Zircon
Zircon (ZrSiO₄) is a naturally occurring zirconium silicate ceramic, catalogued as C728, with refractory, fused and zircon-flour forms.
Reference datasheet — Zircon 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 C728 condition
Zircon tempers and conditions
Zircon is supplied in 4 conditions, soft to hard. C728 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 |
|---|---|---|---|---|---|---|
Bonded zircon refractory brick / shape | Choose for glass-tank paving, ladle and slide-gate refractories where slag/glass corrosion resistance matters more than strength. | — | — | — | 900 HV | 3 W/m·K |
Fused-cast / electrofused zircon | Choose for glass-furnace throat and paver blocks or high-grade refractory grain where maximum density and glass-corrosion resistance are required. | — | — | — | 1,100 HV | 4 W/m·K |
C728Default Dense sintered zircon porcelain | Choose for gas-tight, high-strength electrical/thermal ceramic parts: insulators, nozzles, thermocouple sheaths, foundry tooling. | — | — | — | 1,150 HV | 5 W/m·K |
Zircon sand / milled zircon flour | Choose as raw material: ceramic-glaze opacifier, investment-casting facecoat and foundry sand, or feedstock for zirconia production. | — | — | 0 | 1,200 HV | 5 W/m·K |
What is Zircon?
Zircon (ZrSiO₄) is a naturally occurring zirconium silicate ceramic, catalogued as C728, with refractory, fused and zircon-flour forms. It is used as a refractory, glaze opacifier and feedstock for zirconia production, valued for low thermal expansion and chemical inertness; the default body gives 3.7 g/cm³ density, 190 GPa elastic modulus, 4.5 W/m·K conductivity, 1500 °C maximum service temperature and a corrosion-resistance score of 88. Machinability is 5: fired parts are finished only by diamond grinding, and shapes are limited to pressed, cast or extruded bodies. Mullite or alumina serve where higher strength is needed. Zircon has a density of 3.7 g/cm³ (0.134 lb/in³), lighter than 63% of ceramic grades. It melts at 1,687°C (3,069 °F). Zircon has a tensile strength of 80 MPa (11.6 ksi), weaker than 53% of ceramic grades. The elastic modulus is 190 GPa (27.6 Msi).
What is Zircon used for?
- foundry sand/refractories
- ceramic glaze opacifier
- kiln furniture
- investment casting shell
- raw material for ZrO2 production
Advantages
- Low embodied carbon — 3 kg CO₂/kg, better than 88% of ceramic grades
- High service temperature — 1,500°C (2,732 °F), better than 80% of ceramic grades
- Good corrosion resistance — 88/100, better than 77% of ceramic grades
Zircon properties
Typical room-temperature values for Zircon-C728; bars are the position among ceramic grades.
Physical4
Zircon has a density of 3.7 g/cm³ (0.134 lb/in³), lighter than 63% of ceramic grades. It melts at 1,687°C (3,069 °F).
Mechanical11
Zircon has a tensile strength of 80 MPa (11.6 ksi), weaker than 53% of ceramic grades. The elastic modulus is 190 GPa (27.6 Msi).
Thermal5
Zircon is rated for continuous service to 1,500°C (2,732 °F). It conducts heat at 4.5 W/m·K (2.6 BTU/hr·ft·°F), worse than 64% of ceramic grades. Thermal expansion is 4.2 µm/m·K (2.33 µin/in·°F).
Electrical5
Zircon is an electrical insulator with a dielectric strength of 12 kV/mm (304.8 V/mil) and a resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (88/100), better than 77% of ceramic grades.
Sustainability4
Producing a kilogram of Zircon takes about 40 MJ of energy and emits 3 kg of CO₂ — less than 88% of ceramic grades. Typical recycled content is 3%.
Manufacturability3
Zircon's machinability is not recommended (5/100, worse than 59% of ceramic 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 ceramic family
Yield strength against density for every ceramic grade FabDigit runs. Zircon is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Zircon
Is Zircon easy to machine?
Green or bisque bodies machine easily with carbide tooling; after firing only diamond grinding, lapping and ultrasonic/laser machining are practical.
Can Zircon be welded?
Not weldable — join by ceramic-to-metal brazing (Mo-Mn metallizing), glass frit sealing or high-temperature cements.
Can Zircon be formed, bent or molded?
Formed by dry pressing, isostatic pressing, slip casting or extrusion of milled zircon flour with clay/binder, then fired at 1500–1700 °C; allow ~12–18 % firing shrinkage.
Zircon 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 |
|---|---|---|
| ZrO2ZrO2+HfO2 basis; stoichiometric ZrSiO4 = 67.2 % ZrO2 | 64 – 67.2 | 66 |
| HfO2naturally substitutes for Zr; usually reported inside ZrO2 | 0.8 – 1.8 | 1.2 |
| TiO2impurity from rutile | ≤ 0.2 | 0.08 |
| Fe2O3impurity | ≤ 0.15 | 0.05 |
| Al2O3impurity / bond phase | ≤ 0.6 | 0.25 |
| U+Th (trace)natural radionuclides — relevant to NORM handling rules | ≤ 0.05 | 0.02 |
| SiO2stoichiometric 32.8 % | ≥ 31.5 (balance) | — |
What surface finishes work on Zircon?
Diamond grind and polish for sealing faces; glazing improves surface sealing and thermal-shock-crack resistance; no plating or anodizing applies.
Equivalent designations
Standards and trade names that resolve to Zircon in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- ZrSiO4
- Similar grades
- C728
How much does Zircon cost?
Zircon is a standard-cost ceramic ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Zircon — frequently asked
What is Zircon used for?
Zircon is typically used for foundry sand/refractories, ceramic glaze opacifier, kiln furniture, investment casting shell and raw material for ZrO2 production. In short: low-expansion refractory silicate; 1500 °C service capability; feedstock for zirconia.
What is the tensile strength of Zircon?
Zircon has a typical tensile strength of 80 MPa (11.6 ksi) — weaker than 53% of ceramic grades. Strength varies by condition: see the 4 listed tempers.
Is Zircon easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 59% of ceramic grades). Green or bisque bodies machine easily with carbide tooling; after firing only diamond grinding, lapping and ultrasonic/laser machining are practical.
Can Zircon be welded?
Not weldable — join by ceramic-to-metal brazing (Mo-Mn metallizing), glass frit sealing or high-temperature cements.
What surface finishes work on Zircon?
Diamond grind and polish for sealing faces; glazing improves surface sealing and thermal-shock-crack resistance; no plating or anodizing applies.
Can Zircon be formed, bent or molded?
Formed by dry pressing, isostatic pressing, slip casting or extrusion of milled zircon flour with clay/binder, then fired at 1500–1700 °C; allow ~12–18 % firing shrinkage.
What is the maximum service temperature of Zircon?
Zircon is rated for continuous use to about 1,500°C (2,732 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Zircon cost?
Zircon is a standard-cost ceramic ($$), cheaper than about 71% 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
- ANSI/ASTM C728 — Standard Specification for Zircon Porcelain (technical ceramic classification) — ASTM International (2019)
- ASM Engineered Materials Handbook, Vol. 4: Ceramics and Glasses — ASM International (1991)
- Handbook of Refractory Practice / Refractories Handbook (zircon and zircon-bonded products) — Harbison-Walker / CRC (2005)
- GB/T 21114 — X (used for zircon assay); GB/T industry grades — SAC (2019)
- Technical zircon ceramic and fused-cast zircon datasheets — CoorsTek / Saint-Gobain / Iluka Resources (2023)
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.