MPS  /  MATERIALS  /  REFRACTORY / AM POWDER  /  C103 NIOBIUM ALLOY
C103
Nb-10Hf-1Ti · Nb ALLOY

C103 Niobium Alloy

The flight-heritage nozzle alloy.   C103 (Nb-10Hf-1Ti) atomized for LPBF and EBM. The historic non-cooled rocket-nozzle alloy — RL10, Apollo LM ascent engine, dozens of upper-stage kick motors — now AM-printable.

Program Intake Program Tiers
Composition
Nb-10Hf-1Ti
Standards
AMS 7857 · ASTM B652
PSD cuts
15–45 · 45–106 μm
Process
PA · EB-melt + atomized
Lead time
4 weeks standard
Flight heritage
RL10 · LM · dozens of upper stages
01METALLURGY

C103 (Nb-10Hf-1Ti) is the reference alloy for radiatively-cooled and film-cooled rocket nozzles operating in the 1200–1500°C range. Its flight heritage includes the RL10 upper-stage engine, the Apollo Lunar Module ascent engine, the Aerojet AJ10, and virtually every solid-rocket kick motor above the third stage of major U.S. launch vehicles.

Historical fabrication was spin-forming and machining from wrought sheet. Additive manufacturing of C103 has been qualified since ~2019 for extension nozzles, and is now in production on multiple upper-stage and reaction-control programs. LPBF of C103 delivers thin-wall (< 1 mm) nozzle skirts impossible to spin-form at the same weight.

02SPECIFICATION
Chemistry — C103
AMS 7857 · ASTM B652 · Nb-10Hf-1Ti nominal
Hafnium
9.0 – 11.0 wt%
Titanium
0.7 – 1.3 wt%
Oxygen
≤ 300 ppm
Nitrogen
≤ 100 ppm
Carbon
≤ 100 ppm
Hydrogen
≤ 15 ppm
Morphology
Spherical (PA)
Apparent density
Reported per lot COA under program qualification
Hall flow
Reported per lot COA under program qualification
PSD (LPBF)
Reported per lot COA under program qualification
Recrystallization temp
~ 1200°C
Traceability
Mine → EB-melt ingot → atomization lot → PO
03GRADES & ALLOYS
C103 (Nb-10Hf-1Ti)
Standard AMS 7857 composition. Radiatively-cooled nozzles.
C129Y (Nb-10W-10Hf-0.1Y)
Higher-temperature Nb alloy. Program-specific.
FS-85 (Nb-28Ta-10W-1Zr)
Historic space-nuclear program alloy. Legacy support.
WC-3009 (Nb-30Hf-9W)
High-temperature strength beyond C103.
Nb-1Zr (baseline)
Standard cooled-thrust-chamber alloy. AMS 7846.
04PROCESSING ROUTES
LPBF
Argon atmosphere, O₂ < 200 ppm. Post-HIP + heat treat per AMS 4999-analog.
EBM
Vacuum atmosphere. Emerging route with excellent oxygen control.
Spin-forming
Traditional route from sheet. Legacy support only.
EB-welding
Standard joining route for C103 assemblies.
Silicide coating (R512E)
MoSi₂-based oxidation coating for atmospheric flight applications.
CVD coating
Alternative to R512E for oxidation resistance.
05APPLICATIONS
Aerospace
Radiatively-Cooled Nozzles
Upper-stage engine nozzle extensions. RL10 and derivatives.
Aerospace
RCS & Attitude Control
Small-thruster combustion chambers. Bipropellant RCS.
Space
Kick-Motor Nozzles
Solid-rocket upper-stage motor nozzle exit cones.
Defense
Missile Divert Thrusters
Endo-atmospheric interceptor divert-and-attitude-control thrusters.
Hypersonic
Leading Edges
Emerging: uncoated C103 leading-edge components.
Nuclear-Thermal
Program-Specific
Fuel-element cladding studies. Program-specific.
06QUALITY CONTROL
Chemistry
LECO (O/N/C/H) · ICP-OES for Hf/Ti · GDMS for trace impurities
PSD
Laser diffraction per ASTM B822
Morphology
SEM per lot
Interstitial oxygen
Critical for oxidation-coating adhesion; O ≤ 300 ppm verified
Flight-heritage documentation
AMS 7857 CofC per lot; mill-to-atomizer chain of custody
Coating compatibility
R512E and Hf-oxide coating trials available on request
Every lot ships with a mill-certified Certificate of Conformance (CofC) documenting chemistry, PSD, morphology, flow, and traceability from mill heat through atomization to PO. Retained samples are held per lot for program-life duration.

Move it to a
program.

MPS-1 qualification, MPS-2 production, or MPS-3 strategic supply. 4-week standard lead time on qualified stock.

Program Intake Compare Program Tiers