Application
Heat Sinks & Electrical Contacts
Where W/Cu grades split — and what we do and do not supply
Overview
Why tungsten-copper here
Tungsten-copper shows up in two more places buyers often ask about: heat sinks for semiconductor and power-device packaging, and arc-resistant contacts for high-voltage switchgear. Both are real applications — but they are dominated by high-tungsten grades (80% W and above), which sit inside China's dual-use export-control descriptions.
Our export range stops below that line. For contact-side needs in lower-tungsten compositions — for example W/Cu 70/30 arc-quenching components in medium-voltage equipment — we can quote to drawing after a composition check. For semiconductor heat sinks in ≥80% W grades, we decline politely and refer you on. Keeping this boundary clear is what lets every order ship through routine customs, with no export-license delays on your side.
-
HV & MV contacts
Arc-erosion resistance makes W/Cu a proven contact material; lower-W compositions are checkable case by case.
-
Semiconductor heat sinks
Mainstream grades are ≥80% W — outside our export range and inside export-control descriptions.
-
The 80% line
We supply sub-80% tungsten alloys only: routine customs, no license delays, predictable delivery.
-
Ask anyway
Not sure where your composition falls? Send the spec — we answer within 24 hours.
In depth
Application notes
The material logic on each side
Both applications buy the same two properties: the tungsten skeleton for arc and erosion resistance, the copper phase for thermal and electrical transport. Heat-sink work leans on the copper — W/Cu spreads heat in power modules while its expansion rate sits between silicon and copper, lowering thermal-cycle stress on soldered joints. Contact work leans on the tungsten — the skeleton resists arc erosion that would crater a pure copper contact in thousands of operations.
That balance is why W/Cu grades span such different industries, and also why the tungsten percentage is the first thing every buyer in these fields asks about.
Why our catalogue stops at 80% tungsten
Mainstream semiconductor heat-sink grades (W90Cu10 and above) and many high-voltage contact grades fall at or above 80% tungsten — compositions that sit inside China's dual-use export-control descriptions. Supplying them is a licensing process we deliberately do not run, because our whole export model is built on routine customs: no licenses, no delays, no surprises for your broker.
Below that line, W/Cu 75/25 and 70/30 ship as ordinary industrial goods with standard documentation — commercial invoice, packing list, certificate of origin where needed — and clear customs on the usual HS classification with no export-license step.
If your spec lands outside the range
Send it anyway. For medium-voltage contact components in sub-80% compositions we can quote to drawing after checking the specification against our export range. For high-tungsten heat sinks we will tell you directly that we are not the supplier — and we will not waste your RFQ cycle pretending otherwise.
What we can always offer, in our two grades, is the machining side: contact assemblies, fixture components and heat-spreader parts cut to drawing where the composition allows. Our custom-parts page covers what our floor can take on.
Related: Custom W/Cu parts
Supplied from our floor
Products for this application
Technical library
Further reading
The guides engineers read before they write the second drawing.
- Copper tungsten thermal conductivity and heat sink grades Conductivity, CTE and hardness by grade, plus the substrate-matching table.
- Copper tungsten CTE and thermal expansion Why expansion, not conductivity, causes most solder-joint failures in service.
- Reading a CuW data sheet Test temperature changes the CTE number by 1–2 ppm/K — here is how to compare fairly.
- How tungsten copper is made: the infiltration process Why infiltrated material holds density where pressed-and-sintered parts do not.
Running heat sinks & contacts on your line?
Send alloy, dimensions and quantity — quote back within 24 hours, held for 7 days.