Abstract
PS304 is a NASA-developed composite solid lubricant for friction and wear reduction at high temperatures. The microstructure, physical properties, and tribological performance of PS304 using standard comminuted BaF2-CaF2 and novel gas atomized BaF2-CaF2 were compared. Two atomized BaF2-CaF2 particle size distributions were used. Overall, feedstock powder with atomized BaF2-CaF2 flowed more freely than standard PS304 feedstock. The cohesion strength of coatings with atomized BaF2-CaF2 was lower than that of standard PS304, while the hardness of all of the studied coatings was essentially the same (approximately 58 HRA). Pin wear was lower against the new coatings and the coefficients of friction were essentially the same for all coatings. These results indicate that atomized BaF2-CaF2 can be substituted for comminuted BaF2-CaF2, providing a high-volume BaF2-CaF2 fabrication technique to reduce the cost of PS304 and improve its commercial availability.
ACKNOWLEDGEMENTS
Thank you to Brian J. Edmonds, Jerome Singleton, and to the late Victor Lukaszewicz for technical assistance during this investigation. The helpful discussions with Dr. Christopher DellaCorte are also greatly appreciated.
Review led by Thierry Blanchet