Ablation properties of ZrC-SiC-HfB₂ ceramic with different amount of carbon fiber under an oxyacetylene flame

Abstract

In the present work, a carbon fiber reinforced ZrC-20 vol% SiC-15 vol% HfB 2 composite was produced by pressureless sintering method. Carbon fiber with various weight percentages (0, 10, 20, 30) was added to the milled ZrC-SiC-HfB 2 . The mixed powders were pressed and sintered at 2200°C for 2 h. The microstructure and mechanical properties of the specimens were investigated by Scanning Electron Microscope (SEM) equipped with EDS spectroscopy, XRD analysis and hardness and toughness tests. The ablation resistance of the composites was performed by oxyacetylene torch. The results showed that as the carbon fiber content was increased, the porosity and toughness were increased as well, while the hardness and density were decreased. During the ablation test, the outer surface of the composite underwent a sintering process and formed a dense layer of Zr-Hf-Si-O on the surface. ZrSiO 4 and HfSiO 4 were also created after cooling, so these phases played a pinning effect and prevented the crack propagation. The results also showed that linear and mass ablation rates were increased with increasing the weight percentage of the carbon fiber. SEM analysis with EDS further revealed that with increasing the carbon content, the defects in the formed oxide layer on the composite surface were increased due to the evaporation of SiO 2 and the decrease in the pinning effect of ZrSiO 4 and HfSiO 4 phases as well as the phase transformation of the remained ZrO 2 and HfO 2 . As a result, as the carbon fiber was increased, the ablation resistance of the composite was decreased.

Optimizing the Parameters of Zirconium Carbide and Rice Husk Ash Reinforced with AA 2618 Composites

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Advances in Ablation or Oxidation Mechanisms and Behaviors of Carbon Fiber-Reinforced Si-Based Composites

“…Table 3 showcases recent ablation and oxidation properties of C/SiZM composites and provides a summary of both historical and recent ablation research results of C/C-SiC-Z composites. [193] Si-Zr-Mo [199] C/C-SiC-HfC-TaC 2D SiC-coated C/C preform HfC-TaC PC; SAPS oxyacetylene torch 0.35 1.05 × 10 −3 [200] Si-Zr-Ti…”

Effect of Graphite Addition on the Microstructure, Mechanical Properties and Oxidation Resistance of HfB2-SiC Composites Prepared by the SPS Method

“…Compounds such as borides, carbides and nitrides of the IV-V group intermediate metals, which have melting temperatures above 3000 °C [1], are known as ultra high temperature ceramics (UHTCs) [2]. Good oxidation resistance [3] and high thermal and electrical conductivity [4] of diboride refractory compounds, as compared to other intermetallic compounds (carbides, nitrides), have led to extensive research on diborides such as (Ta, Nb, Hf, Zr, Ti)B2 [5].…”