Glenair Engineering Handbook Excerpt: Plating Codes and Reference Tables
Thoroughly tested and recommended by NAVSEA over nickel-PTFE and zinc-nickel. Glenair TZ is qualified to VG95234 and M28840, and has completed all qualification testing for the yet-to-be-released MIL- DTL-38999 Tin-Zinc specification. Glenair Tin-Zinc alloy—also recently defined as class V in AS85049(5) and class codes L and M (classes T and TJ) in MIL-DTL-28840(8)—consists of an outer layer of chromated conversion coated Tin-Zinc alloy, with a galvanic potential within 0.15V of both aluminum and cadmium, meeting the criteria of an anodic sacrificial finish which makes the material the most viable across-the-board replacement for cadmium. Glenair TZ plating is a RoHS and REACH compliant material and demonstrates improved resistance to SO2 and mixed gases—a critical requirement for the material’s use in naval and armored vehicle applications. Abrasive wear or galling is a critical concern in thread- mating components, and is usually defined as the undesired removal of material from contacting surfaces by mechanical action. Abrasive wear can damage surface plating leading to unwanted corrosion of substrate materials. Glenair Tin-Zinc (TZ) has demonstrated outstanding lubricity and resistance to both adhesive and abrasive wear and has passed all mating cycle durability requirements for connectors and backshells.
Tin-Zinc Cost $ $ $ $ $ Conductivity + + + + + Corrosion Resistance -65° to +175°C Glenair Code TZ
Cadmium Cost $ $ $ $ $$ Conductivity + + + + + Corrosion Resistance -65° to +175°C Glenair Code NF, LF, JF
Cadmium plated aluminum is still in broad use and demand in the defense/aerospace industry. Offering up to 1000 hours of salt spray protection when deposited over
Glenair code TZ is a 70/30 Tin-Zinc alloy sacrificial plating with green / gold chromate over electroless nickel. Tin-Zinc is the most recent and best alternative to cadmium to
electroless nickel, cadmium is highly conductive, and provides good lubricity and resistance to galling. As plated, cadmium has a silvery appearance. A subsequent chromic acid passivation bath creates a chromate topcoat over the cadmium, enhancing corrosion protection. Olive drab chromate is widely used, followed by gold chromate and clear chromate.
be approved by both SAE and the DLA, and offers base metal corrosion protection to 4000+ hours, and remains conductive after 2000+ hours of exposure to salt spray. Tin-Zinc is galvanically similar and compatible to cadmium, and may be used interchangeably with this older (non-RoHS compliant) material.
Zinc-Nickel Cost $ $ $ $ $$ Conductivity + + + + + Corrosion Resistance -65° to +175°C Glenair Code ZN
Electroless Nickel Cost $ $ $ $ $ Conductivity + + + + + Corrosion Resistance -65° to +200°C Glenair Code M, ME
Black Zinc Nickel
Cost $ $ $ $ $ Conductivity + + + + + Corrosion Resistance -65° to +175°C Glenair Code ZR, ZNU
Zinc-nickel plated aluminum was developed as a cost-effective alternative to cad over nickel. Supplied with an olive drab chromate conversion coatings, zinc-nickel plated
Aluminum plated with electroless nickel offers excellent conductivity, wear resistance, and adequate corrosion resistance. Typically specified on electrical connectors and
RoHS-compliant black zinc-nickel is approved for MIL-DTL-38999, AS85049 and other major military specifications as a replacement for cadmium and hexavalent chromium platings.
aluminum may be specified for military airframe and other applications that need to remove non-compliant cad materials but want to maintain the olive drab appearance of interconnect components
accessories used in avionics boxes, exoatmospheric equipment, and missiles, electroless nickel is a good choice when exposure to marine or corrosive atmospheres is not a primary concern. The plating process is purely chemical, and once started, is autocatalytic (it runs by itself). Code M delivers 48 hours salt spray protection, Code ME is higher-durability with 96 hours salt spray.
The non-reflective finish and adequate conductivity make the Glenair ZNU finish a reasonable choice for cadmium- free tactical systems. Corrosion resistance is comparable to cadmium.
QwikConnect • April 2023
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