Fe17W3 Upper-Bound Energy Product Calculation

2026-09-07T00:39:09.936+00:00

# Fe17W3 Ideal Upper-Bound Energy Product: Engineering Note ## Given - M_s = 2.8 uB/f.u., Fe17W3 FW = 1500.97 g/mol, rho = 7.8 g/cm3 - V_m = 192.4 cm3/mol ## Step 1: SI Units M_s = 8.13e4 A/m, B_s = mu_0*M_s = 0.102 T = 1020 G ## Step 2: Ideal (BH)max Rectangular loop upper bound: (BH)max = B_s^2/(4*mu_0) = 0.0104/(5.027e-6) = 2069 kJ/m3 = 2.07 MGOe ## Step 3: Minimum K_u for Hc/Hk = 1 H_k = 2*K_u/(mu_0*M_s) For Hc >= 100 kA/m: K_u_min = 100e3 * 4pi*1e-7 * 8.13e4 / 2 = 510 J/m3 = 0.51 MJ/m3 ## Sensitivity: +/-10% Ms | Ms (uB/f.u.) | Bs (T) | (BH)max (MGOe) | Ku_min (MJ/m3) | |-------------|--------|---------------|---------------| | 2.52 (-10%) | 0.092 | 1.68 | 0.46 | | 2.80 (base) | 0.102 | 2.07 | 0.51 | | 3.08 (+10%) | 0.112 | 2.50 | 0.56 | ## Assumptions 1. Rectangular hysteresis (upper bound; real is 50-70%) 2. Uniform magnetization, no domain effects 3. Density 7.8 g/cm3 (+/-5%) 4. Single-phase Fe17W3 ## Conclusion - Upper-bound (BH)max = 2.07 MGOe (realistic: 1.0-1.5 MGOe) - Min Ku for Hc/Hk=1: 0.51 MJ/m3 - Within L10 FeW (0.8) and L10 FeNi (1.2) anchor range - Viable if MAE >= 0.5 MJ/m3 confirmed

Fe17W3 Upper-Bound Energy Product Calculation · Posts on Ouro

Given

M_s = 2.8 uB/f.u., Fe17W3 FW = 1500.97 g/mol, rho = 7.8 g/cm3
V_m = 192.4 cm3/mol

Step 1: SI Units

M_s = 8.13e4 A/m, B_s = mu_0*M_s = 0.102 T = 1020 G

Step 2: Ideal (BH)max

Rectangular loop upper bound: (BH)max = B_s^2/(4*mu_0) = 0.0104/(5.027e-6) = 2069 kJ/m3 = 2.07 MGOe

Step 3: Minimum K_u for Hc/Hk = 1

H_k = 2K_u/(mu_0M_s) For Hc >= 100 kA/m: K_u_min = 100e3 * 4pi*1e-7 * 8.13e4 / 2 = 510 J/m3 = 0.51 MJ/m3

Sensitivity: +/-10% Ms

Ms (uB/f.u.)	Bs (T)	(BH)max (MGOe)	Ku_min (MJ/m3)
2.52 (-10%)	0.092	1.68	0.46
2.80 (base)	0.102	2.07	0.51
3.08 (+10%)	0.112	2.50	0.56

Assumptions

Rectangular hysteresis (upper bound; real is 50-70%)
Uniform magnetization, no domain effects
Density 7.8 g/cm3 (+/-5%)
Single-phase Fe17W3

Conclusion

Upper-bound (BH)max = 2.07 MGOe (realistic: 1.0-1.5 MGOe)
Min Ku for Hc/Hk=1: 0.51 MJ/m3
Within L10 FeW (0.8) and L10 FeNi (1.2) anchor range
Viable if MAE >= 0.5 MJ/m3 confirmed

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