DOWSIL 340 SILICONE HEAT SINK GREASE
Harmonization Code : 2710199990 |
Main features
- Reworkable Thermal Interface Material
- Device-to-Heat-Sink Heat Transfer
- No-Mix No-Oven Processing
Product Description
DOWSIL™ 340 Heat Sink Compound is a one-part, white, non-curing and non-flowing silicone-based thermally conductive compound designed to improve heat transfer between electronic components and heat sinks. It provides 0.67 W/m·K thermal conductivity, low thermal resistance, and high-temperature stability without requiring curing or ovens. This makes it suitable for PCB assemblies and electronic devices requiring efficient thermal coupling, improved reliability, and simple dispensing processes. :contentReference[oaicite:0]{index=0}
Key features
- One-part silicone compound - supplied as a ready-to-use thermal compound with no mixing, curing, or catalyst required.
- Non-curing and non-flowing - maintains a stable thermal interface throughout service life while minimizing movement after application.
- Efficient heat transfer - 0.67 W/m·K thermal conductivity and low thermal resistance help transfer heat away from electronic components.
- High-temperature stability - silicone formulation maintains a reliable thermal interface under elevated operating temperatures.
- Low bleed formulation - engineered for low bleed performance while maintaining thermal contact between components and heat sinks.
- Simple dispensing process - suitable for both automated and manual dispensing without requiring heat curing or post-processing.
Applications
DOWSIL™ 340 Heat Sink Compound is suitable for electronic assemblies where efficient thermal coupling between heat-generating devices and heat sinks is required to improve heat dissipation and long-term reliability.
- Heat sink attachment: suitable for filling microscopic air gaps between electronic devices and heat sinks to improve thermal transfer.
- PCB assemblies: supports thermal management of printed circuit board assemblies by transferring heat from components to chassis or heat sinks.
- Power semiconductor devices: suitable for transistors, power modules, rectifiers, and other high-power electronic devices requiring thermal coupling.
- Consumer and industrial electronics: helps improve operating efficiency and long-term reliability in compact electronic systems with increasing heat generation.
Related resources
- Dow thermal management materials portfolio and application guides.
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Physical Properties
Thermal Properties
Additional Information
DOWSIL™ 340 Heat Sink Compound
DOWSIL™ 340 Heat Sink Compound is a one-part, white, non-curing and non-flowing silicone thermal compound designed for thermal coupling of electronic devices and PCB assemblies to heat sinks, chassis, and other cooling hardware. It fills microscopic air gaps between mating surfaces to reduce interface resistance and improve heat transfer away from heat-generating components.
Serviceable thermal interface compound
- One-part silicone thermal compound with no mixing step required.
- Non-curing formulation supports reworkable and serviceable heat sink assemblies.
- Non-flowing paste helps keep the compound in place after application.
- 0.67 W/m·K thermal conductivity supports heat transfer from components to cooling hardware.
- Low bleed formulation helps maintain thermal contact over time.
- Suitable for manual or automated dispensing.
Ready-to-use thermal grease
Improve heat transfer across imperfect surfaces
Even flat-looking metal surfaces contain microscopic peaks, valleys, and air pockets. Air is a poor thermal conductor, so direct metal-to-metal contact can create unnecessary thermal resistance. DOWSIL™ 340 Heat Sink Compound fills these microscopic gaps to create a more continuous thermal path between the heat source and heat sink. This helps move heat away from electrical and electronic devices more efficiently, supporting cooler operation, improved performance, and longer device reliability.
When to choose DOWSIL™ 340 instead of a thermal adhesive
| Material type | Typical behavior | Best fit | Selection note |
|---|---|---|---|
| DOWSIL™ 340 Heat Sink Compound Non-curing thermal grease |
Remains as a serviceable thermal interface paste. | Heat sink coupling where mechanical fasteners or clamps provide attachment. | Select when reworkability, no cure step, and simple assembly are required. |
| Thermally conductive adhesive Heat-cure or room-temperature cure adhesive |
Cures into a bonded interface. | Applications where the thermal material must also provide structural attachment. | Select when permanent bonding is needed and rework is not a priority. |
| Thermal pad or gap filler Compressible interface material |
Conforms under compression to fill larger gaps. | Uneven surfaces, larger gaps, or assemblies needing controlled thickness. | Select when the interface gap is too large or variable for grease alone. |
Process points to confirm before qualification
- Apply to clean, dry mating surfaces.
- Remove oils, dust, handling residues, and loose particles before application.
- Review surface flatness and roughness, since these influence thermal contact.
- Apply only enough compound to fill microscopic air gaps.
- Avoid excessive thickness that can increase thermal resistance.
- Use controlled manual or automated dispensing depending on production volume.
- Use screws, clips, clamps, or fixture pressure to maintain intimate contact.
- Confirm uniform pressure across the interface area.
- Review pump-out, squeeze-out, and edge bleed after assembly and thermal cycling.
- Verify thermal performance in the final device configuration.
- Review operating temperature, duty cycle, vibration, and service requirements.
- Confirm that the interface remains stable after reliability or aging tests.
Where DOWSIL™ 340 fits
Frequently asked questions about DOWSIL™ 340 Heat Sink Compound
What is DOWSIL™ 340 Heat Sink Compound used for?
It is used for thermal coupling of electrical and electronic devices, PCB assemblies, and power components to heat sinks, chassis, or other cooling surfaces.
Does DOWSIL™ 340 cure?
No. DOWSIL™ 340 is a non-curing thermal compound. It remains as a grease-like interface material and does not require oven curing.
Is DOWSIL™ 340 an adhesive?
No. It is a thermal compound, not a structural adhesive. Mechanical fastening, clamping, or fixture pressure is typically needed to hold the heat sink or assembly in place.
What is the thermal conductivity of DOWSIL™ 340?
The typical thermal conductivity is 0.67 W/m·K. Thermal performance should still be verified in the final assembly because bond-line thickness, pressure, surface flatness, and contact area affect total thermal resistance.
Can DOWSIL™ 340 be reworked?
Yes. Since it does not cure into a solid bond, the assembly can generally be opened for inspection or service more easily than assemblies using cured thermal adhesives.
How much compound should be applied?
Apply a thin, uniform amount sufficient to fill microscopic surface irregularities. Too much compound can increase the effective bond-line thickness and reduce thermal efficiency.
