Is the coating on the oil film bearing easy to be knocked off?

Nov 25, 2024

The coating on the oil film bearing will not fall off with a touch. The firmness of the coating depends on many factors, including the selection of coating materials, the quality of the coating process, the pretreatment of the substrate, and the conditions of the use environment.

1. Coating materials and selection

The coating materials on the oil film bearing usually include metal coatings, alloy coatings, and hard coatings. The selection of these materials needs to be determined according to the working environment, load conditions, and performance requirements of the bearing.

Metal coatings: Metal coatings such as nickel and chromium have good corrosion resistance, wear resistance, and hardness. These materials are easy to form a dense crystalline structure during the coating process, thereby improving the firmness of the coating.

Alloy coatings: Alloy coatings are usually composed of two or more metal elements, such as copper-tin alloys, nickel-phosphorus alloys, etc. These alloy coatings not only have the advantages of metal coatings but also have good toughness and fatigue resistance.

Hard coatings: Hard coatings such as tungsten carbide (WC) and titanium nitride (TiN) have extremely high hardness and wear resistance. These coatings are usually formed on the surface of the substrate through processes such as physical vapor deposition (PVD) or chemical vapor deposition (CVD).

2. Plating process and quality

The cleanliness and roughness of the base material surface have a direct impact on the adhesion of the coating. The following are some key factors that affect the firmness of the coating:

Substrate pretreatment: The cleanliness and roughness of the substrate surface have a direct impact on the adhesion of the coating. Before coating, the base material needs to be thoroughly cleaned, degreased, rust removed and activated to ensure a good bond between the coating and the base material.

Plating solution formula and operating conditions: The formula and operating conditions of the plating solution (such as temperature, current density, pH value, etc.) have an important impact on the structure and performance of the coating. Reasonable plating solution formulas and optimized operating conditions can improve the uniformity and density of the coating, thereby improving the firmness of the coating.

Post-treatment: After the coating is completed, post-treatment is also required to improve the performance and firmness of the coating. For example, heat treatment of the coating can eliminate stress and improve the hardness and wear resistance of the material; sealing the coating can prevent corrosive media from penetrating the coating.

3. Matching of substrate and coating

The matching between the substrate and the coating is also one of the important factors affecting the firmness of the coating. When selecting coating materials, it is necessary to consider the composition, thermal expansion coefficient, hardness and other properties of the substrate to ensure good combination and coordination between coating and substrate.

Matching of thermal expansion coefficient: When the difference in thermal expansion coefficient between substrate and coating is too large, it is easy to cause cracks or peeling of the coating during temperature change. Therefore, when selecting coating materials, it is necessary to try to match the thermal expansion coefficient of the coating with the substrate.

Hardness matching: The difference in hardness between substrate and coating will also affect the firmness of the coating. If the hardness of the substrate is too high and the hardness of the coating is too low, the coating is easy to be squeezed and peeled off by the substrate. On the contrary, if the hardness of the substrate is too low and the hardness of the coating is too high, the coating is easy to crack when subjected to an external force.

4. Influence of use environment

The use environment of oil film bearing will also affect the firmness of the coating. The following are some common environmental factors and their effects on the firmness of the coating:

Temperature: High temperature environment will accelerate the oxidation and corrosion rate of the coating, thereby reducing the firmness of the coating. Therefore, oil film bearings used in high-temperature environments need to choose coating materials with high-temperature resistance.

Humidity: Excessive humidity will cause a water film to form on the surface of the coating, thereby accelerating the corrosion process. In addition, humidity will also reduce the firmness of the coating. Therefore, oil film bearings used in environments with high humidity need to choose coating materials with corrosion resistance.

Friction and wear: Oil film bearings are subject to friction and wear during operation. If the hardness of the coating is not high enough or the wear resistance is not good enough, it is easy to peel off or wear during the friction process. Therefore, when selecting the coating material, its wear resistance, hardness, and other properties need to be considered.

Chemical medium: Some chemical media will corrode the coating, thereby reducing the firmness of the coating. For example, corrosive media such as strong acids and strong alkalis will accelerate the corrosion rate of the coating. Therefore, oil film bearings used in chemical medium environments need to choose coating materials with corrosion resistance.

5. Measures to improve the firmness of the coating

In order to improve the firmness of the coating on the oil film bearing, the following measures can be taken:

Optimize the coating process: By optimizing the plating solution formula, operating conditions and post-treatment process, the uniformity and density of the coating can be improved, thereby improving the firmness of the coating.

Select suitable coating materials: According to the working environment, load conditions and performance requirements of the oil film bearing, selecting suitable coating materials can improve the firmness and service life of the coating.

Strengthen the pretreatment of the substrate: Thoroughly cleaning, degreasing, rust removal and activation on the substrate can improve the bonding force between the coating and the substrate, thereby improving the firmness of the coating.

Improve the use environment: By reducing the impact of environmental factors such as temperature and humidity on the coating, the service life of the coating can be extended, and its firmness can be improved. For example, in a high-temperature environment, a lubricating oil with high-temperature resistance can be used to reduce the impact of temperature on the coating.

Regular inspection and maintenance: Regular inspection and maintenance of oil film bearings, timely detection and treatment of problems such as coating peeling or wear, can extend the service life of the coating and improve the reliability of the entire equipment.

In summary, the coating on the oil film bearing will not fall off at the touch of a finger. Its firmness depends on the combined effect of many factors. By optimizing the coating process, selecting suitable coating materials, strengthening the pretreatment of the substrate, improving the use environment, and regular inspection and maintenance, the firmness and service life of the coating on the oil film bearing can be improved.