An oxidation mechanism map for tungsten

Nagy, Dóra; Humphry-Baker, Samuel A.

doi:10.1016/j.scriptamat.2021.114373

Cited by 17 publications

(9 citation statements)

References 40 publications

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“…A compilation of data relating temperature, critical width w * , and oxide phase is provided in table A1 (appendix A.2). These are based on measurements performed by Gulbransen and Andrew [16] and analyzed by Nagy and Humphry-Baker [26]. As the table shows, the WO 2 phase is common to all oxidation conditions, consistent with the expectation that it should be the layer immediately adjacent to the metal substrate 6 .…”

Section: Critical Fragmentation Widthsmentioning

confidence: 54%

“…In their analysis of oxidation kinetics data, Nagy and Humphry-Baker identified three bands of oxygen partial pressure, low (0.1 atm), medium (0.2 atm), and high (3.4∼13.6 atm). They extracted effective activation energies of 1.22, 1.40, and 1.94 eV for each one [26]. By mapping O partial pressures to oxygen/metal ratio, these can loosely be ascribed to diffusion in WO 2.72 , WO 2.9 , and WO 3 , respectively.…”

Section: Wo 29 and Wo 272 Layersmentioning

confidence: 99%

“…Linear growth can also coexist with parabolic (diffusive) growth. Indeed, the presence of exponents between 0.5 and 1.0 in oxidation experiments is suggestive of the coexistence of cracked layers and protective layers [19,26]. By its own definition, these stresses set in only between the oxide phase immediately in contact with the metallic base.…”

Section: Critical Fragmentation Widthsmentioning

confidence: 99%

“…Understandably, the multi-parametric nature and microstructural complexity of tungsten oxidation presents a difficult challenge for developing predictive material models and design guidelines. Recently, Nagy and Humphry-Baker have provided an oxidation mechanism map from an extensive compilation of experimental data [26]. These maps are an excellent visual tool to quickly determine the expected oxidation behavior of tungsten samples as a function of temperature and time.…”

Section: Introductionmentioning

confidence: 99%

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Multilayer interface tracking model of pure tungsten oxidation

Huang¹,

Kerr²,

Murphy³

et al. 2022

Modelling Simul. Mater. Sci. Eng.

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We present a numerical model to predict oxide scale growth on tungsten surfaces under exposure to oxygen at high temperatures. The model captures the formation of four thermodynamically-compatible oxide sublayers, WO2, WO2.72, WO2.9, and WO3, on top of the metal substrate. Oxide layer growth is simulated by tracking the oxide/oxide and oxide/metal interfaces using a sharp-interface Stefan model coupled to diffusion kinetics. The model is parameterized using selected experimental measurements and electronic structure calculations of the diffusivities of all the oxide subphases involved. We simulate oxide growth at temperatures of 600$^\circ$C and above, extracting the power law growth exponents in each case, which we find to deviate from classical parabolic growth in several cases. We conduct a comparison of the model predictions with an extensive experimental data set, with reasonable agreement at most temperatures. While many gaps in our understanding still exist, this work is a first attempt at embedding the thermodynamic and kinetic complexity of tungsten oxide growth into a comprehensive mesoscale kinetic model that attempts to capture the essential features of tungsten oxidation to fill existing knowledge gaps and guide and enhance future tungsten oxidation models.

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Section: Critical Fragmentation Widthsmentioning

confidence: 54%

Section: Wo 29 and Wo 272 Layersmentioning

confidence: 99%

Section: Critical Fragmentation Widthsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Multilayer interface tracking model of pure tungsten oxidation

Huang¹,

Kerr²,

Murphy³

et al. 2022

Modelling Simul. Mater. Sci. Eng.

View full text Add to dashboard Cite

show abstract

“…The thermal analysis curve of multilayer samples in the air also shows an obvious weight gain stage, which starts at 480 °C and ends at 600 °C. This indicates that when the organics are burning in air, the W metal is oxidized, which seriously affects the film resistance performance of the metal circuit [ 29 ]. In the N 2 atmosphere, the thermal analysis curve of the multilayer shows a continuous weight loss of 11.1% from 200 °C to 500 °C.…”

Section: Resultsmentioning

confidence: 99%

Study on Tungsten Metallization and Interfacial Bonding of Silicon Nitride High-Temperature Co-Fired Ceramic Substrates

Wang

Zhou

et al. 2023

Materials

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For the first time, Si3N4 HTCC has been prepared using W as the metal phase by high-temperature co-firing (1830 °C/600 KPa/2 h) as a potential substrate candidate in electronic applications. It was discovered that the addition of Si3N4 to the W paste has a significant impact on thermal expansion coefficient matching and dissolution wetting. As the Si3N4 content increased from 0 to 27.23 vol%, the adhesion strength of W increased continuously from 2.83 kgf/mm2 to 7.04 kgf/mm2. The interfacial bonding of the Si3N4 ceramic and the conduction layer was discussed. SEM analysis confirmed that the interface between Si3N4 and W exhibited an interlocking structure. TEM, HRTEM and XRD indicated the formation of W2C and W5Si3 due to the interface reactions of W with residual carbon and Si3N4, respectively, which contributed to the reactive wetting and good adhesion strength between the interface. Suitable amounts of Si3N4 powder and great interfacial bonding were the main reasons for the tough interfacial matching between the Si3N4 ceramic and the conduction layer.

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