrix composite is successfully prepared by using the powder metallurgy technique these composites were tested for Vickers Hardness number and corrosion behaviour and tested under an optical microscope to study on microstructure of the prepared composites (Gurcan and Baker in Wear 188:185–191, 1995). During these tests, it showed that the purest iron specimen produced at 160 KN load and sintered at 12,000 C showed a hardness of 126HV against a 100HV of 6% of Cr in the Fe matrix, that clearly shows that Cr is not contributing much to the hardness of the composites (Yih and Chung in Int J Powder Metall (1986) 31(4):335–340, 1995). Corrosion tests on these sample show that adding Cr to Fe matrix will definitely delay the corrosion to a good extent and microstructure studies revealed that chromium reinforcement in the iron matrix is uniformly distributed and no internal defects are found (Saheb in ARPN J Eng Appl Sci 6:41–46, 2011).