PURPOSE: To improve strength of the title sintered compact by adding silicon and oxygen in the surface layer part of sintered compact at an amount larger than that of the center part in the sintered compact containing silicon nitride and specific sintering assistant.
CONSTITUTION: In the aimed silicon nitride sintered compact containing silicon nitride and at least element compound of the group IIIa of the periodic table, silicon and oxygen in the surface layer part is contained at an amount larger than that in the central part. The aimed sintered compact is e.g. obtained as follows: The above-mentioned ingredients are formed and burned according to well known method to afford high-density sintered compact having no difference between inner and outer parts. Then the sintered compact is subjected to heat treatment in atmosphere containing SiO. By the heat treatment, SiO gas is converted into SiO2 on the surface of sintered compact at high temperature or in cooling process and silicate glass layer is formed on the surface of sintered compact while element oxide of the group IIIa of the periodic table which is a sintering assistant ingredient is partially reacted with SiO2. Thereby difference of silicon and oxygen amounts occurs between surface layer and inner part of the sintered compact.
| JP2609053 | HEAT RESISTANT BURNER DIFFUSER |
| JP2015232394 | ROTOR |
| JPH08119744 | PRODUCTION OF SILICON NITRIDE SINTERED COMPACT |
MATSUNAKA MASAFUMI
TANAKA TAKEMOTO
| JPS54142219A | 1979-11-06 | |||
| JPS58194776A | 1983-11-12 | |||
| JPS60186476A | 1985-09-21 | |||
| JPS60200881A | 1985-10-11 | |||
| JPS61251588A | 1986-11-08 | |||
| JPS63100087A | 1988-05-02 |