CVD coating on Jewelry
Chemical Vapor Deposition (CVD) coating is widely used in the industrial world and is commonly found in many consumer merchandises such as Jewelry. CVD is known to be environmentally friendly and has a strong durable thin film. Some common applications of CVD coating can on found in machine tools, wearable components such as jewelry and accessories, analytical flow path components, and other materials that require performance-based thin films.
Considering the vast amount of coating techniques present, what makes CVD coating superior and a better choice compared to others? How is the coating done? How thick is the coating? What are the Pros and Cons of CVD coating? Well, all these questions and more will be answered.
Let’s jump right into it!
What is CVD Coating?
A Chemical Vapor Deposition (CVD) coating is the deposition of a hard layer of materials unto a product or accessory in a Gas Phase Process. CVD is an atmospherically controlled process carried out at high temperatures in a reactor (~1925° F).
During the process, a thin film of coating is formed due to the reaction between the gases present and the heated surface of the material to be coated. By utilizing different gases in the process, several CVD coating layers are formed on the material of choice.
Why CVD coating?
The main reason behind using CVD coating on tools and accessories is to lower the manufacturing cost per part. In addition to lower costs, there is also increased efficiency and durability. You can operate CVD-coated appliances at increased speeds and wear CVD-coated jewelry for extended periods without worrying.
By using CVD coating, you will be able to save a lot. CVD coating offer:
Increased production rates + Reduced jewelry cost due to extended life with coating = Significant savings for your company.
With CVD coating, you can save more which can go towards the company’s profit. Not only that but there will be increased customer satisfaction as CVD coating provides a beautiful long-lasting finish. Research has shown that CVD coating offers 10x life expectancy compared to an uncoated piece of jewelry.
How is the CVD Coating Process on Jewelry carried out?
The Chemical vapor deposition process involves injecting a volatile material into a chamber (under vacuum) that will be heated and deposited on a piece of jewelry or accessory. The volatile material is heated inside the chamber to a high temperature where it will start to react and break down into vapor form which will act as the coating. It will then be bonded to the surface of the jewelry.
CVD is normally used to administer titanium nitride coatings on tools and jewelry. The process is as follows:
1) Several chemicals, titanium tetrachloride, nitrogen, and hydrogen, are fed into a chamber at a high temperature to produce Titanium Nitride.
2) The titanium tetrachloride will be in liquid form and must be completely vaporized so it can react with the other chemicals to produce Titanium Nitride. Improper vaporization of titanium tetrachloride can lead to contamination from different gaseous mixtures.
3) The titanium nitride produced will be deposited on the jewelry as the coating material. To produce the proper coating uniformity and thickness, the accurate delivery of the chemicals into the chamber must be controlled.
4) Extreme care must be exercised to prevent contamination from the room air. The chamber must be checked for leaks regularly.
What Jewelry Material can be used with CVD coating?
Several coating materials can be used for chemical vapor deposition:
- nitrides like titanium nitride
- silicon compounds
- carbon
- organofluorine or fluorocarbons
Some materials can be double-coated to improve their functionality, performance, or durability by using various combinations from the list above. Titanium nitride is the most used material for coating. It is extremely hard and gives a golden-coated appearance. Because of this, it is commonly used on jewelry, medical devices, and an advanced biomedical device such as in-vivo biosensors, automotive trims, and household fixtures.
Several Jewelry Materials that can be CVD coated include:
- Platinum jewelry
- Tungsten jewelry
- Titanium jewelry
- Ceramic jewelry
- Metal Alloys
The thickness and hardness of CVD coating?
Chemical vapor deposition produces a coat that has an average thickness of 5-10 µm. Due to the hardness and adhesive strength of titanium compounds, the thin layers formed are known as heavy-duty layers.
CVD coatings have an average relative hardness of well over 80 Rc. The higher the RC value, the harder the material or coating is. The high hardness value gives forming tools, cutting tools, and jewelry greater resistance to wear and tear. It offers greater protection.
The Pros and Cons of CVD coating
| Pros | Cons |
| It is a versatile procedure. It can be applied to a variety of materials such as glass, metals, metal alloys, and ceramics. | CVD uses a lot of energy as it is applied at high temperatures. This is dependent on the coating material used. |
| Can be applied to intricate and precise surfaces including internal surfaces and seal areas. | There is a limited number of coating materials that are non-toxic, highly volatile, and nonpyrophoric. |
| CVD coating can withstand drastic temperature variations. So, it is resilient to low and high temperatures. | It is difficult to mask the jewelry’s surface completely. The size of the coating is limited to the capacity of the reaction chamber. |
| It is flexible and durable. Due to its adhesive properties, CVD coating remains bonded when the material’s surface flexes or stretches. | |
| You can choose different coating materials to use depending on the desired jewelry properties. If you want wear resistance, corrosion resistance, high lubricity, high purity, fouling resistance, or chemical inertness, you can get it. |
What are the differences between PVD and CVD Coating?
| Category | CVD | PVD |
| Definition | A Chemical Vapor Deposition (CVD) coating is the deposition of a hard layer of materials unto a product or accessory in a Gas Phase Process. CVD is an atmospherically controlled process carried out at high temperatures in a reactor (~1925° F). During the process, a thin film of coating is formed due to the reaction between the gases present and the heated surface of the material to be coated. | PVD, physical vapor deposition, is used to describe several thin-film deposition techniques. It involves the vaporization of solid material in a vacuum environment which is then deposited onto a substrate as an alloy composition coating or pure material. So, it is simply transferring the coating material to the desired item. |
| Application | CVD is used to produce high-performance, high-quality, and thin films on materials. It is used on semiconductors, forming tools, cutting tools, and jewelry. | PVD coating is an essential component for performance in products such as optical lenses, self-cleaning tinted windows, displays, computer microchips, semiconductor devices, photovoltaic applications for solar panels, medical devices, and products that require a durable protective film like jewelry. |
| Temperature | The CVD process uses very high temperatures, approximately 1112°F to 2012°F. A vacuum heat treatment is carried out after coating. | Relatively low, approximately 385°F-950°F. |
| Hardness | Harder than PVD coating. CVD coatings have an average relative hardness of well over 80 Rc. | Not as hard as CVD coating |
| Color Available | The color is dependent on the coating material. You can get gold, blue, grey, brown, etc. | Some common colors that you can choose from are: Gold, Rose Gold, Black, Blue, Bronze, Chrome, Yellow, Silver, Platinum, and Dark red. |
| Durability | CVD coating is very durable. It can withstand drastic temperature variations. CVD coating remains bonded when the material’s surface flexes or stretches. | Long-lasting coat that can last for generations. |
| Thickness | Chemical vapor deposition produces a coat that has an average thickness of 5-10 µm. | The ideal PVD layer is normally 0.25 microns to ~ 5 microns thick. |
| Cost | Less expensive | More expensive |
| Cleaning Requirements | Low | High |
Final Thoughts
There are several factors to consider when choosing an appropriate coating for a piece of Jewelry. Chemical Vapor Deposition (CVD) coating is widely used in the industrial world and is commonly found in many consumer merchandises such as Jewelry. CVD is known to be environmentally friendly and produces a strong, durable, and long-lasting thin film. So, if you’re looking for all these qualities in a piece of jewelry, then CVD-coating is the way to go.
