What Temperature Can MoSi2 Elements Reach? EQ1700, EQ1800, EQ1850 Explained

“How hot can it go?” is usually the first question when someone specs a MoSi2 element. The short answer: the material melts near 2030°C, but a real heating element is rated far below that, and the usable temperature also depends on the gas around it. This article explains the actual limits of the EQ1700, EQ1800 and EQ1850 grades and why atmosphere matters as much as the grade.

Melting point vs working temperature

MoSi2 is an intermetallic compound with a melting point around 2030°C. That number is misleading for design, because an element is never run close to melting. What matters is the temperature at which the protective silica (SiO2) film stays stable and the element survives long term. In air that is about 1850°C for the best grade — which is exactly why HeatingDriver’s top production grade is EQ1850.

The three grades in practice

Grade	Max element temp	What it is really for
EQ1700	1700°C	Everyday high-temperature firing where 1650°C chamber is enough. The most economical choice for ceramics and heat treatment.
EQ1800	1800°C	The dental and technical-ceramics workhorse. Dental zirconia sintering holds around 1450–1550°C, so EQ1800 gives comfortable headroom and long life.
EQ1850	1850°C	Lab and advanced-materials work that genuinely needs 1750–1800°C chambers.

Choosing the grade is about your hold temperature, not the peak. If your process sits at 1700°C, spec EQ1800 so the element never runs at its ceiling — that single decision often doubles service life.

Why the cold end must stay cool

Only the U-bend hot zone runs at the rated temperature. The thick cold ends that exit the furnace wall must stay below about 250°C, otherwise the low-resistance section overheats and the element fails at the clamp. Furnace design therefore has to pull heat out of the terminals — a detail we check on every Φ6/12 element installation drawing.

Temperature versus surface load

The hotter the element, the lower the safe surface load (power per cm² of heated area). Our complete MoSi2 specs page lists the planning values, but the trend is the key takeaway:

At 1700°C a Φ6/12 element can carry roughly 14 W/cm².
At 1800°C that drops to about 11 W/cm².
At 1850°C it is near 8 W/cm².

If you need more power at high temperature, go to a larger diameter (Φ9/18) rather than overloading a small one.

Atmosphere changes the limit

This is the part many buyers miss. The SiO2 protection film only forms and heals in oxidising gas. In reducing atmospheres the limit drops hard:

Atmosphere	Approx. usable limit
Air / oxygen	up to grade max (1700–1850°C)
Nitrogen (inert)	~1500°C (above this it nitrides and embrittles)
Hydrogen / cracked ammonia	~1350°C
Vacuum	Not recommended — the film cannot self-heal

If your process is reducing, read our dedicated guide on how atmosphere affects MoSi2 life before choosing a grade.

Bottom line

For clean air furnaces, EQ1800 covers almost everything dental and ceramic, and EQ1850 covers the extreme end. The real constraints are surface load, cold-end cooling and atmosphere — not the melting point.

About the author: Written by the HeatingDriver technical team, engineers with nearly 20 years of experience in high-temperature heating elements for dental, ceramics and research furnaces. See our full MoSi2 range or send us your temperature and atmosphere profile for a recommendation.

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Why specify with HeatingDriver

Why specify with HeatingDriver — HeatingDriver is a manufacturer and exporter of MoSi2 (molybdenum disilicide) heating elements with nearly 20 years of experience. We supply EQ1700U / EQ1800U / EQ1850U grades for 1700–1850°C, free drawing review, custom sizes and shapes, and technical support for furnace builders worldwide. Browse our MoSi2 heating elements.

What temperature can MoSi2 elements reach?

MoSi2 elements reach up to 1700°C (EQ1700U), 1800°C (EQ1800U) and 1850°C (EQ1850U), depending on the grade.

What does the EQ grade number mean?

The number indicates the maximum continuous furnace temperature in °C, so EQ1800U is rated for service up to 1800°C.

Does temperature depend on atmosphere?

Yes. In air the grades reach their rated temperatures, but in nitrogen, hydrogen or vacuum the usable temperature is capped well below the air rating.