Y. Gudimenko

Synthesis of carbon nitride thin films by vacuum arcs

Abstract Carbon nitride (CN) thin films were synthesized by combining vacuum arcs and plasma ion implantation techniques. Three methods were investigated: plasma ion implantation into carbon films deposited by anodic vacuum arcs (AAPII), continuous cathodic vacuum arc with plasma ion implantation (CAPII) and pulsed cathodic vacuum arc (PCA). The films were found to be amorphous by X-ray diffraction (XRD). X-Ray photoelectron spectroscopy (XPS) and Raman spectroscopy analysis indicated the formation of C N, C N and C≡N bonds. Calculations of the surface tension components (dispersion and polar) of the films using the contact angle measurement technique suggested the formation of covalent carbon-nitrogen bonds. The CN films exhibited improved adhesion relative to the pure carbon films as indicated by adhesion calculations and the reduction in interfacial tension between the films and the substrate. A hardness of 18.9 GPa was obtained by nanoindentation measurements for CN films with an N/C ratio of 0.135.

METAL ION IMPLANTATION AND DYNAMIC ION MIXING FOR THE PROTECTION OF HIGH-PERFORMANCE POLYMERS FROM SEVERE OXIDATIVE ENVIRONMENT

Low energy high-dose Plasma Immersion Ion Implantation, combining both ion and recoil implantation (dynamic ion mixing), was used to enrich thin surface layers of high-performance polymers with an appropriate amount of specially selected reactive metal element such as Al. Both oxygen plasma and fast (E∼2–3 eV) atomic oxygen (FAO) beam have been used as aggressive environments for testing the implanted polymers. The modified materials successfully survived these test environments, including FAO, which is the main danger for carbon-based materials in space, in low Earth orbit. The retained doses of implanted and recoil implanted elements were controlled by RBS. The content, structure and morphology of the modified protective surface layers were examined by XPS and scanning electron microscopy (SEM). It was shown that protective oxide(s)-based surface structures were formed. Implantation and conversion conditions were found for which the appearance and important thermo-optical properties of treated polymer films, such as solar absorptance and thermal emittance, were practically unchanged.

Improvement of oxidation and erosion resistance of polymers and composites in space environment by ion implantation

Abstract A novel approach based on ion implantation has been developed and used to investigate the influence of a selection of metal and semi-metal ions or their combinations with selected non-metal elements, the implantation energy range, and ion fluencies, on the behaviour of implanted materials under fast atomic oxygen fluxes (FAO). The preferential conditions of single- or multiple-ion implantation in a number of high-performance polymers, graphite and composite materials were examined. Highly stable, oxidation- and erosion-resistant new surface structures were created on graphite, Kapton, PEEK and Mylar, and on carbon-fibre/PEEK composites by exposing the implanted materials to FAO in a unique atomic oxygen beam facility. A number of complementary surface analysis techniques such as RBS, XPS, SEM/EDS were used to study the content and structure of the modified surfaces, and their resistance to oxidation and erosion in FAO conditions.

Surface Modification of Polymer-Based Materials by Ion Implantation - a New Approach for Protection in Leo

Atomic oxygen is known to be the most prominent hazard for polymers and carbon- based materials in low Earth orbit (LEO), causing accelerated erosion and surface texturing. Vacuum ultraviolet (VUV) radiation is another important LEO environmental hazard for many of these materials. This study presents a new approach for protection of these structural materials for space applications.

Research Aspects of Scaling-Up Implantox Technology for Protection of Polymers in Space by Ion Implantation

High-dose Plasma Immersion Ion Implantation, that combines both low-energy ion and recoil implantation (dynamic ion mixing) and can be performed on flat materials or intricate three-dimensional parts, was used to enrich the thin surface layers of high-performance space-related polymers with an appropriate amount of AI, one of the reactive metal elements. The retained dose and distribution of the implanted AI and intermixed oxygen was controlled by RBS. Oxygen plasma asher and fast (E∼2–3 eV) atomic oxygen (FAD) beam, that are often used for accelerated ground-based testing as imitating low Earth orbit (LEO) environmental conditions, have been used as reactive oxidizing environments for surface conversion and testing of the implanted polymers. The surface modified materials have been shown to be resistant to both testing environments, including FAO, which is the main danger for polymers and other carbon-based materials in space, in LEO. The content, structure and morphology of the modified surface layers were examined by XPS and scanning electron microscopy (SEM). It was shown that protective oxide(s)-based surface structures were formed in the top surface layers of the treated polymers. Implantation and surface conversion conditions were found, where the appearance and important thermal-optical properties of treated polymer films, such as solar absorptance and thermal emittance, have been left practically unchanged, or altered in a specific manner.