Conductor Bulk Resistivity & Skin Depths
Available bulk resistivity values (ρ) and relative permeability (μr)used to calculate skin depths (δσ) can vary considerably depending on the source. In fact, the values for permeabilities are so far-ranging that I hesitated to even include any of them in the table. The ones used here are typical, gathered from many of the links listed at the bottom of the page. Therefore, it is incumbent upon the user to determine his own value based on a trusted source. Even NIST1 and CRC2 do not fully agree on bulk resistivity values for materials as well-known as copper and aluminum. Most common conductors used in cabling have a relative permeability of very near unity (1).
(click here for the equation for skin depth)
(click here for a skin depth calculator)
| Material | Chemical Formula | Bulk Resistivity @20C µΩ×cm (Ω×10-8m) | Relative Permeability μ/μ0 | Skin Depth (µm@f) | |||||
| 1 MHz | 10 MHz | 100 MHz | 1 GHz | 10 GHz | 100 GHz | ||||
 | |||||||||
| Aluminum | Al | 2.65 | 1 | 81.9 | 25.9 | 8.19 | 2.59 | 0.819 | 0.259 |
| Beryllium | Be | 3.3 | 1 | 91.4 | 28.9 | 9.14 | 2.89 | 0.914 | 0.289 |
| Brass | Cu70/Zn30 | 7 | 1 | 133 | 42.1 | 13.3 | 4.21 | 1.33 | 0.421 |
| Bronze | Cu89/Sn11 | 15 | 1 | 195 | 61.6 | 19.5 | 6.16 | 1.95 | 0.616 |
| Carbon | C (graphite) | 1375 | 1866 | 590 | 187 | 59.0 | 18.7 | 5.90 | |
| Cadmium | Cd | 7.3 | 136 | 43.0 | 13.6 | 4.30 | 1.36 | 0.430 | |
| Chromium | Cr | 13.2 | 1 | 183 | 57.8 | 18.3 | 5.78 | 1.83 | 0.578 |
| Cobalt | Co | 6.34 | 600 | 5.8 | 1.6 | 0.52 | 0.16 | 0.052 | 0.016 |
| Constantan | Cu60Ni40 | 49 | 352 | 111 | 35.2 | 11.1 | 3.52 | 1.11 | |
| Copper | Cu | 1.69 | 1 | 65.4 | 20.7 | 6.54 | 2.07 | 0.654 | 0.207 |
| Dural | Al95/Cu 4/Mg 1 | 5 | 112.54 | 35.6 | 11.3 | 3.56 | 1.13 | 0.356 | |
| Gallium | Ga | 15.5 | 198 | 62.7 | 19.8 | 6.27 | 1.98 | 0.627 | |
| Gold | Au | 2.2 | 1 | 74.7 | 23.6 | 7.47 | 2.36 | 0.747 | 0.236 |
| Graphite | C | 783.7 | 1409 | 446 | 141 | 44.6 | 14.1 | 4.46 | |
| Inconel alloy 600 | Ni72/Cr16/Fe 8 | 103 | 1 | 511 | 162 | 51.1 | 16.2 | 5.11 | 1.62 |
| Indium | In | 8.8 | 149 | 47.2 | 14.9 | 4.72 | 1.49 | 0.472 | |
| Iridium | Ir | 5.1 | 114 | 35.9 | 11.4 | 3.59 | 1.14 | 0.359 | |
| Iron | Fe | 10.1 | 500 | 7.2 | 2.3 | 0.72 | 0.23 | 0.072 | 0.023 |
| Lead | Pb | 20.6 | 1 | 228 | 72.2 | 22.8 | 7.22 | 2.28 | 0.722 |
| Lithium | Li | 9.29 | 153 | 48.5 | 15.3 | 4.85 | 1.53 | 0.485 | |
| Magnesium | Mg | 4.2 | 1 | 103 | 32.6 | 10.3 | 3.26 | 1.03 | 0.326 |
| Mercury | Hg | 95.9 | 1 | 493 | 156 | 49.3 | 15.6 | 4.93 | 1.56 |
| Molybdenum | Mo | 5.7 | 1 | 120 | 38.0 | 12.0 | 3.80 | 1.20 | 0.380 |
| Monel alloy 400 | Ni65/Cu33/Fe 2 | 49 | 352 | 111 | 35.2 | 11.1 | 3.52 | 1.11 | |
| mu-Metal | 47 | 30,000 | 2.0 | 0.64 | 0.20 | 0.064 | 0.020 | 0.0064 | |
| Nickel | Ni | 6.9 | 200 | 9.3 | 3.0 | .093 | 0.30 | 0.093 | 0.030 |
| Nichrome | Ni80/Cr20 | 108 | 523 | 165 | 52.3 | 16.5 | 5.23 | 1.65 | |
| Palladium | Pd | 10.8 | 1 | 165 | 52.3 | 16.5 | 5.23 | 1.65 | 0.523 |
| Platinum | Pt | 10.58 | 1 | 164 | 51.8 | 16.4 | 5.18 | 1.64 | 0.518 |
| Potassium | K | 6.8 | 131 | 41.5 | 13.1 | 4.15 | 1.31 | 0.415 | |
| Rhodium | Rh | 4.7 | 1 | 109 | 34.5 | 10.9 | 3.45 | 1.09 | 0.345 |
| Silver | Ag | 1.63 | 1 | 64.3 | 20.3 | 6.43 | 2.03 | 0.643 | 0.203 |
| Sodium | Na | 4.9 | 111 | 35.2 | 11.1 | 3.52 | 1.11 | 0.352 | |
| Steel | 100 | ||||||||
| Tantalum | Ta | 13.5 | 185 | 58.5 | 18.5 | 5.85 | 1.85 | 0.585 | |
| Tantalum Nitride | TaN | 252 | 799 | 253 | 79.9 | 25.3 | 7.99 | 2.53 | |
| Tin (pure) | Sn | 12.6 | 1 | 179 | 56.5 | 17.9 | 5.65 | 1.79 | 0.565 |
| Titanium | Ti | 54 | 1 | 370 | 117 | 37.0 | 11.7 | 3.70 | 1.17 |
| Tungsten | W | 5.4 | 1 | 117 | 37.0 | 11.7 | 3.70 | 1.17 | 0.370 |
| Urnaium | U | 27 | 262 | 82.7 | 26.2 | 8.27 | 2.62 | 0.827 | |
| Yttrium | Y | 53 | 366 | 116 | 36.6 | 11.6 | 3.66 | 1.16 | |
| Zinc | Zn | 5.96 | 123 | 38.9 | 12.3 | 3.89 | 1.23 | 0.389 | |
| Zirconium | Zr | 44 | 334 | 106 | 33.4 | 10.6 | 3.34 | 1.06 | |
1: National Institute of Standards and Technology
2: Chemical Rubber Corporation
HyperPhysics Reference
hyperphysics.phy-astr.gsu.edu/hbase/Tables/rstiv.html
Institute of Science Technology
www.istonline.org.uk/Handbook.htm
Hamilton Precision Metals
http://www.hpmetals.com/metals.php
IMI Scott Ltd
www.imiscott.co.uk/reswire_table.html
H Cross Company
hcrosscompany.com/metals/metals.htm
WebElements Periodic Table
The Cemtach Group
http://www.cemtach.com/cgi-bin/emMaterialSearch.cgi?order_by=mur&order=321&page=2
Webmaster: Kirt Blattenberger, BSEE, UVM 1989