Thin film selection for Diamond/Nickel interface

In summary: I'm not sure what the interface chemistry is for chromium deposition onto nickel, so I can't really say.In summary, the thin film will be sandwitched between a diamond and nickel alloy, and will need to adhere strongly to the alloy without diffusion, stay together up to 700K, and be thermally conductive.
  • #1
toasty1231
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Hello everyone. My task is to select a thin film and deposition method that will achieve a few goals.
The thin film will be sandwitched between a diamond and nickel alloy. The thin film needs to:

  • Adhere to a diamond and nickel alloy strongly without inter diffusion.
  • Stay together up temperatures of 700K, and be decently thermally conductive.

The film can be deposited via standard methods like sputtering, Evaporation, JDC, CVD, ect...

I know that diamond and nickel have similar bond structures (sp3) and a thin film with a similar structure would help maintain a strong bond.

Any info would be greatly appreciated!
 
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  • #2
Typical film structure put down on diamond to enable solder attachment is Ti/Pt/Au. The Ti reactively bonds with the diamond surface, the Pt prevents inter diffusion, and the Au makes a good bond with solder.

There's some work with Cr as the first layer on diamond. It forms a carbide, so adheres to diamond. Don't know how it would stick to nickel, nor do I know about its inter diffusion barrier properties.

Most of the diamond adhesion systems I worked with were put on by sputtering. You have to have a good (low oxygen background pressure) sputtering system to successfully deposit Ti because it's very reactive and forms a super stable oxide if you have any background oxygen in the chamber.

An alternative might be active brazing alloys, which contain a little bit of Ti that combines with diamond and whatever else you're bonding to the diamond when the braze melts. I used some products from S-bond to attach copper microprocessor heat spreaders to CVD diamond plates and it worked reasonably well. I think there are active braze alloys that might make your 700°C requirement, but I'm not sure. I used the S-bond material because it was easier than waiting through the out of house sputtering service turnaround.

It probably doesn't help with adhesion that diamond and Ni have similar crystal systems. Ni doesn't form a carbide under normal conditions. Diamond abrasive makers sell Ni-coated diamond abrasives, so clearly they can stick Ni to diamond very well. They use fluidized-bed deposition, but I have no idea what the interface chemistry is.
 
  • #3
hha
 

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  • #4
I can't express any opinion! Thank you for the topic, I need the same answer!
 
  • #5
Chromium is the first thing that comes to mind. It bonds strongly to to nickel and nickel is often used as a substrate for chrome surface treatments.
 
  • #6
graphite?
 

1. What factors should be considered when selecting thin film for a Diamond/Nickel interface?

When selecting thin film for a Diamond/Nickel interface, it is important to consider the properties of both materials. This includes their crystal structure, melting point, thermal expansion coefficient, and chemical compatibility. Additionally, the desired application and the intended use of the interface should also be taken into account.

2. How does the crystal structure of Diamond and Nickel affect the selection of thin film?

The crystal structure of Diamond and Nickel can significantly impact the selection of thin film. For instance, Diamond has a face-centered cubic (FCC) structure, while Nickel has a hexagonal close-packed (HCP) structure. This difference in crystal structure can result in lattice mismatches and strain at the interface, which may affect the film's adhesion and performance.

3. What is the role of thermal expansion coefficient in thin film selection for a Diamond/Nickel interface?

The thermal expansion coefficient of Diamond and Nickel can affect the stability and durability of the interface. A large difference in thermal expansion coefficients between the two materials can lead to thermal stresses and cracks in the film, which may compromise the integrity of the interface. Therefore, it is crucial to select a thin film with a similar thermal expansion coefficient to minimize these effects.

4. What are the most commonly used thin films for a Diamond/Nickel interface?

The most commonly used thin films for a Diamond/Nickel interface include titanium, chromium, tungsten, and molybdenum. These materials have good adhesion to both Diamond and Nickel and have a similar thermal expansion coefficient. Additionally, they also have high melting points, making them suitable for high-temperature applications.

5. Can the thin film selection for a Diamond/Nickel interface affect the performance of the interface?

Yes, the thin film selection can significantly impact the performance of the Diamond/Nickel interface. A poor selection of thin film can result in weak adhesion, increased thermal stresses, and reduced durability of the interface. This can lead to premature failure and affect the overall performance of the system.

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