| abstract |
REFRACTORY CORES WHICH CAN BE USED IN INVESTMENT CASTING WITHOUR FIRST HAVING BEEN FIRED TO AN ELEVATED TEMPERATURE ARE MADE BY A PROCESS CHARACTERIZED BY THE STEPS OF: (1) MOLDING A CORE FROM REFRACTORY MIXTURE INCLUDING A SUBLIMABLE BINDER, (2) SUBLIMING THE BINDER FROM THE CORE TO PRODUCE A POROUS STRUCTURE, (3) IMPREGNATING THE PORE STRUCTURE WITH A HARDENING AND STRENGTHENING AGENT, AND (4) HARDENING THE MATERIAL USED FOR IMPREGNATION. |