Patent ID: 7514383
Filing Date: 2009-04-07
Classification: C04B

Abstract:
1. A compact comprising: 80 to 95 vol % component A comprising alpha- and beta-SiAlON and a partially crystalline grain-boundary phase; and 5 to 20 vol.% of component B comprising a hard material which is in globular form and an average grain size of from 1 to 5 microns; wherein the compact is sintered and has a sintered surface and a hardness of at least 1550 HV 10 and wherein said compact has an alpha-SiAlON gradient which decreases from the sintered surface to an inside of the sintered compact; wherein the sintered surface has an alpha-SiAlON content of up to 100%, wherein said hard material is SiC, wherein the state of the hard material remains unchanged after sintering; wherein the content of grain-boundary phase is less than 10 vol.% and comprises phases of aluminum containing melilite or disilicate; wherein in the inside of the sintered compact comprises from 15 to 50 vol.% alpha-SiAlON and wherein the amount of beta-SiAlON ranges from 50 to 85 vol.%.