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 production of particles in different sizes and shapes, the difference between the experimental values of their sizes, and the potential of using individual size fractions taking into account the industrial production requirements were analyzed and summarized. The gas spraying method used for the KhTN-37 alloy did not yield the required amount of suitable powder and was thus inexpedient. The centrifugal spraying method for the production of KhTN-61 alloy powders was characterized by a significant number of spherical/needle particles formed in the sprayed material, affecting its flowability and complicating sieving. In addition, this method did not reliably protect the sprayed material against oxygen. The cryogenic spraying process for producing KhTN-61 alloy powders turned out to be unsuitable because it changed the chemical composition. The method involving melt ultrasonic atomization turned out to be the most acceptable for producing KhTN-62 alloy powders. It yielded a fine spherical powder with the required particle size. The use of this rapidly hardened powder is promising for the development of wear- and oxidation-resistant surface layers on responsible components of friction units in power equipment, particularly in aircraft structures. The high-temperature wear-resistant alloy powders can be recommended for strengthening and restoring the surfaces of components in friction units in aviation equipment and for additive manufacturing of bulk parts (3D printing), possessing high wear resistance at elevated temperatures.