An improved diamond-like carbon coating with exceptional wear properties

Parameters for the deposition of diamond-like carbon thin films using a hybrid magnetron sputter/plasma-enhanced chemical vapour deposition (PECVD) system have been optimised in order to improve the properties for high load-bearing applications. An extensive tribological testing program has been carried out. The main results from this testing program are described. A typical unlubricated pin-on-disc test in air using a 5-mm-diameter WC–Co pin under a load of 100 N gave a specific wear rate of 9×10−18 m3 N−1 m−1 and a coefficient of friction of 0.02. Extremely low counter-surface wear was also observed. Dry cold forming simulation tests, carried out using coated WC–Co balls against tin, indicate much lower friction than for uncoated carbide tools under the same conditions. Due to these properties, the coatings are considered to be suitable for a wide range of industrial applications. Some current applications are described

Performance and limitation of hybrid PECVD (hard coating)—PVD magnetron sputtering (MoS2/Ti composite) coated inserts tested for dry high speed milling of steel and grey cast iron

In the industry, High Speed Machining (HSM) is recognised as one of the key manufacturing technologies for higher productivity and lower production costs. Existing cutting tools are coated to improve the tool life and the performance. These coatings are all based on the principle that the coating is much harder than the work piece material. The objective of this paper is to present the new coatings for cutting tools based on a new approach: Low friction self-lubricant MoS2/Ti composite coatings (MoST) deposited by PVD magnetron sputtering technique. Dry machining (DM) is an important objective in machining industry to reduce environmental- and production costs. DM using MoST is possible in some cases: because of the low friction, the use of coolant is not necessary. Also, better chip evacuation and a smoother cutting process will occur, which can lead to higher accuracy of products. The paper included an assessment of machining performance of state of the art PECVD coated inserts (grade, geometry, coating). The consortium included manufacturers of milling machines and lathes, a coating company, a tool manufacturer, a university and two research institutes. Partners have contributed their particular expertise to the paper. The main results obtained with these new ‘'hybrid’’ inserts are: (1) Tools with MoST can be used in dry milling operations at normal cutting speeds; (2) MoST coatings reach good tool life (1.5–2 times longer than ‘State of the art’ tools) at normal cutting speeds

Performance and limitations of MoS2/Ti composite coated inserts

Self-lubricating low friction MoS2/Ti composite coatings were deposited onto hard coated carbide inserts using a hybrid process 2 and were tested for dry high-speed milling and turning of steel. Dry machining is an important objective in industry to reduce environmental and production costs. It was shown that dry machining using MoS2/Ti composite coatings is possible in some 2 cases. Following an already good knowledge in low speed dry operations including drilling, tapping and threading, the coatings were tested under dry high-speed machining operations (milling and turning) where the temperatures involved are higher. Cutting tool parameters and tool grade and geometry were found to have an influence on the performance of the tools. Temperature and oxidation were investigated separately and correlated to the mechanical, chemical, oxidation and structural behaviour of the tools during machining tests