Selective metallization of plastic parts for the aerospace and defense industrie
Replacing all-metal subassemblies with functionalized polymer parts—featuring EMI/EMC shielding, localized conductivity, and environmental resistance—has become a strategic driver for structural weight reduction programs in both civil and military aircraft. DEMGY has mastered the entire range of selective metallization processes, from DFM co-design through to series qualification in a certified EN 9100:2018 / AS9100D environment.
Why is metal being replaced by metallized plastic in the aerospace industry?
Design engineering teams and Tier 1 and Tier 2 suppliers are facing increasingly stringent requirements: weight reduction for electric or hybrid-powered programs, functional integration to limit the number of part numbers managed in each configuration, and EMC compliance in increasingly dense RF environments (multifunction avionics, tactical communications, AESA systems).
Selective metallization of plastic parts addresses all three of these challenges at once:
- Weight reduction without compromising functionality: replacement of aluminum covers, housings, and brackets with engineering polymers (PEEK, PPS, LCP) featuring localized metal plating — typical weight savings of 30% to 55% on an avionics LRU or an onboard communications housing.
- Functional integration: conductive tracks, ground interfaces, EMI shielding, and electrical contacts integrated into the plastic part, eliminating the need for separate components and assembly operations.
- EMC compliance from the design stage: measured and controlled attenuation (≥ 60 dB per DO-160G §21), selective areas defined through co-design with the Tier 1 engineering team.
- Complex geometries: metallization follows 3D surfaces, ribs, undercuts, and channels that are inaccessible to machining—areas where a metal part would require a multi-component assembly.
- Lower total cost of ownership: fewer parts in the bill of materials, shorter assembly cycles, simplified logistics, and a single supplier for the qualified finished part.
Processes mastered: autocatalytic chemical processes, electroplating, PVD
DEMGY has two complementary in-house process families, selected based on the client’s functional requirements and material specifications:
| Method | Deposits | Typical thickness | Primary use in aerospace and defense |
|---|---|---|---|
| Autocatalytic chemical plating (electroless) | Nickel-phosphorus, Copper, Nickel | 3–25 µm | EMC/EMI shielding, galvanic isolation, uniform 3D coverage |
| Electroplating (electrolysis) | Cu, Ni, Cr, Au, Ag | 5–100 µm | Conductive tracks, electrical contacts, wear resistance |
Precision masking — defining functional areas
The geometric precision of the masking determines the quality of the shielding and the integrity of the non-metallized interfaces (RF-transparent areas, sealing surfaces, assembly areas). DEMGY uses:
- Photomasks and dry-resist films for masking tolerances of less than ±0.1 mm on complex parts.
- Custom-machined plugs and collars (PEEK, silicone) for protecting bores and functional surfaces.
- UV resist for geometries with limited access.
- Compliant 3D-printed masks for prototypes and small production runs (rapid iteration during the qualification phase).
Surface activation and adhesion on engineering polymers
The adhesion of the metal coating to high-performance polymers (PEEK, PPS, LCP, PEI)—which are notoriously difficult to metallize—is a key differentiator. DEMGY specializes in the appropriate surface treatments: controlled chemical etching, plasma activation, selective etching, and adhesion promoters specific to each polymer grade. Adhesion is qualified according to ISO 2409 (cross-hatch test) and ASTM B571 (peel test), with results archived in the qualification file.
Application Examples — Avionics and Airframe Components
Application Examples · Avionics
Glass-fiber-reinforced PPS LRU enclosure — Selective Ni/Cu/Ni EMC shielding
Background: Replacement of an aluminum cowling on a Line Replaceable Unit (LRU) for a flight management system, medium-range program.
Problem statement: Achieve an attenuation of ≥ 60 dB between 100 MHz and 1 GHz in accordance with DO-160G §21 and MIL-STD-461G RE102, while integrating grounding interfaces without an insert, on a 14-sided geometry with 4 through-hole connectors.
DEMGY Solution: DFM co-design with the Tier 1 engineering team; electroless Cu (10 µm) + Ni (5 µm) plating on internal surfaces and mounting flanges; precise masking of connector areas (tolerance ±0.08 mm); ASTM B571 adhesion test on qualification samples per batch.
Use Cases · Navigation
PEEK GNSS antenna mount — Galvanized traces and selective contacts
Background: Structural component for a multi-constellation GNSS antenna on a military transport helicopter. Requirements include RF transparency on the radiating surfaces, conductivity on the connection traces, and resistance to salt corrosion (marine environment).
Challenge: Combining non-plated areas (RF transparency) and plated areas (reliable contacts, resistance ≤ 5 mΩ) on a PEEK part with a convex geometry, in a DO-160G §14 (vibration) and §6 (temperatures –55 °C / +85 °C).
DEMGY Solution: Masking of radiating areas with UV-resistant film; PEEK plasma activation + electroless Cu (6 µm) + Au electroplating (1 µm) on contact areas; 500-hour salt spray qualification per ASTM B117. Full batch traceability; COC provided.
Polymer
PEEK 450G (Victrex) — grade certified for fire, smoke, and toxicity according to FAR 25.853
Measured resistivity
3.2 mΩ/sq on conductive tracks — target of ≤ 5 mΩ/sq achieved
Application Examples · Thermal
Composite DHW pipes — Al-PVD reflective coating
Background: Sections of ductwork for an air conditioning system (Environmental Control System) made of thermoplastic composite, for a regional aircraft program.
Challenge: Reduce heat loss in sections passing through areas with variable ambient temperatures; protect assembly areas from condensation without altering the mechanical interfaces.
DEMGY Solution: Aluminum PVD coating (0.5 µm) on the outer surfaces of critical sections; masking of assembly sleeves and mounting flanges; final surface roughness Ra ≤ 0.4 µm to optimize infrared reflectivity.
Applications — Defense systems and onboard equipment
Applications · Electronic Defense
Tactical communications enclosure — Selective Cu/Ni EMI shielding + external reinforcements
Background: Tactical radio unit mounted on an armored vehicle. EMI shielding requirements per MIL-STD-461G (RE102 / RS103), chemical resistance to military fluids (MIL-PRF-5606, JP-8 fuel), and vibration resistance per MIL-STD-810H Method 514.8.
DEMGY Solution: PPS-GF40 housing with internal plating (15 µm Cu + 8 µm Ni) and a passivation layer; external reinforcements located in impact zones (50 µm thick Ni); full environmental qualification with archived test report. Management of waivers and engineering modifications in accordance with defense processes.
Application Examples · Optronics
LCP optical mount — Conductive traces for thermal sighting system
Background: Optronic chassis component for an on-board targeting system for short-range missiles (classified program). Very strict dimensional requirements (controlled thermal expansion), conductivity on integrated power tracks, resistance to pyrotechnic shocks.
DEMGY Solution: LCP (Liquid Crystal Polymer) with low coefficient of thermal expansion; electroless Cu (8 µm) + electroplated Ag (3 µm) on traces; shock qualification per MIL-STD-810H Method 516.8. Part qualified as a FIRST ARTICLE per AS9102.
Certified and compatible polymer materials
The material selection is carried out in collaboration with the client’s engineering team, taking into account the client’s material specifications (AIMS for Airbus, BMS for Boeing, and internal specifications for Safran/Thales/MBDA) and machinability constraints:
| Polymer | Thermal clothing | Typical applications | Metallization compatibility |
|---|---|---|---|
| PEEK | up to 250 °C continuous | Avionics, structural engineering, fluid dynamics | Excellent (plasma activation) |
| Reinforced PPS GF/CF | up to 220 °C | Enclosures, mounts, conduits | Very good |
| LCP | up to 280 °C | Connectors, optoelectronics, high precision | Good (specific etching) |
| PEI (Latest) | up to 170 °C | FFT-certified cabin interior | Very good |
| PSU / PPSU | up to 190 °C | Galley equipment, fluid systems | Bonne |
| PA 6/6, PA 12 | up to 130 °C | Low-voltage connectors, clips, mounts | Excellent (standard) |
| Reinforced civil engineering composites | variable | Structural, secondary aerostructures | Under review (surface and resin) |
Quality, certification, and compliance with aerospace and defense requirements
This is the section that Tier 1 buyers and quality managers read first. DEMGY operates within a quality framework designed to meet the requirements of aerospace and defense programs:
Certifications and quality standards
EN 9100:2018 / AS9100D NADCAP Chemical Processing ISO 9001:2015 EN 13485 (medical sector)
Inspections during manufacturing and upon receipt
| Controlled parameter | Method | Reference standard |
|---|---|---|
| Deposition thickness | X-ray fluorescence (XRF), metallographic sections | ASTM B568, EN ISO 3497 |
| Deposit Adhesion | Test de quadrillage (cross-hatch), peel test | ISO 2409, ASTM B571 |
| Electrical resistivity / continuity | 4-point measurement, mΩ/sq | IPC-TM-650 |
| EMC attenuation / RF shielding | Measurement in an anechoic chamber | DO-160G §21, MIL-STD-461G |
| Surface roughness and appearance | Profile measurement, visual inspection against drawings | ISO 4287 |
| Microhardness | Vickers (HV0.1) | ISO 6507 |
Environmental certification
Deposits are qualified under actual operating conditions: thermal cycles of –55 °C / +125 °C (long-haul flight profiles or engine areas), salt spray for 500 hours per ASTM B117, humidity/heat at 85 °C / 85% RH (500 h), vibration testing on flight profiles and firing tests (DO-160G §8 and MIL-STD-810H).
Traceability and Document Management
- Full batch-to-batch traceability: batch number, operator, date, equipment.
- Certificate of Conformity (COC) provided with every shipment.
- First Article Inspection Report (FAIR) in accordance with AS9102 for the first production shipment.
- Management of waivers and engineering orders in accordance with the client's requirements.
- Monitoring plan and process FMEA available upon request.
Our Project Approach — From Co-Design to Production Qualification
A selective metallization project in the aerospace industry is not just a surface treatment process: it is a collaborative engineering effort between the Tier 1 design office, the DEMGY DFM team, and process experts. Here’s how we work:
- Functional Scope and Requirements Analysis
Review of the client’s EMC, thermal, and mechanical specifications (AIMS, BMS, Thales/Safran specs). Identification of critical interfaces, RF zones, and integration constraints (connectivity, sealing, thermal expansion). - Material Selection and Design for Metallization (DFM)
Selection of polymer based on thermal stability, fluid compatibility, and metallizability. Review of part geometry: draft angles, surface finishes, masking areas, and bath accessibility. Design recommendations if necessary (addition of test areas, modification of fillets). - Process Selection and Rapid Prototyping
Selection of the process sequence (electroless plating / electroplating / PVD). Production of test specimens, functional prototypes, or DOE (Design of Experiments) to validate the combination of polymer × process × thickness. Prototype lead time: 2 to 6 weeks depending on complexity. - First Article Qualification
Test campaign: adhesion, thickness, resistivity, EMC, environmental testing. Preparation of the FAIR in accordance with AS9102. Qualification review with the customer. Freezing of the product range and process parameters. - Industrialization and mass production
Final masking tools. Approved manufacturing procedures and inspection plans. In-line inspection, SPC for critical parameters. Logistics management and scheduled deliveries in line with the production schedule.
Let's discuss your project
Are you working on an aerospace program (A320 Family, A350, H160, ATR, Falcon, CSeries, etc.) or a defense system (FREMM, VBCI, missiles, MALE drones, etc.) that requires selective EMC shielding, localized conductivity, or functional surface resistance on plastic parts?
