Zájem o nové kvaternární materiály SiBCN roste díky jejich vysokoteplotním vlastnostem a použití v nepříznivých podmínkách. Tvrdé (22-24 GPa) amorfní vrstvy SiBCN s vysokoteplotní stabilitou a oxidační odolností (nad 1500°C) byly deponovány na různé substráty (Si, SiC, WC-Co s vrstvou 250 nm TiN nebo CrN) pulzním magnetronovým naprašováním použitím terče B4C-Si (25:75 %) ve směsi Ar-N2 (50:50 %). Teplota substrátů byla 350 °C, celkový pracovní tlak 0,5 Pa a předpětí na substrátech -100 V nebo byly substráty na plovoucím potenciálu. Byl zjišťován vliv pulzního výboje na kvalitu vrstev, jejich vysokoteplotní vlastnosti a na adhezi vrstev k průmyslově zajímavým substrátům.
Anotace v angličtině
Novel quaternary SiBCN materials are becoming increasingly attractive because of their possible
high-temperature and harsh-environment applications. Hard (22 - 24 GPa) amorphous Si-B-C-N
coatings with high thermal stability and oxidation resistance (even above 1500 °C) were deposited on
various substrates (Si, SiC, WC-Co and WC-Co with 250 nm TiN or CrN interlayers) by pulsed dc
magnetron sputtering using a single B4C-Si (25:75 %) target in an Ar-N2 (50:50 %) gas mixture. The
substrate temperature of 350 °C and the total pressure of 0.5 Pa were held constant during the
depositions on the substrates at a floating potential or an rf induced bias of -100 V. A planar
rectangular (127 x 254 mm2) unbalanced magnetron was driven by a pulsed dc power supply operating
at the repetition frequency of 10 kHz and the average target power over a period of about 500 W with
50 % and 85 % duty cycles. Here, the aim was to avoid any discharge instabilities leading to possible
defects in the coatings. Laser confocal scanning microscopy showed a very smooth surface
morphology of the as-deposited coatings with an average roughness Ra = 6 nm determined over the
surface area of 120×90 microns2. Prior to deposition, a modification of the substrate surfaces (etching,
shallow implantation and ion mixing) was performed by pulsed magnetron sputtering of the B4C-Si
target in Ar gas at the same pressure, the duty cycle of 20 % and the average target power over
a period of about 250 W, the substrate temperature from 350 °C to 480 °C and the rf substrate bias of -
1300 V for 12 min to enhance adhesion of the deposited Si-B-C-N coatings to various substrates. The
adhesion measurements were carried out by a scratch tester using a spherical diamond indenter with
a tip radius of 200 mm and a linearly increasing normal load from 0 to 80 N. The critical load (Lc) was
revealed by optical microscopy and confirmed by a sharp change in the slope of the corresponding
dependences measured for the friction coefficient. A substantial increase in the critical load (from 16
to 70 N for the WC-Co substrate) caused by the substrate surface modification was proved.
Klíčová slova
vrstva SiBCN, magnetronové naprašování, vysokotepltoní stabilita, oxidační odolnost
Zájem o nové kvaternární materiály SiBCN roste díky jejich vysokoteplotním vlastnostem a použití v nepříznivých podmínkách. Tvrdé (22-24 GPa) amorfní vrstvy SiBCN s vysokoteplotní stabilitou a oxidační odolností (nad 1500°C) byly deponovány na různé substráty (Si, SiC, WC-Co s vrstvou 250 nm TiN nebo CrN) pulzním magnetronovým naprašováním použitím terče B4C-Si (25:75 %) ve směsi Ar-N2 (50:50 %). Teplota substrátů byla 350 °C, celkový pracovní tlak 0,5 Pa a předpětí na substrátech -100 V nebo byly substráty na plovoucím potenciálu. Byl zjišťován vliv pulzního výboje na kvalitu vrstev, jejich vysokoteplotní vlastnosti a na adhezi vrstev k průmyslově zajímavým substrátům.
Anotace v angličtině
Novel quaternary SiBCN materials are becoming increasingly attractive because of their possible
high-temperature and harsh-environment applications. Hard (22 - 24 GPa) amorphous Si-B-C-N
coatings with high thermal stability and oxidation resistance (even above 1500 °C) were deposited on
various substrates (Si, SiC, WC-Co and WC-Co with 250 nm TiN or CrN interlayers) by pulsed dc
magnetron sputtering using a single B4C-Si (25:75 %) target in an Ar-N2 (50:50 %) gas mixture. The
substrate temperature of 350 °C and the total pressure of 0.5 Pa were held constant during the
depositions on the substrates at a floating potential or an rf induced bias of -100 V. A planar
rectangular (127 x 254 mm2) unbalanced magnetron was driven by a pulsed dc power supply operating
at the repetition frequency of 10 kHz and the average target power over a period of about 500 W with
50 % and 85 % duty cycles. Here, the aim was to avoid any discharge instabilities leading to possible
defects in the coatings. Laser confocal scanning microscopy showed a very smooth surface
morphology of the as-deposited coatings with an average roughness Ra = 6 nm determined over the
surface area of 120×90 microns2. Prior to deposition, a modification of the substrate surfaces (etching,
shallow implantation and ion mixing) was performed by pulsed magnetron sputtering of the B4C-Si
target in Ar gas at the same pressure, the duty cycle of 20 % and the average target power over
a period of about 250 W, the substrate temperature from 350 °C to 480 °C and the rf substrate bias of -
1300 V for 12 min to enhance adhesion of the deposited Si-B-C-N coatings to various substrates. The
adhesion measurements were carried out by a scratch tester using a spherical diamond indenter with
a tip radius of 200 mm and a linearly increasing normal load from 0 to 80 N. The critical load (Lc) was
revealed by optical microscopy and confirmed by a sharp change in the slope of the corresponding
dependences measured for the friction coefficient. A substantial increase in the critical load (from 16
to 70 N for the WC-Co substrate) caused by the substrate surface modification was proved.
Klíčová slova
vrstva SiBCN, magnetronové naprašování, vysokotepltoní stabilita, oxidační odolnost