Improved Oxidation Resistance of Zirconium Carbide at 1500°C by Lanthanum Hexaboride Additions

Abstract

Addition of LaB6 is adopted to improve the oxidation resistance of ZrC at 1500°C. Mixed powder of ZrC‐25 vol% LaB6 is reactively hot pressed at 1900°C for 30 min under vacuum with an applied pressure of 25 MPa. The LaB6 reacts with ZrC to form ZrB2 and a layered La‐containing phase. ZrB2 improves the oxidation resistance of ZrC in static air. The La‐containing phase is beneficial to increasing the relative density of oxide scale during oxidation and in enhancing the oxide scale stability during exposure to thermal cycles.

Low temperature sintering of ZrC–SiC composite

“…This relative density is higher than that (92.2%) of monolithic ZrC sintered with similar condition [3]. ZrC-SiC has much better oxidation resistance than monolithic ZrC [7]. Therefore, ZrC-SiC is a promising ceramic composite.…”

Microstructure and Ablation Behavior of W Coating Prepared by Atmospheric Plasma Spraying for Zr/Cu Infiltrated C/C Composites

“…Some reported studies showed that when oxygen was dissolved in carbides, ZrC (1‐x) O x was first formed during the oxidation of ZrC . ZrO 2 was produced when dissolved oxygen in ZrC (1‐x) O x reached saturation, and ZrO 2 layer became thick and acted as a barrier to oxygen diffusion at low oxygen partial pressures.…”

Effect of Monolithic LaB6 on the Ablation Resistance of ZrC/SiC Coating Prepared by Supersonic Plasma Spraying for C/C Composites

“…Zirconium carbide (ZrC), as a member of ultra-high temperature ceramics (UHTCs), is an attractive coating material due to its relatively low density, high strength and modulus [10][11][12] . High efficiency supersonic atmospheric plasma spray (SAPS) has been successfully developed to deposit ceramic and metallic coatings [13] .…”