What Is The Adhesion of Thermal Spray Coatings To Different Materials

The adhesion of thermal spraying coating on different materials is affected by many factors, including the type of substrate material, surface pretreatment, spraying process parameters and the choice of coating material. The following is a general overview of the adhesion of several common base materials to thermal spray coatings:

1, steel: steel is a commonly used matrix material, thermal spraying coating and its binding force is strong. Pretreatment, such as sandblasting to Sa2.5 grade or above, can significantly enhance the adhesion of the coating.

2, aluminum alloy: Aluminum alloy surface is easy to form a natural oxide film, affecting the coating adhesion. The adhesion can be improved by chemical cleaning and blasting pretreatment of glass-ceramics beads. Specific materials such as nickel-coated aluminum powder can effectively improve the bonding strength between the coating and aluminum.

3, titanium alloy: titanium alloy surface also has an oxide layer, requiring strict pretreatment to ensure adhesion. After ultrasonic cleaning, pickling, sandblasting, etc., suitable materials such as nickel-based alloy or ceramic coating can be applied to obtain satisfactory results.

4. Cast iron: The surface of cast iron is rough, and the combination of coating and cast iron can be improved by flame spraying preheating and selecting appropriate alloy materials such as cobalt-based alloy.

5, ceramic material: ceramic material itself is more brittle, thermal expansion coefficient and metal difference, poor adhesion. The selection of matching transition layer materials (such as molybdenum, nickel) and low temperature spraying process help to improve adhesion.

6, composite materials: composite materials such as fiber reinforced plastics, need to be coated with metal bottom, and then spray the required coating to ensure adhesion.

The main influencing factors are as follows:

1, surface roughness: the micro-roughness generated by pretreatment is conducive to mechanical occlusion and increase adhesion.

2. Thermal matching between coating and substrate: materials with similar thermal expansion coefficient can reduce thermal stress and reduce stripping risk.

3, spraying process: temperature, nozzle distance, spray Angle, shot blasting material, etc., will affect the coating quality.

4, post-treatment: cooling rate, sealing treatment and other steps can also affect the adhesion.

5, material compatibility: the coating material should be matched with the substrate to avoid chemical reaction or excessive diffusion and ensure the stability of the interface.

It is an important step to evaluate the properties of substrate materials and select suitable coating materials and processes to ensure the adhesion of thermal spraying coatings. In practice, it is often necessary to experiment and accumulate experience, and constantly optimize to achieve good adhesion effect.