AlSi12 eutectic powder (577°C) for CAB furnace brazing of radiators, condensers and EV battery cooling plates. Paste and spray cuts, AlSi7.5/10 variants.
QUICK ANSWER
AlSi12 is an aluminum-silicon eutectic alloy powder (12% Si) melting at 577 °C, used as the brazing filler for aluminum heat exchangers — automotive radiators, condensers, evaporators, and battery cooling plates — and as a spray and cladding alloy for aluminum surface modification. Its eutectic melting behavior gives sharp, predictable flow in the CAB (controlled atmosphere brazing) furnaces that produce the world's aluminum heat exchangers.
Aluminum brazing is a hidden giant: every car contains multiple aluminum-brazed heat exchangers, and the EV transition is multiplying demand through battery cooling plates and thermal management modules. AlSi12 powder is consumed as paste for joint application, as filler in flux-cored wire, and in thermal spray form for localized clad repair. The alloy's near-eutectic composition gives a narrow 577-582 °C melting window that flows at 600-610 °C — safely below the 660 °C melting point of the aluminum components being joined.
MATERIAL DATA
Lot-level controls focus on the chemistry, particle characteristics, and process values that influence manufacturing consistency and finished-part performance.
| Element | Content | Performance Role |
|---|---|---|
| Aluminum (Al) | Balance (~88 wt%) | Base matching the heat exchanger alloys being joined |
| Silicon (Si) | 11-13 wt% | Eutectic former — drops melting to 577 °C and drives fluid flow |
| Iron (Fe) | < 0.8 wt% | Impurity limit per standard specifications |
| Copper (Cu) | < 0.3 wt% | Limited — excess copper degrades corrosion resistance |
| Zinc + others | < 0.3 wt% combined | Trace control for consistent brazing behavior |
Final limits can be aligned with the agreed purchase specification.
APPLICATIONS
Automotive heat exchanger production is the dominant market: radiators, condensers, charge-air coolers, and evaporators are brazed in continuous Nocolok CAB furnaces where AlSi12-based filler flows into thousands of fin-to-tube joints per unit. Tier-1 suppliers consume the alloy primarily as clad sheet, but powder-paste application serves prototype lines, aftermarket radiator repair, and complex joint geometries that clad sheet cannot reach — a steady specialty market that buys on particle size consistency and flux compatibility.
The EV thermal management boom is the growth story: battery cooling plates, motor cooling jackets, and power electronics cold plates are brazed aluminum assemblies, and their low-volume high-mix production favors paste-applied filler over clad sheet. AlSi12 thermal spray powder also serves aluminum surface hardening and repair — spraying wear-resistant Al-Si layers onto aluminum substrates and rebuilding worn aluminum castings where welding would distort thin sections.
BRAZING FILLER & SOLDER POWDERS
CUSTOM SUPPLY
We supply AlSi12 in paste-grade -325 mesh and thermal spray cuts, plus AlSi7.5, AlSi10, and zinc-bearing variants for different melting windows. Low-magnesium versions for vacuum brazing, flux-compatible surface condition for Nocolok paste formulation, and EV cooling-plate qualification lots are available. Not export-controlled.
We supply AlSi12 in paste-grade -325 mesh and thermal spray cuts, plus AlSi7.5, AlSi10, and zinc-bearing variants for different melting windows.
Low-magnesium versions for vacuum brazing, flux-compatible surface condition for Nocolok paste formulation, and EV cooling-plate qualification lots are available.
MATERIAL COMPARISON
| Comparison Point | This Product | AlSi7.5 |
|---|---|---|
| Melting range | 577-582 °C — sharp eutectic | 577-615 °C — wide mushy range |
| Flow behavior | Excellent — floods fine joints | Sluggish — better for gap filling |
| Joint gap suitability | Tight, consistent joints | Wider, variable gaps |
| Erosion of thin fins | Higher risk — very fluid | Lower — partial melting control |
| Typical use | CAB heat exchangers, fine joints | Repair, variable fit-up, torch brazing |
| Cost | Baseline | Similar |
TECHNICAL FAQ
Need a different chemistry, particle range, or processing route? Our material team can review the requirement and supply window.
In vacuum brazing with magnesium-bearing variants, yes. In atmospheric CAB furnaces, Nocolok flux is required to break the aluminum oxide — our powder is supplied in surface condition compatible with flux paste formulation.
Excess filler quantity and over-temperature dissolve thin fin stock. The fixes are precise paste dosing, a 600-605 °C peak, and minimizing time above liquidus — our narrow-melting lots give the widest process window.
Yes — it is the standard filler for 3003/6060/6061 assemblies. Keep peak temperature below 610 °C to protect the extrusion temper.
Yes — flame or arc-sprayed AlSi12 rebuilds worn aluminum surfaces and seals porous castings, machineable to dimension. The spray cut differs from paste grade; specify the application when ordering.
No. Aluminum-silicon powders ship without licensing requirements.
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