Our earth's interior - like the sun - provides incredibly high amounts of energy. This source of energy - geothermal energy - yields warmth and power that we can use without polluting the environment. Geothermal energy is one of the best natural energies around. Geothermal power plants are developed to harness the thermal energy stored within the earth’s crust. However, existing technologies to harvest this kind of energy can dramatically be improved, on a technical point of view. And thanks to the environmental friendliness of the geothermal energy it is now a political and strategic objective to improve these harvesting technologies. One major disadvantage of geothermal plants is the need for expensive metals to manufacture extraction components like pipes and joints. These specific metals are required due to the high level of corrosion met at such deepness in the ground. Currently, titanium alloy and stainless steel are commonly employed for dealing with these problems. But they are more expensive and require the application of corrosion-preventing passive oxide layers. Once they are corroded replacing these components is very costly and time consuming. In spite of these if inexpensive carbon steel components are used coated with cost-effective high-hydrothermal temperature stable & anti-corrosion materials, it will decrease the costs of operations and maintenance of the geothermal plant.