Roadmap for densification in cold sintering: chemical pathways

Summary¶

Cold sintering (CSP) densifies ceramics at unusually low temperatures (often below ~400 °C) by coupling pressure with transient chemical media (solvents, hydrates, salt additives) that mediate mass transport at interfaces without requiring full high-temperature lattice diffusion. This Open Ceramics roadmap article—co-authored by Adri C. T. van Duin—provides a taxonomy of chemical pathways observed or proposed across ceramic and composite families, emphasizing that many recipes rely on transient phases that are not present in the final microstructure. The local pdf_path is a journal pre-proof (papers/Ndayishimiye_Roadmap_ColdSintering_preproof_2020.pdf); a sibling wiki page may track a cleaner PDF variant ([[2020ndayishimiye-open-ceramic-roadmap-densification]]).

Methods¶

This Open Ceramics contribution is a qualitative review and process taxonomy for cold sintering (CSP), not a single numerical benchmark. 4 — Reviews / non-simulation (literature scope). The text synthesizes transient-solvent, additive, and interfacial-reaction classes across ceramic families, cites how XRD, microscopy, calorimetry, and related methods are used in the field, and situates pressure-solution style densification next to other creep limits. It references reactive MD and ReaxFF-style work as examples in the cited literature rather than reporting one new MD protocol here. For sintering “methods” the manuscript illustrates typical lab flows (manual mixing, ~10 min room-temperature press to reorder particles, ~20 °C min⁻¹ ramps, dwells, and uniaxial tooling with process parameters collected in Supplementary Table S1 as referenced in §2.1. 1–3 (MD, FF, static QM): N/A — no primary atomistic dataset is executed in the roadmap itself; read cited papers for ReaxFF and DFT settings. N/A (full MD checklist) for this page by design. Provenance: local pdf_path is a journal pre-proof; for presentation details prefer [[2020ndayishimiye-open-ceramic-roadmap-densification]] when the VOR is needed.

Findings¶

The roadmap argues that CSP chemistry is heterogeneous across materials classes: what limits densification is often a chemical step (dissolution–reprecipitation, complexation, interfacial amorphization) rather than purely mechanical compaction, but the dominant mechanism can change with solvent chemistry, particle size, and electric field history in field-assisted variants. The authors stress a need to separate rate-limiting chemical steps from mechanical contact-area evolution to mature predictive processing models. Reactive MD is positioned as a tool to propose atomistic sequences for interfacial reactions when paired with experimental validation.

Limitations¶

Pre-proofs can differ from version-of-record text in minor editorial details; prefer the sibling page noted above for stable reader citation when both PDFs exist in the corpus.

Reproducibility notes¶

Cold sintering studies that cite atomistic models should specify solvent activity, particle surface chemistry, and whether electric fields are present—each pathway class has distinct timescales. When using ReaxFF snapshots to interpret interfacial reactions, pair them with in situ evidence where possible because CSP often involves amorphous interlayers not obvious from ideal crystal interfaces.

Pre-proof PDFs sometimes omit final editorial figure polish; when two corpus paths exist, compare schematic process flow diagrams between pre-proof and VOR siblings before citing a specific panel label in downstream automation.

Relevance to group¶

Manifest record for the pre-proof file path (van Duin co-author); links to CSP + ReaxFF literature.

reaxff-family