# Deposition of 3 YSZ-TiC PVD Coatings with High-Power Impulse Magnetron Sputtering (HiPTMS)
## 1 Introduction  
Stabilized tetragonal zirconia, as investigated in this study, shows exceptional mechanical properties. Like alumina, it is interesting as part of a wear protection coating of cutting tools in machine material with high cutting speeds. With a high cutting speed, a lot of heat is generated and transferred from the machined material into the tool, decreasing tool life. To minimize this heat transfer, wear protection coatings with oxide ceramics can be used because of their low heat conductivity. Unfortunately, oxides cannot be deposited with standard physical vapor deposition (PVD) processes such as direct current magnetron sputtering or are evaporation. Most PVD technologies are based on a setting with a material spending cathode (often called a target) and an anode, which is often also the substrate. If the substrate (anode) is coated with a non-conductive material, it vanishes (i.e., the current flow collapses and the electrical discharge disappears). This is also called the disappearing anode effect (DAE). Previous studies by [PERSON] and [PERSON] showed possibilities for changed settings to avoid the effect [1, 2]. These settings, however, are quite expensive and laborious for application in industry. Instead of changing hardware, this study shows an approach to solving the DAE problem originating from studies of electrical discharge machinable (EDM) ceramics. By alloying oxide ceramics with a percolating electrically conductive dispersion (such as a transition metal carbides), it is possible to obtain an overall electrically conductive ceramic compound [3, 4, 5, 6, 7]. In this study, we tried to use thisknowledge in a magnetron sputter process: high-power impulse magnetron sputtering (HiPIMS). HiPIMS, also known as high-power pulsed magnetron sputtering (HPPMS), is the latest iteration of PVD technology, based on direct current magnetron sputtering (DCMS). Like DCMS, an HiPIMS apparatus consists of a sputtering target mounted on a cathode combined with permanent magnets. By ion bombardment, surface atoms from the target material are expelled and accelerated to the anode and the substrate [8]. On the substrate surface, these atoms condense, and a coating is formed. The main difference between DCMS and HiPIMS is the high-frequency pulsing of the cathode, observed by [PERSON] [9]. By pulsing the cathode with really short pulses (usually 10-100 \(\upmu\)s), high ion ratios of 90% or more can be reached in HiPIMS. A higher rate of ionized atoms enables different morphologies and therefore better mechanical properties in the coatings [10,11].  
The pulse parameters in HiPIMS deposition have a huge impact on the process stability and coating properties. The current at the substrate table, which is a measure for the metal ions that reach the substrate table and build up the coating [8], is measurable with an oscilloscope. However, the current at the substrate table is not only influenced by the pulse parameters of the table, but also by the pulse parameters of the cathode. Depending on the target material and the gas used for the process, different cathode pulse, bias (table) pulse and bias offset values are necessary [12,13].  
In this study, the main goal was to examine the impact of five different HiPIMS parameters on the measured current at the substrate table, which is a measure for the metal ions that reach the substrate table and build up the coating.