Hot plating wire is a common metal surface treatment method, which can provide a protective coating for the metal surface, thereby enhancing the corrosion resistance and beauty of the metal. However, in the process of hot plating wire, the adhesion between the coating and the substrate is crucial, which will directly affect the quality and performance of the coating. This paper will analyze and discuss the adhesion of hot plated wire from the aspects of the definition of adhesion, testing method and influencing factors.
I. Definition and test method of adhesion
Adhesion refers to the bonding strength between the coating and the substrate. The strength of the adhesion can be assessed by a number of physical or chemical methods. Some of the more common methods include:
1. Shear strength test method: Use a tensile test machine to cut the coating away from the substrate, measure the thickness and area of the coating leaving the substrate, so as to calculate the shear strength.
2. Abrasion test method: use tools such as scraper and grinding wheel to scrape or wear the coating, and then observe the change of the coating and whether there is peeling between the coating and the substrate.
3. Microscopic observation method: Using electron microscope, SEM and other tools to observe the combination between the coating and the substrate, and find the defects, holes, cracks and other conditions between the coating and the substrate.
Second, the factors affecting the adhesion of hot plated wire coating
1. Surface roughness of the substrate: the surface roughness of the substrate is an important factor affecting the adhesion of the coating. The greater the surface roughness, the greater the contact area between the coating and the substrate, and the stronger the adhesion. Therefore, the substrate needs to be polished, sandblasted and other surface treatment before hot plating wire.
2. Surface treatment before and after hot plating wire: It is necessary to clean the surface of the substrate and remove the oxide film before hot plating wire, so as to facilitate the combination between the coating and the substrate. At the same time, after the formation of the coating, it is also necessary to perform surface treatment for reinforcement. For example, the surface can be passivated by electrochemical deposition and other methods to remove the chemical reaction between the substrate and the environment.
3. Coating material and thickness: The selected coating material and thickness will also affect the adhesion. Common coating materials are nickel, chromium, zinc and other different types. In addition, in the case of the same material, the greater the thickness of the coating, the contact area will also increase accordingly, thereby increasing the adhesive force between the coating and the substrate and enhancing the adhesion.
4. Heat treatment process: Heat treatment is an important process that affects the adhesion of hot plated wire. During heat treatment, the coating will expand and expand due to the change of temperature and the change of environment, which will affect the adhesion. If the heat treatment is not proper, it will lead to separation and peeling between the coating and the substrate. Therefore, it is necessary to pay attention to the control of process parameters and environment during heat treatment.
Post time: 01-02-24