Preparation and Characterization of Powders and Coatings Containing Solid Lubricants

In this work, HVOF sprayed hard metal multi-component Cr₃C₂-25Ni+10 vol-% solid lubricant coatings were prepared by HVOF spraying. CaF₂, BN, MnS and WS₂ were used as solid lubricants. Powders were prepared by the spray drying and sintering method. This method produces homogeneous and spherical powders. Powders were sprayed with DJH 2600 HVOF-system. Microstructures, phase structures and compositions of powders and coatings were analysed with optical microscope, scanning electron microscope with EDS-analysator and x-ray diffractometer. The particle size distributions of sintered powders were determined by laser diffractometer. The amount of retained solid lubricant in the sprayed coatings was evaluated by EDS and compared to that in the spray powder. This study showed that spray drying and sintering method is a preferable method for manufacturing multi-component solid lubricant containing thermal spray powders. In sintering processes, solid lubricant phases remained in powders except for the Cr₃C₂-25Ni+10vol-%WS₂-powder. Also, after HVOF spraying, coatings contained solid lubricants.