Method to improve the oxidation resistance of ZrB 2 -based ceramics for reusable space systems

Silvestroni, L.; Failla, Simone; Neshpor, I. P.; Grigoriev, O. N.

doi:10.1016/j.jeurceramsoc.2018.01.025

Cited by 53 publications

(17 citation statements)

References 32 publications

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“…This effect can be better appreciated looking at the elemental maps in phases. This hypothesis has been confirmed in a recent specific study [38].…”

Section: Effect Of Mo On the Oxidation Behavior At Ultra-high Temperasupporting

confidence: 71%

Understanding the oxidation behavior of a ZrB2–MoSi2 composite at ultra-high temperatures

et al. 2018

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This basic research investigates the microstructure evolution of a composite based on ZrB 2-MoSi 2 from the as-sintered features to the changes occurring upon oxidation at ultra-high temperatures, 1650 and 1800°C, in a bottom-up loading furnace for 15 minutes. Scanning and transmission electron microscopy evidenced the formation of a matrix typified by ZrB 2-cores surrounded by (Zr,Mo)B 2-rims with dispersed MoSi 2 particles and SiO 2 glass trapped at the triple junctions. The oxidation at 1650°C induced the migration of silica to the surface, which formed a continuous and protective scale. Below this scale, the matrix evolved into ZrO 2 grains encasing MoB nano-inclusions, as a result of the oxygen and boron oxide partial pressures established in the subscales. Underneath, a MoSi 2-depleted boride region, but substituted by SiO 2 and MoB was found. The same phases were observed upon oxidation at 1800°C, but a thicker and more turbulent oxidized layer formed as a consequence of the rapid evolution of MoO 3 , SiO and B 2 O 3 gases from the scales beneath the outermost silica-layer. According to the observed phases and the calculated phase stability diagrams, the partial pressures gradient within the oxide layer were defined and the effect of Mo-doping in boride matrices on the oxidation behavior was compared to that of other transition metals to establish a criterion design for the realization of ceramics with improved oxidation resistance.

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“…This effect can be better appreciated looking at the elemental maps in phases. This hypothesis has been confirmed in a recent specific study [38].…”

Section: Effect Of Mo On the Oxidation Behavior At Ultra-high Temperasupporting

confidence: 71%

Understanding the oxidation behavior of a ZrB2–MoSi2 composite at ultra-high temperatures

et al. 2018

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“…Among the additives already studied, SiC is one of the most used and it seems to be the most valuable to enhance the resistance to oxidation by the formation of borosilicate glass, to promote densification by restricting the growth of diboride grains and to lower their sintering temperature [4,6,9]. The double phase materials are usually obtained by a hot pressing process, which, despite the high pressures required (30–50 MPa), allows us to reduce the densification temperature [13,14,15].…”

Section: Introductionmentioning

confidence: 99%

Machinability and Energy Efficiency in Micro-EDM Milling of Zirconium Boride Reinforced with Silicon Carbide Fibers

2019

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Several types of advanced materials have been developed to be applied in many industrial application fields to satisfy the high performance required. Despite this, research and development of process suited to machine are still limited. Due to the high mechanical properties, advanced materials are often considered as difficult to cut. For this reason, EDM (Electrical Discharge Machining) can be defined as a good option for the machining of micro components made of difficult to cut electrically conductive materials. This paper presents an investigation on the applicability of the EDM process to machine ZrB2 reinforced by SiC fibers, with assessment of process performance and energy efficiency. Different fractions of the additive SiC fibers were taken into account to evaluate the stability and repeatability of the process. Circular pocket features were machined by using a micro-EDM machine and the results from different process parameters combinations were analyzed with respect to material removal, electrode wear and cavity surface quality. Discharges data were collected and characterized to define the actual values of process parameters (peak current, pulse duration and energy per discharge). The characteristics of the pulses were used to evaluate the machinability and to investigate the energy efficiency of the process. The main process performance indicators were calculated as a function of the number of occurred discharges and the energy of a single discharge. The results show interesting aspects related to the process from both the performances and the removal mechanism point of view.

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“…Zirconium diboride (ZrB 2 ), an ultra-high temperature ceramic material, is a promising candidate for specialized applications as nose cones for hypersonic vehicles, nuclear industry components, or thermal protection systems due to its ultra-high melting point, excellent hardness and stiffness, and relatively low thermal expansion coefficient and density. [1][2][3] However, the intrinsic brittleness of ceramics often becomes a key limitation to their application. 4 Once microcracks occur on the surface or within the material due to internal stress or external forces, catastrophic failure is most likely to occur, thus greatly reducing the reliability of the material.…”

Section: Introductionmentioning

confidence: 99%

“…Zirconium diboride (ZrB 2 ), an ultra‐high temperature ceramic material, is a promising candidate for specialized applications as nose cones for hypersonic vehicles, nuclear industry components, or thermal protection systems due to its ultra‐high melting point, excellent hardness and stiffness, and relatively low thermal expansion coefficient and density . However, the intrinsic brittleness of ceramics often becomes a key limitation to their application .…”

Section: Introductionmentioning

confidence: 99%

Strong and tough ZrB₂ materials using a heterogeneous ceramic–metal layered architecture

Bai

Sun

et al. 2019

J Am Ceram Soc

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ZrB2‐SiCw ceramic sheets produced by tape casting and tailored ductile Ti foil were alternatively stacked and sintered by spark plasma to synthesize a multi‐layered ceramic. Following mechanical processing, a high flexural strength (621 MPa) and fracture toughness (15.3 MPa·m1/2) in uniaxial tension were achieved in comparison to laminated ceramics with a weak BN interlayer. Scanning and transmission electron microscopy revealed a characteristic macroscopic heterogeneous lamella as well as a three‐tier microstructured interface, termed the L‐T structure. This novel structure provides a new path for the development of ceramic/metal layered composites with superior mechanical properties in the near future.

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Method to improve the oxidation resistance of ZrB 2 -based ceramics for reusable space systems

Cited by 53 publications

References 32 publications

Understanding the oxidation behavior of a ZrB2–MoSi2 composite at ultra-high temperatures

Understanding the oxidation behavior of a ZrB2–MoSi2 composite at ultra-high temperatures

Machinability and Energy Efficiency in Micro-EDM Milling of Zirconium Boride Reinforced with Silicon Carbide Fibers

Strong and tough ZrB₂ materials using a heterogeneous ceramic–metal layered architecture

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Method to improve the oxidation resistance of ZrB 2 -based ceramics for reusable space systems

Cited by 53 publications

References 32 publications

Understanding the oxidation behavior of a ZrB2–MoSi2 composite at ultra-high temperatures

Understanding the oxidation behavior of a ZrB2–MoSi2 composite at ultra-high temperatures

Machinability and Energy Efficiency in Micro-EDM Milling of Zirconium Boride Reinforced with Silicon Carbide Fibers

Strong and tough ZrB2 materials using a heterogeneous ceramic–metal layered architecture

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Strong and tough ZrB₂ materials using a heterogeneous ceramic–metal layered architecture