General Clean Energy

Corrosion-resistant mechanical seals, bearings and valves for power engineering

Under corrosive operating conditions in power engineering, the service life of conventional DiaCer® materials (diamond-coated ceramics) is too short due to the formation of stress cracks. Based on the existing systems, a new material system consisting of a novel, graded diamond-SiC composite material and an extremely dense CVD diamond layer is to be developed, which has a lower friction value and thus achieves higher corrosion resistance in power generation.

 

Summary

The project is concerned with mechanical seals, bearings and valves made of diamond-coated ceramics, which are exposed to corrosive operating conditions, especially hot water, in power engineering and the chemical industry and are increasingly. In contact with hot water occurs often failing due to infiltration or stress corrosion cracking.
A new material system "DiaDiSc" made of graded SiC-diamond composite material with 40-50 vol% diamond in the edge zone was developed. The extremely low defect polycrystalline diamond layer achieves a particularly good protection against infiltration due to the high diamond content. The new material system was manufactured and tested under corrosive conditions. In addition, the corrosion mechanisms were linked to the load parameters in order to be able to make a reliable estimate of the service life.
Overall, the project objective of developing a material system with significantly better corrosion resistance was achieved. The diamond coating also led to a reduction in the coefficient of friction, which not only increases the corrosion resistance but also the energy efficiency of the tribochemically stressed bearing and seal components.

Results:
- Proof of the suitability of the diamond layers was provided
- Technology for the production of discs was developed
- The pre-selection of suitable layers has been made, but there is still a need for optimisation
- A cost analysis was carried out
- Proof of function has been provided, but no endurance test has been carried out in the project period.
- The material cannot be used as a slider, as the necessary flatness has not yet been achieved

More Project Information

Project title: EkoDiSc - Entwicklung eines korrosionsbeständigen Diamant-Siliciumcarbid-Werkstoffsystems für die Energietechnik

Reference number: 03X3583

Project period: 2013 - 2016

Project region: Germany

Project contact: This email address is being protected from spambots. You need JavaScript enabled to view it.

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* only available in german *

 

Source: German National Library of Science and Technology Hannover (TIB)