Does the surface need to be polished when using ceramic epoxy coating?

In the field of industrial equipment wear protection, wear-resistant ceramic particle adhesives, with their excellent wear and impact resistance, are widely used for the repair and pre-protection of equipment such as fan impellers, chutes, and pump casings. However, the root cause of many application failures lies not in product quality issues, but in neglecting the most basic and critical step: substrate pretreatment.

Substrate Pretreatment
1. Decontamination: Remove contaminants such as oil, grease, moisture, and dust from the substrate surface. These substances form a barrier layer, severely weakening the bond between the adhesive and the substrate.
2. Oxidation Layer/Old Coating Removal: For metal substrates, remove rust and oxide layers; for concrete substrates, remove laitance and loose surface layers. If old coatings exist on the substrate surface, they must be completely removed. These weak layers have poor adhesion and can cause the adhesive layer to separate from the underlying layer.
3. Desmoothing: Create a rough, clean, and fresh application surface through sanding. This significantly increases the effective bonding area (typically by several to dozens of times), providing a foundation for mechanical interlocking. 4. Activation Enhancement: Roughening the surface significantly increases the surface energy of the substrate, enabling better wetting and spreading of the adhesive, and forming strong intermolecular forces.

Even with the best ceramic granule adhesive, an improperly treated substrate is like building a wall on smooth glass, inevitably leading to weak adhesion and premature delamination.

Key Inspection Criteria After Pretreatment

After pretreatment, the substrate must meet the following criteria to determine if it is acceptable. Otherwise, retreatment is required:

1. Cleanliness Inspection: Wipe the treated substrate surface with a clean, dry cloth. If no stains, dust, or residue are visible, the cleanliness meets application requirements.

2. Roughness Inspection: The surface of the metal substrate should exhibit a uniform matte finish without glossy reflections. Concrete substrates should have a solid internal aggregate structure visible. Smooth substrates such as stone or tile should have a matte finish and a noticeable roughness to the touch. When this condition is achieved, the roughness is considered acceptable.

3. Dryness Inspection: The moisture content of the concrete substrate can be measured using specialized instruments to ensure it is fully dry. Other substrates can be inspected for signs of moisture. If the ambient humidity is high, appropriate measures should be taken to extend the drying time or provide additional heating to ensure the substrate reaches the required dryness for application.

After all pretreatment steps have been completed, the application of the wear-resistant ceramic granule adhesive should be completed within the specified timeframe to prevent secondary contamination of the substrate surface and the effects of ambient humidity. If, for any reason, application is delayed and the interval exceeds the specified timeframe, the substrate surface must be re-dusted and re-inspected for cleanliness and dryness before application can resume.