VERBUNDWERKSTOFF AUS GESINTERTEM SILICIUMNITRID UND DARAUS HERGESTELLTES SCHNEIDWERKZEUG.

摘要

Composite sintered Si3N4 material particularly suitable as a cutting tool material for cutting cast iron is composed of: a sintered Si3N4 substrate containing 0.1 to 10 weight % of Y2O3, 0.1 to 10 weight % of ZrO2 and if necessary 1 to 15 weight % of at least one member selected from the group consisting of compound and solid solution thereof of elements of IVa (except Zr), Va and VIa of the Periodic Table and the balance being of Si3N4; a first layer of Ti compound coated on the sintered Si3N4 substrate; a second layer of Al2O3 coated on the first layer; and the total thickness of the first and second layers being in the range of 1 to 20 microns. The above composite sintered Si3N4 material has an improved abrasive resistance particularly in the case of cutting cast iron at high speed, while retaining the excellent physical properties of Si3N4. Such a composite sintered Si3N4 material is useful for preparing a cutting tool of a long life time.