Before deciding which coating configuration to offer on Alibaba.com, suppliers must understand the technical characteristics of plasma spray alumina. This section breaks down the key properties that buyers evaluate when sourcing ceramic coatings.
Plasma Spray Alumina Coating: Technical Specifications from Leading Suppliers
| Property | A&A Coatings LT-Al2O3 | A&A Coatings HT-Al2O3 | ASB Industries Al2O3 | Industry Standard Range |
|---|
| Composition | 98.5% Al2O3 | 98.5% Al2O3 |
99.5% Al2O3
| 97-99.5% Al2O3 |
| Deposition Temperature | 250°C | 530°C | Variable | 200-600°C |
| Hardness (DPH300) | 690 | 1100-1300 | 19-21 GPa | 600-1300 DPH |
| Coating Thickness | 4-6 μm | 1-3 μm | Up to 0.5mm | 50-500 μm |
| Density | 3.3 g/cc | 3.3 g/cc | 3.3-3.9 g/cc | 3.2-3.9 g/cc |
| Electrical Insulation | 300-400V per 0.001" | 300-400V per 0.001" |
1 GΩ (air)
| Varies by thickness |
| Max Operating Temp | 3000°F (1649°C) | 3000°F (1649°C) | 600°C tested | 1400-1700°C |
| Surface Finish (as sprayed) | 325-400 μin RMS | 325-400 μin RMS | Variable | 200-500 μin RMS |
| Porosity | Low | Low | <5% | 2-10% |
Data compiled from A&A Coatings
[4], ASB Industries
[5], and ScienceDirect research
[3]. LT = Low Temperature, HT = High Temperature. Note: Thickness limitations apply - coatings thicker than 0.5mm risk cracking and delamination
[4].
Key Technical Considerations:
1. Coating Thickness Limitations
A critical finding from supplier data is that plasma spray alumina coatings should not exceed 0.5mm (0.020") thickness. A&A Coatings explicitly warns that thicker coatings significantly increase the probability of cracking and delamination [4]. This is a common limitation across all fine ceramic powders, not unique to alumina.
Practical Implication for Suppliers: When listing products on Alibaba.com, clearly specify maximum achievable thickness and warn buyers about limitations. Over-promising on thickness capabilities leads to quality disputes and negative reviews.
2. Electrical Insulation Performance
Alumina's dielectric strength of 16 kV/mm [3] makes it suitable for electrical insulation applications. However, research shows that in plasma environments, coating performance can vary based on porosity and density. ScienceDirect research indicates that while alumina coatings show resistance >1 GΩ in air, dense layers are critical for maintaining dielectric strength under operational stress [3].
3. Hardness and Wear Resistance
The hardness range (600-1300 DPH300) positions alumina as a premium wear-resistant coating. HT-Al2O3 (high-temperature deposition) achieves significantly higher hardness (1100-1300 DPH) compared to LT-Al2O3 (690 DPH) [4]. This trade-off between deposition temperature and final hardness is important for buyers selecting coating specifications.
4. Surface Preparation Requirements
All suppliers emphasize that proper substrate preparation is critical. A&A Coatings notes that substrates must be cleaned to remove surface oxides, typically through light grit blasting, and a bond coat is required in most cases [4]. ASB Industries similarly emphasizes surface preparation for optimal adhesion [5].
Action Item for Alibaba.com Sellers: Include detailed surface preparation requirements in product listings. Buyers appreciate suppliers who provide complete technical documentation, not just price quotes.
A&A Coatings Plasma Sprayed White Alumina was designed for use in thin coatings, not more than .5mm (.020″) thick. If sprayed thicker, the probability of cracking and delamination will increase rapidly, as is the case of thick coatings of all fine powders [4].
