Development of ZrB₂–SiC–Ti by multi stage spark plasma sintering at 1600°C

Abstract

Zirconium diboride based ceramics, owing to their superior high temperature properties are potential materials for use as leading edge components in hypersonic space vehicles. However, the difficulty in sintering these ultra high temperature ceramics limit their applications to some extent. Sintering of such materials is usually accomplished by resorting to advanced sintering techniques such as Spark Plasma Sintering (SPS) accompanied by sinter aids to improve the sinterability. In this backdrop, the current work investigates the effect of Ti addition on the mechanical properties and sinterability of ZrB 2 based ceramic composites. Tailored addition of Ti to ZrB 2 18 wt. % SiC baseline composites not only improves the densification but also increases hardness and indentation toughness, when sintered using Multi Stage Spark Plasma Sintering technique. Microstructure and X-ray diffraction analysis reveals the presence of ultrafine grains of ZrB 2 and SiC, which is found to be effective in obtaining a good hardness (up to 29 GPa) and reliable indentation toughness (up to 9 MPa•m 1/2).

Shock wave‐material interaction in ZrB2–SiC based ultra high temperature ceramics for hypersonic applications

“…Careful comparison of the post-shock wave exposure micrographs between ZST0 ( Figure 7C) and ZST10 ( Figure 7D) reveals sparse distribution of oxide granules in the ceramic containing Ti as an additive (see Figure S3). 5 After shock tube experiments, both the ceramic composites exhibit marginal increase in H v and E. This can also be noted in the load vs. displacement plot recorded during the instrumented indentation, as shown in Figure 8B. This qualitatively ascertains the betterment in oxidation resistance of ZST10, which is substantiated by XPS results.…”

“…[5][6][7][8] For the present study, wire-electric discharge machined thin discs of the ceramic pellets ZST0 | 6927 GOPINATH eT Al. More details on processing, properties, and performance qualification testing of the aforementioned ceramics are given elsewhere.…”

“…Subsequently, the fluid domain is assigned with the properties of the shock heated gas, obtained from NASA CEA code (see Table 1). [5][6][7][8]28,29 This is followed by applying the initial and boundary conditions to the computational model. [5][6][7][8]28,29 This is followed by applying the initial and boundary conditions to the computational model.…”

“…At the fluid-solid interface, the average "hot wall" heat flux is about 82 MW/m 2 at the start of shock wave exposure, which respectively reduces to ~17 MW/m 2 and ~15 MW/m 2 in case of ZST0 and ZST10, at the end of the test time. [5][6][7][8]28,29 at ambient pressure conditions and exposure duration of 1 hour. The initial heat flux is higher in magnitude when compared to the arc-jet experiments, wherein the typical "cold wall" heat flux lies in the range of 1-12 MW/m 2 , at the stagnation point.…”

“…[4][5][6][7][8][9][10][11] When UHTCs are employed as the leading edges, intense shock loading adversely affects the performance due to high thermomechanical loads generated by shock interaction. However, there is a limited focus on integrated experimental-computational approach, coupled with performance qualification and performance limiting tests, for accelerated development of advanced technologies, such as thermal protection systems for hypersonic vehicle.…”