Key Takeaways
- ◆N35 delivers 33-36 MGOe (BHmax); N42 delivers 40-42 MGOe. That 20% energy product gap means N35 needs roughly 20% more magnet volume to deliver the same flux as N42 in the same magnetic circuit.
- ◆Remanence: N35 is 1.17-1.22 T; N42 is 1.28-1.32 T. In a motor or sensor, higher Br means more torque or more signal per unit volume, which usually matters more than the per-kilogram price difference.
- ◆Both are standard N-grade (no thermal suffix) with max operating temperature of 80 C and minimum Hcj of 12 kOe. Neither is suitable for motors that operate above 80 C without moving to an H-series variant.
- ◆N35 costs roughly 15-20% less per kilogram than N42. But because you need more N35 material to match N42 performance, the installed-cost difference is often only 5-10% once you account for the larger magnet volume.
- ◆N35 is the standard choice for magnetic closures, consumer products, and hobby applications where absolute flux density is not critical. N42 is the workhorse for BLDC motors, sensors, actuators, and any application where space is constrained.
Overview
N35 and N42 bracket the low-to-mid range of the standard NdFeB grade spectrum. N35 is the entry-level sintered NdFeB grade, often the first grade engineers encounter and the default offering in magnet catalogs. N42 is the most widely specified grade for industrial applications, sitting at the sweet spot of performance, availability, and cost. The choice between them is straightforward: if your design is space-constrained or performance-sensitive, N42 is worth the modest premium. If you are filling a large volume with magnets and flux density is not the bottleneck, N35 saves money.
Side-by-Side Comparison
| Criterion | N35 | N42 |
|---|---|---|
| BHmax (energy product) | 33-36 MGOe | ✓40-42 MGOe |
| Remanence (Br) at 20 C | 1.17-1.22 T | ✓1.28-1.32 T |
| Intrinsic coercivity (Hcj) at 20 C | >= 12 kOe | >= 12 kOe |
| Max operating temperature | 80 C | 80 C |
| Cost per kilogram | ✓Lowest standard grade | +15-20% vs N35 |
| Availability | Universally stocked | Universally stocked |
| Mechanical strength | ✓Slightly tougher (lower Nd content) | Standard NdFeB brittleness |
| Volume needed for equivalent flux | ~20% more than N42 | ✓Baseline |
Green tick indicates the better option for the criterion. Winner assignment reflects typical engineering practice; your application may weight criteria differently.
When N35 Is the Right Choice
- •Application is cost-driven and the magnet volume is not constrained (magnetic closures, holding magnets, large magnetic assemblies)
- •Flux density is not the performance bottleneck (e.g., the magnet is oversized for assembly reasons and already delivers excess field)
- •Prototype or short-run production where the 15-20% per-kg savings offsets any volume penalty
- •Educational kits, hobby projects, or consumer products where the end user does not differentiate between 1.2 T and 1.3 T field strength
When N42 Is the Right Choice
- •Motor, actuator, or sensor design where the available magnet volume is fixed and more flux means more torque or more signal
- •Miniaturization is a priority and the smallest possible magnet package is required
- •The magnetic circuit is already designed around N42-class Br values and downgrading to N35 would require mechanical redesign
- •Industrial automation or robotics application where the magnet cost is a small fraction of the total BOM and the performance-per-dollar of N42 is clearly better
- •Application may eventually migrate to an H-series thermal variant (N42H, N42SH) and starting with N42 keeps the magnetic circuit compatible
Decision Framework
Calculate the magnet volume you need at N42 Br (1.30 T) to meet your flux or torque requirement. Then calculate the volume at N35 Br (1.20 T). If the N35 volume fits in your assembly without mechanical changes, compare the total magnet cost: N35 at 15-20% less per kg but 20% more volume often nets out to only 5-10% savings. If that savings matters at your production volume, use N35. If the N35 volume does not fit, the decision is made. For new designs without legacy constraints, N42 is the default recommendation because it gives more headroom for thermal migration (N42H, N42SH) without redesigning the magnetic circuit. N35 has no commonly produced thermal variants, so if your application later needs higher operating temperature, you would need to redesign for a completely different grade family.
Related NdFeB Grades
N35
80°CEntry-level sintered NdFeB grade for cost-sensitive permanent-magnet applications at or below 80°C.
N38
80°CCost-efficient mid-range sintered NdFeB for general permanent-magnet assemblies up to 80°C.
N40
80°CUpper-mid sintered NdFeB grade for compact motor and actuator designs operating at or below 80°C.
N42
80°CHigh-performance sintered NdFeB grade widely used in compact motors, generators, and precision actuators.
Related Applications
EV Motors
High-performance NdFeB magnets for electric vehicle traction motors, auxiliary drives, and e-axle systems — with the temperature stability and flux density required for continuous high-torque service.
Robotics
Radial multi-pole rings, joint-motor magnets, and high-torque servo-motor assemblies for humanoid robots, collaborative robots, and industrial robotic systems.
Industrial Automation
NdFeB magnets for stepper motors, servo drives, linear actuators, magnetic couplings, and factory automation equipment across European and North American manufacturing.
Frequently Asked Questions
Is N42 twice as strong as N35?
+
No. N42 has roughly 20% higher energy product (42 vs 35 MGOe) and about 8% higher remanence (1.30 T vs 1.20 T). The pull force difference at the magnet surface is roughly 15-20% for the same geometry, not double. The numbering system (N35, N42, N52) refers to the nominal energy product in MGOe, not a linear strength scale. Doubling the pull force requires either doubling the magnet volume or moving to a fundamentally different magnet design.
Can I use N35 in a BLDC motor?
+
You can, but it is rarely the best choice. BLDC motors benefit from high Br because torque scales directly with flux. Using N35 instead of N42 means either accepting 8% less torque at the same motor size or increasing the magnet volume by 20% to compensate. For most BLDC motors in industrial and robotics applications, N42 or N42H is the standard starting grade. N35 is sometimes used in low-cost consumer BLDC motors (fans, small pumps) where the cost saving is prioritized over torque density.
Does N35 have better temperature resistance than N42?
+
No. Both N35 and N42 are standard N-grade magnets rated to 80 C max operating temperature with minimum Hcj of 12 kOe. The temperature coefficient of Br and Hcj is essentially the same for both grades. If you need higher temperature resistance, you must move to an H-series grade (N35H or N42H at 120 C, N42SH at 150 C). There is no thermal advantage to choosing N35 over N42.
Why is N35 cheaper than N42?
+
N35 requires less neodymium per kilogram and is easier to sinter to specification because the microstructure targets are less demanding. The Nd2Fe14B grain alignment does not need to be as perfect as in higher grades, which means the pressing and sintering process has wider tolerance windows and lower scrap rates. The raw material savings (roughly 5-8% less Nd content by weight) combined with higher manufacturing yield accounts for the 15-20% price difference.
Need help deciding?
Share your application requirements and our engineering team will recommend the correct specification with real design margin. Human response within 1 business day.