Sintering of Zirconium Dіboride and Phase Transformations in the Presence of Cr3С2

  
L.I.Klimenko,
   

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Omeliana Pritsaka str.,3, Kyiv, 03142, Ukraine
Powder Metallurgy - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2016, #03/04
http://www.materials.kiev.ua/article/2171

Abstract

The kinetics of sintering and phase interactions in the diffusion contact zones of Cr3C2 and ZrB2 are investigated. It is found that using Cr3C2 as sintering activator for ZrB2 sintering reduces the hot pressing temperatures from 2200 °C to 1500–1750 °C, depending on the Cr3C2 content. The phase formation accompanied with the formation of new high-temperature refractory compounds like zirconium carboborides, chromium borides and carboborides, and zirconium-chromium carboborides rapidly develops at the Cr3C2 and ZrB2 interface within the diffusion zone. An intense diffusion of chromium and carbon into zirconium diboride accompanied by the formation of nonporous states in zirconium diboride (to a depth of 50–100 µm at 1360 °C) near diffusion contact zone is observed. It is established that the contact interaction during sintering in the diffusion zone results in the formation of eutectic liquid vanishes phase, which is consumed to forming the new high-refractory compounds (phases based on zirconium carbide and chromium borides).


CHEMICAL MICRO INHOMOGENEITY, CHROMIUM BORIDE, CHROMIUM CARBIDE, CONTACT INTERACTION, DIFFUSION ZONE, DISAPPEARING EUTECTIC LIQUID PHASE, HOT PRESSING IN VACUUM, STRESS-STRAIN CURVES, STRUCTURIZATION AND PHASE FORMATION, X-RAY MICROANALYSIS, XRPD, ZIRCONIUM BORIDE, ZIRCONIUM-CHROMIUM CARBOBORIDE