Solder Connection

Solutions in Soldering Technology

NR-205 - Rework Soldering Flux

ALPHA® NR-205 is a halide-free, rosin/resin free, low solids, no-clean flux. It is formulated for wave soldering of through-hole, mixed technology and surface mount assemblies. The flux is particularly effective when soldering in an inert atmosphere. The flux produces a tack-free surface with high surface insulation resistance and very little residue to interfere with electrical testing. ALPHA NR-205 fully conforms to the requirements of Bellcore TR-NWT-000078. The flux has been specifically formulated to resist degradation in surface insulation resistance and electromigration, even in situations where the flux does not experience soldering temperatures and when heavy levels of flux have been applied. The residues are non-corrosive and do not cause "greening" when in contact with copper or copper-bearing alloys. 

ALPHA NR-205 is particularly well-suited for touch-up/rework when supplied in a flux pen. Alpha “WriteFlux” pens make local flux application an easily controlled process.

Key Product Features & Benefits: 

  • High activity
  • Meets bellcore requirements & other critical sir tests
  • Very safe residues
  • Non-corrosive residues
  • Good soldering in air; excellent soldering in nitrogen for low defects
  • High reliability assemblies, even when the flux does not experience soldering temperatures
  • Excellent for touch-up/rework applications
  • Will not cause "greening" on exposed copper/copper alloys

Classified J Standard ORLO
Shelf Life - 18 Months from DOM


Product Number : NR205

Prod. No. 10432
NR205 Cleanline Flux Pen

Prod. No. 22176
NR205 Flux - 5L

Prod. No. 22175
NR205 Flux - 1L

Data Sheets and Info

Health & Safety

Technical Bulletin

ROHS Certificate


Q - What does Halide free mean?
A - In many fluxes halides are added to the activation package to promote solderability. In the case of this flux solderability and wetting has been achieved using a range of chemistries which do not contain halides. The inclusion of halides within a flux can promote post soldering residues to become active in the presence of moisture and temperature fluctuations and promote corrosion long term which in turn can cause pcb failure.

Q - What is colophony and can it cause any health issues?
A - Colophony is a generic term for rosin, this is the sap or sticky substance that derives from pine and spruce trees. Its "stickiness" lends itself to being used in a wide range of products. We have traditionally used this product in fluxes due to these specific properties it can however lead to breathing difficulties and skin sensitivity. Always use fume filtration when soldering and change filters regularly.

Q - What is the difference between rosins and resins?
A - The terms are often used interchangeably, but rosin is a naturally occurring substance, and resin is either a modified rosin or completely synthetic material. Rosins are plant based products and are subject to more natural variation than resins, however resins are commonly used in newer flux formulations due to their more consistent performance.

Q - How does IPCJ-STD-004B flux classification work.
A - Flux designation has three components. The first two letters, RO, RE or OR, represent the basic chemical composition: rosin-based, resin-based or organic acid-based. The next component is flux designation, L, M or H, which describes the flux’s activity level as low, medium or high, and the final component, 0 or 1, this indicates if halides are present.

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