spore: profile id: molybdenum-tungsten spore_version: 0.2 family: refractory-metals name: Molybdenum-tungsten alloy (Mo-30W) abbreviation: Mo-30W role: high-temperature molybdenum-tungsten alloy for furnace hot zones, crucibles, zinc-bath heaters and sputtering targets category: metals type: refractory-metals summary: | Mo-30W is a molybdenum alloy with about 30 % tungsten (Climelt, Polema, ASTM B386 Alloy 366). Polema sells it as sintered and forged crucibles with minimum densities of 10.9 and 11.2 g/cm3, and it also lists the alloy for vacuum and hydrogen furnace parts and for sputtering targets. Burman (1984) gives a melting point of 2829 °C. A powder-metallurgy bar of the alloy had a tensile strength of 170 MPa at 1600 °C and 385 MPa at 1500 °C after full recrystallisation. In molten zinc, a factory test of heater casings ties corrosion to bath temperature and to aluminium in the zinc, although an older datasheet calls the alloy chemically inert in molten zinc. Thermal conductivity, electrical resistivity, expansion and modulus were not found in any readable source. best_for: Refractory parts that must hold shape at high temperature in vacuum or inert furnaces, where the 2829 °C melting point and the 10.9 g/cm3 sintered minimum density are the reference figures weakest_at: Strength falls off above about 1500 °C in the powder-metallurgy bar tested by Wang et al., and the zinc-bath factory test found aluminium in the bath attacks the alloy identity: formula: 'Mo-30W: molybdenum base with about 30 wt % tungsten (28 to 32 % in Polema, 27 to 33 wt % in ASTM B386 Alloy 366, nominal 30 % in Climelt)' source: polema where: 'Section 3, Chemical composition of crucibles: molybdenum is the base, with 28-32% tungsten' designations: - system: ASTM code: '366' note: Molybdenum Alloy 366, vacuum arc-cast Mo-30W, plate, sheet and strip under ASTM B386 source: gsalloy-b386 where: 'Grade definitions: Molybdenum Alloy 366, vacuum arc-cast molybdenum-30 % tungsten alloy' - system: Trade name code: CLIMELT Mo-30W source: climelt-mo30w where: Page title of the Alloy Digest entry, Mo-9 - system: Trade name code: MoW30-PM note: Polema grade, sintered and forged crucibles and rod source: polema where: Section 3, crucibles, and Section 4, products for high-temperature furnaces tags: environments: [] stresses: - extreme-heat applications: - electronics-and-chips - thermal-control properties: - benchmark: melting_point label: Melting point of Mo-30W value: 2829 unit: °C scope: material conditions: composition: Mo-30W, 30 % tungsten method: Value printed in the summary text of the 1984 ASTM symposium paper; no test method printed status: ground source: burman1984 where: Summary text on the ASTM store page (paper visible in summary; full text paywalled) - benchmark: density label: Minimum density of sintered MoW30-PM crucibles value: 10.9 unit: g/cm3 scope: material conditions: form: sintered MoW30-PM crucible spec: guaranteed minimum method: Manufacturer minimum specification for crucible density status: ground source: polema where: 'Section 3, Crucible density: sintered MoW30-PM crucibles, at least 10.9 g/cm3' - benchmark: density label: Minimum density of forged MoW30-PM crucibles value: 11.2 unit: g/cm3 scope: material conditions: form: forged MoW30-PM crucible spec: guaranteed minimum method: Manufacturer minimum specification for crucible density status: ground source: polema where: 'Section 3, Crucible density: forged MoW30-PM crucibles, at least 11.2 g/cm3' - benchmark: ultimate_tensile_strength label: Tensile strength of Mo-30W bar at 1600 °C value: 170 unit: MPa scope: material conditions: temperature: 1600 °C form: bar made by powder metallurgy state: tested as reported in the abstract method: Tensile test as reported in the Wang et al. abstract status: ground source: wang2018 where: Abstract, sentence beginning 'the tensile strength of Mo-30 W molybdenum alloy bar at 1600' - benchmark: elongation label: Elongation of Mo-30W bar at 1600 °C value: 10 unit: '%' scope: material conditions: temperature: 1600 °C form: bar made by powder metallurgy method: Tensile test as reported in the Wang et al. abstract status: ground source: wang2018 where: Abstract, same sentence as the 170 MPa value - benchmark: ultimate_tensile_strength label: Tensile strength of fully recrystallised Mo-30W at 1500 °C value: 385 unit: MPa scope: material conditions: temperature: 1500 °C state: completely recrystallised bar method: Tensile test as reported in the Wang et al. abstract; lowest strength in the study status: ground source: wang2018 where: Abstract, sentence beginning 'The Mo-30 W molybdenum alloy are completely recrystallized at 1500' - benchmark: hardness_vickers label: Vickers hardness of fully recrystallised Mo-30W at 1500 °C value: 185 unit: HV10 scope: material conditions: temperature: 1500 °C state: completely recrystallised bar method: Vickers hardness as reported in the Wang et al. abstract; lowest hardness in the study status: ground source: wang2018 where: Abstract, HV10 185 at 1500 °C (hardness_vickers is not in property-canon.yaml; see gaps) corrosion: - environment: Molten zinc in a hot-dip galvanizing bath (heater casing) headline: Corrosion speeds up with bath temperature, and aluminium in the zinc is the main cause. effect: The factory test of Mo-30W inner heating casings in molten zinc found that bath temperature is an important factor and that higher temperature speeds corrosion. The abstract says aluminium in the molten zinc reacts with Mo-30W and is the main reason for corrosion. Heater life also depends on impurities in the bath, heater design, heating power and alloy quality. The abstract prints no corrosion rate. rating: unknown conditions: bath: hot-dip galvanizing, three working conditions (not quantified in the abstract) source: mattest where: Abstract of the Chinese-language article, title 热镀锌用Mo-30W合金内加热套管的腐蚀性能 - environment: Molten zinc, high-purity Mo-30W grades headline: Claimed chemically inert in molten zinc, with no rate given. effect: Burman (1984) says Mo-30W is commercially used for its melting point of 2829 °C and its chemical inertness in corrosive molten zinc, especially the high-purity grades. The Climelt datasheet abstract says the alloy is recommended for resistance to molten zinc. Neither source gives a corrosion rate, and this claim is at odds with the aluminium-attack finding above. rating: low conditions: basis: claim in a 1984 paper and a datasheet abstract; no test conditions printed source: burman1984 where: Summary text on the ASTM store page risks: hazards: - text: 'PubChem GHS aggregated notifications for the element molybdenum: H228 flammable solid (30 % of reports), H361 suspected of damaging fertility or the unborn child (29.5 %), H315 causes skin irritation and H319 causes serious eye irritation. PubChem also says 57.4 % of 1523 reports meet no GHS criteria.' ghs: - H228 - H361 - H315 - H319 source: pubchem-mo where: GHS Classification, aggregated notifications (CID 23932) - text: 'PubChem GHS aggregated notifications for the element tungsten: H228 flammable solid (73.4 % of reports), H252 self-heating in large quantities, H320 eye irritation and H335 respiratory irritation. These describe the element, not the alloy, and the record does not give the physical form.' ghs: - H228 - H252 - H320 - H335 source: pubchem-w where: GHS Classification, aggregated notifications (CID 23964) failure_risks: - mode: Loss of strength at high temperature trigger: Testing or service above the 1300 to 1500 °C range in the powder-metallurgy bar consequence: Strength and hardness stay stable between 1300 and 1500 °C and then drop significantly. The fully recrystallised bar was lowest, at 385 MPa and HV10 185 at 1500 °C. severity: moderate source: wang2018 where: Abstract - mode: Aluminium attack on a heater casing in zinc trigger: Aluminium in a hot-dip galvanizing bath at higher bath temperature consequence: Heater life is shortened. The factory test calls aluminium in the zinc the main reason for corrosion. severity: high source: mattest where: Abstract side_effects: - text: The zinc-bath heater casing is a surface that wears by corrosion, so its life sets how often the heater is replaced. The sources do not give a replacement rate. affects: Zinc bath maintenance source: mattest where: Abstract handling: - text: During use, the products should not be subjected to shocks. source: polema - text: Specify the form, because the minimum density differs between sintered (10.9 g/cm3) and forged (11.2 g/cm3) crucibles. source: polema mitigations: - text: Heater life depends on bath temperature, impurities in the bath, heater design, heating power and alloy quality, and the factory test lists these as the factors to control. source: mattest uses: - application: electronics-and-chips device: Sputtering target for thin-film coatings example: Polema lists MoW alloy sputtering targets for thin films in electronic components and other functional coatings, and says MoW layers etch well in thin-film transistor work (matmatch, not opened). source: polema where: Section 5, Products from Molybdenum-tungsten alloy MoW10-PM for sputtering targets (the section title says MoW10-PM while the text says MoW30-PM (MoW10)) - application: thermal-control device: Hot-zone parts of vacuum and hydrogen furnaces example: Polema lists heat zones for smelting quartz glass, sapphire crystal growth and furnaces for annealing uranium fuel. source: polema where: Section 4, Products made from molybdenum, tungsten and their alloys for use in high-temperature furnaces - application: thermal-control device: Crucible for melting corundum to grow sapphire monocrystals example: Sintered and forged MoW30 crucibles (TMB30-MP) used primarily to melt corundum for extremely pure sapphire. source: polema where: Section 3, Crucibles from molybdenum-tungsten alloy - application: thermal-control device: Inner heating casing (heater sleeve) in a hot-dip galvanizing zinc bath example: A factory test of Mo-30W heater casings in molten zinc, reported in the Chinese-language article in the sources list. source: mattest where: Abstract. No application slug in the taxonomy fits a zinc-bath heater; the thermal-control slug is used as the nearest match. supply: - subject: Molybdenum abundance: World mine production 260,000 t in 2025 (estimated), 256,000 t in 2024. World reserves 17,000 thousand t. Identified resources are about 5.4 million tons in the United States and about 20 million tons in the rest of the world. producers: - country: China mine_production_t: 97000 year: 2025 - country: Chile mine_production_t: 42000 year: 2025 - country: United States mine_production_t: 40000 year: 2025 - country: Peru mine_production_t: 39000 year: 2025 - country: Mexico mine_production_t: 17000 year: 2025 critical_lists: [] recycling: Molybdenum recycled in new and old steel and other scrap may be as much as 30 % of the apparent supply of molybdenum (USGS). There is no separate recovery process for secondary molybdenum from its alloys. substitutes: - There is little substitution for molybdenum in its major application in steels and cast irons (USGS). source: usgs-mo-2026 where: 'Molybdenum chapter: Events, Trends and Issues; World Mine Production and Reserves table; Recycling; Substitutes' - subject: Tungsten abundance: World mine production 85,000 t in 2025 (estimated), 82,000 t in 2024. China 67,000 t in both years, with reserves of 2,500,000 t. World reserves more than 4,700,000 t. producers: - country: China mine_production_t: 67000 year: 2025 - country: Russia mine_production_t: 2000 year: 2025 - country: Vietnam mine_production_t: 3000 year: 2025 critical_lists: [] recycling: Not read in this run. substitutes: [] source: usgs-w-2026 where: 'Tungsten chapter: World Mine Production and Reserves table; Events, Trends and Issues' note: China implemented new export controls on selected tungsten items in February 2025 (USGS). media: [] documents: - title: 'USGS Mineral Commodity Summaries 2026: Molybdenum' type: report url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.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: Molybdenum (CID 23932), GHS classification summary' type: database url: https://pubchem.ncbi.nlm.nih.gov/compound/23932 year: 2026 - title: 'PubChem: Tungsten (CID 23964), GHS classification summary' type: database url: https://pubchem.ncbi.nlm.nih.gov/compound/23964 year: 2026 - title: Study on recrystallization behavior of Mo-30W molybdenum alloy (Powder Metallurgy Technology 2018) type: paper url: https://pmt.ustb.edu.cn/en/article/doi/10.19591/j.cnki.cn11-1974/tf.2018.06.003 year: 2018 - title: 'POLEMA: molybdenum-tungsten alloy products, crucibles and sputtering targets' type: datasheet url: https://polema.net/en/catalog/molibden/molibdenovye-splavy-mow-mola-i-drugie/ - title: CLIMELT Mo-30W High Temperature Alloy, Alloy Digest Mo-9 (abstract only, full datasheet paywalled) type: datasheet url: https://dl.asminternational.org/alloy-digest/article/19/4/Mo-9/1733/CLIMELT-Mo-30WHigh-Temperature-Alloy year: 1970 gaps: - 'Thermal conductivity of Mo-30W: no readable source found (Climelt datasheet paywalled, Plansee MoW30 datasheet not reachable, Wieland and matmatch not opened).' - 'Electrical resistivity of Mo-30W: no value found in any readable source.' - 'Coefficient of thermal expansion of Mo-30W: no value found in a readable source (a third-party comparison page printed one for a grade called 366, but it could not be re-opened in this run).' - 'Elastic modulus of Mo-30W: no value found in a readable source.' - 'Yield strength of Mo-30W: the Polema page gives only a conditional yield limit for MoW-2-PM, with no number. Not used, since its composition is not stated.' - 'Hardness at temperatures other than 1500 °C: no value found; the Wang abstract gives stability between 1300 and 1500 °C but no numbers.' - 'The Polema hot-rolled sheet (MoW-PM) and extruded stock (MoW-2-PM) tables are not used: neither page states the tungsten content, so the values may not belong to Mo-30W.' - Polema's sputtering section is titled MoW10-PM but its text says MoW30-PM (MoW10). The product name is inconsistent and was not resolved. - Hardness is named hardness_vickers because property-canon.yaml has no Vickers hardness name; the value is in units of HV10. - No application slug in the taxonomy fits a zinc-bath heater; thermal-control is the nearest match. - Corrosion rate in molten zinc is not printed in any readable source. The factory-test full text was not available, only the Chinese abstract. - Burman (1984) calls the alloy chemically inert in molten zinc, but the Mo-30W factory test names aluminium in the zinc as the main cause of corrosion. The two claims conflict and were not resolved. - No oxidation or high-temperature atmosphere data for Mo-30W were found in a readable source. - Critical-mineral list status for molybdenum and tungsten is not stated in the USGS summaries read in this run. The EU and BGS lists were not checked. - Tungsten recycling and substitutes were not in the USGS tungsten summary read in this run. - PubChem hazard codes are aggregated notifications for the pure elements, not for the alloy. No Mo-30W safety data sheet was found. - Publication year of the Polema page is not printed on the page. - Year and author of the Chinese-language zinc-bath article were not visible in the fetched abstract. - No openly licensed image was checked, so media is empty. - The Plansee MoW30 datasheet, the matmatch MW30 page and the gsalloy product page were not reachable for full text (403 or DNS failure), so values from them are not used except the designation text from the gsalloy page. sources: usgs-mo-2026: title: 'Mineral Commodity Summaries 2026: Molybdenum' id: USGS MCS 2026 url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.pdf year: 2026 kind: report license: public domain usgs-w-2026: title: 'Mineral Commodity Summaries 2026: Tungsten' id: USGS MCS 2026 url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tungsten.pdf year: 2026 kind: report license: public domain polema: title: 'POLEMA: molybdenum-tungsten alloy products (MoW-PM, MoW-2-PM, MoW30-PM crucibles, MoW10-PM sputtering targets)' id: Polema catalogue page, molybdenum alloys url: https://polema.net/en/catalog/molibden/molibdenovye-splavy-mow-mola-i-drugie/ kind: datasheet license: supplier catalogue; facts cited wang2018: title: Study on recrystallization behavior of Mo-30W molybdenum alloy id: DOI 10.19591/j.cnki.cn11-1974/tf.2018.06.003 url: https://pmt.ustb.edu.cn/en/article/doi/10.19591/j.cnki.cn11-1974/tf.2018.06.003 year: 2018 kind: paper license: Powder Metallurgy Technology (journal abstract) burman1984: title: Symposium paper by R. Burman (AMAX Specialty Metals), ASTM STP 326, 1984 (full title not read) id: DOI 10.1520/STP32629S (STP 326) url: https://store.astm.org/stp32629s.html year: 1984 kind: paper license: ASTM (summary only) climelt-mo30w: title: CLIMELT Mo-30W High Temperature Alloy, Alloy Digest Mo-9 (Climax Molybdenum) id: DOI 10.31399/asm.ad.mo0009 url: https://dl.asminternational.org/alloy-digest/article/19/4/Mo-9/1733/CLIMELT-Mo-30WHigh-Temperature-Alloy year: 1970 kind: datasheet license: ASM Alloy Digest (abstract only) mattest: title: 热镀锌用Mo-30W合金内加热套管的腐蚀性能 (Corrosion properties of Mo-30W alloy inner heating casing for hot-dip galvanizing) id: Chinese-language article, mat-test.com record url: https://fsyfh.mat-test.com/article/id/60433c86-e02c-4b74-bf52-93dddd198504 kind: paper license: abstract read; full text not opened gsalloy-b386: title: ASTM B386 molybdenum and molybdenum alloy plate and sheet (supplier product page, Mo Alloy 366) id: ASTM B386/B386M url: https://gsalloy.com/product/astm-b386-molybdenum-and-molybdenum-alloy-plate-and-sheet/ kind: web license: supplier page pubchem-mo: title: 'PubChem: Molybdenum (CID 23932), GHS classification' id: CID 23932 url: https://pubchem.ncbi.nlm.nih.gov/compound/23932 kind: database license: PubChem, public domain pubchem-w: title: 'PubChem: Tungsten (CID 23964), GHS classification' id: CID 23964 url: https://pubchem.ncbi.nlm.nih.gov/compound/23964 kind: database license: PubChem, public domain license: CC-BY-4.0 updated: '2026-10-26' review: status: draft method: assistant checked_values: 7 unreachable: 4 caveats: 3 note: Written by an AI assistant on 2026-10-26. Seven property values were read in this run. Thermal conductivity, electrical resistivity, expansion and modulus were not found. The Plansee, matmatch, Climelt full-text and mat-test full-text pages were not reachable. story: recipe: line: Mo-30W is a molybdenum-base alloy with about 30 % tungsten. Polema gives 28 to 32 % tungsten for its crucibles, ASTM B386 Alloy 366 is 27 to 33 wt %, and Climelt is nominal 70 % Mo to 30 % W. Polema makes it as sintered or forged shapes, and the Wang et al. bar was made by powder metallurgy. ASTM B386 Alloy 366 is vacuum arc-cast. parts: - name: Molybdenum symbol: Mo share_note: balance (about 70 %) role: The matrix of the alloy, with a body-centred cubic structure. - name: Tungsten symbol: W share_percent: 28 share_high: 32 role: Forms a solid solution with molybdenum, which Polema credits for the alloy's creep resistance and machinability. risk_groups: - title: For people lead: The hazard notifications are for the pure elements, not the alloy. level: 1 verdict: Mixed notifications points: - label: Molybdenum as a substance line: PubChem notifications for molybdenum give H228 flammable solid for 30 % of reports and H361 for 29.5 %, but 57.4 % of 1523 reports meet no GHS criteria. - label: Tungsten as a substance line: PubChem notifications for tungsten give H228 flammable solid for 73.4 % of reports, with H252, H320 and H335 also listed. - title: If it fails lead: The failure route in the sources is high temperature and aluminium in the zinc. points: - label: High temperature line: Strength and hardness stay stable between 1300 and 1500 °C in the Wang et al. bar and then drop significantly, with 385 MPa and HV10 185 at 1500 °C after full recrystallisation. - label: Aluminium in zinc line: The Mo-30W heater casing factory test calls aluminium in the molten zinc the main reason for corrosion. - title: Handling and storage points: - label: Shock line: Polema says the products should not be subjected to shocks during use. - label: Specify the form line: Sintered and forged crucibles have different minimum densities (10.9 and 11.2 g/cm3), so state the form when you order. why: Mo-30W is a molybdenum alloy with about 30 % tungsten. It is used where the part must keep its shape at high temperature, in vacuum or hydrogen furnaces, for sapphire crucibles and for thin-film sputtering targets. Burman (1984) gives a melting point of 2829 °C, and Polema gives minimum crucible densities of 10.9 g/cm3 (sintered) and 11.2 g/cm3 (forged). The zinc-bath use depends on bath temperature and aluminium content. uses: - where: Sputtering targets line: Polema lists MoW alloy sputtering targets for thin-film electronic components and functional coatings. - where: Furnace hot zones line: Polema lists heat zones of vacuum and hydrogen furnaces, for smelting quartz glass and growing sapphire crystals. - where: Zinc-bath heater casings line: A factory test of Mo-30W inner heating casings in molten zinc was reported in a Chinese-language article (abstract read). can_do: - label: Melting point value: 2829 °C benchmark: melting_point line: Burman (1984) gives 2829 °C, cited for its high melting temperature and its inertness in molten zinc. - label: Weight value: 10.9 g/cm3 minimum benchmark: density line: Polema gives at least 10.9 g/cm3 for sintered MoW30-PM crucibles. - label: Strength when hot value: 170 MPa at 1600 °C benchmark: ultimate_tensile_strength line: The Wang et al. bar has a tensile strength of 170 MPa and 10 % elongation at 1600 °C. - label: Strength after recrystallisation value: 385 MPa at 1500 °C benchmark: ultimate_tensile_strength line: The fully recrystallised bar has a tensile strength of 385 MPa and HV10 185 at 1500 °C, the lowest values in the study. compare: Polema says Mo-30W has temperature resistance and creep resistance higher than molybdenum, and higher machinability than tungsten. No numeric comparison with pure molybdenum was read in this run, so the compare rows show Mo-30W values only. compare_rows: - label: Density (crucible minimum) benchmark: density - label: Melting point benchmark: melting_point - label: Tensile strength at 1500 °C benchmark: ultimate_tensile_strength handling: - Do not subject the products to shocks during use (Polema). - Specify sintered or forged form, because the minimum density differs (Polema). - Test the zinc-bath heater casing against the bath temperature and aluminium content in the bath, since the factory test ties corrosion to both. good_for: - 'High-temperature furnace and hot-zone parts in vacuum or hydrogen: melting point 2829 °C (Burman, 1984).' - 'Sapphire crucibles and thin-film sputtering targets: Polema lists both uses.' - Heat resistance with better creep resistance and machinability than tungsten (Polema). watch_out: - Strength falls significantly above the 1300 to 1500 °C range in the Wang et al. bar. - Aluminium in a galvanizing bath is named as the main cause of corrosion of Mo-30W heater casings. - The zinc-bath claim of chemical inertness (Burman 1984, Climelt) conflicts with the factory-test finding, and no corrosion rate is printed. - Thermal conductivity, electrical resistivity, expansion and modulus for Mo-30W were not found in a readable source. verdict: Mo-30W is a molybdenum alloy with about 30 % tungsten, used for furnace hot zones, sapphire crucibles and sputtering targets. Burman (1984) gives a melting point of 2829 °C, Polema gives minimum crucible densities of 10.9 and 11.2 g/cm3, and the Wang et al. bar holds 385 MPa at 1500 °C after recrystallisation. For zinc baths the sources disagree, and the factory test names aluminium in the zinc as the main cause of corrosion. The thermal and electrical data that a designer would need are not in any source read here, so they should be obtained from the manufacturer before a design is fixed.