Silicon carbide heating elements can operate at temperatures that would destroy most metal alternatives, and they do it reliably, sometimes for years at a stretch. Yet two names dominate the field so completely that engineers and procurement teams frequently find themselves comparing them side by side: Starbar and Globar. Both are silicon carbide. Both are capable. Picking the wrong one for your application, though, can mean shortened element life, uneven heating, and expensive downtime.
This guide breaks down the real differences between the two, and more importantly, how to match the right element to your specific furnace environment.
What Are Silicon Carbide Heating Elements?
Before comparing the two products, it helps to understand what silicon carbide (SiC) heating elements actually are and why they occupy such a specific niche in industrial heating.
SiC elements are resistive heating devices made from recrystallized silicon carbide. They generate heat by electrical resistance and are capable of reaching temperatures above 1600°C in the right configuration. Unlike metallic elements such as Kanthal or Nichrome, SiC does not oxidize quickly at high temperatures, and it handles thermal cycling better than most alternatives.
They’re common in ceramics firing, glass manufacturing, semiconductor processing, powder metallurgy, and laboratory research furnaces. The American Society for Testing and Materials (ASTM) has documented SiC’s thermal properties extensively, and the material’s high thermal conductivity combined with low thermal expansion makes it particularly well-suited to precision heating applications.
Starbar and Globar: The Basics
Both names refer to silicon carbide heating elements, but they come from different design philosophies and are optimized for slightly different performance profiles.
Starbar elements are manufactured by I Squared R Element Co. and have been a benchmark in the industry for decades. They are available in a wide range of configurations, including straight, hairpin, multi-shank, and spiral designs.
Globar is a product historically associated with Kanthal (now part of the Sandvik Group). Globar elements are also recrystallized silicon carbide and share the same fundamental operating principles.
The differences lie in construction specifics, resistance characteristics, and the configurations available for particular furnace geometries.
Key Factors to Consider When Choosing
1. Operating Temperature Range
Both element types can handle continuous service temperatures in the range of 1300°C to 1600°C, depending on the specific grade and atmosphere. However, the practical upper limit varies by product grade.
Starbar elements are available in grades suited to particularly demanding high-temperature applications, with some configurations maintaining stable resistance characteristics closer to 1650°C. If your process routinely pushes toward the upper end of that range, confirming the exact grade specification matters more than the brand name itself.
Ask the manufacturer or supplier for the derating curves. These show how element life is affected as you approach the rated maximum temperature, and they tell you far more than a single headline temperature figure.
2. Furnace Atmosphere
This is often the deciding factor, and it gets overlooked more than it should.
Silicon carbide elements perform differently depending on whether the furnace atmosphere is:
- Oxidising (air, or with controlled oxygen levels)
- Reducing (hydrogen, cracked ammonia, nitrogen-hydrogen blends)
- Inert (nitrogen, argon)
- Vacuum
Unprotected SiC elements degrade faster in strongly reducing atmospheres because the protective silica layer that forms on the surface at high temperatures can be stripped away. Certain Starbar grades include specialized surface treatments or coatings designed to extend life in reducing or inert atmospheres. Globar has offered similar grades for these environments.
The key is to specify your exact atmosphere, including any contaminants or process byproducts, before selecting a grade. Your supplier should be able to give you a concrete recommendation based on atmosphere composition.
3. Element Geometry and Furnace Configuration
Heating element selection is as much about geometry as it is about material grade. The physical layout of your furnace, where the elements mount, how they connect electrically, and how much clearance exists around them all affect which product works.
Starbar elements are available in a particularly broad range of geometries. The hairpin (U-shape) design is popular for top-loading furnaces where both terminals need to exit from the same end. Multi-shank designs allow for more surface area in compact spaces. Spiral-wound elements offer lower surface loading, which can extend life in applications where surface watt density needs to be managed carefully.
Globar elements historically emphasized straight rod configurations and certain specialized geometries for the semiconductor and specialty glass industries.
If your furnace has a specific footprint or mounting constraint, geometry availability may narrow your choice quickly.
4. Electrical Resistance Characteristics
SiC elements age. Resistance increases over time, and furnace transformers and controllers need to accommodate this drift without compromising temperature uniformity or tripping protection circuits.
This aging behavior is predictable, but the rate varies by element grade, surface loading, and operating atmosphere. When comparing elements, ask for the initial resistance values and the expected resistance at end-of-life. A larger resistance swing means you need more headroom in your power supply design.
The resistance matching of elements within a furnace zone also matters. Mismatched elements create hot and cold spots. Most reputable suppliers will match elements to within a tight tolerance band, but it’s worth confirming that specification before ordering.
5. Surface Loading and Element Life
Surface loading, expressed in watts per square centimetre of element surface area, is one of the strongest predictors of element life. Running elements at lower surface loading extends their service life considerably, sometimes doubling or tripling it.
As a general rule, SiC elements in continuous high-temperature service should be operated at surface loadings that give a reasonable safety margin below the manufacturer’s stated maximum. For most applications, staying at 70 to 80 percent of the rated maximum is a reasonable starting point.
When comparing Starbar and Globar for a specific application, calculate the surface loading for both based on your required wattage and available element dimensions. The option that gives you more margin at your target wattage is usually the better long-term choice, even if upfront cost is slightly higher.
When Starbar Is Typically the Stronger Choice
Starbar elements have a strong reputation in ceramics, glass, and specialty materials processing, partly because of the depth of available configurations and the technical support infrastructure behind them. Starbar® Silicon Carbide Heating Elements cover an extensive range of grades and geometries, making it easier to find a product that fits an unusual furnace design without resorting to custom fabrication.
For operations that cycle frequently between temperature extremes, the documented thermal shock resistance of certain Starbar grades is worth factoring in. Frequent thermal cycling is one of the fastest ways to shorten SiC element life, and selecting a grade specifically rated for cyclic service can make a measurable difference.
When Globar May Have an Edge
Globar has historically been the specification of choice in some semiconductor processing environments and in furnaces built by OEMs who integrated it into their original designs. If you are maintaining or replacing elements in an existing Globar-equipped furnace, there is practical value in staying with the original specification during an initial replacement cycle, simply to establish a performance baseline before making any changes.
That said, cross-referencing between Starbar and Globar is well-established in the industry, and experienced suppliers can match geometries and resistance values across both product lines.
A Practical Decision Framework
Rather than approaching this as a brand decision, treat it as a specification exercise. Work through these questions in order:
- What is the maximum continuous operating temperature?
- What is the furnace atmosphere and does it contain any reactive gases or contaminants?
- What physical dimensions and terminal configuration does the furnace require?
- What is the total required wattage per zone, and what does that mean for surface loading?
- How frequently does the furnace cycle?
- What is the available transformer voltage range and how much resistance aging can the power supply tolerate?
Once you have clear answers to those six questions, the product selection becomes significantly more straightforward. I Squared R Element Co. maintains detailed technical documentation and application guidance that can help match specific grades to these parameters.
Key Takeaways
- Temperature range, furnace atmosphere, and element geometry are the three most important selection criteria, not brand preference
- Resistance aging over element life needs to be built into your power supply and transformer sizing from the start
- Surface loading is one of the most controllable variables affecting element life; staying below the rated maximum extends service considerably
- Starbar offers a particularly wide range of configurations, which makes it easier to specify for unusual furnace geometries
- When in doubt, work through a formal specification checklist with your supplier rather than selecting based on familiarity alone
Frequently Asked Questions
Can Starbar and Globar elements be mixed in the same furnace zone? It is not recommended. Even if resistance values appear similar at installation, aging rates can differ between element types, leading to imbalanced loading across the zone over time. Where elements need to be replaced, the standard practice is to replace a full zone with matched elements of the same type and grade.
How do I know when a silicon carbide element is approaching end-of-life? The most reliable indicator is resistance. As SiC elements age, their electrical resistance increases. Most furnace operators track resistance during scheduled maintenance and flag elements whose resistance has increased beyond a defined threshold, typically 100 to 150 percent of the initial value, depending on the transformer’s range.
Does furnace atmosphere really affect element life that significantly? Yes, considerably. In a well-controlled oxidising atmosphere, premium SiC elements can deliver thousands of hours of service. In a strongly reducing atmosphere without appropriate element grades or protection, life can be a fraction of that. Always specify atmosphere conditions when selecting a grade.
What is the best way to extend silicon carbide element life? The most effective strategies are: operating at lower surface loading, avoiding unnecessary thermal cycling, ensuring even airflow or atmosphere distribution within the furnace, and not exceeding the rated maximum temperature. Gradual warm-up procedures during initial installation or after a furnace has been cold for an extended period also help.
Is it worth switching from Globar to Starbar if my furnace is already running well? If the furnace is performing within specification and element life is acceptable, there is no compelling reason to switch mid-operation. The practical time to evaluate alternatives is when you are planning a furnace upgrade, changing your process conditions, or finding that current element life is not meeting your expectations. At that point, it is worth doing a proper specification comparison with a knowledgeable supplier. You can contact I Squared R Element Co. to discuss application-specific requirements and get guidance on whether a grade or product change would offer a meaningful benefit.
Conclusion
The Starbar vs Globar question rarely has a universal answer. Both are proven products with long track records in demanding industrial environments. The choice comes down to the specifics of your application: the temperature, the atmosphere, the geometry, and the operating pattern.
What matters most is approaching the selection with the right criteria rather than defaulting to habit or procurement convenience. Silicon carbide elements are a precision tool, and matching the specification carefully to the application is the most reliable way to get consistent performance and acceptable element life from whichever product you choose.