High-temperature refractory. Semiconductor furnace. 1800 °C service.

Molybdenum forms volatile MoO3 above 500 °C in oxidizing atmosphere — the oxide sublimes away, exposing fresh metal, which oxidizes further. Catastrophic loss of material. In vacuum or inert atmosphere, Mo is stable to 1800 °C+. In reducing atmosphere (hydrogen), similar. For Mo service above 500 °C in air: oxidation-resistant coating required (silicide, aluminide), or switch to oxidation-resistant refractory (e.g., niobium alloys).

Pure Mo: 550 MPa strength at room temperature, 200 MPa at 1000 °C. Standard for shields, structural in vacuum. TZM alloy: 900 MPa at room temp, 500 MPa at 1000 °C. Better creep resistance. Used where Mo must maintain strength at temperature. TZM is premium cost (roughly 2× pure Mo) — justify only when elevated-temperature strength is needed.

Pure Mo is brittle at room temperature — can crack from over-aggressive machining. Sharp tools, light cuts, moderate speeds. TZM is slightly tougher but similar. Use carbide tooling, flood coolant, climb milling. Avoid sharp notches in design (stress concentrators). Plan for slightly longer machining time vs steel. Our experience includes Mo furnace components for semiconductor industry.

Molybdenum matrix infiltrated with copper. Balances thermal conductivity (from Cu) with low thermal expansion (from Mo). CTE can be tuned from 5-12 ppm/°C by adjusting Cu content. Matches silicon (3 ppm/°C), GaAs (6 ppm/°C), and ceramic packaging materials. Critical for high-power RF electronics, laser diode mounts, power transistor thermal management. Standard product form for semiconductor packaging.

Pure Mo raw material: $50-100/kg. TZM: $80-150/kg. Mo-Cu: $100-200/kg. Machining similar cost to steel. Finishing (grinding, stress relief) adds cost. Typical finished Mo parts: 3-5× cost of equivalent steel parts. For applications where Mo's unique properties are needed, cost is justified by enabling the application.

Pure Mo: 3-4 weeks for standard bar stock sizes. TZM: 4-6 weeks. Mo-Cu composites: 6-8 weeks. Sheet Mo: 2-3 weeks for standard thicknesses. Custom sizes: add 2-4 weeks. With stress relief or coating: add 1-2 weeks. Plan 6-10 weeks for typical Mo project lead time.