Microstructure and Mechanical Properties of Annealed Wc/C Coatings Deposited With Different Gas Mixtures in an RFMS Process

Abstract

The optimised indented hardness (H IT ) of WC/C coatings deposited using an RF magnetron sputtering technique in relation to the vacuum chamber pressure and bias is presented in this paper. Based on the investigation, the maximal values of hardness (ca. 22.3 GPa) and Young's modulus (ca. 298 GPa) are shown. Besides the hardness and Young's modulus values, the minimal value of the coefficient of friction (COF) ca. 0.29 was obtained. WC/C coatings were deposited with and without N 2 and N 2 + SiH 4 (in a gas mixture) and they were subsequently annealed at 200 °C, 500 °C and 800 °C. Finally, they were evaluated from the aspect of H IT , E IT , COF and morphology as well as from the structural composition of the WC/C coatings before and after annealing.

Microstructure and Mechanical Properties of Annealed WC/C PECVD Coatings Deposited Using Hexacarbonyl of W with Different Gases

“…The achieved hardness ( ca . 28 GPa) is 33% lower when compared to Horňák et al [ 4 ] (37.2 ± 4.8 GPa), who used the DCMS method with the carrying gas of Ar, and 22% higher when compared to Horňák et al [ 14 ] (22.2 ± 1.3 GPa), who used the RFMS method with the carrying gas of Ar.…”

“…After annealing at the temperature of 200 • C, COF has decreased to 0.36 ± 0.06 and after annealing at the temperature of 500 • C, a tremendous decrease of the value of COF occurred, down to 0.27 ± 0.05. That is one-third more than in Reference [14], and 25% less when compared to Reference [4]. Ar inhibited the degradation of WC coating by swelling (Figure 5b).…”

“…This work aimed to evaluate the effect of temperature on the thermal stability, hardness, Young s modulus, and COF of the WC/C coatings, with and without the added gases, such as Ar and N 2 . Obtained results were compared with other published results and results from articles published by us [4,14], to which this work relates.…”

“…2550 • C) [1]. Out of all PVD methods, the most used methods are direct current magnetron sputtering (DCMS) [2][3][4][5][6][7][8][9][10] and radiofrequency magnetron sputtering (RFMS) [9,[11][12][13][14][15] with Ar. Reactive sputtering of W, C, or WC from a target, in the presence of hydrocarbon [2] or other added gases [3,4,14], is used, too.…”

“…Out of all PVD methods, the most used methods are direct current magnetron sputtering (DCMS) [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ] and radiofrequency magnetron sputtering (RFMS) [ 9 , 11 , 12 , 13 , 14 , 15 ] with Ar. Reactive sputtering of W, C, or WC from a target, in the presence of hydrocarbon [ 2 ] or other added gases [ 3 , 4 , 14 ], is used, too. Other effective methods of sputtering include High Target Utilization Sputtering (HiTUS) [ 15 ] and High-Power Impulse Magnetron Sputtering (HiPIMS) [ 3 ].…”