(Science and Technology on Advanced High Temperature Structural Materials Laboratory, AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China)
Nowadays gas atomization is the main technology for large-scale preparation of high-quality alloy powder. The gas-atomized powders possess the advantages of homogeneous composition, narrow particle size distribution, low impurity gas content, low inclusion level and high sphericity. It is widely applied in the fields such as powder metallurgy, additive manufacturing, thermal spraying and brazing. The atomization process determines powder quality, therefore it is significant to study the atomization process. The traditional methods mostly use the contact measurement technology through indirect experiments, which have many disadvantages such as time consuming, high cost, difference with actual conditions, and difficulty of carrying out transient process research, and bring less guidance to the study of atomization mechanism and the structure design of atomization system. In recent years, scholars have utilized some non-contact measurement experiments used in the field of hydrodynamics. According to the classification of the research objects, the non-contact measurement techniques adaptive for the study of flow field morphology, velocity distribution, droplet size distribution and temperature field are summarized, the principles of these techniques and some related applications are introduced, the future development direction of the measurement techniques for gas atomization process is prospected.