Masamichi Udaka1, Kazuhiro Kawasaki1,Takao Yamazaki1 and Minoru Umemoto2
1Technical Department, Neturen Co., Ltd., Hiratsuka
Cu/AlN mixed ultrafine particles (UFP) were subjected to either pressurized or nonpressurized sintering to produce sintered compacts with ultrafine microstructure. Original Cu UFP 90 nm in mean surface diameter and AlN UFP 54 nm in mean surface diameter, produced by thermal plasma method respectively, were mixed by ultrasonic mixing in acceton. Their sintering behavior and characteristics were examined, and effects of AlN UFP as second phase particles on densification and on grain growth of the compacts were investigated.
The results obtained were as follows; (1) Grain size of Cu UFP compacts increased with increasing sintering time; however, that of Cu/AlN mixed UFP compacts became stationary by sintering in excess of 7.2 ks at 1273 K. (2) The stationary grain size of Cu/AlN mixed UFP compacts, were in inverse proportion to the volume fraction of AlN UFPs. It was consistent with the grain size predicted by the pinning effect. (3) In the case of Cu/AlN mixed UFP compacts, the densification was retarded as compared with the Cu UFP compacts, by decreasing the mobility and the driving force of sintering as decreasing the contact area of Cu UFPs by AlN UFPs. (4) Grain growth in the mixed UFP compacts were restrained by AlN UFPs and pores during sintering. Because of such effects of AlN UFPs, sintering of the mixed UFPs can be completed without grain growth, and a submicronsized microstructure in which the grain size were stationary, can be obtained.
(Received April 12, 1995)
thermal plasma, ultrafine-particles, pressurized sintering, nonpressurized sintering, pinning effects, aluminum nitride, submicronsized microstructure
Please do not copy without permission.