Versatile Performance, Precise Machinability
MACOR® delivers the thermal stability, electrical insulation, and chemical resistance of a high-performance ceramic, while remaining fully machinable using conventional metalworking tools — without the need for post-machining firing or specialist equipment. This combination of properties makes it uniquely practical for prototyping and precision component manufacture across industries where ceramic performance is required but complex grinding or sintering processes are not feasible.
Goodfellow supplies MACOR® across a comprehensive range of forms and dimensions, serving applications in nuclear power generation, aerospace, vacuum technology, and scientific instrumentation. Custom machining is available for applications that require components built to exact customer specification.
MACOR® Glass-Ceramic Properties
Thermal, Electrical & Chemical Performance
MACOR® operates continuously at temperatures up to 800°C and withstands peak temperatures up to 1000°C, making it reliable in high-temperature environments where most polymers and many metals would fail.
Its exceptional electrical insulation properties make it a trusted choice for electronic and vacuum applications, while its chemical resistance ensures long-term durability in corrosive or reactive environments.
Dimensional Stability & Precision
MACOR® exhibits zero porosity and excellent dimensional stability, maintaining its geometry under thermal cycling and mechanical stress.
This consistency makes it particularly valuable in critical applications where component tolerances must be held across a wide range of operating conditions — from cryogenic temperatures to sustained high-heat environments.
Mechanical & Environmental Performance
MACOR® combines its thermal, electrical, and chemical properties with strong mechanical performance, withstanding vibration, shock, and harsh environmental conditions with reliable stability.
This breadth of performance across multiple property requirements makes it one of the most versatile technical ceramics available for demanding scientific, industrial, and defence applications.
Machinability with Standard Tools
Unlike conventional technical ceramics, MACOR® can be machined to tight tolerances using standard metalworking tools — no specialist grinding equipment or post-machining firing is required.
This significantly reduces fabrication time and cost, and makes it practical for both prototype development and precision component production where complex geometries are required.
MACOR® Technical Datasheet
| Property | SI / Metric Value | Imperial Value | Significance | |||
|---|---|---|---|---|---|---|
| Value | Unit | Condition / Notes | Value | Unit | Key Feature | |
| I — Thermal | ||||||
| CTE (low temp)−100 °C → 25 °C | 81 × 10−7 | /°C | Matches most metals & sealing glasses | 45 × 10−7 | /°F | Metal-Matched CTE |
| CTE (25 °C → 300 °C) | 90 × 10−7 | /°C | — | 50 × 10−7 | /°F | — |
| CTE (25 °C → 600 °C) | 112 × 10−7 | /°C | — | 62 × 10−7 | /°F | — |
| CTE (25 °C → 800 °C) | 123 × 10−7 | /°C | — | 68 × 10−7 | /°F | — |
| Specific Heat | 0.79 | kJ/kg·°C | At 25 °C | 0.19 | Btu/lb·°F | — |
| Thermal Conductivity | 1.46 | W/m·°C | At 25 °C; rises to ~1.75 W/m·°C at 800 °C | 10.16 | Btu·in/hr·ft²·°F | Low Thermal Cond. |
| Thermal Diffusivity | 7.3 × 10−7 | m²/s | At 25 °C | 0.028 | ft²/hr | — |
| Continuous Use Temp. | 800 | °C | Stable; no creep or deformation | 1472 | °F | 800 °C Continuous |
| Max. No-Load Temp. | 1000 | °C | Peak; no applied load | 1832 | °F | — |
| II — Mechanical | ||||||
| Density | 2.52 | g/cm³ | — | 157 | lbs/ft³ | — |
| Porosity | 0 | % | Zero porosity; no outgassing | 0 | % | Zero Porosity |
| Young's Modulus | 66.9 | GPa | At 25 °C; decreases to ~45 GPa at 800 °C | 9.7 × 106 | PSI | — |
| Poisson's Ratio | 0.29 | — | — | 0.29 | — | — |
| Shear Modulus | 25.5 | GPa | At 25 °C | 3.7 × 106 | PSI | — |
| Knoop Hardness | 250 | kg/mm² | 100 g load; enables conventional metal machining | — | — | Soft Enough to Machine |
| Modulus of RuptureFlexural Strength | 94 | MPa | Min. specified avg. at 25 °C; rises above 150 MPa at ~400 °C | 13,600 | PSI | — |
| Compressive Strength | 345 (up to 900) | MPa | Standard; up to 900 MPa after polishing | 49,900 (up to 130,000) | PSI | High Compressive Str. |
| III — Electrical | ||||||
| Dielectric ConstantAt 1 kHz, 25 °C | 6.01 | — | Increases significantly at elevated temperatures | 6.01 | — | — |
| Dielectric ConstantAt 8.5 GHz, 25 °C | 5.64 | — | Stable at high frequencies | 5.64 | — | — |
| Loss TangentAt 1 kHz, 25 °C | 0.0040 | — | — | 0.0040 | — | — |
| Loss TangentAt 8.5 GHz, 25 °C | 0.0025 | — | — | 0.0025 | — | — |
| Dielectric Strength (AC) | 45 | kV/mm | Avg. at 25 °C; 0.3 mm thickness | 1,143 | V/mil | High-Voltage Insulator |
| Dielectric Strength (DC) | 129 | kV/mm | Avg. at 25 °C; 0.3 mm thickness | 3,277 | V/mil | — |
| DC Volume Resistivity | 1017 | Ω·cm | At 25 °C; decreases at elevated temperature | 1017 | Ω·cm | Excellent Insulation |
| IV — Chemical Durability | ||||||
| 5% HCl (Hydrochloric Acid)pH 0.1 · 95 °C · 24 hr | ~100 | mg/cm² | Significant attack; avoid strong acid exposure | — | — | Poor Acid Resistance |
| 0.002 N HNO₃ (Nitric Acid)pH 2.8 · 95 °C · 24 hr | ~0.6 | mg/cm² | Dilute acid: low weight loss | — | — | — |
| NaHCO₃ (Sodium Bicarb.)pH 8.4 · 95 °C · 24 hr | ~0.3 | mg/cm² | Very low weight loss in mild alkali | — | — | — |
| Na₂CO₃ (Sodium Carbonate)pH 10.9 · 95 °C · 6 hr | ~0.1 | mg/cm² | Excellent resistance at moderate alkalinity | — | — | Alkali Resistant |
| 5% NaOH (Sodium Hydroxide)pH 13.2 · 95 °C · 6 hr | ~10 | mg/cm² | Moderate attack in strong base; use with caution | — | — | — |
| DIN Water ClassDIN 12111 / NF ISO 719 | HGB2 | — | Class 2 hydrolytic resistance | — | — | — |
| DIN Acid ClassDIN 12116 | 4 | — | Class 4 (lowest acid resistance category) | — | — | — |
| DIN Alkali ClassDIN 52322 / ISO 695 | A3 | — | Class 3 alkaline resistance | — | — | — |
All data sourced from the Corning MACOR® technical datasheet (Corning SAS). Composition: 55% fluorophlogopite mica / 45% borosilicate glass. Material is white, nonwetting, odorless, and non-outgassing. Tolerances achievable: ±0.013 mm (dimensions), <0.5 µm (finished surface), 0.013 µm (polished surface). Actual properties of specific production batches may vary — consult individual datasheets for specification-critical applications. MACOR® is a registered trademark of Corning Incorporated.
Choosing the Right MACOR® Product
Goodfellow has supplied MACOR® to aerospace, semiconductor, medical, and nuclear programmes for over 75 years. Our technical team has the application knowledge to help you identify the right product form and specification for your requirements.
Our MACOR® range covers three primary forms.
- Rods are available in a range of diameters for machined components, insulators, and spacers.
- Sheets provide precise dimensional control and tight tolerances for fabrication projects where flat, thin ceramic stock is required.
- Precision-machined disks are specified for electrical insulators, seals, and other close-tolerance applications.
The entire Goodfellow MACOR® range complies with European Directives 2015/863/EU (RoHS 3) and 2000/53/EC (ELV), and is supplied under our ISO 9001 certified quality management system — giving you full confidence in both the environmental credentials and the consistency of every product we deliver.
Our MACOR® Product Range
Goodfellow stocks MACOR® in sheets, bars, rods, and disks to cover the full range of machining and fabrication requirements.
- Sheets are available from 0.5mm to 55mm thick
- Rods from 1.6mm to 76mm diameter
- Bars from 10mm x 10mm up to 50.8mm x 50.8mm — with custom-machined components available beyond standard stock dimensions.
Our Technical Solutions team is available to help identify the right product form and dimensions for your application at no charge. With over 75 years of experience supplying MACOR® across demanding industries, we have the expertise to ensure you specify the right solution first time.
Precision Machining and Materials Analysis for MACOR®
For applications requiring complex geometries beyond conventional metalworking, MACOR® can be precision-machined using micro CNC and laser micromachining techniques. Our Goodfellow microfabrication division has direct experience working with ceramic substrates to achieve tight tolerances and intricate features that standard machining cannot deliver.
Where material verification is required, MACOR® ceramic properties — including elemental composition, microstructure, and surface quality — can be analysed through our ISO/IEC 17025-accredited materials testing laboratory.
MACOR® Applications
Aerospace
MACOR®'s exceptional resistance to high temperatures and thermal shock makes it an ideal material for aerospace applications, such as engine components, insulators and satellite systems.
Medical
With its biocompatible properties and chemical resistance, MACOR® is the go-to choice for various medical applications, including surgical instruments and analytical equipment.
Electronics
The excellent electrical insulation properties of MACOR® make it well-suited for electronic applications, including circuit boards, high-voltage insulators and electrical housings.
Automotive
Many applications in the automotive industry make use of MACOR® due to its thermal stability and reliability. These include high-temperature sensors, ignition systems and exhaust components.
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