In order to obtain higher energy efficiency and greater thrust, and heavy duty gas turbine engine turbine inlet temperature is as high as 1600 degrees above, only on the improvement of the performance of the materials and the improvement of structure design, has been unable to meet the rapid development of aviation engine and gas turbine industry needs
In order to obtain higher energy efficiency and greater thrust, and heavy duty gas turbine engine turbine inlet temperature is as high as 1600 degrees above, only on the improvement of the performance of the materials and the improvement of structure design, has been unable to meet the rapid development of aviation engine and gas turbine industry needs, high temperature protective coating technology is essential. Zirconia thermal barrier coating, the fourth generation of high temperature protective coating, has been applied in some high temperature parts of aero-engines (guide blade, flame cylinder, heat shield, etc.), and has achieved good results.
Steam turbine is one of the three main engines in thermal power plant -- boiler, steam turbine and generator. It is composed of rotating part and fixed part. The rotating part is composed of impeller, spindle, coupling and blade; The fixed part consists of nozzle, cylinder, seal, baffle, fastener, bearing, etc. In the process of thermal power generation, it is the steam turbine that converts heat into mechanical energy. In the process of power generation, the efficiency of the power plant and the safety of the unit will be affected by the steam turbine. In the operation of the turbo-generator unit, after the steam enters the turbine, due to various impurities carried into the turbine by the steam, scale corrosion will be formed. In particular, the final blade operates under extremely harsh conditions, and is subjected to the combined action of high temperature, high pressure, centrifugal force, steam force, steam excitation force, corrosion and vibration, and water droplet erosion in the wet steam area. The damage is even more pronounced. And with the increase of load, due to the superheated steam carrying impurities, more and more serious corrosion, salt accumulation occurs in the turbine blade, the unit's safe operation and efficiency are more and more significantly affected.
When the steam turbine starts up, if the superheated steam quality does not meet the required standards, if it is put into operation, the salt will enter the steam turbine through the dissolution and carrying of the steam, and gradually deposit on the steam turbine blades at all levels, increasing the weight of the blades and affecting the steam turbine output; Uneven salt accumulation will also cause uneven weight, which is likely to cause vibration. Corrosion of blades under scaling will seriously damage the material and strength of blades, which is easy to cause malignant accidents during the operation of steam turbines.
The service life of turbine blade can be improved effectively by using supersonic spraying cermet coating. Adopt repair welding, sandblasting, spraying transition layer, spraying layer, coating sealant, blade protection process method. With the combination of coating and blade surface has high strength, does not fall off, the coating life can reach more than four years, but also has reduced the use of 1/3 ~ 1/6 cost, suitable for the blade in wet steam area and low load working conditions of the final stage blade, new and old blade can be applied.
