Sintering of aluminum nitride by using alumina crucible and MoSi2 heating element at temperatures of 1650 deg C and 1700 deg C

摘要

Aluminum nitride (A1N) ceramics, prepared with Y_2O_3 and CaO sintering additives, have been densified in an Al_2O_3 crucible at temperatures of up to 1650 deg C and 1700 deg C using a conventional MoSi_2 heating element furnace. The results of this study show that relative densities in excess of 99 percent of theoretical and a relatively high-thermal conductivity of 147 W m~(-1) K~(-1) have been achieved for feedstock materials prepared with combined addition of 1 wt. percent Y_2O_3 and 1 wt. percent CaO. All of the phases in sintered samples have been shown to be crystalline A1N and minor amount of secondary phases, were detected such as enriched Y- and Ca-aluminates by the XRD patterns, back-scattered imagery and microprobe analysis. The advantage of using the particular experimental system and sintering condition is considered to be amenable to lower production cost and enhance the feasibility of mass production. Critical temperature for AlN densification to obtain the highest density is about 1650 deg C.