SIALON

Period of Performance: 01/01/1984 - 12/31/1984

$50K

Phase 1 SBIR

Recipient Firm

Gorham Advanced Materials Inst
Po Box 250
Gorham, ME 04038
Principal Investigator

Abstract

THE OBJECTIVE OF THE PROPOSED STUDY IS TO DETERMINE THE FEASIBILITY OF FULLY DENSIFYING A SIALON VIA SINTER/HIP PROCESSING. SINTER/HIP IS AN INNOVATIVE APPROACH TO MATERIALS CONSOLIDATION WHICH INCORPORATES SINTERING AND CONTAINERLESS HIP'ING (HOT ISOSTATIC PRESSING) INTO A SINGLE, UNINTERRUPTED CYCLE CONDUCTED IN A HIP SYSTEM. IN THIS PROPOSED PROCESS TECHNOLOGY, GREEN PREFORMS ARE SINTERED UNDER MODERATE N2 PRESSURE TO HIGH DENSITY AND CLOSED POROSITY IN THE HIP VESSEL; FOLLOWING COMPLETION OF THE DESIGNATED SINTERING PHASE OF THE CYCLE, THE VESSEL IS RAPIDLY PRESSURIZED TO A SUITABLE HIP'ING PRESSURE (E.G., 30 KPSI), AND THE HIP PHASE OF THE CYCLE IS THEN CONDUCTED. SINTER/HIP THUS DIFFERS FROM THE "CONVENTIONAL" CONCEPT OF CONTAINERLESS HIP'ING, SINCE SINTER/HIP DOES NOT REQUIRE OR EMPLOY SEPARATE SINTERING AND HIP'ING SYSTEMS. ADDITIONALLY, SINTER/HIP MAKES POSSIBLE PROCESSING CONDITIONS DIFFERENT FROM THOSE USED IN THE "CONVENTIONAL" SINTER + CONTAINERLESS HIP APPROACH. THUS SINTER/HIP MAY YIELD TECHNICALLY UNIQUE MATERIALS WITH PROPERTIES AND MICROSTRUCTURES UNLIKE THOSE PRODUCED VIA OTHER PROCESS TECHNOLOGIES. THE PROPOSED STUDY WILL AIM AT FULLY DENSIFYING A 92 WT.% SI3N4 + 6 WT.% Y2O3 + 2 WT.% AL2O3 SIALON VIA SINTER/HIP. ROOM TEMPERATURE MODULUS OF RUPTURE VALUES FOR SINTER/HIP'ED SPECIMENS WILL BE GENERATED AND COMPARED WITH MOR VALUES FOR COMPOSITIONALLY SIMILAR SINTERED AND SINTERED + CONTAINERLESS HIP'ED SPECIMENS.