JPH0527454B

PURPOSE:To reduce the size of a crystal particle of a formed compound, by placing a powder mixture of raw materials consisting of plural kinds of element powders within a specific vacuum range under a condition that temp. shows a value generating self-combustion by the heat of reaction generated at the time of synthetic reaction. CONSTITUTION:A powder mixture 4 prepared by sufficiently mixing raw materials is put in a refractory crucible 3, which is inserted in the electric furnace 2 within a high vacuum container 1. Next, the high vacuum container 1 is evacuated by a high vacuum exhaust system 6 to be brought to high vacuum of 5X10torr or less. Thereafter, the vacuum degree in the high vacuum container 1 is held to a vacuum degree range of 5X10-5X10torr by the vacuum exhaust system 6 and the electric furnace 2 is regulated to hold the environmental temp. of the raw material powder mixture 4 to temp. generating the self-combustion of the raw material powder mixture within a temp. range of ambient temp.-2,000 deg.C to perform synthetic reaction. After the finish of synthesis, the high vacuum container 1 is returned to atmospheric pressure to be opened and the crucible 3 containing the synthetic compound is taken out.