MoSi₂ Heating Element

MoSi₂ (molybdenum disilicide) heating elements can be used in air (oxygen atmosphere) at temperatures of up to 1800 °C. They are able to generate higher temperatures than other materials also used in air, such as Kanthal® (FeCrAl alloy) wire, Nichrome wire, or SiC (silicon carbide) heating elements. Depending on the furnace design, in some cases they can be used at temperatures even higher than 1800 °C. Their many and varied uses include sintering of ceramics (Al₂O₃, ZrO₂, MgO, etc.), glass melting and heat treatment, power semiconductor wafer annealing, and sintering and tempering of various metals. The high-purity MoSi₂ heating elements developed by JX Metals are available in the following grades. Together with their long life (deformation resistance, base material strength, etc.), we provide MoSi₂ heating elements that solve such issues as workpiece contamination (discoloration), overheating, and pest oxidation.

JX Metals has succeeded in extending the lifetime MoSi₂ heating elements by achieving higher purity of the surface oxide layer (oxidation protection layer).The high-purity oxide layer greatly reduces the oxygen diffusion rate, for longer lifetime in a high-temperature oxidizing atmosphere.

Anti-Discoloration Grade keeps a stable oxide layer even after extensive heating use.

We have developed a MoSi₂ heating element that can be use at even higher temperatures than Standard Grade.

Available for furnace temperatures higher than 1800 ℃ even in air,
1900 ℃ Grade can cover wider range of temperature condition than conventional products.

A robust oxide layer is formed on the surface of 1900 ℃ Grade, providing excellent durability in high-temperature use.

Trace of degassing was observed on surface of oxidation layer in Standard Grade.

We have developed a MoSi₂ heating elements that is suppressing “pest oxidation” in low-temperature use. It enabled to use for a long use at low temperatures, which was considered as very difficult conventionally.
This grade would be also applicable for terminal part alone for jointing to other kinds of grades.

In above 1000℃, Si would be oxidized selectively on MoSi₂ (Ⅰ) and an excellent anti-oxidation layer would be formed. On the other hand, at 600 ℃ and below, Mo and Si would be oxidized simultaneously （Ⅱ） and cause to pulverization phenomenon “Pest”. Furthermore, if MoO₃ is formed in defects site, pulverization accelerated due to volume expansion and high vapor pressure of itself.

5MoSi₂ + 7O₂ → Mo₅Si₃ + 7SiO₂…（Ⅰ）
2MoSi₂ + 7O₂ → 2MoO₃ + 4SiO₂…（Ⅱ）

We have developed a MoSi₂ heater that does not release alkali metals and heavy metals, which are sources of contamination, from the heater surface during the high-temperature heat treatment process. It provide a clean heat treatment circumstance such as semiconductor wafers.

SC Grade is confirmed to contain much less impurities than that of competitor.

• Note: Only for reference (NOT guaranteed).

The volume of impurities collected in the test is lower for SC Grade than competitor.

• The deposited Au was deliberately stripped off and accumulated. It is apparent that the surface of inner wall is smooth with no impurities on it.