Interfacial reactions in Ti/Si3N4 and TiN/Si diffusion couples

Abstract

Stability and formation kinetics of TiN and silicides in Ti/Si3N4 and Tii/Si diffusion joints have been investigated. Reactions in the diffusion couples were studied experimentally in the temperature range between 950 and 1100 "C. Isothermal sections and activity diagrams of the Ti-Si-N system were calculated using the recent thermodynamic data. Both the thermodynamic calculations and experimental results indicate that TiN and Si react with each other and form TiSi, and even S&N4 if the activity of nitrogen is high enough. Similarly, results from the TiiSi,N4 couple were in good accordance with calculated phase equilibria. The experiments carried out in vacuum ampoules and in a vacuum furnace showed that the gas phase has a strong effect on the reactions. 0 1995 American Institute of Physics.

The thermodynamic assessment of the Ti–Si–N system and the interfacial reaction analysis

“…The driving force of the Si 3 N 4 phase was calculated to be positive and maximum at the interface TiN/TiSi 2 , where the Si 3 N 4 phase will precipitate. Similar experimental results were reported by Paulasto et al [7]. When the TiN/Si joint annealed in Fig.…”

“…[7,8] studied the Ti/Si 3 N 4 couple experimentally and similar results were obtained. The schematic diagram of the phase sequence in Ti/Si 3 N 4 joint at 1373 K was given by Paulasto et al [7].…”

“…[21][22][23] show the equilibrium between TiN and Si but not between TiSi 2 and Si 3 N 4 . But Paulasto et al [7] pointed out that TiN and Si could react with each other and form Si 3 N 4 and/or TiSi 2 depending on the activity of nitrogen (see Fig. 7).…”

“…[7,19,[21][22][23], it can be proposed that there might be no conflict as to whether the tie line between TiN-TiSi exists or not. Below and above 1300 K may correspond to the existence and the non-existence of this tie line, respectively.…”

“…Paulasto et al [7] investigated the stability and formation kinetics of TiN and silicides in Ti/Si 3 N 4 and TiN/Si diffusion joints and studied experimentally the interfacial reactions in these diffusion couples in the temperature range between 1223 and 1373 K. Gotman and Gutmanas [8] observed the sequences of the phase formation at the Si 3 N 4 /Ti powder interface at different temperatures (1173, 1223 and 1323 K).…”