Spinel SC (Single-crystal spinel)
Finish state
Choose for epitaxial substrates (GaN, SOS-type), UV–IR laser windows and where zero grain-boundary scattering is required.
Values for the SC condition
Other Spinel tempers and conditions
Spinel is listed in 4 conditions; see the grade overview at Spinel.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SINT-DENSEDefault pressureless-sintered dense polycrystalline spinel (opaque, >99 % TD) | Default technical-ceramic form: dense opaque spinel parts for semiconductor chamber components, kiln furniture and corrosion-exposed structural ceramics. | — | — | — | 1,350 HV | 15 W/m·K |
transparent spinel, hot-pressed + HIP optical grade | Pick for visible-to-MWIR windows, missile domes and transparent armour where sapphire is too costly or too anisotropic. | — | — | — | 1,400 HV | 15 W/m·K |
SCThis page Single-crystal spinel | Choose for epitaxial substrates (GaN, SOS-type), UV–IR laser windows and where zero grain-boundary scattering is required. | — | — | — | 1,450 HV | 24 W/m·K |
Refractory-grade spinel | Low-cost porous form for cement-kiln transition zones, steel-ladle linings and slag-resistant castables. | — | — | — | — | 6 W/m·K |
What is Spinel SC?
Spinel SC is Spinel supplied in the SC condition — choose for epitaxial substrates (GaN, SOS-type), UV–IR laser windows and where zero grain-boundary scattering is required. Spinel SC has a tensile strength of 120 MPa (17.4 ksi), stronger than 51% of ceramic grades. The elastic modulus is 277 GPa (40.2 Msi). Spinel SC has a density of 3.58 g/cm³ (0.129 lb/in³), lighter than 65% of ceramic grades. It melts at 2,135°C (3,875 °F). SINT-DENSE is the default condition FabDigit quotes; SC is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 98/100, better than 100% of ceramic grades
- Good corrosion resistance — 92/100, better than 88% of ceramic grades
- High service temperature — 1,400°C (2,552 °F), better than 77% of ceramic grades
Spinel SC properties
Typical room-temperature values for Spinel SC; 12 are specific to this condition. Other listed values are Spinel reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical5
Spinel SC has a density of 3.58 g/cm³ (0.129 lb/in³), lighter than 65% of ceramic grades. It melts at 2,135°C (3,875 °F).
Mechanical11
Spinel SC has a tensile strength of 120 MPa (17.4 ksi), stronger than 51% of ceramic grades. The elastic modulus is 277 GPa (40.2 Msi).
Thermal5
Spinel SC is rated for continuous service to 1,400°C (2,552 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), better than 53% of ceramic grades. Thermal expansion is 6 µm/m·K (3.33 µin/in·°F).
Electrical5
Spinel SC is an electrical insulator with a dielectric strength of 16 kV/mm (406.4 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (92/100), better than 88% of ceramic grades.
Sustainability4
Producing a kilogram of Spinel SC takes about 75 MJ of energy and emits 6.5 kg of CO₂ — less than 69% of ceramic grades. Typical recycled content is 0%.
Manufacturability3
Spinel SC's machinability is not recommended (3/100, worse than 95% of ceramic grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Spinel SC
Is Spinel easy to machine?
Green machining before firing is the economical route; fired parts require diamond grinding, lapping and ultrasonic/laser drilling with light passes to avoid subsurface damage.
Can Spinel be welded?
Not weldable — join by active-metal brazing (Ti/Ag-Cu), glass frit sealing or metallised Mo-Mn plus Ni plating for vacuum-tight assemblies.
Can Spinel be formed, bent or molded?
Uniaxial/isostatic pressing, slip or tape casting and injection moulding of fine MgAl2O4 powder; transparent grades need vacuum sintering or hot pressing followed by HIP at 1750–1900 °C / 150–200 MPa; allow ~15–18 % firing shrinkage.
What surface finishes work on Spinel?
Diamond lapping then colloidal-silica or CeO2 polishing gives optical λ/10 flatness and <1 nm Ra; AR coatings are applied for IR window use, and no anodising/plating is applicable.
Spinel 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 |
|---|---|---|
| MgOstoichiometric MgO·Al2O3; Al-rich (MgO·1.5–2Al2O3) grades are used for transparent and refractory products | 27 – 29.5 | 28.3 |
| LiFsintering aid used in hot-pressed transparent grades; removed/volatilised during HIP | 0 – 1 | 0.5 |
| SiO2+CaO+Fe2O3 (impurities)≤200 ppm total for optical grades | 0 – 0.5 | 0.1 |
| Al2O3 | ≥ 70.5 (balance) | — |
Spinel SC — frequently asked
What is Spinel SC used for?
Spinel SC is typically used for transparent armor/windows, refractory linings, IR domes and molten metal handling refractories. In short: transparent structural ceramic; optically isotropic cubic oxide; good thermal shock resistance.
What is the tensile strength of Spinel SC?
Spinel SC has a typical tensile strength of 120 MPa (17.4 ksi) — stronger than 51% of ceramic grades. Strength varies by condition: see the 4 listed tempers.
Is Spinel SC easy to machine?
Not especially — machinability is rated not recommended (3/100, worse than 95% of ceramic grades). Green machining before firing is the economical route; fired parts require diamond grinding, lapping and ultrasonic/laser drilling with light passes to avoid subsurface damage.
Can Spinel SC be welded?
Not weldable — join by active-metal brazing (Ti/Ag-Cu), glass frit sealing or metallised Mo-Mn plus Ni plating for vacuum-tight assemblies.
What surface finishes work on Spinel SC?
Diamond lapping then colloidal-silica or CeO2 polishing gives optical λ/10 flatness and <1 nm Ra; AR coatings are applied for IR window use, and no anodising/plating is applicable.
Can Spinel SC be formed, bent or molded?
Uniaxial/isostatic pressing, slip or tape casting and injection moulding of fine MgAl2O4 powder; transparent grades need vacuum sintering or hot pressing followed by HIP at 1750–1900 °C / 150–200 MPa; allow ~15–18 % firing shrinkage.
What is the maximum service temperature of Spinel SC?
Spinel SC is rated for continuous use to about 1,400°C (2,552 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASM Engineered Materials Handbook Vol.4: Ceramics and Glasses — ASM International (1991)
- Transparent Spinel Ceramic Window Material Data — Surmet / II-VI optical ceramics datasheets (2022)
- Technical Ceramics Material Properties — Spinel and Oxide Ceramics — CoorsTek / Kyocera (2023)
- ACerS-NIST Phase Equilibria Diagrams — MgO–Al2O3 system — American Ceramic Society / NIST (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.