PVD & ATM Explained – PVD Coatings Part II
Welcome to part II of understanding PVD Coatings. We will discuss how you can obtain solid and repeatable results with your coating selection, while avoiding the most common mistakes and sales gimmicks.
Following the ATM acronym, you will benefit from a better understanding of “how” and “why” your changes matter, so that you can apply them to other applications with equal success. It also allows you to speak to your coating supplier with common reference, in order to troubleshoot and improve your product’s performance.
Cathodic Arc PVD Coatings
Cathodic Arc PVD Coatings are essential for projects that require an erosion-resistant hard coating. The Cathodic Arc coating allows for a tremendous amount of energy during deposition. It has the ability to receive the best adhesion between the substrate and coating – with proprietary Angstrom Metal Etch and dynamic substrate (Ts/Tm) surface matching – which will ensure the correct surface preparation, prior to deposition of nano-structured materials.
Cathodic Arc PVD Coatings are applied in extremely thin coating layers. They are measured in nanometers, specifically estimating at .0001 of an inch. As a result, DCT can repeat that coating on the surface of your part, precisely ranging +/- 10%. Cathodic Arc PVD coatings will offer you the “Adhesion”, “Thickness Control” and stoichiometric balance “Morphology” that your parts deserve.
Advantages Of Cathodic Arc PVD Coatings:
- Extraordinary adhesion and energy
- Continuous and repeatable, hassle-free performance with consistent thickness
- Accurate and proper control of 3D surface stoichiometry, to ensure consistent and repeatable coating composition (morphology)
PVD Coatings Explained
Out of all the PVD Coating options, the Cathodic Arc PVD allows for the greatest amount of energy provided by PVD Coatings. This is due to the process’s energy originating from the directly ionized cathode target material. In contrast, other PVD Coating Processes – like sputtering – will energize (ionize), an inert gas, causing a ricochet ion to deflect another target material atom (ion) to travel and rest on your part. This “sputtering” coating technique supplies less energy, creating an environment where PVD coatings will not adhere as well to the tool substrate.
The Cathodic Arc PVD Coating Process involves the use of polarity and ionization of metallic materials. These metallic target materials will respond to the use of advanced random arc reducing power supplies and material specific induction (magnetic) fields. This allows for the metallic materials to, gradually, sublimate onto the surface of a substrate. This process, of allowing the ions to discharge through a gas plasma field, creates a “percolated” dense uniform surface. It is run at an atomic level, with the purpose of achieving precisely balanced material properties in a consistent and repeatable manner.
Dayton Coating Technologies can offer you a simple solution, with our problem-solving acronym ATM.
ATM Explained
Our problem-solving acronym ATM will highlight each factor’s value, which goes into determining how well PVD Coatings will perform.
Adhesion is the first and most important factor, in determining how useful a coated part is. Adhesion is worth ten times more than a coated part’s thickness and surface roughness, while a coated part’s surface roughness and thickness is worth ten times more than the morphological structure. For instance, a basic coating, like TiN, can be perfectly adherent with proper thickness and surface roughness. A manufactured part with a TiN basic coating can successfully outperform a premium coating, like AlCrN, that’s poorly adherent with unacceptable thickness and surface roughness.
Much like penicillin as a basic strong antibiotic, certain applications need a higher performance product. However, with an incorrect application, it may be redundant, nowhere near cost effective or just plain incorrect. Allow Dayton Coating Technologies to help you pick the correct PVD coating for your specific application, without any of the smoke and mirrors.
The problem-solving acronym ATM offers you a solid coating solution for your tool’s needs. This dialogue can stay with you, the mutually understood terms and specific observations of ATM. Therefore, DCT’s PVD coating team can adapt to the way that your part is processed, providing just what your part needs on a repeatable basis and with unbeatable results. Open communication between us both can ensure that you receive desirable results.
Being aware of the key questions that are asked, through the PVD Coating Process, will make you an educated customer and, in turn, allow you to choose the best coater for your parts. Just say the word and Dayton Coating Technologies will be more than happy to do it for you. The ATM acronym will make it easier for everyone.
A Data-Proven Acronym
The highly effective strategy DCT employs is the acronym ATM; Adhesion, Thickness, and Morphology.
The answer to PVD and ATM explained is in the pretreatment of your manufactured part, prior to coating. Your manufacturing, and DCT’s application and processing, will determine how well your coated parts perform.
Adhesion
Regardless of the coating you use, you must, initially, prepare the surface of your part to correctly accept the coating that is building on it. Even if the coating is extremely thin, about 2.5 Microns and built up atomically, the surface must be accurately prepared. Modern PVD Coatings are composed of many complex steps with differentiated nanostructured layers.
Manufacturing methods can produce heat and leave behind trace elements or oxide. As a result, it would, then, keep the coating from successfully adhering to the surface. Three of the manufacturing processes that are likely to result in this outcome are EDM, grinding, and machining.
What Prevents Successful Adhesion?
- Lubricants (coolants and oils)
- Nitrides (EDM, surface treatments)
- Oxides (from heat treat or rusting)
PVD Coatings do not adhere to lubricants, oils, recast layers or oxides. In order for your coating to successfully form, oils, oxides and many reacted layers – like FeN (Iron Nitride) – need to be completely removed from your manufactured part. Each surface contaminant is going to require something different, though.
Ultrasonic cleaning lines are a common method, in order to remove oils and loose particles. However, it will not be as effective in reacting surface oxides, like FeO (rust), Nickel Oxides (NiO) and CrOx. Each part will need to be dried completely and correctly, in order to prevent problems – such as rusting, cobalt leaching or left behind water spots. This involves the use of Coating Technicians and Engineers, over a general laborer just running your parts through an expensive dishwasher. Variable frequency ultra-sonics, DI water, pure gas blow offs and precise chemical additions, through the use of active dosing with rigorous titration, are a must.
Careful Handling & Knowledgeable Inspection
A good PVD coating provider thoroughly understands the difference between materials and the use of various techniques. This ensures that the surface of your part is properly conditioned, so that it receives the coating that you requested correctly, in the reactor.
Our highly qualified and experienced team uses a method referred to as HF Scale (Daimler-Benz Rockwell-C adhesion test). We will only authorize HF 0 through HF 2 levels of adhesion. However, others in the industry often allow for HF 3 or 4 levels.
Dayton Coating’s team achieves this with their proprietary Angstrom Metal Etch and Dynamic Substrate (Ts/Tm) Surface Matching, which allows for in chamber Ion cleaning of your parts, even beyond industry standards. It also offers surface stress control that is world class and based on decades of problem solving in the Medical, Aerospace, Automotive and Tooling Industries.
To ensure the perfect pretreatment, based on the substrate material and apparent manufacturing process, your tools will be examined upon receipt. Our team will need to know what the heat treat is, if any polishing is needed, what your part is made of and what areas your tool can be held. These are all important considerations for each and every application.
Thickness & Surface Roughness Control
When having a manufactured part PVD coated, there are some relevant questions to consider:
- Does your part’s surface need a 4 finish or a 12 finish?
- Does your part’s coating need to be in a class 1 or class 3 thickness?
- Are there areas on your part that need extra or very little thickness?
- How do you ensure the coating process is successful and efficient?
- Is a post-treatment needed?
An experienced PVD coater will ensure that these little details are not overlooked. There’s a variety of manufacturing outcomes that can cause dreaded galling and it’s important to discuss those with your coater. That way, you can receive the best overall tool experience.
Manufacturing Outcomes That Cause Dreaded Galling:
- Back taper clearances
- Directional surface conditioning
- Burrs
- Polished over pits
- Oxide on your leading edge
Communicate with our expert customer service technicians. Our team will get to know you better and adjust for your unique manufacturing style. You are the expert and DCT will make every possible adjustment to create a PVD Coating that truly surpasses your adhesion expectations. If there’s an opportunity for improvement, or a challenge, it is critical that we get to the bottom of it and make the solutions stick.
Morphological Structure
High-tech and high-quality PVD Coatings can only be repeated, if the team applying them comprehends the complete manufacturing process.
Remember, materials only include the properties they essentially possess. Regardless of the application, the most successful coating only becomes the solution after the other challenges have been discovered and a plan implemented. A (adhesion) and T (thickness) have to be done perfectly, before moving on to M (morphological). It’s all about the ATM.
Your PVD coating success is, now, a matter of repeatability and DCT is a master at creating a repeatable result. Be it logistics or the physical structure of the coating applied to your part, rest assured our team will be diligent in maintaining the regularity and performance of your product, through monitoring data from every load ever processed and for over twenty years at the facility.
Dayton Coating Technologies is one of the largest CAT ARC PVD suppliers in the area, with half a dozen multi-million dollar reactors from the finest supplier in the world. Check them out at PVT Plasma und Vakuum Technik GmbH.
Customer Success Guaranteed
Allow Dayton Coating Technologies to help guide you in enhancing your tools overall performance. Our quality team only uses the best, advanced technology and methods to bring you highly effective results. Contact our team, today, to get started!
For further reading, check out our Part III of getting to know PVD Coatings.