The Complete Guide To Diamond Like Coating(DLC)

Table of Contents

I. Introduction

Material wear has been one of the biggest reasons for many manufacturers’ sleepless nights and worries. The fear of being unable to protect the integrity of a product due to wear often leads manufacturers in many directions to seek a viable solution for maintaining the durability of their products. Thank heavens, diamond-like coating (DLC) has been the saving grace for many manufacturers over the years, helping them keep their products serving their purposes for several years. Fortunately, this article gives you all the information you need to start applying the diamond-like coating in your next project. So, if you are ready, hop on, and let’s ride together. 

II. Understanding Diamond-Like Coating

Diamond-like coating (DLC) is a versatile material protection method used across several industries. It is employed majorly for the preservation of the mechanical properties of a material, including wear resistance and hardness. However, this coating method uses a thin film containing hydrogen, carbon, and other minor elements to enhance the surface finish of most manufacturing materials. Furthermore, the addition of this coating layer gives the substrate or the coated material similar mechanical properties to that of diamond, considering that diamonds are the hardest naturally occurring substance on earth. 

Also, the chemical composition of this coat can vary depending on the proportion giving rise to different types of DLC coating. Tetrahedral amorphous carbon and amorphous carbon, a softer, more malleable variant of the coating, are two DLC coating types. It is also noteworthy that the harder grade of the coating, the tetrahedral amorphous carbon, has more resistance to wear and is applicable for projects with high stress and impact as a critical consideration. 

However, both kinds of DLC coatings have various other advantages, such as corrosion resistance, decreased friction, and biocompatibility, which is important when constructing medical equipment. Though it is not without its downsides, including high cost and decreased film thickness, it still provides more benefits that outweigh its drawbacks.  

III. Applications of DLC Coating

Because it improves the durability, performance, and lifetime of their goods, the unique qualities of this material-enhancing technology easily attract manufacturers and designers. These benefits also reflect the increased profit of many manufacturers, and it’s no wonder they use DLC. 

A typical example of an avid user of DLC is the automotive industry, where several of the parts manufactured will be in motion and in constant contact with other components causing friction. DLC helps significantly reduce these components’ wear, thereby increasing their durability and lifespan. These components include valves, pistons, shafts, and gears coated using DLC coats to improve performance. 

Another industry with critical use of DLC coatings is the aerospace sector, where the allowable margin for error in performance is very small. DLC is often used to increase the performance and quality of several components assembled to form critical modules of various aircraft. Some DLC-coated elements include gears and rotating parts often subjected to friction and rapid wear. 

Again, bioengineers rely on DLC coating’s biocompatibility when building medical equipment such as implants and medical gadgets that must never become contaminated. At the same time, it is being used, as this can be fatal. DLC coating’s biocompatibility ensures that implants remain sterilized and unreactive to chemicals or other biological compounds inside the body. This feature also guarantees the longevity of the medical device. 

Furthermore, innovative manufacturing procedures such as plastic injection molding consider DLC coating during the mold design phase as it can help increase the effectiveness of the molds. Furthermore, DLC coating is frequently applied to equipment and machine bits to enhance performance and minimize wear on the cutting tool, hence increasing the tool’s lifespan. DLC continues to save manufacturers from an early loss and replacement of tools and equipment that can cost significant amounts of money while increasing their efficiency and performance. 

IV. DLC Coating Processes

For a coating process like DLC, unique deposition processes make it more accessible and allow it to be used for various scenarios and project needs. However, each has its own set of pros and downsides. PVD, CVD, and PECVD are three prominent DLC coating processes. 

Physical Vapor Deposition (PVD)

PVD is a popular technique for depositing thin films, including DLC coatings. PVD involves depositing coating material onto a substrate by transferring atoms or molecules from a solid or liquid source through a vacuum or low-pressure gas environment. The arrangement of the substrate and the coating machine is such that the substrate is always in line with the coating equipment, allowing for easy coat deposition on the substrate. The most common PVD methods used for DLC coatings are magnetron sputtering and cathodic arc deposition. In magnetron sputtering, the coating material is vaporized by ion bombardment in plasma, while cathodic arc deposition involves the vaporization of a metal target by an electric arc.

Chemical Vapor Deposition (CVD)

CVD is another popular method for applying DLC coatings. CVD is a method of forming a solid coating that involves reacting a gas-phase precursor with a heated substrate. It produces coating material by decomposing a gas or vapor-phase precursor, which then interacts with the substrate surface to form a solid coating. CVD can provide conformal coatings, which adapt to the substrate’s geometry, making it excellent for coating complicated shapes and geometries.

Plasma-Enhanced Chemical Vapor Deposition (PECVD)

PECVD is a kind of CVD that employs plasma to speed up the deposition process. The gas-phase precursor is activated by plasma in PECVD, which subsequently interacts with the substrate surface to generate a solid coating. PECVD has the ability to create high-quality, homogeneous coatings with outstanding adhesion and mechanical qualities.

Several aspects should be considered when selecting a coating process, including the unique application requirements, the characteristics of the substrate material, the required coating attributes, and the available equipment and expertise. It is critical to thoroughly assess each coating procedure to determine which will best fulfill the demands of the application.

Regardless of the coating processes used, DLC coatings created by any of the technologies listed above have remarkable qualities that make them acceptable for a variety of applications.

V. Material Compatibility and Substrate Preparation

Before applying DLC coatings, it is vital to ensure that the coated material is compatible with the coating. Commonly used materials include stainless steel, titanium, and aluminum sometimes after going through CNC machining or other forms of preparation. Substrates prone to corrosion or having poor adhesion properties may require pre-treatment before coating.

Surface preparation is critical in achieving high-quality DLC coatings. It involves cleaning, degreasing, and removing any contaminants from the substrate. This process can be done through various methods, such as chemical cleaning, mechanical cleaning, and plasma cleaning. Choosing the appropriate cleaning method is essential depending on the substrate and its intended use.

Once the substrate is clean and free from impurities, it is subjected to pre-treatment methods such as ion implantation, surface roughening, or surface activation. Ion implantation involves bombarding the substrate with ions to modify its surface properties. Surface roughening, on the other hand, improves the adhesion of the coating by increasing the surface area. Surface activation techniques such as plasma treatment enhance the wetting and adhesion of the coating to the substrate.

High-quality DLC coatings require good material compatibility and substrate preparation. Choosing the appropriate cleaning and pre-treatment method can significantly improve the adhesion and performance of the coating.

VI. Characteristics of DLC Coatings

Diamond Like Coating

You can be sure to find DLC useful for various types of applications based on its unique features. DLC coatings are notable for their remarkable hardness, wear resistance, and low coefficient of friction. These qualities are obtained by depositing an amorphous carbon thin layer on a substrate. The hardness of DLC coatings is one of its most noteworthy characteristics. DLC coatings are exceptionally hard relative to other coating types, including CrN and TiN.

DLC coatings are therefore suited for use in situations where abrasion and wear are a problem since they can provide greater wear and tear resistance.

Another important feature of DLC coatings is their low coefficient of friction. This property is fundamental in applications such as automotive engines, where reducing friction can result in improved fuel efficiency and reduced wear on moving parts.

DLC coating, in addition to its mechanical qualities, provide high corrosion resistance, making them appropriate for severe situations. You’ll find them very useful in the medical sector, where their biocompatibility has been used in the design and production of medical equipment and devices.

DLC coatings can also exhibit unique optical and electrical properties. Some DLC coatings, for example, have a high refractive index, making them valuable in optical applications. Other DLC coatings, which can be conductive or semiconductive, are valuable in electrical applications.

Overall, DLC coatings are an appealing solution for a variety of applications because of their superior hardness, wear resistance, low friction, corrosion resistance, biocompatibility, and unique optical and electrical features.

VII. Quality Control and Inspection

It is critical to maintain the optimal performance and functionality of Diamond-Like Coatings (DLC) by ensuring appropriate adherence and homogeneity. As a result, quality control and inspection are critical components of the DLC coating process.

To assure the quality of the DLC coatings, several things must be addressed. 

To begin with, critical parameters, including pressure, temperature, and film deposition rate, are essential and need careful assessment and inspection during the coating process. Monitoring these values ensures a quality coating job that leaves a consistent DLC coat on the substrate. 

Secondly, preparing the substrate surface appropriately before coating is important to ensure proper adhesion and avoid coating delamination.

Also, a critical examination of the quality of the coating process is a requirement, and essential non-destructive testing tools like Raman spectroscopy are effective for detecting any errors. These techniques ensure the quality of the coating using factors such as the microstructure of the film and its content to ascertain its quality. Faults and anomalies like discontinuity and cracks are some of the coating defects that these quality assessment methods help to identify. 

Testing and evaluation methods such as microhardness, tribological, corrosion resistance, and scratch testing can be used to assess the mechanical and physical properties of the DLC coatings. These tests can also determine the durability and wear resistance of the coating under different environmental conditions and stress levels.

Proper quality control and inspection ensure that the DLC coatings meet the desired specifications and performance requirements. 

VIII. Cost Factors and ROI

Several factors, most of which are apparent, can significantly affect the cost of carrying out a DLC coating process. One is the complexity of the substrate’s geometry, and another is its size. Also, the coating method adopted during design can significantly add to the coating cost. However, despite the initial investment required, many companies find that the benefits of DLC coating can outweigh the costs, resulting in a positive return on investment (ROI).

The initial investment for DLC coating equipment and setup can range from tens of thousands to millions of dollars, depending on the size and capacity of the coating system. 

The associated overhead cost is another crucial consideration, as the cost of maintaining and running equipment can quickly rack up in a short time. Again, the power consumption and cost of coating materials all add to the cost of running a DLC operation. 

Assessing ROI for implementing DLC coatings involves considering the potential cost savings and performance improvements resulting from the coating. For example, DLC coatings can improve components’ wear resistance and durability, leading to longer service life and reduced maintenance and replacement costs. 

Furthermore, the cost savings from using DLC coatings can be significant when compared to alternative surface treatments or material upgrades. Evaluating the potential cost savings and weighing them against the initial investment and ongoing costs is crucial to determine the ROI of implementing DLC coatings.

A comprehensive cost-benefit analysis is necessary to assess the financial feasibility of implementing DLC coatings, especially in manufacturing procedures like rapid prototyping. Considering the long-term benefits and ROI, many companies find that investing in DLC coating technology is a wise decision that can lead to improved performance, reduced costs, and increased profitability.

IX. Environmental Impact and Sustainability

As sustainability and environmental impact become increasingly important factors in manufacturing, it is essential to consider the eco-friendliness of diamond-like coating (DLC) processes. One significant advantage of DLC coatings is their ability to reduce the use of harmful chemicals commonly found in traditional coating methods. However, the DLC process still generates waste, making examining ways to reduce its environmental impact crucial.

One approach to minimizing waste involves recycling materials used in the DLC process. For example, leftover DLC material can be reclaimed and reused, reducing the waste produced. Another way to reduce waste is to optimize the coating process to minimize material usage.

Compared to other surface treatments, DLC coatings have a smaller environmental footprint due to their reduced use of harmful chemicals. In addition, eco-friendly DLC coatings are available that use only non-toxic gasses during the coating process, further reducing environmental impact.

Innovations and advances in eco-friendly DLC coating practices continue to emerge. For example, some companies are working to develop sustainable DLC coating methods that use renewable energy sources, such as solar power. A couple of other companies are seeking ways to employ sustainable, eco-friendly solvents to replace conventional cleaning chemicals. 

By reducing waste and minimizing the use of harmful chemicals, DLC coatings offer an eco-friendlier option for surface treatment. As the demand for sustainable manufacturing practices continues to grow, developing eco-friendly DLC coating methods will become increasingly important.

X. Choosing the Right DLC Coating Service Provider

Choosing an appropriate DLC coating agency can sometimes be tricky, but a few rules of thumb can easily get you on the right track. An important rule of thumb in locating an ideal DLC coating vendor is to seek one with a consistent history of success and positive reviews. Most times, customer feedback is an excellent way of finding a DLC coating service provider with the capability and expertise to meet your coating needs. The more positive feedback, the higher the probability of getting a high-quality job from such a company. 

Next, assess the technical knowledge and capabilities of the service provider. Do they thoroughly understand DLC coating technology and the latest advancements in the field? Can they provide the specific type of coating you need for your application?

Another equally crucial consideration is the professionalism of the customer service team. Look for a responsive, communicative, and willing provider to work closely with you throughout the coating process. There is an excellent chance that a company with such a customer service team will attend adequately to your coating needs. 

With the world going green, it is safe to say that a company with an eco-friendly bouquet of services will be innovative. Choosing an environmentally conscious provider that uses eco-friendly coating methods can help minimize the environmental impact and promote sustainability.

Take the time to research and evaluate potential DLC coating service providers to ensure that you are choosing the right partner for your project.

To say the future of DLC coating is bright might be an understatement considering the rate at which new technologies keep popping up daily. 

Materials with greater durability and anti-wear properties are predicted to improve DLC coating compatibility for even higher performance and lifetime. Consequently, markets will open for investors willing to fund research and development to proffer solutions to the problem of material corrosion. There is also the possibility of integrating coating into mold manufacturing rather than the post-manufacturing coating process presently available. 

There will also likely be an increase in the demand for DLC coating for industries like the automotive and medical sectors, where the need to improve product performance will majorly depend on the material. 

Nevertheless, challenges will be inevitable as limitations of DLC coating, including peeling and chipping of coating layers under extreme conditions, will require extensive research to solve these challenges. Other limitations that will be extensively researched include environmentally friendly coating techniques. 

On the flip side, one way to make the most out of the increased demand for DLC coating is to invest in researching alternative materials and methods that can give you an edge as a coating provider. 

Furthermore, there is every likelihood that companies and industries will continue to adopt DLC coating as they seek increased product performance which will open opportunities for providers of DLC coating. 

XII. DLC Coating vs. Alternative Surface Treatments

While DLC is a popular coating method employed by several industries for different applications, other coating methods, including TiN and CrN, are also used for material surface finish. Nevertheless, DLC and these other coating alternatives have their best use cases based on their unique properties, substrate shape, complexity, and size, even though their suitability for most anti-corrosion and anti-wear coating, TiN, and CrN has limitations where thermal stress and extreme temperatures are part of the process. DLC, on the other hand, is ideally suited for high-temperature applications and other anti-corrosion and anti-wear coatings. Nevertheless, it is less effective where high adhesive power is required considering that DLC has low adhesive capabilities. When carefully examined, these considerations help decide the best coating method for your coating project. 

XIII. Maintenance and Care of DLC-Coated Components

Employing an innovative coating method such as DLC coating is one thing. Keeping it effective throughout its lifetime is another ball game entirely. The maintenance of these coated items requires consistency and careful consideration. 

Firstly, using harsh chemicals is unacceptable when cleaning a DLC-coated material, as it can adversely affect the integrity of the coat. Also, abrasive materials should never be an option when cleaning these coated components. Soft fabric or brush with water is often adequate. 

Another maintenance consideration for DLB-coated material is their exposure to excessive moisture, as the coating is more effective when dry. Also, routine and periodic checks to identify any defect, including cracks, dents, and chips, to quickly carry out repair works. 

XIV. Conclusion

It might be almost impossible to put a cost to the peace of mind that having a preservation method like a diamond-like coating (DLC) gives a manufacturer, among other numerous benefits like wear resistance. But it might be quite instructive to carefully consider the requirements of any project before deciding to use DLC for material protection in your project. While it also offers dividends in terms of environmental benefits, DLC understands that choosing a DLC service provider can determine if you can enjoy these environmental benefits. Working with the right DLC service provider gives you ample opportunity to enjoy the many benefits DLC can offer you on your project, including high-performing material. The information laid out in this post should come in handy the next time you want to improve your project material’s durability. 


Gary Liao

Gary Liao

Gary Liao is the Engineering Manager of TDL Company and has more than 20 years of mold design experience.

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