ZnO Varistor
ZnO Varistor material is a grain-boundary functional ceramic, zinc oxide doped with Bi2O3 and other oxides, whose highly non-linear voltage-current response is the basis of metal-oxide varistors for surge protection.
Reference datasheet — ZnO Varistor 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.
ZnO Varistor tempers and conditions
ZnO Varistor is supplied in 3 conditions, soft to hard.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Low-voltage varistor ceramic | Pick for low-voltage MOVs and multilayer chip varistors protecting 3–60 V electronics; coarse ZnO grains give low varistor voltage but very high capacitance. | 48 | 0.05 | 370 HV | 20 W/m·K | |
High-energy arrester block | Pick for MV/HV metal-oxide surge arresters (IEC 60099-4, GB/T 11032): large-diameter blocks optimized for energy absorption and long-term ageing stability rather than compactness. | 58 | 0.05 | 410 HV | 20 W/m·K | |
High-gradient fine-grain ceramic | Pick where volume must be minimized — GIS/HVDC arresters, compact surge modules; fine grains raise the switching gradient but demand tight sintering control to keep energy handling. | 65 | 0.05 | 450 HV | 15 W/m·K |
Supply forms, finishes and certifications
Ways ZnO Varistor is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
STDDefault | Standard surge-suppressor disc ceramic | Standard supply |
What is ZnO Varistor?
ZnO Varistor material is a grain-boundary functional ceramic, zinc oxide doped with Bi2O3 and other oxides, whose highly non-linear voltage-current response is the basis of metal-oxide varistors for surge protection. It is supplied as pressed discs and blocks or tape-cast chip laminates in LV, STD, ARR and HG conditions, with a density of 5.55 g/cm3 and 18 W/(m.K) thermal conductivity. Maximum continuous service temperature is 125 C, the fired body is brittle and diamond-ground only, and side surfaces must be passivated to prevent flashover. ZnO Varistor has a density of 5.55 g/cm³ (0.201 lb/in³), heavier than 55% of ceramic grades. It melts at 1,975°C (3,587 °F). The elastic modulus is 120 GPa (17.4 Msi).
What is ZnO Varistor used for?
- surge arresters
- MOV transient suppressors
- power line protection
Advantages
- Low embodied carbon — 3.6 kg CO₂/kg, better than 80% of ceramic grades
Limitations
- Limited service temperature — 125°C (257 °F), worse than 94% of ceramic grades
- Needs corrosion protection — 45/100, worse than 90% of ceramic grades
- Hard to polish — 60/100, worse than 79% of ceramic grades
ZnO Varistor properties
Typical room-temperature values; bars are the position among ceramic grades.
Physical3
ZnO Varistor has a density of 5.55 g/cm³ (0.201 lb/in³), heavier than 55% of ceramic grades. It melts at 1,975°C (3,587 °F).
Mechanical9
The elastic modulus is 120 GPa (17.4 Msi).
Thermal5
ZnO Varistor is rated for continuous service to 125°C (257 °F). It conducts heat at 18 W/m·K (10.4 BTU/hr·ft·°F), worse than 56% of ceramic grades. Thermal expansion is 6.5 µm/m·K (3.61 µin/in·°F).
Electrical5
ZnO Varistor is an electrical insulator with a dielectric strength of 0.2 kV/mm (5.08 V/mil) and a resistivity of 1×10⁸ Ω·m.
Chemical & Environmental2
Corrosion resistance is fair (45/100), worse than 90% of ceramic grades.
Sustainability4
Producing a kilogram of ZnO Varistor takes about 55 MJ of energy and emits 3.6 kg of CO₂ — less than 78% of ceramic grades. Typical recycled content is 5%.
Manufacturability3
ZnO Varistor's machinability is not recommended (10/100, better than 76% of ceramic grades).
Common Calculations2
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. ZnO Varistor is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ZnO Varistor
Is ZnO Varistor easy to machine?
Green bodies are readily machined/punched; fired ceramic requires diamond grinding or lapping — barrel/edge grinding before side passivation is the normal finishing step.
Can ZnO Varistor be welded?
Not weldable; blocks are joined to metal end caps by flame/arc-sprayed Al electrodes, solder or conductive adhesive, and stacked with spring compression in the arrester housing.
Can ZnO Varistor be formed, bent or molded?
Spray-dried doped ZnO powder is uniaxially or isostatically pressed (or tape cast/laminated for chip varistors), binder-burned at ~500 °C and liquid-phase sintered at 1050–1250 °C with a controlled slow cool to develop grain-boundary barriers.
ZnO Varistor 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 |
|---|---|---|
| Bi2O3grain-boundary liquid/barrier former (Pr6O11 in some formulas) | 0.3 – 2.5 | 1 |
| Sb2O3forms spinel phase, inhibits grain growth | 0.3 – 2 | 1.2 |
| CoOraises nonlinearity coefficient α | 0.2 – 1.5 | 0.6 |
| MnO2deep-level acceptor, improves the barrier | 0.1 – 1 | 0.4 |
| Cr2O3aging resistance | 0.1 – 1 | 0.3 |
| NiOaging resistance / lower leakage current | 0.1 – 1.5 | 0.5 |
| SiO2controls grain size; high content in high-gradient formulas | 0 – 1.5 | 0.5 |
| Al2O3donor dopant, lowers grain resistivity | 0 – 0.05 | 0.01 |
| B2O3 / glass fritside insulating glaze/flux (process dependent) | 0 – 1 | 0.2 |
| ZnOmain phase, semiconducting grains | ≥ 88 (balance) |
What surface finishes work on ZnO Varistor?
Side surfaces are coated with high-resistivity glass/ceramic passivation or silicone/epoxy to suppress flashover; flat faces are ground then Al-metallized (arc spray) for ohmic contact.
How much does ZnO Varistor cost?
ZnO Varistor is a high-cost ceramic ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
ZnO Varistor — frequently asked
What is ZnO Varistor used for?
ZnO Varistor is typically used for surge arresters, MOV transient suppressors and power line protection. In short: non-linear surge protection ceramic; basis of metal-oxide varistors; grain-boundary functional oxide.
Is ZnO Varistor easy to machine?
Not especially — machinability is rated not recommended (10/100, better than 76% of ceramic grades). Green bodies are readily machined/punched; fired ceramic requires diamond grinding or lapping — barrel/edge grinding before side passivation is the normal finishing step.
Can ZnO Varistor be welded?
Not weldable; blocks are joined to metal end caps by flame/arc-sprayed Al electrodes, solder or conductive adhesive, and stacked with spring compression in the arrester housing.
What surface finishes work on ZnO Varistor?
Side surfaces are coated with high-resistivity glass/ceramic passivation or silicone/epoxy to suppress flashover; flat faces are ground then Al-metallized (arc spray) for ohmic contact.
Can ZnO Varistor be formed, bent or molded?
Spray-dried doped ZnO powder is uniaxially or isostatically pressed (or tape cast/laminated for chip varistors), binder-burned at ~500 °C and liquid-phase sintered at 1050–1250 °C with a controlled slow cool to develop grain-boundary barriers.
What is the maximum service temperature of ZnO Varistor?
ZnO Varistor is rated for continuous use to about 125°C (257 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does ZnO Varistor cost?
ZnO Varistor is a high-cost ceramic ($$$$), 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
- IEC 61051-1/-2 Varistors for use in electronic equipment — IEC (2018)
- IEC 60099-4 Surge arresters — Metal-oxide surge arresters without gaps for a.c. systems — IEC (2014)
- Engineered Materials Handbook Vol.4: Ceramics and Glasses — ASM International (1991)
- Varistor Ceramics — review of ZnO grain-boundary devices (J. Am. Ceram. Soc.) — American Ceramic Society (1999)
- EPCOS/TDK Metal Oxide Varistors — general technical information — TDK Electronics (2023)
- Littelfuse Varistor Products — MOV application notes — Littelfuse (2022)
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.