RHEA Coating Technology

Refractory High Entropy Alloys represent the next generation of protective coatings — multi-principal-element systems engineered at the atomic level for performance in environments where conventional alloys fail.

Five-Element Refractory System

DRS RHEA coatings are based on quinary refractory alloy systems combining Mo, W, Ta, Nb, and Re in compositions optimized for target performance profiles. The high configurational entropy of these alloys promotes single-phase BCC or dual-phase BCC+HCP microstructures with exceptional thermal stability.

Unlike conventional binary or ternary alloys, RHEA systems resist phase decomposition at elevated temperatures — maintaining hardness and oxidation resistance where conventional coatings degrade within hours.

42
Mo
Molybdenum
Strength
74
W
Tungsten
High-Temp
73
Ta
Tantalum
Oxidation
41
Nb
Niobium
Ductility
75
Re
Rhenium
Creep Res.

Performance Specifications

Hardness
Vickers, room temperature
700–1200 HV
Max Service Temperature
RHEA TBC systems
1800°C+
Adhesion Strength
ASTM C633 pull-off
>70 MPa
Porosity
Image analysis, HVOF process
<2%
Coating Thickness
Optimized for application
50–500μm
Corrosion Rate
Fluoride salt immersion, 700°C
<10 μm/yr

The DRS Optimization Approach

STEP 01

Computational Alloy Design

CALPHAD thermodynamic modeling and DFT calculations predict phase stability, elastic constants, and high-temperature behavior before any powder is synthesized.

STEP 02

Powder Synthesis & Characterization

Gas-atomized or mechanically alloyed RHEA powders characterized by XRD, SEM/EDS, and particle size analysis to verify composition and morphology.

STEP 03

Spray Parameter Development

Systematic DOE-based optimization of standoff distance, feed rate, carrier gas flow, and flame temperature to achieve target porosity and adhesion.

STEP 04

Performance Validation

Hardness mapping, cross-section SEM, pull-off adhesion, thermal cycling, and corrosion immersion testing against application-specific acceptance criteria.

50–500μm: Precision Thickness Control

DRS coatings are engineered to deliver full protection at 50–500μm — thin enough to preserve dimensional tolerances on precision components while thick enough for long-term service life. Conventional thermal spray often requires 1–2mm for equivalent protection.

50μm
Range
200μm
Range
500μm
Range

REACH-Compliant Chrome-Free Formulations

Hexavalent chromium (Cr6+) is subject to increasing regulatory restriction under REACH and RoHS. DRS RHEA coatings provide equivalent or superior corrosion and wear protection without chromium, enabling compliance with current and anticipated future regulations.

REACH Compliant
RoHS Compatible
No Cr6+ Hazardous Waste
Aerospace Qualified Path

Ready to see process capabilities?

Learn how DRS translates RHEA alloy design into production-ready thermal spray processes.

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