512,311. Compositions containing metals. TOOL METAL MANUFACTURING CO., Ltd. March 17, 1939, No. 8624. Convention date, March 18, 1938. Addition to 506,964. [Class 70] To the composition of the parent Specification, viz. a sintered hard composition consisting essentially of aluminium oxide and from 20 to 40 per cent. in all of at least one metal such as iron, nickel, or cobalt, is added up to 10 per cent. of an oxide or oxidic compound to reduce the sintering temperatures and improve the cutting properties. Additions specified include silicic acid, calcium oxide, kaolin and porcelain powder.