CERAMICS RESISTOR AND ITS MANUFACTURE

• Main Authors: TAKAHASHI KEN, SAITO YUKIO, KANAI TSUNEYUKI, CHIBA AKIO
• Format: Patent
• Language: English
• Published: 11.08.2000
• Edition: 7
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; RESISTORS

PROBLEM TO BE SOLVED: To restrain resistivity at normal temperature and improve stability of characteristics, reliability and reproducibility by dispersing a specified amount in Si3N4 as free carbon of deposited SiC. SOLUTION: The mixing ratio of C powder to Si3N4 powder is set in the range of at least 1 wt.% and less than 15 wt.%. In order to reduce the temperature dependence of free carbon, free carbon amount is set to be at least 100 PPM and less than 10,000 PPM. Proper amount of dispersant is added to those powders. They are sulbjicted to thermal treatment in inert gas at 1,500-1,800 deg.C is performed, material powder is decomposed and/or composed by chemical reaction, and SiC particles and/or SiC whiskers are formed in Si3N4 matrix. SiC particles, SiC whiskers and free carbon can be formed uniformly and finely and decomposed in Si3N4. As a result, free carbon as a material with which SiC restrains resistivity can be decreased in temperature dependence of a resistor.