{ "spore": "profile", "id": "silver-tungsten", "spore_version": "0.2", "family": "refractory-metals", "name": "Silver-tungsten", "abbreviation": "W-Ag", "role": "electrical contact and electrode composite", "category": "metals", "type": "refractory-metals", "summary": "Silver-tungsten (W-Ag, also written AgW) is a pseudo-alloy, not a true alloy. Goodfellow describes it as tungsten particles in a silver matrix, and it is made by powder metallurgy (Goodfellow; a 2006 powder metallurgy congress paper). One supplier data sheet for ASTM B631 rod lists grades from AgW30, with 70 % silver, to AgW80, with 20 % silver, with conductivity of 37 to 75 % and bending strength of 657 to 726 MPa. Goodfellow lists its W90/Ag10 composite for switchgear contacts, relays and circuit breakers. Silver tarnishes in air that contains sulfur compounds.\n", "best_for": "Electrical contacts for switchgear, relays and circuit breakers (uses listed by Goodfellow)", "weakest_at": "Tarnish in sulfur-containing air, and few sourced numbers: no thermal, flight or vacuum data for the composite was found in a readable source", "identity": { "formula": "Tungsten-silver composite: tungsten (W) particles in a silver (Ag) matrix, 20 to 70 % Ag in the grades of one supplier (AgW80 to AgW30), tungsten the balance", "designations": [ { "system": "ASTM", "code": "B631", "note": "rod, ASTM B631 silver-tungsten composite", "source": "sam-wag-tds", "where": "Specification table, Standard row" }, { "system": "Trade name", "code": "AgW50", "note": "one supplier grade with 50 % Ag, tungsten the balance", "source": "sam-wag-tds", "where": "Chemical Composition table, row AgW50" }, { "system": "Trade name", "code": "W90/Ag10", "note": "composite named by one other supplier, 10 % Ag", "source": "goodfellow-wag", "where": "Page title and Material Overview" } ], "source": "sam-wag-tds", "where": "Chemical Composition table, Ag % and W % columns, rows AgW30 to AgW80" }, "tags": { "environments": [], "stresses": [], "applications": [ "electronics-and-chips", "mechanisms" ] }, "properties": [ { "benchmark": "density", "label": "Density, AgW30 to AgW80 (data sheet range)", "value": 11.75, "value_high": 16.1, "bound": "range", "unit": "g/cm3", "scope": "material", "conditions": { "grade": "AgW30 to AgW80 (70 % to 20 % Ag)", "temperature": "not printed on the page" }, "method": "Range printed in a supplier technical data sheet for ASTM B631 rod; the page does not say which grade gives which value", "status": "ground", "source": "sam-wag-tds", "where": "Properties table, row Density, unit g/cm3", "source_detail": { "title": "Stanford Advanced Materials, Technical Data Sheet, Tungsten Silver Composite, catalog SV0138, standard ASTM B631", "url": "https://samaterials.com/tds/1718617741-SV0138.pdf", "kind": "datasheet", "license": "supplier data sheet, linked not reproduced" } }, { "benchmark": "electrical_resistivity", "label": "Electrical resistivity, AgW30 to AgW80 (data sheet range)", "value": 2.3, "value_high": 4.6, "bound": "range", "unit": "µΩ·cm", "scope": "material", "conditions": { "grade": "AgW30 to AgW80 (70 % to 20 % Ag)", "temperature": "not printed on the page" }, "method": "Range printed in a supplier technical data sheet", "status": "ground", "source": "sam-wag-tds", "where": "Properties table, row Resistivity, unit µΩ·cm", "source_detail": { "title": "Stanford Advanced Materials, Technical Data Sheet, Tungsten Silver Composite, catalog SV0138, standard ASTM B631", "url": "https://samaterials.com/tds/1718617741-SV0138.pdf", "kind": "datasheet", "license": "supplier data sheet, linked not reproduced" } }, { "benchmark": "electrical_conductivity", "label": "Electrical conductivity, AgW30 to AgW80 (data sheet range)", "value": 37, "value_high": 75, "bound": "range", "unit": "%", "scope": "material", "conditions": { "grade": "AgW30 to AgW80 (70 % to 20 % Ag)", "temperature": "not printed on the page" }, "method": "Range printed in a supplier technical data sheet; the page gives % only, not %IACS, so the basis is not known", "status": "ground", "note": "The IACS basis is not stated, so the range is not compared with copper or aluminium percentages.", "source": "sam-wag-tds", "where": "Properties table, row Conductivity, unit %", "source_detail": { "title": "Stanford Advanced Materials, Technical Data Sheet, Tungsten Silver Composite, catalog SV0138, standard ASTM B631", "url": "https://samaterials.com/tds/1718617741-SV0138.pdf", "kind": "datasheet", "license": "supplier data sheet, linked not reproduced" } }, { "benchmark": "flexural_strength", "label": "Bending strength, AgW30 to AgW80 (data sheet range)", "value": 657, "value_high": 726, "bound": "range", "unit": "MPa", "scope": "material", "conditions": { "grade": "AgW30 to AgW80 (70 % to 20 % Ag)", "temperature": "not printed on the page" }, "method": "Range printed in a supplier technical data sheet", "status": "ground", "source": "sam-wag-tds", "where": "Properties table, row Bending Strength, unit Mpa", "source_detail": { "title": "Stanford Advanced Materials, Technical Data Sheet, Tungsten Silver Composite, catalog SV0138, standard ASTM B631", "url": "https://samaterials.com/tds/1718617741-SV0138.pdf", "kind": "datasheet", "license": "supplier data sheet, linked not reproduced" } }, { "benchmark": "hardness", "label": "Hardness, AgW30 to AgW80 (data sheet range)", "value": 75, "value_high": 180, "bound": "range", "unit": "-", "scope": "material", "conditions": { "grade": "AgW30 to AgW80 (70 % to 20 % Ag)", "temperature": "not printed on the page" }, "method": "Range printed in a supplier technical data sheet; the unit column shows a dash, so the hardness scale is not stated", "status": "ground", "note": "No scale is printed, so this value is not compared with Brinell or Vickers figures.", "source": "sam-wag-tds", "where": "Properties table, row Hardness, unit column shows -", "source_detail": { "title": "Stanford Advanced Materials, Technical Data Sheet, Tungsten Silver Composite, catalog SV0138, standard ASTM B631", "url": "https://samaterials.com/tds/1718617741-SV0138.pdf", "kind": "datasheet", "license": "supplier data sheet, linked not reproduced" } }, { "benchmark": "hardness", "label": "Hardness, as-sintered W+30 wt % Ag (2006 study)", "value": 130, "bound": "exact", "unit": "HB", "scope": "material", "conditions": { "composition": "W+30 wt % Ag", "process": "double-pressed and double-sintered at 1100 °C for one hour in hydrogen (as-sintered)", "temperature": "not printed on the page" }, "method": "Value printed in Table 2 of a 2006 powder metallurgy congress paper, as-sintered rows", "status": "ground", "source": "koreascience-wag", "where": "Table 2, As-sintered composites, row W+30%Ag, column Hardness [HB]", "source_detail": { "title": "Leżański and Madej, The Influence of Production Process Parameters on Properties W-Ag, Mo-Ag Composites, 2006 Powder Metallurgy World Congress", "url": "https://koreascience.kr/article/CFKO200617317791372.pdf", "kind": "paper", "license": "conference paper, linked not reproduced" } }, { "benchmark": "flexural_strength", "label": "Bending strength, as-sintered W+30 wt % Ag (2006 study)", "value": 260, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "composition": "W+30 wt % Ag", "process": "double-pressed and double-sintered at 1100 °C for one hour in hydrogen (as-sintered)", "temperature": "not printed on the page" }, "method": "Value printed in Table 2 of a 2006 powder metallurgy congress paper, as-sintered rows", "status": "ground", "source": "koreascience-wag", "where": "Table 2, As-sintered composites, row W+30%Ag, column Bending Strength [Mpa]", "source_detail": { "title": "Leżański and Madej, The Influence of Production Process Parameters on Properties W-Ag, Mo-Ag Composites, 2006 Powder Metallurgy World Congress", "url": "https://koreascience.kr/article/CFKO200617317791372.pdf", "kind": "paper", "license": "conference paper, linked not reproduced" } } ], "corrosion": [ { "environment": "Air containing sulfur compounds", "headline": "Silver tarnishes in air to form black silver sulfide, the film that forms on silver exposed to sulfur.", "effect": "The Wikipedia silver article says silver does not react with air even at red heat, but in the presence of sulfur compounds it tarnishes in air to form black silver sulfide. The article gives no rate, and no contact-resistance figure is recorded here.", "rating": "moderate", "conditions": { "basis": "qualitative statement, no rate or concentration given", "product": "silver phase of the composite" }, "source": "wikipedia-silver", "where": "Article text, statements on air and tarnishing" }, { "environment": "Air at red heat", "headline": "Tungsten reacts with oxygen when red-hot to form the trioxide WO3.", "effect": "The Wikipedia tungsten article says tungsten does not react with oxygen or air at room temperature, but at elevated temperatures (red-hot) it reacts with oxygen to form WO3. No oxidation rate is given.", "rating": "moderate", "conditions": { "basis": "qualitative statement, no temperature or rate given", "product": "tungsten phase of the composite" }, "source": "wikipedia-tungsten", "where": "Article text, statements on reaction with oxygen" } ], "risks": { "hazards": [ { "text": "PubChem's aggregated GHS notifications for silver metal list very toxic to aquatic life (H400, 70.4 % of notifications) and very toxic with long-lasting effects (H410, 69.3 %). These are for silver metal, not for the composite.", "ghs": [ "H400", "H410" ], "source": "pubchem-silver", "where": "Safety and Hazards, GHS Classification, aggregated statements" }, { "text": "Finely divided tungsten is pyrophoric, so the powder form needs its own hazard review.", "ghs": [], "source": "wikipedia-tungsten", "where": "Article text, pyrophoric statement" } ], "failure_risks": [ { "mode": "Tarnish of the silver phase", "trigger": "Exposure to air that contains sulfur compounds", "consequence": "A black silver sulfide film forms on the silver. The source gives no rate and no effect on contact resistance.", "severity": "moderate", "source": "wikipedia-silver", "where": "Article text, tarnishing statement" }, { "mode": "Oxidation of the tungsten phase in hot air", "trigger": "Air at red heat", "consequence": "Tungsten reacts with oxygen to form WO3. The source gives no oxidation rate.", "severity": "moderate", "source": "wikipedia-tungsten", "where": "Article text, reaction with oxygen statement" } ], "side_effects": [], "handling": [ { "text": "Treat finely divided tungsten powder as pyrophoric, and plan for fire when it is handled.", "source": "wikipedia-tungsten", "where": "Article text, pyrophoric statement" }, { "text": "Silver tarnishes in sulfur-containing air, so keep contacts in clean, sulfur-free packaging until they are fitted. This is a precaution drawn from the tarnish statement, not a tested storage condition.", "source": "wikipedia-silver", "where": "Article text, tarnishing statement" }, { "text": "Specify the grade, because silver content changes density, conductivity and strength across the data sheet range.", "source": "sam-wag-tds", "where": "Chemical Composition table; Properties table" } ], "mitigations": [] }, "uses": [ { "application": "electronics-and-chips", "device": "Switchgear contacts, relays and circuit breakers", "example": "Goodfellow lists its W90/Ag10 composite for switchgear contacts, relays and circuit breakers. It also presents the material as a lower-cost option to palladium-silver alloys in sulfur-bearing environments.", "source": "goodfellow-wag", "where": "Applications and Advantages section" }, { "application": "mechanisms", "device": "Aerospace actuators and connectors", "example": "Goodfellow lists aerospace connectors and actuators among the applications of its W-Ag composite. No flight record was found in this run.", "source": "goodfellow-wag", "where": "Applications and Advantages section" } ], "supply": [ { "subject": "Tungsten (world mine production, the tungsten content of W-Ag)", "producers": [ { "country": "China", "share_percent": 78.8, "year": 2025 }, { "country": "Vietnam", "share_percent": 3.5, "year": 2025 }, { "country": "Kazakhstan", "share_percent": 2.8, "year": 2025 }, { "country": "Russia", "share_percent": 2.4, "year": 2025 } ], "critical_lists": [], "recycling": "USGS: the quantity of secondary tungsten produced in 2025 is withheld to avoid disclosing company proprietary data.", "substitutes": [ "USGS: depleted uranium or lead for tungsten or tungsten alloys in applications requiring high density or the ability to shield radiation." ], "source": "usgs-mcs2026-tungsten", "where": "World Mine Production and Reserves table, 2025 column: China 67,000; Vietnam 3,000; Kazakhstan 2,400; Russia 2,000; world total 85,000 t, tungsten content. Shares calculated here (67,000 / 85,000 = 78.8 %). Recycling and Substitutes sections." }, { "subject": "Silver (world mine production)", "producers": [ { "country": "Mexico", "share_percent": 24.2, "year": 2025 }, { "country": "Peru", "share_percent": 13.8, "year": 2025 }, { "country": "China", "share_percent": 13.1, "year": 2025 }, { "country": "Bolivia", "share_percent": 5.8, "year": 2025 } ], "critical_lists": [ { "list": "USGS 2025 Final List of Critical Minerals (silver added in 2025)", "listed": true } ], "recycling": "USGS: about 1,000 tons of silver was recovered from new and old scrap in 2025, about 11 % of apparent consumption.", "substitutes": [], "source": "usgs-mcs2026-silver", "where": "World Mine Production and Reserves table, mine production 2025e, silver content in metric tons: Mexico 6,300; Peru 3,600; China 3,400; Bolivia 1,500; world total 26,000. Shares calculated here. Critical minerals and Recycling text." } ], "media": [], "documents": [ { "title": "Stanford Advanced Materials, Technical Data Sheet, Tungsten Silver Composite, catalog SV0138 (ASTM B631)", "type": "datasheet", "url": "https://samaterials.com/tds/1718617741-SV0138.pdf" }, { "title": "Goodfellow, Tungsten/Silver W90/Ag10 material information", "type": "datasheet", "url": "https://www.goodfellow.com/usa/resources/tungsten-silver-w90-ag10-material-information/" }, { "title": "Leżański and Madej, The Influence of Production Process Parameters on Properties of W-Ag, Mo-Ag Composites (2006 Powder Metallurgy World Congress, PC11-W-02)", "type": "paper", "url": "https://koreascience.kr/article/CFKO200617317791372.pdf", "year": 2006 }, { "title": "USGS Mineral Commodity Summaries 2026: Silver", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf", "year": 2026 }, { "title": "USGS Mineral Commodity Summaries 2026: Tungsten", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tungsten.pdf", "year": 2026 }, { "title": "PubChem compound record, Silver (CID 23954), GHS classification", "type": "database", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/23954", "year": 2026 }, { "title": "Wikipedia: Silver", "type": "database", "url": "https://en.wikipedia.org/wiki/Silver" }, { "title": "Wikipedia: Tungsten", "type": "database", "url": "https://en.wikipedia.org/wiki/Tungsten" } ], "gaps": [ "Only seven values are recorded. No thermal conductivity, thermal expansion, melting point or %IACS value for the composite was found in a readable source in this run, so the profile is below the 12-property target.", "The hardness scale is not printed on the supplier data sheet (unit column shows a dash). The range is recorded with unit - and no scale is inferred.", "The supplier conductivity is printed as % with no IACS basis.", "The 2006 paper's as-infiltrated rows (251 HB, 650 MPa) are labelled W+30%Ag, but its infiltration text describes W+5 wt % Ag compacts infiltrated with Ag-1 wt % Ni. Those rows are not recorded because the composition is unclear.", "The 2006 paper's relative density values (87,5 % and 97,2 %) are printed with a decimal comma and are not recorded.", "Goodfellow's page gives 19.3 g/cm3 and 3422 °C, which are tungsten values, and 63 × 10⁶ S/m, which is silver. None is recorded as a property of the composite.", "EDM electrode use is not confirmed. Supplier EDM grade pages (Hogen Durakut H20S, Ampco) returned HTTP 403 or did not list silver-tungsten, so no EDM grade or EDM data is recorded.", "No UNS, EN, DIN, JIS or W.Nr. number for silver-tungsten was found on a page read in this run.", "Critical-mineral status for tungsten: the USGS 2026 tungsten text read here does not print a critical-minerals entry, so critical_lists is empty. The EU critical raw materials list was not checked for silver or tungsten.", "The USGS silver text names no substitute for silver in electrical contacts, so substitutes is empty.", "No outgassing, mass loss, atomic-oxygen or cold-welding result for W-Ag in vacuum or low Earth orbit was found in a readable source. No spacecraft flight use was found.", "Silver tarnish rates and contact-resistance effects are not quantified. The DTIC report on silver sulfide and the IEEE article were not readable in this run (DTIC returned an HTML page).", "No W-Ag safety data sheet was read. Hazards come from the PubChem silver notifications and the Wikipedia tungsten pyrophoric statement.", "Atomic weights were not recorded, so the recipe gives shares only.", "No media were added, because no image was fetched and licence-checked in this run." ], "story": { "why": "Silver-tungsten pairs a refractory tungsten phase with a silver phase that carries current. The supplier range for conductivity is 37 to 75 %, and the bending strength range is 657 to 726 MPa. Because the two metals are combined by powder metallurgy rather than melted into one alloy, the material is a composite whose properties depend on the silver content. Goodfellow lists it for switchgear contacts, relays and circuit breakers, which explains its use in electrical contacts.", "uses": [ { "where": "Switchgear, relays and circuit breakers", "line": "Goodfellow lists its W90/Ag10 composite for switchgear contacts, relays and circuit breakers." }, { "where": "Aerospace connectors and actuators", "line": "Goodfellow lists aerospace connectors and actuators among the applications. No flight record was found." } ], "can_do": [ { "label": "Conductivity", "line": "The supplier range for ASTM B631 rod grades from AgW80 to AgW30 is 37 to 75 %. The data sheet does not state the IACS basis.", "benchmark": "electrical_conductivity", "scope": "material", "value": "37 to 75 %" }, { "label": "Bending strength", "line": "The supplier range for the same grades is 657 to 726 MPa.", "benchmark": "flexural_strength", "scope": "material", "value": "657 to 726 MPa" }, { "label": "Hardness", "line": "The data sheet hardness range is 75 to 180. No scale is printed, so the figure cannot be read against Brinell or Vickers values.", "benchmark": "hardness", "scope": "material", "value": "75 to 180" } ], "compare": "Within the supplier range, silver content sets the balance: the data sheet lists 20 to 70 % silver across the AgW grades, and the conductivity and bending strength ranges are each wide. The 2006 study adds one as-sintered point at W+30 wt % Ag (130 HB, 260 MPa). No number here is compared with copper-tungsten or other contact materials, because no comparable value was read in this run.", "compare_rows": [ { "label": "Density", "benchmark": "density", "scope": "material" }, { "label": "Electrical conductivity", "benchmark": "electrical_conductivity", "scope": "material" }, { "label": "Bending strength", "benchmark": "flexural_strength", "scope": "material" } ], "handling": [ "Specify the grade, because silver content changes density, conductivity and strength across the data sheet range.", "Keep finely divided tungsten powder under a fire plan, since it is pyrophoric.", "Keep silver contacts in clean, sulfur-free packaging to limit tarnish." ], "good_for": [ "Electrical contacts for switchgear, relays and circuit breakers, per Goodfellow's listed uses.", "Grade choice where conductivity matters: the data sheet gives 37 to 75 % across grades, so specify the grade." ], "watch_out": [ "Silver tarnish in sulfur-containing air (Wikipedia).", "Hot air above red heat: tungsten reacts with oxygen to form WO3 (Wikipedia).", "Broad supplier ranges: density 11.75 to 16.1 g/cm3 and conductivity 37 to 75 % across the grades.", "No thermal conductivity, thermal expansion or vacuum data for this composite was found in a readable source." ], "verdict": "Silver-tungsten is a composite for electrical contacts. The supplier range is wide: conductivity from 37 to 75 % and bending strength from 657 to 726 MPa across the grades. Its limits are tarnish in sulfur-containing air and oxidation of the tungsten phase in hot air. This profile has seven sourced values and no flight or vacuum data.", "recipe": { "line": "Silver-tungsten is a composite of tungsten particles in a silver matrix, not a true alloy (Goodfellow). In a 2006 study, W+30 wt % Ag was made by mixing the powders, pressing at 600 MPa in a rigid die, and sintering twice at 1100 °C for one hour in hydrogen (Korean paper). The same paper also describes infiltration, in which a porous tungsten skeleton is sintered in hydrogen and then infiltrated with liquid silver alloy (Korean paper).", "parts": [ { "name": "Tungsten", "symbol": "W", "role": "Refractory particle phase embedded in the silver matrix (Goodfellow)." }, { "name": "Silver", "symbol": "Ag", "role": "Matrix phase in which the tungsten particles sit (Goodfellow)." } ] }, "risk_groups": [ { "title": "For people", "lead": "The sources read here give no hazard classification for the composite. The hazards found are for silver metal and for powdered tungsten.", "points": [ { "label": "Powder", "line": "Finely divided tungsten is pyrophoric (Wikipedia). Treat the powder form as a fire hazard." }, { "label": "Silver", "line": "PubChem's aggregated GHS notifications for silver metal list H400 and H410, very toxic to aquatic life. These are not specific to the composite." } ], "level": 1, "verdict": "No composite classification found" }, { "title": "If it fails", "lead": "The sources name two failure routes: tarnish on the silver phase, and oxidation of the tungsten phase in hot air. No flight or vacuum test was found.", "points": [ { "label": "Tarnish", "line": "Silver tarnishes in air that contains sulfur compounds, forming black silver sulfide. No rate or contact-resistance figure was found." }, { "label": "Hot air", "line": "Tungsten reacts with oxygen when red-hot to form WO3. No oxidation rate was found." } ] }, { "title": "Handling and storage", "points": [ { "label": "Grade", "line": "Specify the silver content. The supplier grades run from 20 to 70 % silver." }, { "label": "Storage", "line": "Keep contacts in clean, sulfur-free packaging. This is a precaution, not a tested storage condition." } ] } ] }, "updated": "2026-10-26", "review": { "status": "draft", "method": "assistant", "checked_values": 7, "unreachable": 4, "caveats": 3, "note": "Values were read by an AI assistant on 2026-10-26 from the pages named in each entry. Unreachable in this run: the Hogen and Prospector EDM grade page (HTTP 403), the GlobalSpec EDM page (HTTP 403), the tungsten.com silver-tungsten page (HTTP 404), and the DTIC silver sulfide report (HTML page, not a PDF). Caveats: the supplier data sheet gives ranges across grades and does not say which grade gives which value; its conductivity has no IACS basis; the hardness has no scale." }, "sources": { "sam-wag-tds": { "title": "Stanford Advanced Materials, Technical Data Sheet, Tungsten Silver Composite, catalog SV0138, standard ASTM B631", "url": "https://samaterials.com/tds/1718617741-SV0138.pdf", "kind": "datasheet", "license": "supplier data sheet, linked not reproduced" }, "goodfellow-wag": { "title": "Goodfellow, Tungsten/Silver W90/Ag10 material information", "url": "https://www.goodfellow.com/usa/resources/tungsten-silver-w90-ag10-material-information/", "kind": "web", "license": "supplier web page, linked not reproduced" }, "koreascience-wag": { "title": "Leżański and Madej, The Influence of Production Process Parameters on Properties W-Ag, Mo-Ag Composites, 2006 Powder Metallurgy World Congress", "url": "https://koreascience.kr/article/CFKO200617317791372.pdf", "kind": "paper", "license": "conference paper, linked not reproduced" }, "usgs-mcs2026-silver": { "title": "Mineral Commodity Summaries 2026, Silver", "id": "USGS MCS 2026, February 2026", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf", "kind": "report", "license": "public domain (USGS)" }, "usgs-mcs2026-tungsten": { "title": "Mineral Commodity Summaries 2026, Tungsten", "id": "USGS MCS 2026, February 2026", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tungsten.pdf", "kind": "report", "license": "public domain (USGS)" }, "pubchem-silver": { "title": "PubChem compound record, Silver (CID 23954)", "id": "CID 23954", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/23954", "kind": "database", "license": "public domain (NCBI)" }, "wikipedia-silver": { "title": "Wikipedia, Silver", "url": "https://en.wikipedia.org/wiki/Silver", "kind": "web", "license": "CC BY-SA 4.0, linked not reproduced" }, "wikipedia-tungsten": { "title": "Wikipedia, Tungsten", "url": "https://en.wikipedia.org/wiki/Tungsten", "kind": "web", "license": "CC BY-SA 4.0, linked not reproduced" } }, "license": "CC-BY-4.0", "url": "https://spacemushroom.com/profiles/silver-tungsten/" }