PRODUCTION OF WEAR-RESISTANT COBALT ALLOY POWDERS

Abstract

To select and optimize the experimental conditions for producing powders from wear-resistant cobalt alloys, the following methods were tested: gas spraying of the KhTN-37 alloy, centrifugal spraying of the KhTN-61 alloy, cryogenic spraying of the KhTN-61 alloy, and ultrasonic plasma atomization of the KhTN-62 alloy melt. The results of producing particles of different sizes and shapes, the difference between the experimental values of their sizes, and the possibility of using individual fractions taking into account the industrial production requirements were analyzed and summarized. The gas spraying method used for the KhTN-37 alloy does not allow producing the required amount of suitable powder, which affected the expediency of its use. The production of powder from the KhTN-61 alloy by the centrifugal spraying method is characterized by the formation of a significant number of spherical/needle particles in the dispersed material, which affects its flowability and complicates sieving. In addition, this method does not reliably protect the sprayed material against oxygen. The cryogenic spraying process for producing powders from the KhTN-61 alloy turned out to be unsuitable because of a change in its chemical composition. The method of ultrasonic atomization of the melt turned out to be the most acceptable for producing powders from the KhTN-62 alloy, which resulted in fine spherical powder with the required particle size. The use of this rapidly hardened powder in the development of wear- and heat-resistant surface layers on the responsible component of friction nodes in power equipment, in particular, aircraft structures, is promising. High-temperature wear-resistant alloys in the form of powders can be recommended for strengthening and restoring the surfaces of parts in friction nodes in aviation technology and for additive manufacturing of volumetric parts (3D printing), which are characterized by high wear resistance at elevated temperatures.