Diamond-like properties shine
The ta-C structured hydrogen free amorphous DIARC diamond coating offers low friction, high hardness, excellent wear resistance, chemical inertness and high thermal conductivity
A next-generation diamond-like coating service from Finland could give dramatic reductions in friction and energy consumption in engines, hydraulic systems and power transmissions.
DIARC-Technology’s system allows the high volume deposition of tetrahedral amorphous carbon (ta-C) diamond-like coatings for industrial applications. The process is targeted at companies who need a hard-wearing protective coating that can deliver increased efficiency and reliability of components operating in challenging and critical wear environments in mechanical systems.
The coatings also offers extremely low friction in the presence of lubricants, hence supporting reductions in energy consumption. The company says the super-lubricant coating has broad industrial applications for all types of wear parts in engines, hydraulic systems and power transmissions and also for precision tool applications.
“In many cases the coated component or tool ensures a trouble free operation of the machine and the production process. On tools, for example, the improvement in service life offered by the coating plays a more important role. Also, improved quality and more efficient production gained when using coated tools is in many cases as important as the service life of the tools,” says Tapani Haikola, Vice President of DIARC.
DIARC pioneered a low temperature vacuum plasma deposition process which can lay down a thin tough layer of diamond like carbon onto a range of materials from metals to plastics. The process is based on a special plasma accelerator technique that creates a highly ionised plasma of the coating material. The plasma is electromagnetically accelerated to a high velocity, directed towards the workpiece and targeted onto the surfaces to be coated. This makes it possible to process well-adhered and dense coatings at low temperatures. A typical deposition temperature is below 100 deg C.
The temperature can be adjusted by the process parameters so that it is possible to make coatings at temperatures right down to room temperature. The thickness of the coating can range from a few nanometres to several micrometres, depending on the application. The coating process has low energy and raw material demands and no hazardous chemicals or gases are used in any phase of the process – thus making it environmentally friendly.
The unique ta-C structured hydrogen free diamond coating developed by the company has five key properties of low friction, high hardness, excellent wear resistance, chemical inertness and high thermal conductivity. The DIARC coating process also allows the properties of the coating to be graded so that the coating properties and performance can be optimised for a specific application. “The excellent wear resistance the coating protects the surfaces as a thin layer. As a comparison one micrometre layer of amorphous diamond wears out in the same time as 1 mm of hardened steel,” notes Tapani Haikola.
The coating ensures reliable and trouble free operation (preventing seizure) of pneumatic components such as valve actuators for process valves in chemical, oil and pulp & paper industry and on plungers of precision pumps of ventilators. In a radial piston hydraulic motor, coating the sliding surfaces of the moving parts increased the efficiency at low speeds by 30 % compared to uncoated parts. In power transmissions, the friction coefficient has been reported to be 25 to 30 % less when the gear wheels are coated with DIARC Diamond coating compared to uncoated steel gear wheels.
The company can coat parts up to 660mm in diameter, 1000 mm long and weighing up to 250 kg.
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