Metal-Backed Alumina Ceramic Grinding Ring for High-Rigidity Lapping Applications
St.Cera’s metal based alumina grinding ring combines a high-purity alumina (99.8% Al₂O₃) ceramic wear layer with a precision-machined metal backing (typically aluminum or stainless steel). This hybrid design provides the exceptional wear resistance and chemical inertness of ceramic on the grinding surface, while the metal base adds mechanical strength, easy mounting, and resistance to brittle fracture. The alumina layer offers flexural strength of 361 MPa, Vickers hardness of 16 GPa, and thermal stability up to 800°C. The metal base is customized with mounting holes, locating pins, or magnetic properties for integration into lapping machines, planetary grinders, and CMP equipment.
Specifications (Alumina layer based on 99.8% Al₂O₃):
| Property | Value |
| Material | 99.8% Alumina (Ivory) |
| Density | 3.93 g/cm³ |
| Flexural Strength | 361 MPa |
| Vickers Hardness | 16 GPa |
| Fracture Toughness | 3–4 MPa·m¹/² |
| Thermal Expansion (25-1000°C) | 7.2×10⁻⁶/℃ |
| Surface Finish (grinding face) | Ra ≤0.4 μm (lapped) |
| Flatness | ≤5 μm over 100mm |
| Typical Materials | Aluminum 6061, Stainless Steel 304/316 |
| Bonding Method | High-temp epoxy or mechanical clamping |
| Thickness | 5–20 mm (customer specified) |
Note: Metal base properties (density, Young’s modulus, etc.) are not provided in the supplied ceramic material tables. They follow standard industry data for aluminum/steel. Please specify metal type and mounting requirements.
Applications:
● Planetary lapping machine grinding rings
● CMP (chemical mechanical polishing) backing rings
● Precision flat lapping of ceramic or metal seals
● Abrasive wear test fixtures
Manufacturing Process:
1. Alumina ceramic ring is sintered from 99.8% powder and precision ground to final ID/OD and flatness.
2. Metal base is CNC machined with mounting holes, counterbores, or keyways.
3. Ceramic ring is bonded to metal base using high-strength epoxy (service temp ≤200°C) or mechanically clamped (allows higher temp, up to 500°C if using metal shims).
4. Final lapping of the ceramic surface to achieve required flatness and surface finish.
5. Ultrasonic cleaning and 100% dimensional inspection.
Quality Control:
● CMM inspection of ID, OD, thickness, and hole positions
● Flatness measurement using laser interferometer
● Bond strength test (pull-off or shear test on witness samples)
● Visual inspection for cracks or voids in ceramic layer
Advantages over All-Ceramic or All-Metal Rings:
● Ceramic surface lasts 5–10× longer than hardened steel
● Metal base provides ductility – no brittle fracture risk during installation
● Easy mounting (threaded holes, dowel pins) directly onto existing machines
● Lower cost than full ceramic ring for large diameters
● Metal base can be designed for magnetic chuck attachment
Limitations (critical remarks):
● Metal base data (thermal expansion, stiffness) not from supplied ceramic tables – refer to standard metal properties.
● Maximum continuous operating temperature limited by epoxy bond (≤200°C for standard epoxy; mechanical clamping allows up to 500°C but reduces sealing).
● Not suitable for aggressive chemical environments that attack the metal base (e.g., strong acids). For full chemical resistance, specify all-ceramic ring.
Customization:
● Metal material: aluminum (lightweight), stainless steel (corrosion resistant), or Invar (low thermal expansion)
● Bonding method: epoxy (≤200°C), mechanical clamp (≤500°C), or brazed ceramic-to-metal (≤800°C, higher cost)
● Mounting features: threaded holes, dowel pin holes, slots, or magnetic backing
● Ceramic layer thickness: 3–20 mm
Contact us for a design review and to select the optimal metal-ceramic combination for your grinding application.
