Silicon carbide (SiC) heating elements are the workhorse of industrial high-temperature furnaces up to roughly…
SiC Heating Elements Complete Guide: Types, Specs & Selection
SiC Heating Elements Complete Guide: Types, Specs & Selection
Before MoSi2 took the ultra-high-temperature segment, silicon carbide (SiC) was — and still is — the default electric heating element for furnaces running up to about 1400–1500°C. If your process sits in that band, SiC is often the cheaper, perfectly adequate choice. This guide covers the element types, the real temperature limits, how SiC behaves electrically, and how to select one.
Already comparing the two? Jump to our MoSi2 vs SiC comparison.
What SiC elements are made of
Heating-grade SiC is made from alpha silicon carbide, formed by recrystallisation or reaction-bonding so the element is a rigid, conductive ceramic. The heated section is the resistive part; ends are treated (or fitted with braided leads) to make the low-resistance terminal connection.
Common types
| Type | Shape | Notes |
|---|---|---|
| ED / UD spiral | Single or double spiral between two terminals | The classic “globar” shape; high surface area in a short length |
| U-type (hairpin) | One bend, two legs | Easy single-wall mounting, common retrofit |
| Straight (rod) | Two terminals, inline | For through-wall mounting |
| Three-piece | Heated rod + separate terminals | Field-replaceable terminals |
See our U-type SiC elements for dental/Ceramil furnaces.
Temperature limits
| Condition | Approx. element limit |
|---|---|
| Air, standard SiC | ~1400°C (element); ~1350°C chamber |
| Air, high-grade / protected | up to ~1500°C (element) |
| Inert / some atmospheres | up to ~1600°C depending on grade |
Above ~1500°C, SiC begins to soften and react, so for anything hotter you should be looking at MoSi2 instead.
Electrical behaviour: SiC ages, and that matters
Unlike MoSi2, SiC has a negative temperature coefficient and, more importantly, its resistance increases with use (“aging”). As the element runs, its surface gradually changes and the cold resistance climbs — sometimes doubling or more over life. That means:
- A transformer or SCR controller must be sized for the end-of-life higher resistance, not the new-element value.
- Matching elements in a circuit by resistance extends pack life.
- When one element drifts too high, the others must push more current — so replace in sets when practical.
We keep reference charts (such as the resistance curve for spiral SiC elements) on hand when sizing replacements.
Surface load
SiC surface-load limits are typically lower than MoSi2 at the same temperature and fall as the element ages. A common planning figure is roughly 8–12 W/cm² at 1300°C for a spiral element, derated for higher temperature and for aged resistance. Underspecifying load is the cheapest insurance against early failure.
How to select SiC
- Confirm temperature: if you need >1500°C chamber, switch to MoSi2.
- Pick the shape that fits your furnace wall and terminal layout.
- Size the controller for aged (higher) resistance, not new.
- Order matched sets so elements age together.
SiC vs MoSi2 at a glance
SiC wins on first cost and is proven up to ~1400°C. MoSi2 wins on temperature ceiling (to 1850°C), stable resistance and long life in air. The detailed trade-off is in our MoSi2 vs SiC guide.
Related guides
- Molybdenum disilicide heating elements
- Silicon carbide heating elements
- MoSi2 vs SiC heating elements guide
- W-type MoSi2 heating elements
- Silicon carbide heating elements complete guide
Why Specify Silicon Carbide (SiC) heating elements with HeatingDriver
HeatingDriver is a manufacturer and exporter of Silicon Carbide (SiC) heating elements with nearly 20 years of experience supplying furnace builders, labs, and integrators worldwide. We stock standard grades and build custom sizes from your drawings, and we review your element drawings free of charge before production. Browse our Silicon Carbide (SiC) heating elements catalog or contact our engineers for a quote.
Frequently Asked Questions
Q: What temperature can SiC heating elements really hold?
In air, standard silicon carbide runs at roughly 1400°C at the element with a chamber temperature near 1350°C, and higher grades or protected conditions reach about 1450°C. Above that band the material begins to soften and react, so MoSi2 is the correct choice for hotter clean air work.
Q: Why does the resistance of a SiC element increase over time?
Silicon carbide ages. The element surface gradually changes in service and the cold resistance climbs, sometimes doubling or more over the life of the element. Size the transformer or SCR controller for the end of life resistance rather than the value of a new element.
Q: What surface load should I use when planning?
A common planning figure is roughly 8 to 12 W/cm2 at 1300°C for a spiral element, derated for higher temperature and for aging. Divide the total wattage by the hot zone area to check the design.
Q: Which SiC element type should I pick?
ED and UD spirals give a large surface area in a short length, U type hairpins mount through a single wall and suit retrofits, straight rods suit through wall mounting, and three piece elements allow the terminals to be replaced in the field.
Related SiC guides
- SiC Heating Element Selection Guide
- SiC Heating Element Specifications
- SiC Heating Element Applications
- double-spiral SiC heating elements
- ED 14/130/105 SiC heating element
- ED 20/24/75 SiC heating element
Explore the full SiC heating element range or contact us for a custom quote.
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