Analyzing titanium carbide ceramics: From tooling to hypersonic applications using ARL X’TRA Companion XRD

Significance of the topic

The structural state and phase composition of titanium carbide (TiC) strongly determine its performance in wear-resistant tooling, protective coatings, cermets, and ultra-high temperature components for aerospace and hypersonic applications. Small changes in stoichiometry, surface oxidation, or microstructural defects affect hardness, oxidation resistance, thermal conductivity and high‑temperature stability. X‑ray diffraction (XRD) with quantitative Rietveld analysis is a primary analytical tool to resolve TiC, its oxides (TiO2 polymorphs) and related nitrides (TiN), enabling quality control of feedstock powders and correlation of structure to functional performance.

Objectives and study overview

This application note demonstrates the use of the Thermo Scientific ARL X’TRA Companion benchtop XRD for rapid, quantitative phase analysis of two commercial TiC powders (visually described as blue–gray and black). Goals were to (1) identify and quantify TiC, TiO2 polymorphs (rutile, anatase) and TiN; (2) estimate crystallite sizes; and (3) evaluate powder suitability for industrial and aerospace use, showing how routine XRD informs processing decisions (e.g., reduction treatments) and supports material selection.

Used instrumentation

• Diffractometer: Thermo Scientific ARL X’TRA Companion X‑Ray Diffractometer, θ/θ Bragg–Brentano geometry, 160 mm goniometer radius.
• X‑ray source: Cu Kα radiation (λ = 1.541874 Å), 600 W option available (also supports Co).
• Beam conditioning: divergence and Soller slits, variable beam knife to reduce air scattering.
• Detector and software: solid‑state pixel detector (55 × 55 μm pitch), Thermo Scientific SolstiX Pronto Instrument Control Software with single‑click Rietveld quantification and LIMS integration.
• Refinement software: Profex (Rietveld refinements).

Methodology

• Samples: Two commercial TiC powders (blue–gray and black); pressed into top‑loading sample cups and measured in reflection geometry.
• Measurement protocol: Cu Kα radiation, sample spinning, 10 minute acquisition per sample.
• Data analysis: Rietveld refinement using Profex to obtain phase fractions and apparent crystallite sizes (from peak broadening analysis).

Results and discussion

The two powders showed distinctly different phase compositions and microstructural signatures:

• Blue–gray powder: TiC 57.3 wt% (apparent crystallite size ~172 nm); rutile (TiO2) 37.7 wt% (CS ~14 nm); anatase 0.9 wt% (CS ~8 nm); TiN 4.1 wt% (CS ~8 nm). The large rutile fraction explains the blue–gray color and indicates extensive surface oxidation of TiC feedstock. Such material would typically require reduction (e.g., carbothermal reduction) prior to use in structural or high‑temperature applications.
• Black powder: TiC 83.0 wt% (CS ~137 nm); rutile 5.6 wt% (CS ~8 nm); anatase 4.6 wt% (CS ~7 nm); TiN 6.7 wt% (CS ~8 nm). Lower oxide content and higher TiC fraction are consistent with a high‑quality feedstock suitable for demanding tooling, coatings, cermets or HT‑ceramic development.

Key analytical observations: Rietveld XRD distinguished rutile vs anatase and quantified TiN—phase discrimination that elemental techniques (e.g., XRF) cannot provide reliably. Apparent crystallite sizes from peak broadening indicate coarser TiC crystallites in the blue sample (likely due to partial sintering/aggregation or measurement artefacts) and nanoscale oxide/nitride secondary phases. The rapid 10‑minute measurement shows benchtop XRD can deliver actionable QC data in routine workflows.

Benefits and practical applications

• Fast, quantitative phase analysis: short measurement times with automated Rietveld provide timely decision support for powder acceptance, need for reduction, or downstream processing.
• Discrimination of similar phases: resolves TiC, rutile, anatase and TiN—important for correlating optical appearance and performance to chemistry and structure.
• Integration and data management: single‑click quantification and LIMS connectivity enable traceable results and streamlined laboratory workflows.
• Applications: quality control of starting powders for hard metal tooling, coating feedstocks, cermets, advanced composites, and screening of candidate materials for hypersonic thermal protection systems.

Limitations and practical considerations

• Depth sensitivity and surface oxides: reflection XRD probes bulk near‑surface; thin surface oxides or carbonaceous surface layers may require complementary surface techniques (GIXRD, XPS) for full characterization.
• Quantification limits: small fractions (<~1 wt%) and amorphous carbon or low‑Z phases may be difficult to detect/quantify reliably by laboratory XRD alone.
• Crystallite size vs strain: apparent sizes derived from peak broadening reflect combined size/strain effects; deconvolution requires careful modelling or complementary TEM/microstructure analysis.
• Sample preparation and preferred orientation: powder packing, particle size and texture can bias intensities—consistent sample mounting and spinning were used here to mitigate these effects.

Future trends and potential applications

• In situ and high‑temperature XRD studies to follow phase evolution, oxidation and carbide‑nitride transformations under processing or service conditions relevant to hypersonic environments.
• Grazing incidence XRD and depth‑profiling to resolve ultrathin surface oxides and coatings on TiC particles or coated tools.
• Higher‑resolution and microdiffraction techniques (lab‑based or synchrotron) combined with TEM and atom probe to characterize nanoscale defects and compositional gradients.
• Machine‑learning assisted phase identification and automated quantification pipelines integrated with LIMS for real‑time process control and supply‑chain QC.
• Multimodal correlative workflows (XRD + XPS + Raman + SEM/EDS) to link phase composition, surface chemistry and morphology to functional performance.

Conclusion

Rapid benchtop XRD with automated Rietveld refinement, as demonstrated on the ARL X’TRA Companion, provides robust, actionable phase and microstructural information for TiC powders. The study showed clear differences between a heavily oxidized (blue–gray) batch requiring reduction and a higher‑quality (black) batch suitable for demanding applications. Routine quantitative XRD strengthens feedstock qualification and accelerates development of TiC‑based components across tooling, coatings and hypersonic systems.

References

1. Döbelin N., Kleeberg R., Journal of Applied Crystallography, 2015, 48, 1573–1580.
2. Thermo Fisher Scientific, Application Note AN41523 (ARL X’TRA Companion XRD), 2025.