In situ microscopy observation of liquid flow, zirconia growth, and CO bubble formation during high temperature oxidation of zirconium diboride–silicon carbide

Gangireddy, Sindhura; Karlsdóttir, Sigrún N.; Norton, Sylvain; Tucker, Joseph C.; Halloran, John W.

doi:10.1016/j.jeurceramsoc.2010.01.034

Cited by 49 publications

(30 citation statements)

References 18 publications

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“…When bubbles burst, exposing underlying material, increased oxidation is allowed in the region. The mechanism presented in Figure 33 is consistent with observations of Gangireddy et al 36 for The formation and bursting of bubbles was attributed there to the pressure of the gaseous products and viscosity of the glass layer. The data reported in Figure 17 …”

Section: Glass Pools and Bubble Formationsupporting

confidence: 90%

“…Bubbles formed in the continuous glass layer in 30 seconds for specimens oxidized at 1500°C in stagnant air, much quicker than the 350 minutes reported by Gangireddy et al 36 .…”

Section: Glass Pools and Bubble Formationmentioning

confidence: 60%

“…Different volume fractions of SiC will result in more or less silica-rich scales, potentially affecting oxidation results. Bubbles were not observed in the glass phase of all specimens (Table 8), however, previous work by Gangireddy et al has shown the time between formation and bursting is one minute, making them difficult to preserve in post-test specimens 36 . Further study of bubble formation is required to confirm this proposed mechanism for a wider range of materials and oxidation conditions.…”

Section: Limitationsmentioning

confidence: 72%

“…Bubble formation due to generation of gaseous oxidation products was assumed as the most likely source of oxidation variability, based off the microstructure and oxide products discussed in the literature 19,22,26,36 and assuming that the activity of all solids and liquids is unity, the equilibrium partial pressure of oxygen at the ZrB 2 /ZrO 2 interface was calculated to be 1.9x10 -16 atm. Using the Equilibrium module, inputting ZrB 2 -SiC, and holding the activity of oxygen at the equilibrium value of P O2 , the partial pressure of other gasses formed were calculated.…”

Section: Glass Pools and Bubble Formationmentioning

confidence: 99%

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Oxidation Behavior of Zirconium Diboride Silicone Carbide Based Materials at Ultra-High Temperatures

Shugart

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ZrB 2 -SiC is of high interest for Thermal Protection Systems (TPS) for future hypersonic vehicles. Both ZrB 2 and its oxidation product, ZrO 2 , possess high melting temperatures (T m =3245°C and 2715°C respectively) needed for this application. SiC is added to improve the oxidation resistance. However, the oxidation resistance of ZrB 2 -SiC at ultra-high temperatures is poor and the oxidation mechanisms are not well understood. The aim of this work was to perform a quantitative study of the oxidation behavior in order to improve life prediction.The oxidation behavior of ZrB 2 -30 vol% SiC was studied using two oxidation procedures. A box furnace was used to oxidize specimens for times between 30 seconds and 100 hours at temperatures of 1300°-1550°C in stagnant air. For ultra-high temperature testing, a resistive heating system was designed and built, which allowed oxidation at temperatures of 1300°-1800°C for times between 5 and 70 minutes in controlled oxygen atmospheres. Oxidation was quantified by measuring mass change and oxidation product layer thicknesses. A combination of scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy, inductively coupled plasma optical emission spectrometry, and time of flight secondary ion mass spectrometry was used to characterize the oxidation products.Two oxidation regimes were identified; 1) low temperature oxidation below 1627°C and 2) high temperature oxidation at and above 1627°C. Low temperature oxidation exhibited a twolayer oxide, which consisted of a borosilicate glass layer above a ZrO 2 +C layer. Key findings indicate that oxygen transport in both zirconia and borosilicate glass must be considered in modeling the low temperature oxidation behavior of ZrB 2 -30 vol% SiC. In addition composition and thickness variations of the borosilicate glass layer must also be considered. ivThe transition between the low and high temperature oxidation regimes is attributed to a change in the thermodynamically favored oxidation products, considering a locally SiC-rich microstructure. High temperature oxidation, T≥ 1627°C, resulted in formation of three oxidation product layers. A borosilicate glass layer was found above a layer with ZrO 2 and borosilicate glass. Beneath these was a porous layer of ZrB 2 resulting from SiC depletion due to active oxidation to SiO(g). Key findings indicate that the oxidation rate is much more rapid in this oxidation regime, that the SiC depletion layer growth is best explained by parabolic gas phase diffusion in the porous layer, and again, oxygen transport in both zirconia and borosilicate glass must be considered in modeling the high temperature oxidation behavior of ZrB 2 -30 vol% SiC.This work provided a quantitative analysis of the oxidation kinetics of ZrB 2 -30 vol% SiC.The thermodynamic and kinetic analyses of the two distinct oxidation regimes of ZrB 2 -30 vol% SiC enable improved life prediction.v

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Section: Glass Pools and Bubble Formationsupporting

confidence: 90%

“…Bubbles formed in the continuous glass layer in 30 seconds for specimens oxidized at 1500°C in stagnant air, much quicker than the 350 minutes reported by Gangireddy et al 36 .…”

Section: Glass Pools and Bubble Formationmentioning

confidence: 60%

Section: Limitationsmentioning

confidence: 72%

Section: Glass Pools and Bubble Formationmentioning

confidence: 99%

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Oxidation Behavior of Zirconium Diboride Silicone Carbide Based Materials at Ultra-High Temperatures

Shugart

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“…Borosilicate glass dissolves ZrO 2 and forms BSZ channels that connect the interface between the oxide layer and the unoxidized substrate. This BSZ glassy phase can act as a carrier of gas species (O 2 , CO, CO 2 , and SiO) that can diffuse in it for the oxidation of the ZrB 2 -SiC material bulk [45,46]. Due to progressive evaporation of B 2 O 3 the microstructure of the oxide scale changes with the temperature.…”

Section: Sic Smentioning

confidence: 99%

Pressureless sintering of (ZrB2–SiC–B4C) composites with (Y2O3+Al2O3) additions

Krishnarao

Alam

Das

et al. 2015

International Journal of Refractory Metals and Hard Materials

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First‐Principles Investigation on the Chemical Bonding and Intrinsic Elastic Properties of Transition Metal Diborides TMB ₂ (TM=Zr, Hf, Nb, Ta, and Y)

Zhou

Wang

et al. 2014

Ultra‐High Temperature Ceramics

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In situ microscopy observation of liquid flow, zirconia growth, and CO bubble formation during high temperature oxidation of zirconium diboride–silicon carbide

Cited by 49 publications

References 18 publications

Oxidation Behavior of Zirconium Diboride Silicone Carbide Based Materials at Ultra-High Temperatures

Oxidation Behavior of Zirconium Diboride Silicone Carbide Based Materials at Ultra-High Temperatures

Pressureless sintering of (ZrB2–SiC–B4C) composites with (Y2O3+Al2O3) additions

First‐Principles Investigation on the Chemical Bonding and Intrinsic Elastic Properties of Transition Metal Diborides TMB ₂ (TM=Zr, Hf, Nb, Ta, and Y)

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In situ microscopy observation of liquid flow, zirconia growth, and CO bubble formation during high temperature oxidation of zirconium diboride–silicon carbide

Cited by 49 publications

References 18 publications

Oxidation Behavior of Zirconium Diboride Silicone Carbide Based Materials at Ultra-High Temperatures

Oxidation Behavior of Zirconium Diboride Silicone Carbide Based Materials at Ultra-High Temperatures

Pressureless sintering of (ZrB2–SiC–B4C) composites with (Y2O3+Al2O3) additions

First‐Principles Investigation on the Chemical Bonding and Intrinsic Elastic Properties of Transition Metal Diborides TMB 2 (TM=Zr, Hf, Nb, Ta, and Y)

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First‐Principles Investigation on the Chemical Bonding and Intrinsic Elastic Properties of Transition Metal Diborides TMB ₂ (TM=Zr, Hf, Nb, Ta, and Y)