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MACOR® Machinable Glass Ceramic Bar
Available Configurations
Properties common to all products in this list
| Cross-Section | Length | Alternative Materials |
|---|---|---|
| 6mm to 50.8mm | 25mm to 300mm | Shapal® Hi-M Soft; BNP-2 AlN; Al₂O₃ |
Need custom configurations? Please contact us.
Learn more about our MACOR® range and machining capabilities HERE.
MACOR® Machinable Glass Ceramic Bar is a rectangular-section stock material that brings the full performance of MACOR® to a flat-sided format well suited to milling, slotting, drilling, and surface grinding. Where rod stock suits turned components, bar is the natural starting point for brackets, mounting blocks, housings, and any part with flat reference surfaces or a rectilinear profile. It offers the same zero porosity, 800 °C continuous service capability, DC volume resistivity of 1017 Ω·cm, and dielectric strength of 45 kV/mm as the rest of the MACOR® range — with the added practical benefit that a rectangular section minimises material waste and simplifies fixturing when milling prismatic components.
Custom Machining from Goodfellow
Milling MACOR® bar effectively means using climb milling to prevent edge pullout, tungsten carbide tooling, chip loads around 0.05 mm per tooth, and continuous coolant to control heat and clear abrasive swarf. With the right process, MACOR® machines to excellent surface finish and holds tight tolerances. If you need finished components rather than raw bar stock, Goodfellow can produce parts to your drawing. Request a quote here and we'll review your requirements.
Key Features
MACOR® Machinable Glass Ceramic possesses a combination of material characteristics that make it particularly well suited for high-precision, high-temperature, vacuum, and electrical insulation applications across aerospace, medical, research, and industrial sectors:
Machinable with Standard Metalworking Tools
MACOR® can be machined to tight tolerances (down to ±0.02mm) using standard carbide-tipped metalworking tools — no specialist ceramic processing equipment is required. Its interlocking plate-like mica crystal structure in a glassy matrix stops microscopic fractures from propagating, allowing controlled material removal by turning, milling, drilling, tapping, sawing, and grinding. No post-machining firing or heat treatment is needed; components are ready for use once cleaned.
High-Temperature Performance (Continuous Use to 800 °C, Peak 1,000 °C)
MACOR® maintains its structural integrity, dimensional stability, and electrical insulation performance up to a continuous use temperature of 800 °C and a peak temperature of 1,000 °C. Unlike high-temperature plastics, it will not creep or deform under sustained thermal load, making it reliable in furnaces, high-temperature processing equipment, and thermal break applications.
Excellent Electrical Insulation Properties
MACOR® is a strong electrical insulator across a broad spectrum of frequencies, performing reliably under high voltages and in demanding RF environments. Its smooth, polishable surface finish resists arcing, making it well suited for high-voltage insulators, coil formers, and precision electrical assemblies where dielectric stability must be maintained across wide temperature and frequency ranges.
Zero Porosity & Vacuum Compatibility
MACOR® has zero porosity and does not outgas in vacuum environments, making it fully compatible with high-vacuum and ultra-high-vacuum systems. It can be hermetically sealed, joined, and metallized, supporting its use in vacuum feedthroughs, coil supports, and sealed assemblies where gas contamination or outgassing would compromise system performance.
Radiation Resistance & Dimensional Stability
MACOR® is radiation resistant and dimensionally unaffected by irradiation, making it a reliable material in power generation and space applications. Its coefficient of thermal expansion is readily matched to most metals and sealing glasses, reducing thermally induced stress at joints and interfaces in precision assemblies.
Low Thermal Conductivity
MACOR®'s low thermal conductivity makes it an effective thermal break and insulating spacer in high-temperature processing equipment, laser assemblies, and power generation components — isolating heat-sensitive elements from high-temperature zones without compromising structural rigidity.
Industrial Applications
MACOR® Machinable Glass Ceramic is used across high-technology industries where precision machinability, electrical insulation, thermal stability, and vacuum compatibility must be combined in a single material:
- ✦ Aerospace & Space Systems
- Used in retaining rings on hinges, windows, and doors of NASA's Space Shuttle, and as supports and components in satellite-borne systems, where thermal and electronic insulation, dimensional stability under irradiation, and low outgassing are all required simultaneously.
- ✦ Vacuum Systems & Feedthroughs
- Employed in coil supports and vacuum feedthroughs where MACOR®'s zero porosity, absence of outgassing, and ability to be hermetically sealed and metallized ensure clean, stable performance without contaminating the vacuum environment.
- ✦ Laser & Photonics Instrumentation
- Used as spacers, cavities, and reflectors in laser assemblies, and as housings for laser instrumentation, where precision machinability, heat resistance, and dimensional stability are essential for maintaining optical alignment and system performance.
- ✦ High-Voltage Electrical Insulation
- Applied as precision coil formers and high-voltage insulators where MACOR®'s smooth surface finish, resistance to arcing, and consistent insulation performance across a broad spectrum of frequencies support long-term reliability under demanding electrical conditions.
- ✦ Power Generation
- Used as fixtures and reference blocks in power generation units, where dimensional stability under irradiation ensures that precision components remain within specification throughout their service life.
- ✦ Additive Manufacturing & 3D Printing Nozzles
- MACOR®'s machinability, thermal stability, and chemical inertness make it suitable for precision nozzle components in high-temperature FDM extruders handling engineering filaments such as PEEK and ULTEM, and in direct-ink-write (DIW) systems processing abrasive or corrosive ceramic and composite slurries — where standard polymer or metal nozzles would degrade or contaminate the material being deposited.
- ✦ Prototyping & Precision Component Development
- Widely used as a prototype material ahead of volume production in sintered ceramics, enabling engineers to produce and test precision ceramic components quickly using standard machine shop equipment — without investment in ceramic-specific tooling or post-machining firing processes.
Synonyms
Material Properties
| Element | Value |
|---|---|
| 5% HCl (Hydrochloric Acid)( mg/cm² ) | ~100 |
| 0.002 N HNO₃ (Nitric Acid)( mg/cm² ) | ~0.6 |
| NaHCO₃ (Sodium Bicarb.)( mg/cm² ) | ~0.3 |
| Na₂CO₃ (Sodium Carbonate)( mg/cm² ) | ~0.1 |
| 5% NaOH (Sodium Hydroxide)( mg/cm² ) | ~10 |
| DIN Water Class | HGB2 |
| DIN Acid Class | 4 |
| DIN Alkali Class | A3 |
| Element | Value |
|---|---|
| Dielectric constant @1 kHz | 6.01 |
| Dielectric constant @8.5 GHz | 5.64 |
| Loss Tangent @1 kHz | 0.0040 |
| Loss Tangent @8.5 GHz | 0.0025 |
| Dielectric Strength (AC)( kV/mm ) | 45 |
| Dielectric Strength (DC)( kV/mm ) | 129 |
| DC Volume Resistivity( Ω·cm ) | 10^17 |
| Element | Value |
|---|---|
| Porosity( % ) | 0 (no outgassing) |
| Tensile modulus( GPa ) | 66.9 |
| Hardness - Knoop( kgf mm⁻² ) | 250 |
| Hardness - Vickers( kgf mm⁻² ) | 400 |
| Shear modulus( GPa ) | 25.5 |
| Modulus of rupture( MPa ) | 94 |
| Compressive Strength( MPa ) | 345 (up to 900 after polishing) |
| Poisson's Ratio | 0.29 |
| Element | Value |
|---|---|
| Refractive index | 0 |
| Useful optical transmission range | 0 |
| Apparent porosity( % ) | 0 |
| Water absorption - saturation( % ) | 0 |
| Density( g/cm³ ) | 2.52 |
| Element | Value |
|---|---|
| CTE (low temp)( °C⁻¹ ) | 81 × 10−7 |
| CTE (25 °C → 300 °C)( °C⁻¹ ) | 90 × 10−7 |
| CTE (25 °C → 600 °C)( °C⁻¹ ) | 112 × 10−7 |
| CTE (25 °C → 800 °C)( °C⁻¹ ) | 123 × 10−7 |
| Specific Heat( kJ/kg·°C @25°C ) | 0.79 |
| Thermal Conductivity( W/m·°C @25°C ) | 1.46 |
| Thermal Diffusivity( m²/s @25°C ) | 7.3 × 10−7 |
| Continuous Use Temperature( °C ) | 800 |
| Maximum No-Load Temperature( °C ) | 1000 |
Tolerances
| Side Length | =<10mm | ±10% |
|---|---|---|
| Side Length | >10mm | ±1mm |
| Side Length (Of Longer Side) | >10mm | ±1mm |
| Side Length (Of Longer Side) | =<10mm | ±10% |
| Side Length (Of Longer Side) | >10mm | 1mm |
| Length | <100mm | ±1mm |
| Length | >=100mm | +5% / -1% |