MgO
MgO is single-crystal periclase, supplied as {100} and {111} oriented substrates (SC-100, SC-111) plus hot-pressed transparent (HP-TRANS) and 99% sintered polycrystalline (SINT-99) grades.
Reference datasheet — MgO is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the SC-100 condition
MgO tempers and conditions
MgO is supplied in 4 conditions, soft to hard. SC-100 is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
alternate-orientation single crystal | Choose this non-(100) oriented wafer when the film demands a specific lattice symmetry, for example hexagonal-phase layers or magnetic tunnel junctions. | 110 | 0 | 650 HV | 50 W/m·K | |
Sintered 99 % | Use the pressed and sintered opaque 99 % ceramic for non-optical high-temperature duty to 1700 °C — crucibles, thermocouple insulating tubes and furnace parts — as the economical option. | 550 HV | 30 W/m·K | |||
SC-100Default SC | Use as the default: the (100) orientation is the most common substrate for epitaxy of perovskite oxide films and also serves as a polished infrared window. | 600 HV | 50 W/m·K | |||
hot-pressed transparent polycrystalline MgO (IR window) | Pick the hot-pressed transparent polycrystalline form for large-aperture infrared windows and domes when higher strength and freedom from cleavage planes outweigh slightly lower transmission. | 640 HV | 40 W/m·K |
What is MgO?
MgO is single-crystal periclase, supplied as {100} and {111} oriented substrates (SC-100, SC-111) plus hot-pressed transparent (HP-TRANS) and 99% sintered polycrystalline (SINT-99) grades. It transmits from the UV into the mid-IR and offers a 249 GPa modulus, 50 W/m·K thermal conductivity and service to 1200 °C, which suits IR windows and lattice-matched substrates for oxide thin-film growth. It is hygroscopic and cleaves on {100}, so blanks need dry storage and diamond-only machining (machinability 5). Sapphire is the usual alternative when moisture resistance matters more than lattice match. MgO has a density of 3.58 g/cm³ (0.129 lb/in³), heavier than 69% of glass grades. It melts at 2,825°C (5,117 °F). MgO has a tensile strength of 100 MPa (14.5 ksi), stronger than 80% of glass grades. The elastic modulus is 249 GPa (36.1 Msi).
What is MgO used for?
- IR windows
- thin-film epitaxial substrates
- high-temperature optics
Advantages
- High service temperature — 1,200°C (2,192 °F), better than 94% of glass grades
- Stiff — 249 GPa (36.1 Msi), better than 93% of glass grades
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 92% of glass grades
- Tough — resists crack growth — 1 MPa·√m (0.91 ksi·√in), better than 87% of glass grades
Limitations
- Difficult to machine — 5/100, worse than 92% of glass grades
- Needs corrosion protection — 45/100, worse than 84% of glass grades
MgO properties
Typical room-temperature values for MgO-SC-100; bars are the position among glass grades.
Physical5
MgO has a density of 3.58 g/cm³ (0.129 lb/in³), heavier than 69% of glass grades. It melts at 2,825°C (5,117 °F).
Mechanical11
MgO has a tensile strength of 100 MPa (14.5 ksi), stronger than 80% of glass grades. The elastic modulus is 249 GPa (36.1 Msi).
Thermal5
MgO is rated for continuous service to 1,200°C (2,192 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 92% of glass grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical5
MgO is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental2
Corrosion resistance is fair (45/100), worse than 84% of glass grades.
Sustainability4
Producing a kilogram of MgO takes about 45 MJ of energy and emits 3 kg of CO₂ — less than 58% of glass grades. Typical recycled content is 0%.
Manufacturability2
MgO's machinability is not recommended (5/100, worse than 92% of glass grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the glass family
Yield strength against density for every glass grade FabDigit runs. MgO is highlighted; hover a dot for its name, or open the interactive family chart.
Working with MgO
Is MgO easy to machine?
Diamond sawing, grinding and lapping only. The {100} cleavage planes chip readily, so orient cuts away from cleavage directions and use low feeds with ample water-free coolant.
Can MgO be welded?
Not weldable as a ceramic. Join to metals by active-metal brazing (Ti/Ag-Cu) or by Mo-Mn metallization followed by nickel plating and brazing, matching CTE to avoid thermal-stress cracking.
Can MgO be formed, bent or molded?
Single crystals are grown by arc fusion or directional solidification and then sliced. Polycrystalline parts are dry- or isostatically pressed from high-purity magnesia and sintered at 1600-1750 °C; transparent grades require hot pressing or HIP.
MgO chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CaOtypical trace impurity | ≤ 0.03 | 0.01 |
| SiO2typical trace impurity | ≤ 0.02 | 0.01 |
| Al2O3typical trace impurity | ≤ 0.02 | 0.01 |
| Fe2O3colouring impurity, degrades IR transmission | ≤ 0.01 | 0 |
| MgOoptical/substrate grade purity; Mg 60.3 wt %, O 39.7 wt % | ≥ 99.9 (balance) |
What surface finishes work on MgO?
CMP gives epi-ready surfaces below 0.5 nm Ra. Store polished parts in dry nitrogen or vacuum bags; IR windows are normally AR-coated, which also serves as a moisture barrier, and a 400-600 °C vacuum anneal before use removes surface hydroxide.
How much does MgO cost?
MgO is a high-cost glass ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
MgO — frequently asked
What is MgO used for?
MgO is typically used for IR windows, thin-film epitaxial substrates and high-temperature optics. In short: lattice-matched oxide substrate; hygroscopic, dry storage required; 1200 °C service limit.
What is the tensile strength of MgO?
MgO has a typical tensile strength of 100 MPa (14.5 ksi) — stronger than 80% of glass grades. Strength varies by condition: see the 4 listed tempers.
Is MgO easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 92% of glass grades). Diamond sawing, grinding and lapping only. The {100} cleavage planes chip readily, so orient cuts away from cleavage directions and use low feeds with ample water-free coolant.
Can MgO be welded?
Not weldable as a ceramic. Join to metals by active-metal brazing (Ti/Ag-Cu) or by Mo-Mn metallization followed by nickel plating and brazing, matching CTE to avoid thermal-stress cracking.
What surface finishes work on MgO?
CMP gives epi-ready surfaces below 0.5 nm Ra. Store polished parts in dry nitrogen or vacuum bags; IR windows are normally AR-coated, which also serves as a moisture barrier, and a 400-600 °C vacuum anneal before use removes surface hydroxide.
Can MgO be formed, bent or molded?
Single crystals are grown by arc fusion or directional solidification and then sliced. Polycrystalline parts are dry- or isostatically pressed from high-purity magnesia and sintered at 1600-1750 °C; transparent grades require hot pressing or HIP.
What is the maximum service temperature of MgO?
MgO is rated for continuous use to about 1,200°C (2,192 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does MgO cost?
MgO is a high-cost glass ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- The Crystran Handbook of Infra-Red and Ultra-Violet Optical Materials — Magnesium Oxide — Crystran Ltd (2023)
- ASM Engineered Materials Handbook Vol.4: Ceramics and Glasses — ASM International (1991)
- CRC Materials Science and Engineering Handbook (4th ed.) — CRC Press (2015)
- MgO single crystal substrate specifications — MTI Corporation / SurfaceNet GmbH (2024)
- Handbook of Optical Constants of Solids — MgO dispersion data — Academic Press (1998)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.