Preparation of hard and moderately ductile Mo2BC coatings by pulsed DC magnetron sputtering
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| Year of publication | 2014 |
| Type | Conference abstract |
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| Description | Standard ceramic materials nowadays used as protective coatings such as TiN, TiAlN, c-BN, etc., exhibit high hardness and high stiffness. However these are often connected to brittle behaviour of the coating thus limiting the lifetime of the coating and of the coated tool as well. To overcome these limitations, a new generation of materials with high hardness and moderate ductility is sought for. Recently, nanolaminate Mo2BC coatings were predicted to have these advantageousproperties. However deposition conditions so far necessary to deposit Mo2BC coatings are a limiting factor. First, deposition process utilizing combinatorial DC magnetron sputtering required substrate temperature of 900°C. Secondly, a low temperature synthesis method reducing the substrate temperature to 380°C required using HiPIMS with compound Mo2BC target [2]. Both of these methods pose significant problems with industrial scale production. High deposition temperatures that are at or above tempering temperature of the tools would worsen the mechanical properties of the coated tools and HiPIMS technology is still not widely used due to its high cost and relatively complicated operation. We propose to utilize pulsed DC magnetron sputtering as relatively simple tool to produce Mo2BC coatings. Combinatorial magnetron sputtering of Mo, C and B4C targets, where two targets are driven by DC and one is driven by pulsed DC to obtain higher energy ions in the plasma to promote crystallization of the Mo2BC material, is used. Substrates are further biased to increase the energy flux onto the substrate. The effect of the pulsing parameters on the properties of the coating is described with emphasis on the structure and the mechanical properties. |
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