Tetragonal and Hexagonal Iron–Manganese Carbides

Abstract

DURING recent studies of the iron–manganese–carbon system, specimens, each weighing approximately 5 g, were carefully prepared according to predetermined compositions. The components were 500-mesh powders of 99.995 per cent pure iron and spectroscopically pure carbon and a 200-mesh powder of 99.995 per cent pure manganese. The component powders were intimately mixed by shaking, then each specimen was packed into a pure alumina crucible the end of which was closed, but not sealed, with high purity alumina cement. Each specimen was then sintered at 960° C for 110 h in a silica capsule containing helium at approximately 0.25 at m. (such time having been previously found sufficient for equilibrium to be attained¹).