The purpose of this project is to use an alternative eco friendly milling media for the development of eco technologies used in the production of advanced cutting tools. For this purpose, water will be used as a milling medium instead of isohexane or acetone. The use of an aqueous milling environment would eliminate the disadvantages generated using organic media (the harmful impact on the environment and risks related to the health and safety of the work, taking into account the volatility of the flammable and toxic solvents currently used). In the previous research, we have shown the possibility of replacing the organic media used industrially with an aqueous milling media, with minimum additional operations, for compacts obtained by uniaxial pressing. The present project will focus on the development of a technology for obtaining extruded compacts, with minimum additional operations. The use of extrusion as a compaction process will allow the production of round or profiled bars, respectively tubes with large length / diameter ratio, necessary to produce drills, mills, reamers or any kind of cutting tools. The implementation of such a milling media involves certain challenges, such as oxidation of constituents during milling, but also the formation of hard agglomerates. The results of this research aim to provide the information necessary to facilitate the substitution of organic milling media with water to reduce the costs and environmental impact of WC Co powder processing techniques.

Objectives:

1. Aqueous milling of the WC Co powders and subsequent sintering; This objective assumes the elaboration and study of the aqueous milled powders.
2. Kneading of aqueous milled samples and subsequent sintering of kneaded and extruded compacts.

Expected results:

– method of milling (parameters) in aqueous medium of WC Co powders;
– WC Co powders with suitable chemical composition and without hard agglomerates;
– compacts sintered from powders milled in aqueous medium situated in the biphasic region (WC + Co);
– a homogeneous mixture of aqueous milled powder and plasticizer usable for extrusion;
– sintered compacts of plasticizer and powder mixture situated in the biphasic zone (WC + Co);
– published scientific papers.

Results:

The main conclusions of this stage/project are the fact that WC powders and compacts with appropriate properties were obtained efficiently by mechanical grinding in aqueous medium. Comparison with methods normally used in industry for grinding reveals similar properties. The conducted research has revealed some important aspects and draws some conclusions:
 

–  by adjusting the pH of an aqueous environment, the appearance of friable agglomerates can be favoured
– the use of an anti-foaming agent having in its composition alkyl polyalkylene glycol ether inhibited the formation of foam and limited the loss of a significant amount of powder
– due to the large specific surface area, the drying of such powders requires a protective atmosphere to avoid oxidation
– spraying aqueous suspensions with a paraffin emulsion in their composition prevents the oxidation of particles and favors the formation of spherical agglomerates
–  for samples ground in aqueous medium, drying in slightly oxidizing atmosphere gives better results.
– replacing the conventional grinding medium with water could easily be used industrially with minor modifications to conventional technology.
– changing the grinding medium does not influence the structural and morphological characteristics of these samples, as revealed by the measurements performed.
– the higher amount of residual moisture in the sample ground in aqueous medium suggests that the drying step must be adapted to the grinding medium.

From the point of view of the objectives regarding the publication of the results, the target was the publication of an ISI article and participation in 1-2 conferences. Within this project, the dissemination of the results obtained by completing the stages completed up to this point were materialized through 2 oral presentations at the International Conference on Advances in Engineering and Management – ADEM 2020 and the International Conference on Innovative Research – ICIR Euroinvent 2022, 2 papers published in Advances in Engineering and Management and Archives of Metals and Metallurgy. The work and results obtained within this project, presented at the International Conference on Innovative Research 2022, were awarded with the “Best Oral Presentation” distinction. Taking into account these from the point of view of scientific publications and the visibility of the results, the proposed objectives of this project have been fulfilled.

Date contract begin: September 1st, 2020
Data contract end: August 31st, 2022
Project duration: 24 months
Total value from budget: 246,256.00 RON
Year 2020: 63,091.00 RON
Year 2021: 108,363.00 RON
Year 2022: 74,802.00 RON

Contact:
horea.chicinas@stm.utcluj.ro
Department of Materials Science and Engineering
Technical University of Cluj-Napoca
103-105 Muncii Avenue 400641 Cluj-Napoca
Tel: +40 728 868 016

Reports: 2020, 2021, 2022