Radio Frequency (RF) Iron Powders
General Material Properties
| Material | Reference Permeability  | 
			Powder Type | Temp Coef of Perm (+ppm/C°)  | 
			Density gm/cm  | 
			Max Frequency (MHz)  | 
			Relative Cost | Color Code Toroid  | 
		
|---|---|---|---|---|---|---|---|
| -0 | 1 | Phenolic | N/A | N/A | N/A | 1.2 | Tan/Tan | 
| -1 | 20 | Carbonyl Iron | 280 | 6.4 | 10 | 3.6 | Blue/Clear | 
| -2 | 10 | Carbonyl Iron | 95 | 5 | 45 | 2.0 | Red/Clear | 
| -3 | 35 | Carbonyl Iron | 255 | 6.5 | 5.0 | 3.2 | Gray/Clear | 
| -5 | 5 | Carbonyl Iron | 280 | 5.0 | 10 | 2.1 | Green/Clear | 
| -6 | 8.5 | Carbonyl Iron | 35 | 5.0 | 55 | 5.1 | Yellow/Clear | 
| -7 | 9 | Carbonyl Iron | 30 | 5.0 | 50 | 3.8 | White/Clear | 
| -8 | 35 | Carbonyl Iron | 255 | 6.5 | 5.0 | 2.7 | Yellow/Red | 
| -10 | 6 | Carbonyl Iron | 150 | 4.9 | 83 | 5.6 | Black/Clear | 
| -15 | 25 | Carbonyl Iron | 190 | 6.4 | 7.0 | 3.2 | Red/White | 
| -17 | 4 | Carbonyl Iron | 50 | 4.8 | 170 | 3.7 | Blue/Yellow | 
- ‐2, ‐5, ‐6 & ‐7 Materials: These are the most popular carbonyl iron mixes. They will provide High Q up to 40 MHz and the most popular for amateur radio and variety of other communication applications. They are also useful for moderate band transformers in the 200 to 400 MHz frequency range
 - ‐1, ‐3, ‐8 & ‐15 Materials: These materials are annealed carbonyl irons providing the highest carbonyl permeability. They are useful for high Q applications below 1 MHz and will provide the broadest band transformers covering a typical range from 50 to 500 MHz.
 
- ‐10 & ‐17 Materials: These materials are the highest frequency carbonyl irons. They will provide high Q up to 150 MHz and are a popular material for cable television applications. They will produce moderate band transformers covering 400 to 700 MHz.
 - ‐0 Material: This is a non‐magnetic material. It provides a solid winding form for winding air coils. It has excellent temperature stability and will provide high Q up to the highest frequencies. It is also useful for moderate band transformer applications covering a typical range from 600 MHz to 1 GHz.