---
title: "Molybdenum Machining | 99.95% Moly & TZM Parts | OpenSpindle"
description: "Get quotes for custom molybdenum and TZM parts from qualified refractory-metal shops. Furnace hardware, sputter-target backing plates, EDM-cut electrodes, and heat sinks. Upload a drawing."
canonical: https://openspindle.com/materials/molybdenum
---

# Get quotes for custom molybdenum parts

Molybdenum is a refractory metal with a melting point above 2600°C, high thermal conductivity, and a very low coefficient of thermal expansion, which is why it shows up in semiconductor equipment, vacuum furnaces, and glass-melt hardware. Only shops set up for refractory metals should run it. Upload your drawing and we'll source quotes from qualified partners.

## Molybdenum grades shops run most

The grade sets temperature capability, strength retention, and ductility. These are the ones to specify by name.

### Molybdenum 99.95% (pure Mo)

Standard commercial-pure molybdenum, 99.95% minimum, available as plate, sheet, rod, and bar from Plansee, H.C. Starck, Edgetech, and Elmet. Excellent thermal and electrical conductivity, poor machinability but routine for refractory shops with the right tooling.

**Best for:** Furnace hot-zone hardware, sputter-target backing plates, glass-melt electrodes, X-ray anodes

### TZM (Mo-0.5Ti-0.08Zr-0.03C)

Titanium-zirconium-molybdenum alloy that keeps most of pure moly's conductivity while roughly doubling strength and extending the useful temperature range. Preferred for stressed hot-zone parts and tooling that would creep in pure Mo.

**Best for:** Hot-zone tooling, aerospace propulsion test hardware, high-temperature fasteners, crystal-growth furnaces

### MHC (Mo-Hf-C)

Hafnium-carbide-strengthened moly for the highest service temperatures where TZM runs out. Rare in general supply chains; typically a specialty order through the same refractory mills.

**Best for:** Extreme hot-zone components, specialty aerospace, research reactors

### Mo-La (lanthanated)

Molybdenum doped with lanthanum oxide for better ductility and resistance to recrystallization at high temperatures. Used where pure moly would embrittle on thermal cycling.

**Best for:** Lamp electrodes, high-cycle thermal components, lighting and optics

## Material Properties

Representative values for 99.95% pure molybdenum. TZM and MHC retain strength further into the high-temperature range.

| Property | Value |
| --- | --- |
| Density | 10.22 g/cm³ (0.369 lb/in³) |
| Melting point | 2623 °C (4753 °F) |
| Tensile strength (annealed) | ~85 ksi |
| Yield strength (annealed) | ~70 ksi |
| Hardness (annealed) | ~160 HV |
| Coefficient of thermal expansion | ~4.8 µm/m·K (near silicon, which is why it is used in semi) |
| Thermal conductivity | ~138 W/m·K |
| Electrical resistivity | ~5.2 µΩ·cm |
| Machinability | Poor; carbide tools, rigid setups, sharp geometry required |
| Ductile-to-brittle transition | ~30 °C -- avoid cold working below room temperature |

Molybdenum oxidizes aggressively above about 400 °C in air. Service is almost always in vacuum, inert atmosphere, or reducing conditions. Note the atmosphere on your drawing.

## Stock Forms

- **Plate & block** -- Sputter-target backing plates, furnace crucibles, heat sinks.
- **Round bar & rod** -- Electrodes, fasteners, machined rotational parts.
- **Sheet & foil** -- Heat shields, lamp parts, thin heat spreaders.

## Processes That Run This Material

- [CNC Machining](https://openspindle.com/capabilities/cnc-machining.md) -- Pocketed plate and block for furnace hardware and sputter backing.
- [CNC Turning](https://openspindle.com/capabilities/cnc-turning.md) -- Rod and bar turned to electrodes and rotational hardware.
- [EDM & Wire EDM](https://openspindle.com/capabilities/edm.md) -- The default for complex Mo and TZM features; cuts without mechanical stress.
- [Precision Grinding](https://openspindle.com/capabilities/precision-grinding.md) -- Flatness and surface finish on sputter backing plates and heat sinks.
- [Micro Machining](https://openspindle.com/capabilities/micro-machining.md) -- Small Mo parts for semiconductor and medical.

## Finishes

Molybdenum is usually left machined or polished. Coatings are specified when service exceeds oxidation threshold or when a specific electrical surface is required.

- **As-machined** -- Standard for vacuum and inert-atmosphere service. Minimal post-processing.
- **Chemically cleaned & etched** -- Removes machining contaminants and residual oxide for high-purity semi and vacuum work.
- **Polished** -- Mirror or near-mirror finish for sputter-target backing and optical hot-zone parts.
- **MoSi2 or oxidation-resistant coating** -- Molybdenum disilicide and similar coatings for service in air above 400 °C.
- **Plated (gold, nickel)** -- Thin plating on electrodes and contacts for specific electrical requirements.

Fume and dust from grinding, EDM, and welding Mo (and especially MoO₃) are documented health hazards. Shops quoting Mo should state their ventilation and PPE protocol; we only route moly RFQs to shops that confirm they are set up for it.

## Applications

- Semiconductor sputter-target backing plates
- Vacuum furnace hot-zone hardware
- Glass-melt electrodes and stirrers
- X-ray tube anodes
- Rocket nozzle inserts and propulsion test hardware
- High-temperature fasteners and support structure
- Heat sinks for GaN and SiC power electronics
- Thermally stable mirror substrates

Molybdenum shows up where temperature or thermal expansion is the hard constraint, and where no cheaper alternative works.

## How It Compares

How molybdenum stacks up against the alternatives for high-temperature and specialty parts.

### Tungsten

- Tungsten has a higher melting point (3422 °C) and higher density (19.3 g/cm³)
- Molybdenum machines (relatively) better and costs less than tungsten per pound
- Both oxidize above a few hundred °C and need inert or vacuum service

**Verdict:** Choose tungsten for the highest temperatures or where density is a feature (shielding, counterweights). Choose Mo for most hot-zone and semi work.

### TZM

- TZM keeps strength further into the high-temperature range than pure Mo
- TZM resists creep much better in loaded hot-zone parts
- Pure Mo has slightly higher thermal and electrical conductivity

**Verdict:** Choose TZM when the part sees high mechanical stress at temperature. Choose pure Mo for conductivity-driven parts and lightly loaded fixtures.

### [Inconel 625/718](https://openspindle.com/materials/inconel.md)

- Inconel is readily machinable and cheaper, but tops out around 980 °C service
- Molybdenum keeps strength and dimensional stability well above where Inconel softens
- Inconel oxidizes safely in air; moly does not

**Verdict:** Choose Inconel when temperature is below ~980 °C and air service is required. Choose moly above that or when CTE match to silicon matters.

## Frequently Asked Questions

### Why is molybdenum used in semiconductor equipment?

Its coefficient of thermal expansion (~4.8 µm/m·K) is close to silicon, so a moly fixture or sputter backing plate expands at nearly the same rate as the wafer or target through heat cycles. That keeps bonds intact and wafers flat. It also conducts heat well and tolerates vacuum, which are the other requirements for process equipment.

### Why do shops decline molybdenum RFQs?

Three reasons. First, mill sourcing: Mo and TZM are specialty orders through Plansee, H.C. Starck, Edgetech, or Elmet with long lead times and lot minimums. Second, machining: it is brittle below room temperature, work-hardens, and gummy at some conditions, so general CNC shops without the tooling library and SFM confidence will scrap parts. Third, safety: Mo dust and MoO₃ fume are health hazards that require ventilation, PPE, and waste handling most shops do not have.

### What is TZM and when do I need it over pure moly?

TZM is molybdenum alloyed with ~0.5% titanium, ~0.08% zirconium, and ~0.03% carbon. The alloying raises recrystallization temperature and roughly doubles strength while keeping most of pure Mo's conductivity. Use TZM for hot-zone parts that carry load -- fasteners, support structure, stressed fixtures. Pure Mo is fine for electrodes and unloaded conductive parts.

### Can molybdenum be welded?

Yes, but it is sensitive. TIG welding in inert atmosphere (argon-filled chamber or trailing shield) is standard; welds are brittle unless post-weld heat treated and are prone to cracking at impurity bands. EDM, mechanical fastening, and brazing are often preferred over welding for Mo and TZM joints. Note the joining method on your drawing so the shop can plan it.

### How is molybdenum machined?

With sharp carbide tooling at modest speeds, rigid setups, generous cutting fluid, and tool paths that avoid feature exits that would chip the brittle edge. Thin-walled geometry is risky because of the low ductility; add stock or revise the design where possible. EDM is often the correct choice for intricate features in Mo.

### What quantities make sense to quote?

Prototype 1–10 and low-volume production 25–200 are typical for moly RFQs. Mill lot minimums for the stock can push one-off parts to several week lead times; shops with existing mill accounts and standing inventory for common forms can turn faster. Say the quantity, size, and date up front and we match the quote accordingly.

### What about export control?

Molybdenum, TZM, and tungsten are not generally on US munitions lists but can be ECCN-controlled for certain end uses (nuclear, defense). We identify end use and destination before routing the RFQ; shops set up for ITAR or export-controlled work can indicate that on their profile.

## Related Materials

- [Tungsten](https://openspindle.com/materials/tungsten.md)
- [Inconel / Nickel Superalloys](https://openspindle.com/materials/inconel.md)
- [Titanium](https://openspindle.com/materials/titanium.md)
- [Hastelloy](https://openspindle.com/materials/hastelloy.md)
- [Cobalt-Chrome](https://openspindle.com/materials/cobalt-chrome.md)
- [Copper](https://openspindle.com/materials/copper.md)

## Need molybdenum or TZM parts machined?

Upload a drawing and we route it to refractory-metal shops with the equipment, PPE protocol, and mill sourcing to run moly. Quantity one is quoted seriously; realistic 3–6 week lead times built in.