1. Physical feasibility
Basic reflective properties
Although the surface of raw aluminum (unoxidized) is reflective, its reflectivity can only reach about 80%~85% (lower than the 95% or more of silver/chrome), presenting a blurred mirror effect.
Through mechanical polishing (sandpaper polishing to 3000 mesh or more) combined with chemical polishing (such as phosphoric acid-sulfuric acid mixture), the surface roughness can be reduced to Ra≤0.01μm, achieving near-mirror reflection (reflectivity increased to ≥90%).
Process Flow Comparison
| Process Stage | Traditional Mechanical Polishing | Chemical-Mechanical Composite Polishing (CMP) |
|---|---|---|
| Surface Pretreatment | Coarse sandpaper (80~240 mesh) to remove the oxide layer | Acid degreasing (pH = 2.5 ~ 3.5) to clean the surface |
| Intermediate Treatment | Step-by-step fine grinding (400~3000 mesh sandpaper) | Nano-alumina abrasive suspension circulation polishing |
| End Point Detection | Visual inspection of gloss (experience-based judgment) | White light interferometer to measure roughness (Ra ≤ 0.01μm) |
| Time Consumption | 6–8 hours (manual operation) | 2–3 hours (automated processing line) |
Selection guide for aluminum materials suitable for mirror polishing
I. High-purity aluminum series (1xxx series)
Recommended grades: 1050 H18 Aluminum Mirror Sheet, 1060 H18 Aluminum Mirror Sheet, 1100 H18 Reflector Aluminum Sheet
Mirror reflectivity: Through precision rolling and polishing composite process, the reflectivity can reach 85%-95% (ordinary aluminum plate is only 30%-50%)
Applicable scenarios: building decoration curtain wall, high reflectivity industrial equipment panel
Technology points: Need to be matched with mechanical polishing (sandpaper grinding step by step) + electrolytic polishing to control the surface roughness Ra≤0.01μm
2. Manganese alloy (3xxx series)
Recommended grade: 3003
Surface treatment: Support mechanical polishing + chemical polishing, can achieve Ra≤0.02μm mirror effect
Elongation performance: Elongation ≥25%, suitable for secondary polishing after stamping (such as curved decorative parts)
