한국분말야금학회지 Vol. 26 No. 6 (p.455-462)

Effect of SiC and WC additon on Oxidation Behavior of Spark-Plasma-Sintered ZrB2

키워드 :
Oxidation,High temperature ceramic,Zirconium diboride,Diffusivity,Thermal degradation

목차

Abstract
1. Introduction
2. Experiment
   2.1 Raw materials and the sample powder preparations
   2.2 SPS sintering
   2.3 Anti-oxidation property analysis
3. Results
   3.1 Oxide scale formations
   3.2 Weight changes analysis of the samples bytorch and TGA
4. Discussion
   4.1 The oxidation reactions and behaviors
   4.2 Diffusion behavior from TGA
5. Conclusions
References

초록

ZrB2 ceramic and ZrB2 ceramic composites with the addition of SiC, WC, and SiC/WC are successfully synthesized by a spark plasma sintering method. During high-temperature oxidation, SiC additive form a SiO2 amorphous outer scale layer and SiC-deplete ZrO2 scale layer, which decrease the oxidation rate. WC addition forms WO3 during the oxidation process to result in a ZrO2/WO3 liquid sintering layer, which is known to improve the antioxidation effect. The addition of SiC and WC to ZrB2 reduces the oxygen effective diffusivity by one-fifth of that of ZrB2. The addition of both SiC and WC shows the formation of a SiO2 outer dense glass layer and ZrO2/WO3 layer so that the anti-oxidation effect is improved three times as much as that of ZrB2. Therefore, SiC- and WC-added ZrB2 has a lower two-order oxygen effective diffusivity than ZrB2; it improves the anti-oxidation performance 3 times as much as that of ZrB2.