Thermal Spray Coating Formations. Thermal spray coatings are produced by the injection of powders, usually in the range of 5 to 50 micron diameter, and/or wire and rod feedstocks into a hot gas jet, through which they travel andare subsequently deposited onto a relatively cool substrate. The total dwell time for particles, which travel at speeds ranging from approximately 75 m/s to almost 1000 m/s for the high velocity processes. The buildup of thermal spray deposite is show in figure as below. Depending on their size, chemistry, phase and trajectory in the spray jet, arriving particle will be either fully or partially molten or unmelted.
Testing and characterization of thermal spray coating
- Oxide content
- Wear test
- Corrosion test
- Adhesion test