Molybdenum Disilicide Powder

molybdenum disilicide powder is an intermetallic ceramic compound with high thermal conductivity, temperature resistance, and oxidation resistance. This guide provides an overview of MoSi2 powder properties, manufacturing methods, industry applications, and suppliers.

Introduction to molybdenum disilicide powder

Molybdenum disilicide is an inorganic chemical compound composed of molybdenum (Mo) and silicon (Si). Key properties include:

Table 1: MoSi2 powder overview

Properties	Details
Composition	Molybdenum – ~65% Silicon – ~35%
Density	6.24 g/cm3
Melting point	2,630°C
Thermal conductivity	~100 W/m-K
Electrical resistivity	18-22 μΩ-cm
Oxidation resistance	Up to ~1,650°C in air

These attributes make MoSi2 useful for heating elements, contacts, and composites able to withstand extremely high temps under load in oxidizing environments.

Chemical Composition and Crystal Structure

The stoichiometric chemistry of molybdenum disilicide consists of:

Table 2: MoSi2 standard composition

Element	Weight %
Molybdenum	~65%
Silicon	~35%

However actual composition can range from MoSi1.75 to MoSi2.2 to tailor properties. The tetragonal unit cell has a body-centered structure with Mo atoms surrounded by Si atoms.

Mechanical and Thermal Properties

Table 3: MoSi2 powder properties

Property	Value
Density	6.24 g/cm3
Melting Point	2,630°C
Thermal Conductivity	~100 W/m-K
CTE	~6.5 x 10-6/K
Flexural Strength	~340 MPa
Compressive Strength	~1,000 MPa
Vickers Hardness	~800 kgf/mm2

The refractory nature, oxidation resistance, thermal shock parameter, and thermal expansion coefficient make MoSi2 suitable for extreme heating element environments.

Production Processes for MoSi2 Powder

Common methods for producing MoSi2 powder include:

Table 4: MoSi2 powder production processes

Method	Description	Particle Characteristics
Self-propagating high-temperature synthesis (SHS))	Combustion synthesis by highly exothermic redox reactions	Irregular morphology, wide distribution
Arc-melting	Electrodes melted in water-cooled copper crucible	Spherical uniform powder
Plasma spheroidization	Arc-melting variant with inert gas plasma	Highly spherical powder
Silicothermic reduction	Reducing molybdenum trioxide with silicon	Agglomerated powder

Advanced methods enable tailoring powder shape, size distribution, purity, density, and microstructure suitable for technical ceramics.

Applications of MoSi2 Powder

Thanks to its thermal and mechanical properties, molybdenum disilicide finds uses across:

Table 5: MoSi2 powder applications

Industry	Application	Components
Heating elements	High temperature furnaces, kilns, boilers	Ignitors, heating coils, plates, rods
Electronics	Contacts, heating elements	Welding electrodes, metallizing contacts
Coatings	Thermal spray, plasma coatings	Shields, inductors, heaters, electrodes
Composites	Discontinuously reinforced composites with metals/ceramics	Crucibles, heat exchangers, radiant tubes

These leverage the exceptional thermal conductivity and stability of MoSi2 for transferring and resisting heat.

MoSi2 Powder Specifications

Typical grades and specifications for molybdenum disilicide powder include:

Table 6: MoSi2 powder specifications

Parameter	Value
Purity	≥ 99.5%
Composition tolerance	MoSi1.75 – MoSi2.2
Particle size	1 – 100 microns
Morphology	Spherical, agglomerated
Phases	α + β MoSi2, traces of Mo5Si3
Applications	Heating elements, contacts, composites

Specialized variations can be produced through doping, alternative production methods, post-processing, and particle size/shape optimization.

Global Suppliers

Leading global producers of molybdenum disilicide powder include:

Table 7: Industrial MoSi2 powder manufacturers

Company	Location
Atlantic Equipment Engineers	United States
Goodfellow	United Kingdom
ESPICorp	United States
Edgetech Industries	United States
Stanford Advanced Materials	United States

These offer MoSi2 powder for heating elements, contacts, and composites applications across grades, particle size distribution, and quantity.

Pricing

Molybdenum disilicide powder pricing depends on:

Table 8: MoSi2 powder price drivers

Parameter	Impact
Quantity	Prices decline with volume from $/g at low quantity to $/kg for bulk
Chemistry	Tighter tolerances and higher purity grades cost more
Size distribution	Broader ranges less expensive than tight distributions
Shape control	Highly spherical powder costs more to produce

In general, MoSi2 powder ranges from $50/lb to $250/lb for specialty grades optimized for additive manufacturing or thermal spray.

Pros vs Cons

Table 9: Advantages vs disadvantages of MoSi2

Pros	Cons
Exceptionally thermally conductive and stable	Relatively brittle with lower strength than metals
Resists oxidation in air to 1650°C	Susceptible to hydrolysis in humid/wet environments
Refractory with high melting point	Very high density results in heavy components
Bio-inert – suitable for food contact	Agglomerated powder can be challenging to fully densify
Enables high energy efficiency electromechanical systems	Limited suppliers compared with metallic materials

With sound design principles, MoSi2 enables lighter, smaller and higher efficiency extreme temperature applications ranging from sensors and semiconductors to aerospace.

Frequently Asked Questions

Q: What is molybdenum silicide used for?

A: Thanks to outstanding thermal stability and conductivity combined with high temperature strength and creep resistance, the primary applications include heating elements, metallizing contacts, composites, and protective coatings.

Q: Is molybdenum silicide conductive?

A: Yes, molybdenum disilicide exhibits electrical resistivity ranging from 18-22 μΩ-cm, making it suitable for heating element contacts able to carry high current densities at extreme temperatures in oxidizing atmospheres.

Q: What is the difference between MoSi2 and MoS2?

A: MoSi2 (molybdenum disilicide) is an intermetallic ceramic compound composed of molybdenum and silicon whereas MoS2 (molybdenum disulfide) contains molybdenum and sulfur. They have vastly different properties, with MoS2 being a lubricant.

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