| Abstract | A limiting feature of the plasma spray process is the need for the powder to melt during its passage through the plasma flame. It is quite impossible to obtain coatings with materials that are difficult to melt. However, metal borides, particularly titanium boride, are attractive. Because of their high melting point, satisfactory coatings based on these materials have not been achieved.
To overcome this problem, a process for making TiB₂-Fe coatings was studied. The TiB₂-based coatings were produced by the reaction of ferrotitanium with boron. The TiB₂ formation was first studied by thermal differential analysis and X-ray diffraction. It was observed that TiB₂ is formed at low temperature by an exothermic reaction. The characteristics of the reaction products obtained at different reaction temperatures are described.
Agglomeration techniques were used to prepare the reagents: fine powders of ferrotitanium alloy and boron. TiB₂-Fe coatings were produced by plasma spraying the agglomerated powders. The influence of the plasma spray process parameters and the powder preparation techniques on the coating microstructure is discussed.
Thick hard coatings comprising compounds of the reagent materials are produced during spraying by this synergetic process. Such coatings may be suitable for wear resistance applications. |
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