Parylene Coating Blog by Diamond-MT

Effects of Adhesion Promotion on Sensors

Posted by Sean Horn on Fri, Oct 26, 2018 @ 07:30 AM

Sensors measure specific aspects of data-driven technology.  Included are such performance properties as acceleration, fluidity, humidity/temperature, position, pressure or vibration.  Sensors collect data  and respond with feedback for a multitude of electronic devices utilizing printed circuit boards (PCBs) and related sensitive electronics.  They have been successfully adapted for use across a wide range of applications, including aerospace/military, appliance, automotive, communications, consumer, industrial, medical and transportation uses.  

PCBs and the larger devices they power often need to function in harsh operating environments.  Conformal coatings -- liquid acrylic, epoxy, silicone and urethane resins, and chemical vapor-deposited (CVD) parylene – provide PCBs and similar electronics excellent barrier, dielectric and insulative protection through most performance conditions, sustaining their expected utility.  Substrate adhesion is necessary to conformal film reliability; coatings do not work if they delaminate or otherwise disengage from the components they are applied to protect. 

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Tags: parylene inpsection, parylene adhesion, sensors

Repairing Parylene Delamination

Posted by Sean Horn on Fri, Apr 21, 2017 @ 07:37 AM

Applied as a conformal coating through a unique chemical vapor deposition (CVD) process, parylene provides micron-thin, resilient barrier protection for an exceptional range of electrical assemblies.  In comparison to liquid coatings -- acrylic, epoxy, silicon, urethane -- parylene is the coating-of-choice for protecting printed circuits boards (PCBs) and medical devices.  It’s films negate the impact of gravity and surface tension during the coating process; . 

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Tags: parylene, parylene adhesion, parylene delamination, parylene disadvantages, parylene issues

Five Common Causes of Parylene Failure

Posted by Sean Horn on Fri, Aug 05, 2016 @ 08:00 AM

Parylene Conformal Coatings

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Tags: parylene, parylene disadvantages, parylene issues, medical device coating, parylene adhesion, parylene delamination

The Impact of Temperature on Parylene Adhesion

Posted by Sean Horn on Fri, May 20, 2016 @ 07:30 AM

Basic Thermal Properties of Parylene Conformal Coatings 

CVD-generated parylene combines high thermal stability with a low dielectric constant, minimal moisture absorption, and other advantageous properties which sustain its adhesion to substrate surfaces.  Among the most beneficial of the parylenes’ thermal properties is their ability to function at an exceptional range of temperatures.  Depending on the parylene type, they are operative at temperatures as low as -271º C, and as high as 450º C, representing an ability to perform within a span of 721º C.  

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Tags: parylene, parylene adhesion, silane 1a74

How to Test Parylene Adhesion

Posted by Sean Horn on Fri, May 06, 2016 @ 07:30 AM

The Need for Adhesion Testing

Applied mechanical processes stimulate the binding force between surface molecules required for parylene adhesion to substrates, which is essential to both good parylene performance and assembly/component functionality.  The emergence of conditions characterized by non-adherence and delamination squander parylene’s typically exceptional substrate protection against chemical attack, corrosion and moisture, as well as its superior dielectric insulation (er = 3.1).  

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Tags: parylene, parylene adhesion, parylene adhesion testing

How to Improve Parylene Adhesion to Noble Metals

Posted by Sean Horn on Fri, Apr 22, 2016 @ 07:00 AM

Characteristics of Noble Metals

Selecting the appropriate pre-treatment procedures is a key factor to this success of parylene adhesion to any substance.  Procedures vary quite considerably, according to the materials designated for conformal coating and substrate.  Chemically inert surfaces like gold, silver and other noble metals, and nonpolar thermoplastics such as parylene, are extremely difficult to bond; they require additional surface treatments besides cleaning.  

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Tags: parylene, parylene adhesion, silane 1a74

Does Parylene Adhere Chemically?

Posted by Sean Horn on Fri, Apr 01, 2016 @ 08:10 AM

            Parylene only adheres to substrates mechanically, and this can require assistance from additive substances; parylene’s chemically-based adherence is nonexistent.  Adhesion is a consequence of molecular attraction stimulating the surface unification of two dissimilar substances; their joining creates a significant physical bond between them.  Of the two primary types of adhesion, chemical adhesion results when a compound joins with another, because they share sufficient mutual chemical interaction to form a bond with each other.  Because parylene is chemically inert, chemical adhesion is impossible; it adheres using the other method -- mechanical adhesion.  Applied mechanical processes can stimulate this binding force between surface molecules.   

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Tags: parylene, parylene process, parylene adhesion

Surface Treatments Prior to Parylene Coating

Posted by Sean Horn on Fri, Mar 11, 2016 @ 08:07 AM

Pre-coating Essentials

Poor parylene adhesion negates many of the coating’s most-valued functional properties, including dielectric strength, and resistance to the effects of chemicals, corrosive agents, and moisture.  Surface treatments that amplify the interface adhesion between the deposited parylene and the coated substrate are therefore highly desirable.  These treatments entail depositing parylene on a clean hydrophobic surface before its chemical vapor deposition (CVD) process is enacted.

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Tags: parylene, parylene masking, parylene adhesion, silane 1a74, surface prep

Causes of Parylene Delamination

Posted by Sean Horn on Fri, Feb 26, 2016 @ 08:39 AM

Delamination Problems of Parylene Conformal Coatings

Providing a uniform and pinhole-free substrate coating that is ultra-thin, lightweight and durable, parylene coatings completely conform to targeted components and assemblies.  Parylene CVD generates a structurally continuous film that, with appropriate pre-treatment, penetrates deep within substrate surfaces, rather than simply attaching themselves to substrates as liquid-application coatings do.  These provide effective, dielectrically efficient safeguards with coatings as thin as a fraction of a micrometer.   Parylene is chemically and biologically inert and stable, an excellent barrier material to abrasive chemicals, bodily fluids, solvents, liquid water and water vapor.

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Tags: parylene, parylene adhesion, parylene delamination, parylene issues

What Is the Proper Adhesion Test for Conformal Coating?

Posted by Sean Horn on Fri, Jan 29, 2016 @ 08:09 AM

You've done your research, chosen a conformal coating provider, and coated your device. Now you want to know if the coating properly adhered.

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Tags: conformal coating, parylene adhesion, conformal coating adhesion, adhesion testing