Nitridation of Titanium and Zirconium Powders Mixed with Ammonium Chloride under High Temperature-High Pressure Ammonia

Abstract

Titanium and zirconium powders did not yield nitrides effectively by the treatment in pressurized ammonia of 1 MPa and above, at 700°C for 3 h. The addition of NH4CI was effective for the nitridation of Ti and Zr. Reactions of titanium powder (99.1% up) mixed with 10 wt% (9.2 mol%) ammonium chloride have been studied at 300–700oC under 0.1 or 1 MPa NH3 (initial pressure) for 3 h. Ti and NH4CI did not react at 300°C, but formed TiHi.924at 400°C, and then TiHi.924changed into TiN above 500°C. When the sample of Ti-10 wt% NH4CI was heated at 300–600°C under 0.4 MPa Ar gas for 3 h, TiHi.924was produced at 400°C and above, but TiN was not produced. When the sample of Zr-10 mol% (6 wt%) NH4CI was heated under 0.1 or 1 MPa NH3, ZrN was formed above 600°C through the formation of ZrH and above 400°C. A small amount of ß-ZrNCl was also produced at 700°C under the same conditions. © 1987, Japan Society of Powder and Powder Metallurgy. All rights reserved.