M. Parco, INASMET TECNICALIA, IRUN, Spain; G. Barykin, Inasmet, San Sebastian, Spain
The quality of thermal sprayed coatings is the complex results of a wide spectrum of parameters or spraying conditions. The coating quality is related essentially to the following two main characteristics: the heating behaviour experienced by each sprayed particle and its kinetic energy at the splashing instant.
From the industrial point of view the most important for the coatings developed for different industrial applications is to have the good quality-cost relationships: ensuring obtaining of a good coating quality at a reduced cost.
It was developed the new promising technology of the coating deposition the oxy-fuel ionisation (OFI) spray process that gives the coating structure and in-service properties similar to those obtained by HVOF spray guns of the third generation (DJH, JP-5000 etc.) but with 50 % reduced coating deposition costs through the much lower amounts of gases consumption necessary for spraying in comparison with HVOF spray techniques and increased OFI efficiency through the possibility to regulate process temperature by using different gas mixtures, additive inert gases and current.
The idea of the oxy-fuel ionisation (OFI) jet is to use the low calories gases such as methane or propane in combination with the ionised gas to reach the increasing of the thermal spray process temperature and by using air to reach process parameters control for receiving high velocity and stabile “cooled” flame.
The process regulated parameters are the level of the electrodes power (up to 400 A and 25-30 V); the oxygen flow rate in the range of 100-300 SLPM; the type and flow rate of the fuel gas (methane, propane, kerosene, etc.); air flow rate in the range of 250-300 SLPM.
The main benefits of the OFI process are reduction of the coating deposition cost by 50 %; reduction in gas consumption by 30-40 %; increasing in the spectrum of the spray parameters controls of the supersonic plasma OFI by using different gas mixtures, additive inert gases and current; increasing in verity of materials deposition starting from low melting Al and Cu without oxidation to metals, carbides and oxides.
Summary: It was developed the new promising technology of the coating deposition the oxy-fuel ionisation (OFI) spray process that gives the coating structures and in-service properties similar to those obtained by HVOF spray guns of the third generation (DJH, JP-5000 etc.) but with 50 % reduced coating deposition costs through the much lower amounts of gases consumption necessary for spraying in comparison with HVOF spray techniques and increased OFI efficiency through the possibility to regulate process temperature by using different gas mixtures, additive inert gases and current.
Performance of the coatings produced by oxy-fuel ionisation spraying in the engine components was compared with conventional thermal spraying technique such as HVOF and plasma.
