The discussion centers on the conductivity of aluminium surfaces protected by a thin aluminium oxide layer. Despite the oxide layer's insulating properties, contact resistance measurements using a multimeter reveal consistently low resistance values, attributed to the oxide layer's thinness and its susceptibility to puncturing under low voltage conditions. Experimental results indicate a contact resistance of 2Ω across a current range of 1 to 100 mA, demonstrating linear behavior without hysteresis. This suggests that the oxide layer does not significantly impede electrical conductivity when proper testing methods are employed.
PREREQUISITESElectrical engineers, materials scientists, and anyone involved in the study of conductive materials and their properties will benefit from this discussion.
The oxide layer is extremely thin, typically up to about https://www.surrey.ac.uk/mes/files/Castle_paper2.pdf. For such thin layers, the breakdown voltage is well within the voltage range that a multimeter can reach (for example a breakdown voltage of 6V is reported http://photonics-benelux.org/proc08/s08p195.pdf for a 10nm crystalline sample)spareine said:Aluminium surfaces are protected by a thin aluminium oxide layer. The oxide layer supposedly does not conduct electricity. However, when measuring the contact resistance between the test pen of a multimeter and the aluminium, this resistance is always small. Why? Is the oxide layer easily punctured?
What is the smallest current range on your multimeter?spareine said:Aluminium surfaces are protected by a thin aluminium oxide layer. The oxide layer supposedly does not conduct electricity. However, when measuring the contact resistance between the test pen of a multimeter and the aluminium, this resistance is always small. Why? Is the oxide layer easily punctured?