Vacuum Brazing Furnace Use Molybdenum Disilicide Heating Elements/MoSi2 Heater

Vacuum Brazing Furnace Use Molybdenum Disilicide Heating Elements/MoSi2 Heater    Product Description     What’s the Molybdenum disilicide(MoSi2) heating element? Molybdenum disilicide(MoSi2) heating element is one resistance heating component made from MoSi2 or as the basic material. When it’s heated to high temperature under the oxidizing atmosphere, one dense MoSi2film will be formed on its surface to protect the element against oxidizing further. Therefore, the element has unique anti-oxidation property under high temperature atmosphere. The highest temperature can reach 1800°C, the applicable temperature is between 500-1700°C. Applications: It can be used as heating elements of industrial high-temperature furnace, like ceramics, magnetic materials, glasses, metallurgy, refractories etc.   The Specifications and Dimension Mark of MoSi2Heating Element DI: Diameter of Hot Zone(mm) D2: Diameter of Cold Zone(mm) Le: Length of Hot Zone(mm) Lu: Length of Cold Zone(mm) A: Shank Spacing(mm)   When you enquiry, please tell us the following data: D1/D2, Le/Lu, A     Physical and Chemical Properties   1. Physical Property

Volume Density	Bending Strength	Vickers Hardness	Porosity	Water Absorption	Heating Elongation Rate
5.5g/cm³	15-25kg/cm³	(HV)570kg/mm³	7.4%	1.2%	4%

  2. Chemistry Property Under high temperature, MoSi2 heating element will form one SiO2 protective film on the surface, which prevents the element from oxidizing continuously. When the element temperature is over 1700 °C, the film becomes melting. It’s not suitable for long time use in the temperature range of 400-700°C, otherwise, the element will be powdering for the strong oxidation under low temperature.   3. The Influence of Different Atmospheres

Atmosphere	The Max Using Temperature of Element
	1700 Grade	1800 Grade
NO2, CO2, O2, Air	1700 °C	1800 °C
He, Ar, Ne	1650 °C	1750 °C
SO2	1600°C	1700°C
CO, H2	1500 °C	1600 °C
Wet H2	1400°C	1500°C
Dry H2	1350°C	1450°C

    Electric Property   1. Resistance Property The resistivity of element rapidly rises as the temperature rises. Under normal operating conditions, the element resistance generally doesn’t change with the service life, so the old elements can be used with the new elements together.   2. Surface Load Choosing element surface load based on furnace structure, temperature as well as atmosphere, is the key of optimizing element service life. The below picture shows the relationship among the furnace temperature, element temperature and surface load under the circumstance that thermal element radiation is not hindered. The shadow part is for common surface load and temperature range. Recommend Surface Load

Furnace Temp(°C)	1400	1500	1600	1650	1700
Surface load of hot zone(w/cm2)	<18	<15	<12	<10	<8

    Advice of Installation   1.  MoSi2 heating element is very brittle under room temperature but plastic in high temperature, so it’s better to install the U type element hanging vertically. The aim is to avoid putting the mechanical stress directly to the Hot Zone of the element, otherwise, the element will be broken easily. If hanging horizontally installation, please use high temperature refractory for support and hang the MoSi2 element horizontally.   2. Please put the taper part of the element bottom into the furnace chamber to avoid local overheating.   3. The lead wire should be a little longer than the linear distance between the element and bus line to avoid putting the stress to the element.   4. Please don’t tighten the screw of clamps too much at one time. It can be tightened when the element heats up to high temperature because of the element’s plasticity.   5. The temperature of the clip should be less than 200°C, the contact voltage between the clip and the elements less than 0.1V.   6. The distance between the lower end of the clip and the upper surface of the through brick should be more than 50mm, to avoid the radiation heat conducting to the clip.   7. To avoid damage, 170A couldn’t be long time used for the element of Ø6/12mm; 300A couldn’t be long time used for Ø9/18mm element.   ACCESSORIES   OTHER PRODUCTS Notice to Furnace Operation To avoid high current surges which may cause damage to MoSi2 Heating Elements, the recommend starting procedure as following:

Small Furnace (Power <100KW)		Big Furnace (Power 100KW-500KW)
Furnace Temperature .C	Voltage	Furnace Temperature .C	Voltage
20-150	1/3 Working Voltage	20-300	1/3 Working Voltage
150-500	2/3 Working Voltage	300-700	1/3 Working Voltage
500-Working Temperature	Full Working Voltage	700-working Temperature	Full Working Voltage

     Packaging & Shipping 1. Packing First carton packaging with plastic inside to protect, then wooden packaging outside; For some special conditions, use iron hanger outside wooden case. 2. Shipping Fedex/DHL/UPS/TNT for samples, Door-to-Door; By Air or by Sea for batch goods; Customers specifying freight forwarders or negotiable shipping methods; Delivery Time: 3-7 days for samples; 5-25 days for batch goods. Our Services   Company Information       FAQ     Any further question, pls feel free to tell us, and we are very glad to be at your service!   Contact Max Lee Dengfeng City Yuhao High-Temperature Component Co.,Ltd ADD: Sanlizhuang High&New Tec. Zone, Dengfeng, Henan Province,452483,China Tel:+86-371-62768333 Web:http://www.yhheater.com What's app:+86 15903670001 Skype:liyan520tear