Ceramic nozzles meter, direct or atomise a fluid, a gas or an abrasive stream. The orifice is the whole point of the part.
Alumina nozzles are the economical choice for general spray and dispensing duty, including corrosive fluids at moderate velocity. They hold the orifice to ±0.005 mm and are unaffected by most process chemicals.
Alumina is the default engineering ceramic. It combines high hardness (1500-1700 HV) with good electrical insulation and chemical inertness at a lower cost than most technical ceramics, and in 99.8% purity it holds strength to 1700°C while resisting most acids, alkalis and solvents.
It is not the toughest option. At 3-4 MPa·m½ fracture toughness, sharp impact or point loading will chip an edge, so chamfers and radii belong in the drawing from the start.
Specifications
| Orifice diameter | 0.1-10 mm |
| Orifice tolerance | ±0.005 mm |
| Outer diameter | 5-60 mm |
| Length | up to 150 mm |
| Orifice concentricity | 0.01 mm |
| Bore finish | Ra 0.4 µm |
| Entry | radiused, conical or sharp edge |
Alumina Properties
| Composition | Aluminium oxide, 96% / 99.5% / 99.8% |
| Density | 3.70-3.95 g/cm³ |
| Vickers hardness | 1500-1700 HV |
| Flexural strength | 300-400 MPa |
| Fracture toughness | 3-4 MPa·m½ |
| Max. service temperature | 1500°C (99.8%: 1700°C) |
| Thermal conductivity | 25-35 W/m·K |
| Thermal expansion (20-1000°C) | 8.0 ×10⁻⁶/K |
Machining and Tolerances
Nozzles are turned and ground from solid stock rather than cast, because bore and outside have to be concentric. Orifices below about 0.5 mm are produced by precision drilling or laser, and the entry is radiused rather than sharp so the flow does not separate.
Where It Is Used
- Abrasive blasting and slurry spray nozzles
- Burner and plasma torch nozzles
- Atomising nozzles for coating and humidification
- Precision dispensing tips in fluid handling
- High-wear spray tips in scrubber and desulphurisation systems
Frequently Asked Questions
How small an orifice can you produce?
Down to about 0.1 mm depending on material and length. Small deep holes are the hardest features to hold, so we normally discuss the length-to-diameter ratio before quoting.
Which material wears longest in abrasive service?
Boron carbide then silicon carbide for pure abrasion, and silicon nitride where impact and thermal shock are present too. We match the material to the abrasive, the velocity and the fluid rather than defaulting to the hardest option.