ICORROSION PROBLEMS N HELICOPTERS
ENTROPY Entropy is a term for a thermodynamic property of materials and is defined as the measure of the disorder or randomness of a system. Coined in 1865 by German physicist Rudolph Clausius in his work on the laws of thermodynamics, it’s from the Greek entropia meaning “a turning toward.” In a nutshell, it refers to the fact that over time, without the input of energy, everything becomes (turns toward) a less organized state and continues to a level where all substance would be evenly random. Think of your garden. If you prep it and plant it but then never touch it again, it will not be the garden of your dreams. Entropy is not a lighthearted subject. In the grand scheme of things it means that everything in the universe will ultimately be randomly and evenly distributed. If you put a paper bag of salt water
JON ROBBINS | CONTRIBUTING AUTHOR AS WE SAY IN THE HELICOPTER BUSINESS, “OXIDANTS WILL HAPPEN.”
into a container of fresh water, over time the high concentration of salt will eventually be equal, both inside the bag and outside the bag. Another analogy is that you can’t get the air back in the balloon (without doing work) once you have let it out, and it will leak out over time even if you don’t let it out. It’s almost as if from the time they are built, helicopters are slowly and continuously trying to take themselves apart. Ashes to ashes, dust to dust.
HOW CORROSION HAPPENS Corrosion of a material starts with something into which a good deal of energy was placed and with no further input made to retard or resist it, causes that material to become less organized and in fact, revert to its base components. Corrosion of metals is more likely when they are alloyed than when they are in pure
26
HelicopterMaintenanceMagazine.com August | September 2019
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44
