Titanium carbo-nitride complex silicon nitride tool

A sintered article of titanium carbo-nitride complex silicon nitride ceramic produced according to the following steps:

• (1) preparing a starting powder mix comprising 10 to 60 vol % of TiC.sub.x N.sub.1-x (0.3<x.ltoreq.0.5), 0.5 to 10 vol % of at least one oxide selected from the group consisting of CeO.sub.2, Y.sub.2 O.sub.3, Yb.sub.2 O.sub.3 and Dy.sub.2 O.sub.3, and the balance being silicon nitride, and
• (2) sintering the starting powder mix under application of pressure in an inert or nitrogen containing atmosphere at a temperature of 1500 to 1900.degree. C.

A titanium carbo-nitride complex silicon nitride tool consisting essentially of titanium carbo-nitride and silicon nitride,

• wherein said tool comprises, based on the total weight of said tool, 10 to 50 wt % of Ti, 11.6 to 51 wt % of Si and 1 to 21 wt % of at least two elements selected from the group consisting of Ce, Y, Yb and Dy.

A method for producing titanium carbo-nitride complex silicon nitride ceramic comprising:

• preparing a starting powder mix comprising 10 to 60 vol % of TiC.sub.x N.sub.1-x (0.3<x.ltoreq.0.5), 0.5 to 10 vol % of at least one oxide selected from the group consisting of CeO.sub.2, Y.sub.2 O.sub.3, Yb.sub.2 O.sub.3 and Dy.sub.2 O.sub.3, and the balance being silicon nitride, and
• sintering the starting powder mix under application of pressure in an inert or nitrogen containing atmosphere at a temperature of 1500 to 1900.degree. C.