In This Article
Key Takeaways
- ◆Specify the coating formulation, thickness on each face, edge coverage, substrate preparation and cure. Agree a corrosion test method, exposure duration and acceptance endpoint for the actual part, then request its report. Salt-spray hours are not a service-life guarantee.
- ◆Nickel is ferromagnetic. Do not describe NiCuNi as a wholly non-magnetic coating.
- ◆Coating names alone do not establish corrosion hours, vacuum suitability or adhesive strength.
- ◆A parylene or PTFE formulation does not automatically establish finished-device biocompatibility or food-contact compliance.
- ◆Confirm the coating route and reports available for the quoted part.
Define the exposure
NdFeB needs corrosion protection suited to its environment. Record humidity, chemicals, salt exposure, temperature, cleaning and contact with adjacent materials. Include damage that can occur during installation. A generic coating-hour table cannot predict the life of a finished motor.
Nickel-copper-nickel
NiCuNi uses nickel and copper layers. Nickel is ferromagnetic, so any claim that the coating has little magnetic effect must be assessed for its actual thickness and circuit. Define the finished dimensions, layer stack and edge coverage. Check the coating with the intended adhesive and preparation method.
Epoxy and zinc
Epoxy coatings use a polymer barrier whose performance depends on formulation, underlayers, thickness and cure. Zinc systems depend on the deposit and any passivation. Neither name establishes a universal temperature, corrosion duration or cost ranking. Ask for a system proposal based on the exposure and verify it on representative parts.
Parylene and specialised uses
Parylene is a deposited conformal polymer coating. Coverage, defects, adhesion and outgassing need the specified formulation and process data. Medical use requires evaluation of the finished device and its contact conditions, as explained in the FDA’s September 2023 ISO 10993-1 guidance.
Coating a magnet does not establish MR compatibility or sterilisation resistance. Food-contact suitability also depends on the exact formulation, use and applicable requirements.
Qualification and acceptance
Specify the coating formulation, thickness on each face, edge coverage, substrate preparation and cure. Agree a corrosion test method, exposure duration and acceptance endpoint for the actual part, then request its report. Salt-spray hours are not a service-life guarantee. Define adhesion and thickness methods suitable for the substrate and layer system, plus the sampling plan.
Check exposed edges, recesses and damage after assembly. Agree any humidity, chemical or thermal conditioning needed to represent the application.
Reports for the order
Agree which qualification and production reports are supplied, their lot references and the acceptance criteria. Confirm the actual coating provider and process route with the contracting supplier. Check the current certificate for the actual manufacturing entity, address and activity. Agree PPAP level and required reports for the order; a network relationship does not certify every plant or assembly. The previous universal per-batch test and retain-sample promises are not used as an order commitment.
Frequently Asked Questions
How many salt-spray hours does each coating provide?
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Specify the coating formulation, thickness on each face, edge coverage, substrate preparation and cure. Agree a corrosion test method, exposure duration and acceptance endpoint for the actual part, then request its report. Salt-spray hours are not a service-life guarantee.
Is NiCuNi non-magnetic?
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Nickel is ferromagnetic. Evaluate the complete layer stack and thickness in the intended magnetic circuit.
Does parylene make a magnet suitable for an implant?
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Parylene is a deposited conformal polymer coating. Coverage, defects, adhesion and outgassing need the specified formulation and process data. Medical use requires evaluation of the finished device and its contact conditions, as explained in the FDA’s September 2023 ISO 10993-1 guidance. Coating a magnet does not establish MR compatibility or sterilisation resistance. Food-contact suitability also depends on the exact formulation, use and applicable requirements.
Which coating should I specify?
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Start with the exposure, assembly, dimensional and thermal requirements, then qualify the proposed system on representative parts.
What records should accompany a shipment?
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Agree which qualification and production reports are supplied, their lot references and the acceptance criteria. Confirm the actual coating provider and process route with the contracting supplier. Check the current certificate for the actual manufacturing entity, address and activity. Agree PPAP level and required reports for the order; a network relationship does not certify every plant or assembly. The previous universal per-batch test and retain-sample promises are not used as an order commitment.
Send the drawing, operating environment and coating acceptance requirements for a part-specific review.
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