Siretta domestic connector mirror coating delamination prevention and control secret

In electronic devices, communication equipment, and industrial IoT terminals, connectors not only undertake the tasks of signal transmission and mechanical bonding but also bear the important responsibilities of vibration resistance, corrosion resistance, and long-term reliable operation. Taking the British brand Siretta as an example, its RF connectors, cable assemblies, and adapters are widely used in industrial, automotive, and IoT devices. Its official website also explicitly states the characteristics of "high-quality RF / Pigtail cable assemblies, controlling VSWR and return loss."
However, when it comes to the realization of domestic alternative connectors, especially to achieve the performance level of imported brands (such as Siretta), it is necessary to pay special attention to the plating issue. The falling off of the plating (peeling, bubbling, cracking) is a surface problem, but it can lead to an increase in contact resistance, a rise in signal loss, and even connector failure.

The following will combine the relevant characteristics of the Siretta brand + the causes of coating peeling + countermeasures and suggestions, to provide a detailed graphic promotional article for the selection of domestic connectors and solving the coating peeling problem, suitable for the company's independent website product promotion.

One, background information about Siretta connectors
Siretta's product line covers RF adapters, antennas, cable assemblies, industrial wireless modules, etc. The RF accessories page explicitly lists various plug/socket adapters (such as FME, MCX, MMCX, SMA, TNC, etc.) that are suitable for industrial environments.
In the product description of Siretta's RF cable (Pigtail) products, it emphasizes "the use of high-quality components, controlling VSWR and return loss; both 1.13 mm and RG174 cable specifications are available." This indicates that its components have higher requirements in terms of mechanical, signal, and assembly processes.
Although Siretta mainly promotes overall RF components, the details in its coating, contact parts, and cable connection structures (such as contact springs, silver-plated/gold-plated/nickel-plated) also imply performance focuses. Taking it as a domestic alternative option can help improve the "benchmarking" capability of domestic connectors.

This means that when we focus on the plating issue in domestic connectors (especially those replacing Siretta types), it is not just about "appearance," but also a key factor for "reliability," "long-term signal stability," "low contact impedance," "corrosion resistance," and "vibration resistance."

Typical causes of coating peeling off from connectors
The falling off, peeling, bubbling, and cracking of coatings are not uncommon in connector structures. Combining relevant information, we can summarize several key reasons:
Raw material surface insufficient cleaning/activation
If the contact piece of the connector is not thoroughly degreased and descaled before plating and is not micro-texturized, the adhesion between the coating and the base material may be insufficient, which may cause delamination under thermal cycling, vibration, or mechanical impact.
Coating/sub-coating design is not properly designed
For instance, if the gold coating is directly applied to copper without a nickel barrier layer, the gold may diffuse or be affected by mechanical fatigue; or if the coating thickness is too thin, the porosity rate within the coating is high, or the plating solution is polluted, these factors can lead to bubbling, cracking, and peeling.
3. Mechanical / thermal stress / vibration effects
During the process of connector use, insertion and extraction, vibration, and temperature cycling will cause shearing, expansion/shrinkage stresses between the coating and the base material. If the elastic match between the coating and the base material is poor, or microcracks exist, it is possible for the coating to peel off.
4. Environmental corrosion or chemical erosion
If the connector is in a humid, salt mist, or sulfidation atmosphere, once the coating is damaged or bubbled, the corrosive medium entering the base material may accelerate the peeling off of the coating or erosion of the base material.
5. Uncontrolled production process or detection
Contamination of the plating solution, fluctuations in temperature/current, incomplete cleaning, improper part alignment, and impurities, etc., can all lead to the plating layer easily developing defects (such as pinholes, cracks, and uneven coverage) and then falling off.

Therefore, when domestic connectors are to replace imported ones, "deterioration of the coating" is not a minor defect, but an important hidden danger that may lead to a decrease in the reliability of the entire connector system.

Solution for the coating peeling off of domestic connectors
Based on the above causes, combined with actual selection and production suggestions, the following executable solutions are proposed.
Strictly control the pretreatment process of the base material
●Before plating connector parts, it is necessary to thoroughly degrease, remove the oxide film, and perform microroughening or microetching treatment to improve the adhesion of the coating.
For mass production, pre-plating inspection should be conducted: for example, surface residual oil detection, check on the thickness and condition of the oxide film, etc.
●For replacement of Siretta grade high-frequency connectors, it is recommended to check the base material (such as brass, phosphor bronze, tin-plated copper, etc.) to ensure it is suitable for high-reliability applications.
Design the coating structure and thickness reasonably
●Before employing gold (Au) plating or silver (Ag) plating, it is recommended to add nickel (Ni) as an intermediate layer to isolate the base material from the surface, reduce diffusion, and improve mechanical stability. The reference material mentions "nickel under plating can prevent gold from diffusing to the base material."
●The coating thickness must meet the application requirements: for example, tin (Sn) plated on connectors is generally recommended to be ≥100 µinch (about 2.54 µm); gold plated at least 30 µinch (about 0.76 µm) is a reliable standard.
In vibration, high-frequency, and high insertion/extraction situations, hard gold (Hard gold) or hardened alloy gold coating should be considered to enhance wear resistance and fatigue resistance.
Optimize mechanical structure design and stress relief
In the design of connector structures, the mechanical stress borne by the coating should be considered: insertion force, vibration frequency, and expansion/contraction caused by thermal cycles. The selection of spring contact structures, detent locking structures, and stress relief designs (such as cable end stress buffering) can reduce micromotion between the coating and the base material, thereby reducing the chance of coating peeling off.
In the domestic substitution, it is recommended to conduct tests such as vibration, thermal cycling, and plug-in life for products that are "benchmarked against Siretta", with particular attention to whether there is a tendency of cracking or peeling of the coating.
Strengthen process monitoring and quality inspection
In the production process, it is recommended to increase post-plating inspection items, such as coating thickness measurement (such as XRF), adhesion test (such as tape peel test), and microscopic inspection for cracks or bubbles in the coating. The material indicates that "peeling or poor adhesion is a common failure mode of coatings."
●Recommend setting up a Process FMEA and establishing critical control points, such as plating liquid temperature, current density, cleaning steps, degassing steps, and post-plating rinsing/drying processes.
For high reliability applications (such as automotive, rail, wind power, etc.), it is recommended to conduct environmental stress tests (such as salt spray, high humidity, thermal cycling) and observe the coating condition.
5. Consider alternative solutions and spare parts mechanisms at the initial selection stage
●When domestic connectors are to replace Siretta brand, it is recommended to specify coating adhesion, lifespan standards, and repair mechanisms in the contract.
●Suggest that the customer (purchaser) and supplier jointly formulate a "Coating Reliability Agreement": if coating peeling is found during the use of batch products, the supplier must provide compensation or replacement.

●Suggest establishing spare parts or backup plans: when there is a risk of plating off after the first domestic use, quickly switch to imported Siretta or other reliable brands to ensure the progress of the project.

Why is it especially important to pay attention to the plating issue for domestic connectors?
Cost pressure: Domestic connectors often enter the market with a cost advantage, but if insufficient investment is made in plating technology, inspection, and life span control, although the unit price is low, it may lead to rework, scrapping, and downtime due to delamination, resulting in higher long-term costs.
●High requirements for alternative import brands: When the goal is to replace products of overseas brands like Siretta, it is not just about "buying" but "benchmarking performance + lifespan + reliability." The falling off of the coating as a weak point in performance will directly affect the success rate of replacement.
●Signal/Reliability requirements are increasing: With the increasing reliability requirements for connectors in application scenarios such as 5G, automotive, and industrial IoT, the coating, although not eye-catching, may become a system bottleneck. The data has already pointed out that coating thickness, contact force, and temperature range have a significant impact on the lifespan of connectors.

Therefore, when promoting domestic connector products (especially as substitutes for Siretta), highlighting "durable coating," "no risk of coating peeling," and "strict process control" will become selling points.

In summary, although the delamination of the coating on connectors is often regarded as a "surface defect," it is associated with contact performance, vibration resistance, long-term signal stability, and project life cost. Taking Siretta as a benchmark brand, in the process of replacing domestic connectors, the coating process cannot be ignored: from the pretreatment of the base material, coating structure design, mechanical structure matching, process monitoring, and type verification, to contract terms and supply chain parts mechanism, a systematic layout must be made. Only by truly treating "coating reliability" as an integrated requirement for design, production, inspection, and procurement can domestic connectors not only "replace parts" but also "meet performance, reduce costs, and ensure progress" when replacing imported brands.
If you are interested in the domestic substitute products of Siretta brand connectors or have purchasing needs, or if you have production or sales channels for this brand's domestic substitute products and wish to engage in in-depth cooperation or communication, please contact us through the following contact information:Manager Zhang (18665383950, same WeChat number)Contact us, we look forward to working together with more industry partners.