Two-dimensional nucleation growth of stepped ZrC skeleton with controllable morphology

Porous zirconium carbide (ZrC) ceramics with stepped morphology were successfully prepared by evaporating solvent combined with high-temperature sintering. Step morphology with different slopes on the skeleton can be tuned by optimizing the sintering temperature. SEM, TEM and in-situ scanning probe image characterizations confirmed that the stepped ZrC ceramic followed a two-dimensional nucleation growth mechanism. Herein a three-dimensional model based on Burton-Cabrera-Frank theory of crystal growth was established to explain the reasons for stepped growth. After 5 thermal shock cycles between 1500 degrees C and room temperature, the stepped morphology has a positive role on improving the adhesion strength between pyrocarbon and ZrC skeleton in the form of mechanical interlocking. This work provides a strategy for improving the interfacial bonding strength of ultra-high temperature composites by morphology design.

Automated summary

Porous zirconium carbide ceramics with stepped morphology were prepared by evaporating solvent combined with high-temperature sintering, where the morphology can be tuned by optimizing the sintering temperature. The stepped morphology was found to improve the adhesion strength between pyrocarbon and ZrC skeleton through mechanical interlocking. This study provides a strategy for enhancing the interfacial bonding strength of ultra-high temperature composites through morphology design.