Experiments on life cycle extensions of geothermal turbines by multi composite technology

• Multi composite powders and plasma spraying will be used for geothermal turbines life extension.
• Plasma spraying provides high wear, corrosion resistance, technologically is very flexible.
• Ceramic coatings were tested for elasticity modulus the influence of heat flux.

These days, many countries are involved in evaluation and development of geothermal projects, and this includes the installation and maintenance of geothermal steam turbine. High reliability and maintainability are required as a basic condition for the geothermal turbines and energetic components in order to provide a stable power supply. For increasing the reliability of geothermal steam turbines the lifespan assessment of materials under geothermal environment conditions is important. A leading cause of reduced availability in geothermal power plant, non-conventional energetic systems’ components is corrosion damages in turbines, especially blades and rotors corrosion. Improved turbine mechanical integrity and increased rotor steam-turbine life cycle demand optimization is achieved thermal spray depositing using multi composite systems. This specific paper objective is design and synthesis of new complex powder mixtures NiCr/NiCoCr with different addition of ZrO2 stabilized with Y2O3 that can be used to obtain protective layers with improved wear, thermal shock and abrasion resistance. These coating will be studied also in “in situ” conditions, in Hellisheiði geothermal system, to investigate the actual effects of geothermal steam on the surface coated with multi-composite structures. The results will be reported in a future paper for comparing laboratory and “in situ” conditions tests results.