{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.hafnium-diboride","code":"thing-q4161099","url":"https://ver.cy/models/thing/q4161099/","name":"hafnium diboride","alternateNames":[],"kind":"thing","status":"published","version":"0.1.0-research.1","language":"en","classifiers":{"family":"Thing Registry","category":"Physical world and living systems","entryKind":"thing","plane":"PHY","domain":["PHY.MAT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"Hafnium diboride (HfB2) is a refractory, electrically conductive ceramic compound of hafnium and boron with a hexagonal aluminium-diboride-type crystal structure, classified as an ultra-high-temperature ceramic.","purpose":"Enable an AI agent to identify hafnium diboride, assess a particular material lot or specimen, and judge its suitability for processing or service from condition-specific evidence.","scope":{"in":["HfB2 chemical identity, phase verification, and substance identifiers","Lot-specific stoichiometry, purity, contaminants, and intentional additions","Powder, consolidated-body, and coating material states","Thermal, mechanical, and transport properties with measurement conditions","Oxidation, recession, and damage under specified environments","Grade-specific handling evidence and material acceptance criteria"],"out":["Complete formulations and performance models of HfB2-based composites","Design and qualification of nozzles, leading edges, or other finished components","Synthesis and sintering equipment or complete manufacturing procedures","Elemental hafnium, elemental boron, and other hafnium compounds as independent substances","Facility-level exposure control and waste-management systems"],"boundaries":[]},"distinguishingFeatures":["Require evidence for a hafnium-boron compound with nominal Hf:B atomic ratio 1:2; the same bulk elemental ratio in a physical mixture does not establish HfB2.","Use phase identification alongside elemental analysis to distinguish HfB2 from hafnium carbide, hafnium nitride, and hafnium oxide.","Resolve hafnium versus zirconium content when distinguishing HfB2 from ZrB2 or mixed hafnium-zirconium diborides.","Distinguish the HfB2 phase from an HfB2-SiC composite: NASA explicitly records HfB2 with 20 volume percent SiC as a composite material. [NASA material record](https://tpsx.arc.nasa.gov/MaterialProperty?id=30&property=3&units=eng)","Separate evidence that HfB2 remains present from evidence that a specimen retains its original composition and integrity after oxidation."],"structure":{"bundles":[{"id":"diboride-identity","name":"Diboride identity","description":"Establishes whether a record or specimen represents the registered HfB2 substance.","layers":[{"id":"composition-and-phase","name":"Composition and phase","description":"Combines elemental and structural evidence for identification.","findings":[{"id":"hfb2-identification","name":"HfB2 identification","description":"Require evidence that hafnium and boron form the claimed diboride phase rather than merely occurring together.","questions":[{"text":"What elemental analysis supports the nominal Hf:B ratio of 1:2, and with what uncertainty?","id":"hfb2-identification-q01","kind":"measurement"},{"text":"Which diffraction or other phase-identification result supports HfB2, and what reference was used?","id":"hfb2-identification-q02","kind":"provenance"},{"text":"Could the observations instead describe a mixture, another hafnium compound, or a mixed-metal diboride?","id":"hfb2-identification-q03","kind":"boundary"}]}]},{"id":"substance-and-product-boundary","name":"Substance and product boundary","description":"Aligns identifiers with the substance actually described.","findings":[{"id":"identifier-and-formulation-match","name":"Identifier and formulation match","description":"Verify identifiers independently and distinguish HfB2 identity from commercial grade and composite identity.","questions":[{"text":"Which authoritative records establish the CAS number, EC number, and PubChem CID for hafnium diboride?","id":"identifier-and-formulation-match-q01","kind":"provenance"},{"text":"Does the supplied name denote HfB2 itself, an HfB2 grade, or an HfB2-containing formulation?","id":"identifier-and-formulation-match-q02","kind":"definition"},{"text":"Which intentional constituents require a linked composite model?","id":"identifier-and-formulation-match-q03","kind":"boundary"}]}]}]},{"id":"grade-and-powder-condition","name":"Grade and powder condition","description":"Captures the composition and surface condition that distinguish usable HfB2 feedstocks.","layers":[{"id":"purity-and-additions","name":"Purity and additions","description":"Records what the purity claim includes and which constituents were deliberately added.","findings":[{"id":"lot-composition-accounting","name":"Lot composition accounting","description":"Represent measured impurities separately from formulation additions and unspecified residuals.","questions":[{"text":"Does the stated purity include or exclude zirconium, and what analytical basis supports that convention?","id":"lot-composition-accounting-q01","kind":"definition"},{"text":"What oxygen, carbon, zirconium, and other impurity concentrations were measured in this lot?","id":"lot-composition-accounting-q02","kind":"measurement"},{"text":"Which additives were introduced intentionally, in what fractions, and for what documented purpose?","id":"lot-composition-accounting-q03","kind":"provenance"}]}]},{"id":"particle-and-surface-state","name":"Particle and surface state","description":"Describes powder geometry, agglomeration, and surface changes.","findings":[{"id":"feedstock-condition","name":"Feedstock condition","description":"Keep primary-particle measurements, agglomerate measurements, and surface characterization distinguishable.","questions":[{"text":"What particle-size distribution, morphology, and specific surface area were measured, using which preparation methods?","id":"feedstock-condition-q01","kind":"measurement"},{"text":"What evidence characterizes surface oxygen-bearing material, moisture, or storage contamination?","id":"feedstock-condition-q02","kind":"measurement"},{"text":"What lot-specific criteria determine whether the powder needs recharacterization before processing?","id":"feedstock-condition-q03","kind":"action"}]}]}]},{"id":"consolidation-and-microstructure","name":"Consolidation and microstructure","description":"Connects the current HfB2 specimen state to its processing history and internal structure.","layers":[{"id":"processing-state","name":"Processing state","description":"Retains processing provenance that can explain the resulting material.","findings":[{"id":"material-history","name":"Material history","description":"Record consequential processing conditions and resulting composition without modeling the manufacturing equipment.","questions":[{"text":"Which synthesis, milling, consolidation, deposition, or heat-treatment steps produced this HfB2 material?","id":"material-history-q01","kind":"provenance"},{"text":"What temperatures, pressures, atmospheres, and additives are documented for those steps?","id":"material-history-q02","kind":"provenance"},{"text":"What post-processing analysis establishes whether the phase assemblage changed?","id":"material-history-q03","kind":"measurement"}]}]},{"id":"density-and-defects","name":"Density and defects","description":"Characterizes the internal state relevant to measured performance.","findings":[{"id":"specimen-integrity","name":"Specimen integrity","description":"Record porosity, grain structure, second-phase distribution, and defects on a stated sampling basis.","questions":[{"text":"What bulk density and open and closed porosity were measured, and what reference density defines relative density?","id":"specimen-integrity-q01","kind":"measurement"},{"text":"What grain sizes, texture, second phases, and cracks were observed, and how representative is the inspected region?","id":"specimen-integrity-q02","kind":"measurement"},{"text":"Which observed defects exceed the acceptance criteria for the intended material use?","id":"specimen-integrity-q03","kind":"action"}]}]}]},{"id":"conditioned-property-evidence","name":"Conditioned property evidence","description":"Organizes thermal, transport, and mechanical measurements by material state and test conditions.","layers":[{"id":"thermal-and-electrical-response","name":"Thermal and electrical response","description":"Distinguishes measured transport behavior and phase-transition evidence from assumed constants.","findings":[{"id":"temperature-dependent-properties","name":"Temperature-dependent properties","description":"Require units, uncertainty, temperature, atmosphere, and specimen state for each thermal or electrical value.","questions":[{"text":"What thermal conductivity, heat capacity, expansion, and electrical resistivity data exist for this HfB2 grade?","id":"temperature-dependent-properties-q01","kind":"measurement"},{"text":"Which reported melting, decomposition, or volatilization observations are supported by stated pressure and atmosphere?","id":"temperature-dependent-properties-q02","kind":"provenance"},{"text":"Over what measured range can these data support interpolation, and where would use require extrapolation?","id":"temperature-dependent-properties-q03","kind":"boundary"}]}]},{"id":"mechanical-and-thermal-shock-response","name":"Mechanical and thermal shock response","description":"Links resistance to loading and thermal transients to a defined specimen and method.","findings":[{"id":"failure-evidence","name":"Failure evidence","description":"Retain test geometry, surface preparation, loading conditions, and failure observations with reported mechanical properties.","questions":[{"text":"Which strength, hardness, elastic, and fracture-toughness measurements apply to this material state?","id":"failure-evidence-q01","kind":"measurement"},{"text":"What heating or cooling transient, environment, and damage criterion defined any thermal-shock result?","id":"failure-evidence-q02","kind":"measurement"},{"text":"Are the results from HfB2 or from an HfB2-based composite whose reinforcement changes their applicability?","id":"failure-evidence-q03","kind":"boundary"}]}]}]},{"id":"oxidation-and-service-envelope","name":"Oxidation and service envelope","description":"Tracks environment-dependent degradation and the limits of supported service judgments.","layers":[{"id":"exposure-and-reaction","name":"Exposure and reaction","description":"Connects observed surface and bulk changes to a fully described environment.","findings":[{"id":"oxidation-evidence","name":"Oxidation evidence","description":"Describe reaction products and material change without assigning a universal oxidation threshold.","questions":[{"text":"What temperature history, oxygen partial pressure, water-vapor content, total pressure, flow, and duration define the exposure?","id":"oxidation-evidence-q01","kind":"measurement"},{"text":"Which reaction products, scale structures, mass changes, and recession depths were actually measured?","id":"oxidation-evidence-q02","kind":"measurement"},{"text":"Does the evidence concern HfB2 alone or a formulation whose added phases affect oxidation behavior?","id":"oxidation-evidence-q03","kind":"boundary"}]}]},{"id":"retained-function-and-limits","name":"Retained function and limits","description":"Turns exposure results into bounded material-level acceptance judgments.","findings":[{"id":"demonstrated-use-envelope","name":"Demonstrated use envelope","description":"Define permissible material use from demonstrated retention of required properties and explicit failure criteria.","questions":[{"text":"Which properties and integrity measures were retained after exposure or repeated thermal cycling?","id":"demonstrated-use-envelope-q01","kind":"measurement"},{"text":"What application-specific limits on recession, cracking, mass change, or retained strength define acceptance?","id":"demonstrated-use-envelope-q02","kind":"action"},{"text":"Which proposed conditions fall outside the tested envelope and require additional evidence?","id":"demonstrated-use-envelope-q03","kind":"boundary"}]}]}]},{"id":"handling-and-material-disposition","name":"Handling and material disposition","description":"Connects the supplied HfB2 form and its subsequent alterations to applicable handling evidence.","layers":[{"id":"grade-specific-safety-evidence","name":"Grade-specific safety evidence","description":"Records authoritative hazard information without inferring safety from missing classifications.","findings":[{"id":"hazard-record-applicability","name":"Hazard record applicability","description":"Require safety records to identify the substance, supplied form, formulation, jurisdiction, and revision date.","questions":[{"text":"Which current SDS and regulatory records apply to this exact HfB2 grade and jurisdiction?","id":"hazard-record-applicability-q01","kind":"provenance"},{"text":"What classifications, exposure limits, and data gaps do those records explicitly report?","id":"hazard-record-applicability-q02","kind":"provenance"},{"text":"Does the assessment cover the particle size and dust-generating operations proposed for this material?","id":"hazard-record-applicability-q03","kind":"boundary"}]}]},{"id":"altered-material-and-release","name":"Altered material and release","description":"Determines whether stored, processed, or degraded material remains covered by its existing acceptance and handling records.","findings":[{"id":"disposition-decision","name":"Disposition decision","description":"Base reuse, recharacterization, segregation, or disposal decisions on measured condition and applicable records.","questions":[{"text":"Has storage, machining, contamination, or oxidation changed the composition or form covered by the original records?","id":"disposition-decision-q01","kind":"boundary"},{"text":"What documented criteria authorize release for processing, reuse, or further testing?","id":"disposition-decision-q02","kind":"action"},{"text":"Which handling and disposal requirements apply to the actual residues and added constituents?","id":"disposition-decision-q03","kind":"action"}]}]}]},{"id":"evidence-and-external-alignment","name":"Evidence and external alignment","description":"What the world already says about this thing, gathered so the model can be checked against it.","layers":[{"id":"reported-evidence","name":"Reported evidence","description":"Findings from the breadth pass, kept separate from the structural claims.","findings":[{"id":"evidence-confidence-notes","name":"Check these first","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these check these first hold for the sense of hafnium diboride this model covers, and on what evidence?","id":"evidence-confidence-notes-q01","kind":"provenance"}]},{"id":"evidence-kinds","name":"Kinds and varieties","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these kinds and varieties hold for the sense of hafnium diboride this model covers, and on what evidence?","id":"evidence-kinds-q01","kind":"provenance"}]},{"id":"evidence-identifiers","name":"Identifiers and schemes","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these identifiers and schemes hold for the sense of hafnium diboride this model covers, and on what evidence?","id":"evidence-identifiers-q01","kind":"provenance"}]},{"id":"evidence-real-world-use","name":"Real-world use","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these real-world use hold for the sense of hafnium diboride this model covers, and on what evidence?","id":"evidence-real-world-use-q01","kind":"provenance"}]},{"id":"evidence-measurements","name":"Typical measurements","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these typical measurements hold for the sense of hafnium diboride this model covers, and on what evidence?","id":"evidence-measurements-q01","kind":"provenance"}]},{"id":"evidence-failure-modes-and-hazards","name":"Failure modes and hazards","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these failure modes and hazards hold for the sense of hafnium diboride this model covers, and on what evidence?","id":"evidence-failure-modes-and-hazards-q01","kind":"provenance"}]},{"id":"evidence-neighbours","name":"Neighbouring kinds and how to tell them apart","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these neighbouring kinds and how to tell them apart hold for the sense of hafnium diboride this model covers, and on what evidence?","id":"evidence-neighbours-q01","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Describe hafnium diboride as an ultra-high-temperature ceramic and its research uses.","Report the hazards listed in its safety data sheet."],"mustNot":["Handle its fine powder without dust control and respiratory protection.","Present laboratory performance data as proven for flight-critical parts without qualification testing.","Dispose of powder or machining waste into drains or general rubbish."],"requiresHuman":["Approving it for use in safety-critical components."]},"ethics":{"considerations":["Materials for extreme environments must be honestly qualified; overstated claims endanger crews."],"affectedParties":["Laboratory and machining workers","Users of components made from it"]},"owners":{"steward":"The laboratory or manufacturer that holds it; the supplier answers for its identity and grade.","roles":[],"masterSystems":[]},"relations":[{"target":"Q11173","type":"parent","note":"registry parent class"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.hafnium-diboride","Wikidata: Q4161099 (https://www.wikidata.org/wiki/Q4161099)"]},"properties":{"applicability":"required","items":["Chemical and registry identity: HfB2; vr.tr.hafnium-diboride; verified CAS, EC, and PubChem identifiers or unresolved","Hafnium-to-boron atomic ratio: Atomic ratio with uncertainty; nominal Hf:B = 1:2","Phase assemblage: Identified phases and mass or volume fractions, with method and detection limits","Purity and impurity basis: Mass percent or mg/kg; explicitly state treatment of zirconium, oxygen, carbon, and other impurities","Material form: Powder; consolidated body; coating material; other documented form","Powder size and surface area: Particle-size distribution in µm; specific surface area in m²/g; methods and dispersion conditions","Density and porosity: Bulk density in kg/m³; relative density and open/closed porosity in percent with reference basis","Thermal properties and transitions: Thermal conductivity in W/(m·K), heat capacity in J/(kg·K), expansion in K⁻¹, transition temperatures in K; conditions required","Electrical resistivity: Ω·m with temperature, direction, composition, and measurement method","Mechanical response: Strength and hardness in MPa or GPa; fracture toughness in MPa·√m; test configuration required","Environmental degradation: Untested; characterized exposure; oxidized; cracked; recessed; acceptance exceeded; unknown","Applicable safety evidence: Links to current grade-specific SDS, jurisdictional records, exposure assessments, and their dates"]},"recognition":{"applicability":"required","items":["A grey to dark metallic-looking powder or dense ceramic part.","Identity needs analysis such as X-ray diffraction, not appearance."]},"capabilities":{"applicability":"required","items":["Identify a candidate material by reconciling composition, phase analysis, and supplier records.","Compare HfB2 lots against application-specific purity, particle-size, and phase requirements.","Select property evidence matching the specimen's composition, porosity, temperature, and processing history.","Assess whether a proposed thermal or atmospheric exposure falls within demonstrated material behavior.","Detect when a composite or altered specimen requires a linked material model.","Request missing characterization or handling evidence before accepting a lot or extrapolating its performance."]},"hazards":{"applicability":"required","items":["Fine powder can irritate the lungs and may be flammable as a dust.","Oxidises at high temperature, which limits real service life."]},"interfaces":{"applicability":"required","items":["Globally Harmonized System of Classification and Labelling of Chemicals (GHS), United Nations."]},"context":{"applicability":"required","items":["Hafnium diboride is encountered in research and engineering involving ceramics for extreme thermal environments.","It is investigated for heat-resistant components, protective materials and electrically conductive ceramics, with suitability depending on oxidation conditions, porosity and composition."]}},"sources":[{"title":"Wikidata item Q4161099: hafnium diboride","url":"https://www.wikidata.org/wiki/Q4161099","note":"identity and sense of the item"},{"title":"Wikipedia: Hafnium diboride","url":"https://en.wikipedia.org/wiki/Hafnium_diboride","note":"general description of the item"}],"openQuestions":["Which authoritative CAS, EC, and PubChem records unambiguously identify HfB2, and how do commercial records distinguish the substance from mixtures?","What crystallographic reference, compositional tolerance, and analytical detection limits should define acceptance as HfB2 rather than a mixed or multiphase material?","Which reliable melting, decomposition, vaporization, and transport-property measurements apply to sufficiently characterized HfB2, and is a meaningful boiling-point value available?","What oxidation and thermal-cycling limits are demonstrated for HfB2 itself, separately from HfB2-SiC and other composites?","What current hazard classifications and exposure limits apply across relevant jurisdictions and supplied forms, and where does the evidence remain insufficient?"],"resources":{"spec":"/models/things/publications/thing-q4161099/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q4161099/spec.json"],"providers":["Codex"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T10:09:55Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"filled","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-07T10:10:30+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}