In hard carbon diamond-like coatings obtained using vacuum pulse arc sputtering of graphite, the morphology of the condensate surface has been studied using scanning atomic-force microscopy. An electron-microscopic investigation of the condensate structure and of the structure of a surface layer of the graphite target has also been performed. Bundles of nanotubes are found to arise at the graphite-target surface upon arc discharge. At the coating surface, there are analogous formations. In accordance with the literature data, the results obtained made it possible to elaborate a mechanism of the formation of comparatively high (with respect to the coating thickness) pyramidal protrusions on the condensate surface. The nucleation centers for such formations are fragments of nanotube bundles that reach the coating surface from the periphery of the arc crater of the target. A rather rapid growth of protrusions on the surface of the diamond-like condensate occurs via carbon diffusion over the coating surface along nanotubes. An impetus to such a directed flux for diffusing atoms is a decrease in the elastic energy of the coating caused by a high (similar to 10 GPa) level of internal stresses.

Aluminum samples with diamond-like coatings (DLCs) applied by the pulse arc sputtering of graphite were tested for friction coefficient, microhardness H, and abrasive resistance. The DLC microhardness was determined from a load dependence of effective microhardness to be H = 75 GPa, which coincides with the value measured with a nanoindenter on DLC-steel samples. Mechanisms of the DLC separation from Al upon impacts of hard particles were considered. It is shown that the DLC on Al substrate is commercially advantageous, and the efficiency of Al strengthening with DLC can be increased only at the expense of thickening of the coat.

The wear of DLCs deposited onto steel substrates using a graphite arc-pulse sputtering technique in a corundum particle jet was studied. Two sample sets had different adhesion strength to the substrate due to different adhesive sublayer structures. It was found that the DLC itself does not wear, so that coating destruction occurs due to peeling. Analysis of the wear results for coatings having different (0.4–2.6 μm) thickness revealed that peeling is a result of two basic crack systems: (i) from the DLC surface inside the coating; and (ii) along the DLC–substrate interface.

We studied the effect of the initial substrate surface roughness and as grown DLC microrelief on the tribological properties of coating. The diamond-like films were prepared by pulse arc sputtering of graphite onto R6M5 and 20Cr13 tool steel substrates. Special attention was paid to production of the DLC having increased the friction coefficients necessary for such device as printing machine valves and chuck’s jaws. The tribological properties of the deposited coatings were studied under conditions of dry sliding friction and under the action of an abrasive-particle jet. It was shown using both testing methods that the substrate surface roughness (R) is the decisive parameter for the wear resistance of the DLC to external loads. The wear resistance of coating is increased several-fold at some optimal R-value as compared to the smoother surface. The optimal R-value depends on the coating thickness, h. The optimal R/h value should not deviate largely from the ratio R/h∼0.2–0.3.

The study is concerned with the influence that bombardment with low-energy (approximately 1 keV) ions of argon, oxygen, nitrogen or hydrogen exerts on properties of the amorphous diamond-like coatings (DLCs) produced by vacuum pulse sputtering of graphite in an arc discharge. It is shown that hydrogen treatment leads to the formation of C:H films whose composition depends on specific bombardment conditions. Bombardment with the other ions results in etching and smoothing of the DLC relief, while the film composition remains unchanged. Ionic bombardment increases the share of the diamond-like component in the film structure.

The surface relief is one of the main factors defining the trybological properties of friction pairs, especially in the case of diamond and diamond like carbon (DLC) coatings. Even such thin as 10 - 100 nm coating can considerably increase the wear resistance and drastically reduce the friction coefficient of friction pairs. The most convenient techniques for investigation microrelief effect on trybologyc properties of thin films seems to be the scanning tunneling microscopy (STM). The microrelief was changed by surface bombardment with 1 keV ions of O, Ar and N. The friction coefficients was found to depend upon ion bombardment time and the minimal value could be achieved. The STM studies showed that namely at this time the surface relief was the most smooth. For the coatings in the initial state the surface relief was about 15 - 20 nm and in the state with minimal friction coefficient - about 1.5 - 3 nm.

We have developed the effect of additional treatment on improvement of tribological properties of diamond-like coatings (DLCs) on steels. It is shown that a maximum realization of the strengthening properties of DLCs is possible either through preliminary hardening of the substrate with ion implantation and additional thermal treatment or using etching of the coating surface with ions of active gas.

A study was made of the protective properties of amorphous C thin films deposited by the method of pulse sputtering of graphite on substrates having a temperature of approximately 175°C. It is shown that the films can be successfully used to improve the service properties of audio or video heads and surgical cutting instruments.

N+ and C+ were implanted (30 keV, 1017–1018cm−2) into amorphous diamond-like coatings (DLCs) produced by pulse-arc sputtering and into the substrates (stainless steel and hard tungsten-cobalt alloy) on which the DLCs were deposited. Wear resistance of the implanted DLCs and that of DLCs on the implanted substrates were studied. It is shown that ion beams stimulate graphitization of the DLCs and thus make the coatings weaker. By contrast, implantation of the ions into the substrates enhances wear resistance of DLCs, thanks to an increase in the material hardness under the coating and improvement of adhesion.

We have developed a high-accuracy test unit that permits the testing of wear of coatings by a flux of solids. The unit features the following advantages: •- Special abrasive particle collectors are provided which enable one to determine accurately the number of particles that have caused the wear of a given specimen;•- Spatial homogeneity of the particle effect on a specimen is ensured, owing to scanning a particle jet perpendicular to the plane of its rotation.