Thermal spraying is a method of coating materials in which fine particles of metallic or non-metallic materials are sprayed onto a surface in molten or semi-molten state, forming a coating. Coating material may consist of powder, ceramic rod, wire or molten materials.
Methods of Thermal Spraying
- Molten metal flame spraying: Material sprayed is in molten form.
- Ceramic rod flame spraying: Material sprayed is in ceramic rod form.
- Powder flame spraying: Material sprayed is in powder form.
- Cold spraying: Materials sprayed is close to room temperature. Unmelted particles plastically deform and join upon impact with the work piece to form a coating.
- Electric arc spraying: An arc is struck between two consumable electrodes consisting of coating materials. Compressed gas atomizes and carries the materials to the work piece.
- High-velocity oxy/fuel spraying: Oxygen is combined with various fuel gases in a combustion chamber and expelled onto a work piece at a very high velocity. Shock diamonds are often produced when the materials exit the spray gun.
- Plasma spraying: A nontransferred arc heats and ionizes a gas, which is used to melt a coating material and deliver it to a work piece.
- Detonation flame spraying: A combination of fuel gas, oxygen and powdered coating liquefies and is applied to the work piece via a controlled explosion.