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In this study, the surface of micro-punches is coated with a ceramic matrix composite, a graded diamond-likecarbon (DLC) film, in order to improve the micro-deep drawing formability. DLC coatings with Zr/ZrC/NZrC were prepared by magnetron sputtering. The effect of graded DLC films, such as surface textures and wear properties on the ability for the deep drawing of micro-cups based on laser diode copper alloy sheet was explored. In addition, the application of the DLC coated SKD11 substrate to the drawability was demonstrated and its applicability was explored in comparison with that of the other films such as SKD11, CrN and ZrN, and the size effect of friction on the formability of drawn circular cups is discussed according to the DLC films coated punch diameters. Experimental results showed that the graded DLC films significantly improved the surface textures and wear behaviors of the micro-punches. The DLC coated punches which dramatically decreased the stamping force and increased the drawing ratio was better than for other films, whose the drawing ratio yielded an increase of about 24% in the coated micro-punch diameter of 2.5 mm types. The applicability of the DLC films for the drawability of micro-cups was successfully demonstrated through the micro-deep drawing process. Accordingly, the DLC films prepared by magnetron sputtering are promising candidates for enhancing the drawability of micro-cups based on laser diode copper. [ABSTRACT FROM AUTHOR]

This study reports that laser-treated HVOF-spray coated surfaces of WC/Co composite were fabricated on 45 carbon substrates using laser treatment technology. The hardfacing coatings were applied by combining two different techniques of HVOF spraying and laser irradiation. Wear behavior of the coatings was systematically investigated, and microstructural evolution of the laser melted HVOF-sprayed coatings was characterized and compared with that of HVOF-sprayed coatings. Microstructural observation shows that both coatings exhibit similar phases, but there are differences in the formation of tungsten carbide, micro-hardness distribution, closely packed structures and wear behaviors of the coatings. Coatings with evenly distributed WC ceramic phases and a better bonding mechanism to the substrate alloy were obtained by laser-based HVOF spraying treatment. The results of this study indicate that the wear behaviors of the HVOF-sprayed WC/Co composite coatings prepared by laser irradiation are much better than those of the plain HVOF-sprayed coating. The wear volume loss of HVOF-sprayed WC/Co composite coating prepared by laser melting treatment is the lowest, only 50% of that of the HVOF-sprayed coating, thereby providing better wear resistant properties. Overall, the increase in wear resistance was attributed to the formation of dendritic-tungsten carbide, high micro-hardness distribution and to closely packed structures of the coatings. [ABSTRACT FROM AUTHOR]