NiCrSiB
AWS A5.8 BNi-2 paste-grade powder, 971-999°C melting, self-fluxing in vacuum or hydrogen. Custom mesh cuts for dispensing, printing and tape. Lot-certified chemistry.
QUICK ANSWER
BNi-2 is a nickel-chromium-silicon-boron brazing filler powder (AWS A5.8 BNi-2) melting at 971-999 °C, used for vacuum and atmosphere furnace brazing of stainless steels, superalloys, and heat exchangers. Its low melting point, excellent flow in tight joints, and good high-temperature strength make it the most widely used nickel filler metal in aerospace, automotive EGR coolers, and plate-fin heat exchanger production.
BNi-2's silicon and boron content gives it outstanding capillary flow — it fills joints down to 0.05 mm and self-fluxes in vacuum or dry hydrogen, which is why heat exchanger manufacturers can braze thousands of joints in one furnace cycle. The trade-off is that boron and silicon form hard, brittle intermetallic phases in thick joints, so BNi-2 is specified for thin, closely fitted gaps where capillary action distributes the alloy fully. Powder form lets manufacturers apply it as paste through dispensing, screen printing, or roller coating onto complex assemblies.
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 |
|---|---|---|
| Nickel (Ni) | Balance (~82 wt%) | Base matrix providing high-temperature strength and corrosion resistance |
| Chromium (Cr) | 6.0-8.0 wt% | Oxidation and corrosion resistance in the brazed joint |
| Silicon (Si) | 4.0-5.0 wt% | Primary melting-point depressant and flow promoter |
| Boron (B) | 2.75-3.50 wt% | Self-fluxing agent and secondary melting depressant |
| Iron (Fe) | 2.5-3.5 wt% | Matrix strengthener within specification limits |
Final limits can be aligned with the agreed purchase specification.
APPLICATIONS
Heat exchanger manufacturing is the volume market: automotive EGR coolers, oil coolers, charge-air coolers, and plate-fin heat exchangers are brazed in vacuum furnaces using BNi-2 paste applied by dispensing or printing. A single EGR cooler contains hundreds of brazed joints, and production volumes run to millions of units annually — the filler powder is bought on flow consistency, mesh-size uniformity for paste rheology, and certified chemistry per AWS A5.8. Any drift in silicon or boron shifts melting behavior and can scrap an entire furnace load.
Aerospace and energy form the premium market: turbine honeycomb seals, fuel system components, and stainless sensor assemblies are brazed with BNi-2 where joint integrity at elevated temperature is flight-critical. Powder metallurgy and tooling industries add another stream — brazing carbide-tipped assemblies and infiltrating powder metal skeletons. In these markets, powder oxygen content and lot traceability are the purchase drivers, and buyers typically qualify a supplier for years rather than shop on price.
BRAZING FILLER & SOLDER POWDERS
CUSTOM SUPPLY
We supply BNi-2 to AWS A5.8 chemistry in standard -325 mesh paste grade and custom cuts for tape casting and preform pressing, gas atomized with low oxygen and full certification. Paste formulation support (binder systems matched to your dispensing equipment), alternative nickel fillers (BNi-1a, BNi-5, BNi-7 for specific melting points or B-free joints), and small qualification quantities are standard. Not export-controlled.
We supply BNi-2 to AWS A5.8 chemistry in standard -325 mesh paste grade and custom cuts for tape casting and preform pressing, gas atomized with low oxygen and full certification.
Paste formulation support (binder systems matched to your dispensing equipment), alternative nickel fillers (BNi-1a, BNi-5, BNi-7 for specific melting points or B-free joints), and small qualification quantities are standard.
MATERIAL COMPARISON
| Comparison Point | This Product | BNi-5 |
|---|---|---|
| Melting point | 971-999 °C — lower | 1075-1135 °C — higher |
| Joint gap tolerance | Thin gaps only (0.025-0.10 mm) | Wider gaps possible |
| Boron content | 2.75-3.5% — embrittles thick joints | None — more ductile joints |
| Corrosion resistance | Good | Better (19% Cr) |
| Flow in tight joints | Excellent | Moderate |
| Best use | Heat exchangers, thin precision joints | Thicker joints, corrosion-first service |
TECHNICAL FAQ
Need a different chemistry, particle range, or processing route? Our material team can review the requirement and supply window.
Boron and silicon diffuse into the parent metal during brazing; in thin joints this diffusion removes the brittle eutectic phase entirely, leaving a strong ductile joint. In thick joints the eutectic remains as a hard, brittle line — the classic BNi-2 failure mode.
Yes — dry hydrogen (dew point below -40 °C) works well and is standard in continuous heat exchanger furnaces. Vacuum is preferred for reactive alloys and the highest joint cleanliness.
Standard paste grade is -325 mesh (< 45 µm). Finer cuts improve dispensing resolution for small dots; coarser cuts reduce paste cost for large-area application. We match the cut to your dispensing or printing process.
Keep brazing time and temperature at the minimum of the window — boron diffuses into and can erode thin foils and fin stock. Our lot-specific liquidus data lets you set the furnace just 15-20 °C above liquidus.
No. Nickel brazing fillers ship without licensing requirements.
RELATED PRODUCTS
Compare neighboring grades from the same material family, then review the complete category for additional chemistry and particle options.
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.
BCuP-2 to BCuP-5 powder for paste, rings and preforms. Self-fluxing on copper, silver-bearing options for brass and wide gaps. AWS A5.8 certified lots.
Cu-14Sn-10Ti active braze forming chemical TiC bonds to diamond and ceramics. Paste-grade cuts, custom titanium levels, qualification lots for toolmakers.
REQUEST THIS GRADE
Share your target chemistry, particle size, process, annual volume, and destination. Our powder specialists will confirm the closest production grade and documentation package.
