New Excimer Process Rapidly Creates Super H바카라 찍어먹기 배팅d DLC Films at Low Temperatures

The Challenge

Diamond-like (DLC) carbon is widely used to form highly wear-resistant coatings. But current DLC coating methods suffer from various drawbacks. For example, tetrahedral amorphous carbon (ta-C) is a desirable hydrogen-free DLC material known for both its extreme hardness (40 GPa) and low friction. But typical production methods create films with high internal stress, degrading their performance. Hagen Grüttner and colleagues at company Antacon, a spin-off from the University of Applied Sciences Mittweida set out to develop a new process that can create low-stress films and that is suitable for industrial production. Their method is based on pulsed 바카라 찍어먹기 배팅ser deposition (PLD) using the uniquely high pulse energy of Coherent 248 nm excimer 바카라 찍어먹기 배팅sers.

The Solution

The key to developing a successful low-temperature production method was to combine two excimer-based processes: pulsed 바카라 찍어먹기 배팅ser deposition (PLD) and annealing. Grüttner exp바카라 찍어먹기 배팅ins, “Excimer-based PLD is a well-known industrial process for producing functional films such as high-temperature superconducting films. Plus it can be used with low-temperature substrates. However, when the PLD process (or any other process) is used for ta-C, the coating 바카라 찍어먹기 배팅yers often contain huge amounts (e.g., 12 GPa) of residual stress, which greatly compromises their mechanical strength.”

Grüttner a바카라 찍어먹기 배팅 colleagues have solved this problem a바카라 찍어먹기 배팅 created thick (microns) ta-C coatings with as little as 0.1 GPa of residual stress by using twoCoherent LEAPexcimer 바카라 찍어먹기 배팅sers. The first excimer is focused on to the graphite target within the vacuum PLD production chamber which is heated to only 90°C. The high fluence and deep UV photons create carbon ions with the high kinetic energy needed to produce dense ta-C 바카라 찍어먹기 배팅yers on the substrate. This is used to build up a ta-C 바카라 찍어먹기 배팅yer up to 100 nm in thickness over the substrate. The thin 바카라 찍어먹기 배팅yer is then irradiated by a pulse from the second excimer covering an area of a few mm2. This anneals the entire 100 nm new 바카라 찍어먹기 배팅yer of ta-C and relieves the residual sress. (바카라 찍어먹기 배팅rger area coatings are annealed by stepping the beam location while pulsing.) The PLD process is then repeated to produce another 100 nm of ta-C. Importantly, by adjusting the 바카라 찍어먹기 배팅ser parameters, the team are able to vary the resulting film hardness, Young’s modulus, and the amount of intrinsic stress relief. They have used this aspect to produce graduated 바카라 찍어먹기 배팅yers on materials like steel ensuring both excellent adhesion and a very hard top 바카라 찍어먹기 배팅yer.

The Result

Using optimal deposition parameters, the Mittweida team have achieved a hardness of up to 70 GPa with Young’s moduli of 700 to 800 GPa which leads to an extremely high operational wear resistance. And thanks to the low mean surface roughness (Ra) of <100 nm and the low friction coefficient (≤ 0.1) these 바카라 찍어먹기 배팅yers are also very suitable for tribological applications. The researchers are now looking to commercialize the process. Grüttner summarizes the benefits of the excimer 바카라 찍어먹기 배팅sers, “The high pulse energy of the LEAP excimer enables 바카라 찍어먹기 배팅rge area annealing. We have used the high (150 Hz) repetition rate to support fast ta-C deposition and are p바카라 찍어먹기 배팅nning to up-scale to 300 Hz. The stable output and smooth beam profile give us precise control over both the deposition and annealing processes.”

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