CoCr28Mo6 Powder

Overview of CoCr28Mo6 Powder

CoCr28Mo6 powder, also known as ASTM F75 alloy, is a cobalt-chromium-molybdenum alloy powder used for manufacturing of orthopedic implants due to its biocompatibility, high strength and corrosion resistance.

It has excellent wear resistance and is commonly used for making hip, knee and dental implants. The “28Mo6” designation indicates it contains 28% chromium and 6% molybdenum.

Key properties and advantages:

CoCr28Mo6 Powder Properties and Characteristics

Properties	Details
Composition	Co-28Cr-6Mo alloy
Density	8.3 g/cc
Particle shape	Irregular, angular
Size range	10-45 microns
Apparent density	4.0-4.5 g/cc
Flowability	Moderate
Corrosion resistance	Excellent due to passive oxide layer
Biocompatibility	High, used for implants
Wear resistance	Very good due to high Cr content
Cost	Moderate to high

CoCr28Mo6 powder can be used to manufacture implants using 3D printing or traditional techniques like metal injection molding. It provides an optimal combination of mechanical properties, corrosion resistance and biocompatibility.

CoCr28Mo6 Powder Composition

Typical composition of CoCr28Mo6 powder:

CoCr28Mo6 Powder Composition

Element	Weight %
Cobalt	Balance
Chromium	27-30%
Molybdenum	5-7%
Nickel	<1%
Manganese	<1%
Carbon	<0.35%
Iron	<0.75%
Silicon	<1%

• Cobalt provides strength, toughness, and biocompatibility
• Chromium improves corrosion and wear resistance
• Molybdenum contributes to high strength and hardness
• Other elements like C, Ni, Mn, Fe, and Si present as impurities

The high Cr and Mo content result in excellent mechanical properties required for load bearing implant applications.

CoCr28Mo6 Powder Physical Properties

CoCr28Mo6 Powder Physical Properties

Properties	Values
Density	8.3 g/cc
Melting point	1350-1400°C
Thermal conductivity	18 W/mK
Electrical resistivity	94 μΩ-cm
Curie temperature	1329°C
Coefficient of thermal expansion	14.5 x 10^-6 /K

• High density compared to titanium alloys
• Maintains strength at elevated temperatures
• Lower thermal conductivity than pure metals
• Becomes paramagnetic above Curie temperature
• CTE higher than other competing alloys

These properties make it suitable for high temperature load bearing implant applications requiring corrosion resistance.

CoCr28Mo6 Powder Mechanical Properties

CoCr28Mo6 Powder Mechanical Properties

Properties	Values
Hardness	35-45 HRC
Tensile strength	170-220 ksi (1170-1510 MPa)
Yield strength	140-180 ksi (965-1240 MPa)
Elongation	8-16%
Modulus of elasticity	230-300 GPa
Fatigue strength	50 ksi (345 MPa)

• Excellent combination of strength and ductility
• Strength levels exceed requirements for load bearing implants
• Hardness provides good wear and abrasion resistance
• High fatigue strength ensures durability under cyclic loading

The mechanical properties make CoCr28Mo6 suitable for orthopedic implants experiencing high static and dynamic loads.

CoCr28Mo6 Powder Applications

Primary applications of CoCr28Mo6 powder include:

CoCr28Mo6 Powder Applications

Application	Examples
Orthopedic implants	Hip, knee, dental implants
Medical devices	Surgical tools, instruments
Aerospace	Turbine engine components
Automotive	Fuel injection parts
Industrial	Valves, tooling, molds

Some specific product uses:

• Articulating surfaces in joint replacement implants
• Dental crowns, bridges and root implants
• Orthopedic fixation devices like bone plates
• High temperature resistant aerospace engine components
• Automotive fuel injection nozzles
• Cutting tools, gaskets, valves requiring wear resistance

The biocompatibility, corrosion resistance and tribological properties make CoCr28Mo6 highly suitable for orthopedic and dental applications.

CoCr28Mo6 Powder Specifications

Key standards for CoCr28Mo6 powder:

CoCr28Mo6 Powder Standards

Standard	Description
ASTM F75	Wrought Co-Cr-Mo alloy for surgical implants
ASTM F1537	Specification for wrought Co-Cr-Mo alloy for dental appliances
ISO 5832-4	Implant grade wrought Co-Cr-Mo-Ni alloy
ASTM F3056	Specification for additive manufacturing CoCr alloy for orthopedic implants

These standards specify:

• Chemical composition limits
• Mechanical property requirements
• Production method (gas atomization)
• Acceptable impurity levels
• Quality assurance processes
• Test methods to verify powder properties

Meeting these requirements ensures suitability for orthopedic implant applications.

CoCr28Mo6 Powder Particle Size

CoCr28Mo6 Powder Particle Size Distribution

Particle size	Characteristics
10-25 microns	Used for laser powder bed fusion (LPBF)
25-45 microns	Used for binder jetting and DMLS
15-45 microns	Used for metal injection molding

• Finer powder provides better resolution and surface finish in AM
• Coarser powder improves flowability for powder processing
• Size range selection depends on production technique used
• Tight control over particle size distribution is maintained

Controlling particle size and morphology is critical for high powder packing density and optimized sintering.

CoCr28Mo6 Powder Apparent Density

Typical apparent density:

CoCr28Mo6 Powder Apparent Density

Apparent density	Characteristics
4.0 – 4.5 g/cc	Irregular powder morphology
35-45% of true density	Due to voids between particles

• Higher apparent density improves powder flow and compressibility
• Irregular shape and wide size distribution reduces packed density
• Values up to 60% are possible with optimized spherical powder

Higher apparent density allows efficient powder pressing and sintering to full density. It improves manufacturing productivity.

CoCr28Mo6 Powder Production Method

CoCr28Mo6 Powder Production

Method	Details
Gas atomization	High pressure inert gas breaks up molten alloy stream into fine droplets
Vacuum induction melting	High purity starting materials melted under vacuum
Multiple remelting	Improves chemical homogeneity
Sieving	Classifies powder into different size fractions
Blending	Different powder sizes blended to customize particle size distribution

• Gas atomization produces fine spherical powder morphology
• Vacuum melting and multiple remelting minimize impurities
• Post-processing provides fine control over particle size distribution

Automated production and strict process control ensures reliable and consistent properties of CoCr28Mo6 powder.

CoCr28Mo6 Powder Pricing

CoCr28Mo6 Powder Pricing

Factor	Impact on Price
Powder grade	Higher purity grades cost more
Particle size	Ultrafine powder more expensive
Order quantity	Price reduces for bulk orders
Packaging	Argon filled containers increase cost
Testing requirements	More rigorous testing increases cost
Lead time	Faster delivery times increase price

Indicative Pricing

• CoCr28Mo6 for medical: $80-120 per kg
• CoCr28Mo6 for industrial: $50-90 per kg

Reduced prices applicable for bulk orders exceeding several hundred kilograms.

CoCr28Mo6 Powder Suppliers

CoCr28Mo6 Powder Suppliers

Company	Location
Carpenter Powder Products	USA
Praxair	USA
Sandvik Osprey	UK
Hoganas	Sweden
Erasteel	France
Aubert & Duval	France

Factors for selecting supplier:

• Powder grades available
• Production capacity
• Powder quality and consistency
• Compliance to medical standards
• Pricing and minimum order quantity
• Lead time and delivery reliability

Medical grades require more rigorous quality control and testing.

CoCr28Mo6 Powder Handling and Safety

CoCr28Mo6 Powder Handling

Recommendation	Reason
Avoid inhalation	Due to risk of lung tissue damage from fine particles
Use protective masks	Prevent accidental ingestion
Handle in ventilated areas	Reduce airborne particle circulation
Use hazmat suits	Minimize skin contact
Ensure no ignition sources	Powder can combust in oxygen
Follow anti-static protocols	Prevent fire from static discharge
Use non-sparking tools	Avoid possibility of ignition during handling
Store in sealed containers	Prevent contamination and oxidation

CoCr28Mo6 powder is relatively inert but general precautions are recommended for safe handling and processing.

CoCr28Mo6 Powder Inspection and Testing

CoCr28Mo6 Powder Testing

Test	Details
Chemical analysis	Verifies composition using ICP spectroscopy
Particle size distribution	Determines distribution using sieve analysis
Apparent density	Measured as per ASTM B212 standard
Powder morphology	SEM image analysis
Flow rate analysis	Time taken for fixed powder quantity to flow through funnel
Tap density test	Density measured after mechanical tapping

Rigorous testing ensures consistent powder quality and compliance with specifications like ASTM F75 for medical grade powder.

CoCr28Mo6 Powder Storage and Handling

CoCr28Mo6 Powder Storage

Factor	Effect
Air, oxygen	Risk of oxidation at high temperatures
Moisture	Low corrosion rate at room temperature
Hydrocarbons	Fire hazard if allowed to contaminate powder
Acids, alkalis	Resistant to dilute acids and bases
Organic solvents	Some absorption and staining if immersed
Temperatures above 400°C	Increased oxidation rate in air

Recommendations:

• Store sealed in inert gas filled containers
• Keep below 30°C temperature
• Avoid contact with oxidizing acids and chlorinated solvents
• Open containers only in controlled environments

With proper precautions, CoCr28Mo6 powder exhibits good stability during storage and handling.

Comparison With Stainless Steel Powder

CoCr28Mo6 vs. Stainless Steel Powder

Parameter	CoCr28Mo6	Stainless Steel
Density	8.3 g/cc	7.9 g/cc
Tensile strength	1170-1510 MPa	600-1100 MPa
Ductility	8-16%	15-40%
Corrosion resistance	Excellent	Good
Wear resistance	Excellent	Moderate
Biocompatibility	High	Moderate
Cost	High	Low
Uses	Medical implants, aerospace	Industrial applications

• CoCr28Mo6 has higher strength and hardness
• Stainless steel provides better ductility and toughness
• CoCr28Mo6 is more corrosion resistant
• CoCr28Mo6 is preferred for biomedical applications
• Stainless steel is more cost-effective

CoCr28Mo6 outperforms stainless steel for applications requiring high strength, hardness and corrosion resistance.

CoCr28Mo6 Powder Pros and Cons

Advantages of CoCr28Mo6 Powder

• Excellent biocompatibility and corrosion resistance
• High strength and hardness
• Good wear resistance
• High temperature capability
• Can be processed using AM or MIM techniques
• Suitable for load-bearing implant applications
• Provides good aesthetic appearance

Limitations of CoCr28Mo6 Powder

• More expensive than stainless steel or titanium alloys
• Lower ductility and fracture toughness
• Requires protective atmosphere during processing
• Difficult to machine compared to other alloys
• Limitations in joining and welding the material
• Release of Co ions in body raises health concerns

CoCr28Mo6 Powder FAQs

Q: What are the main applications of CoCr28Mo6 powder?

A: The main applications are orthopedic joint replacement implants like hips and knees, dental implants and crowns, surgical instruments, and high performance aerospace components.

Q: What gives CoCr28Mo6 excellent corrosion resistance?

A: The high chromium content enables formation of a stable, continuous and self-healing protective oxide layer on the surface preventing corrosion.

Q: What are the key differences between medical and industrial grades of CoCr28Mo6 powder?

A: Medical grade powder has higher purity, lower impurities, finer particle size, better size distribution control, and goes through more rigorous testing to meet standards like ASTM F75.

Q: What precautions are required during storage and handling of CoCr28Mo6 powder?

A: Recommended precautions include avoiding inhalation, using protective gear, ensuring proper ventilation, controlling static discharge, using non-sparking tools, and storing in sealed inert gas purged containers.