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The effects of nitrogen implantation conditions (ion energy, dose rate, and processing time) on the thickness and wear behavior of N-rich layers produced on 304 stainless-steel surfaces are examined. Surfaces implanted at elevated temperatures ( ~400°C) with 0.4 to 2 keV nitrogen ions at high dose rates (1.5 to 3.8 mA/cm 2 ) are compared to surfaces implanted at higher energies (30 to 60 keV) and lower current densities (0.1 to 0.25 mA/cm 2 ). The most wear-resistant surfaces are observed when the implanted-ion energy is near 1 keV and the dose is very large (>2xl0 19 ions/cm ). Typically, surfaces implanted under these optimum conditions exhibit load-bearing capabilities at least 1000 times that of the untreated material. Some comparisons are also made to surfaces processed using conventional plasma-nitriding. Samples treated using either process have wear-resistant surface layers in which the nitrogen is in solid solution in the fee phase. It is argued that the deep N migration ( >l\x,m) that occurs under low-energy implantation conditions is due to thermal diffusion that is enhanced by a mechanism other than radiationinduced vacancy production.

In order to help establish the role of Cr in high-dose, high-dose-rate, elevated temperature N implantation of austenitic (fcc) stainless steels, similar implantations into fee Ni80Fe20 and Ni80Cr20 alloys have been made and characterized by Auger depth profiling and X-ray diffraction. For the Ni-Fe alloy a shallow layer fcc(∼ 0.2 μm) containing an ordered fee γ'-(Ni0.8Fe0.4)4N phase is induced. In contrast, for the Ni-Cr alloy a much thicker N-containing layer (∼ 0.2 μm) is produced consisting primarily of a high-N solid solution fee phase. The fractions of the implanted N retained in Ni-Fe and Ni-Cr were approximately 10 and 100%, respectively. The mechanisms by which Cr is promoting the deep migration and high retention of N in solid solution are proposed.

Cathodic arc plasma deposition was used to coat Al2O3 powder (mesh size 60) with platinum. the power particles were moved during deposition using a mechanical system operating at a resonance frequency of 20 Hz. Scanning electron microscopy and auger electron microscopy show that all particles are completely coated with a platinum film having a thickness of about 100 nm. the actual deposition time was only 20 s, thus the deposition rate was very high (5 nm/s).

The electrical and chemical properties of the interfaces of thin oxides grown on strained GexSi1−x layers are analyzed in detail using capacitance-voltage measurements and Auger electron spectroscopy. It is found that the electrical properties (interface states and fixed oxide charges) of the interface depend on various parameters such as oxidation temperature, oxidation time, Ge distribution near the interface, and Ge distribution in the entire epilayer. The Ge distribution at the interface can be described using concentration-dependent diffusivity of Ge in the epilayer. The electrical properties are improved with the increase in oxidation temperature, but for a given oxidation temperature, the quality of the interface degrades with the increase in oxidation time. At a very high oxidation temperature the Ge distribution in the entire epilayer is altered due to the high diffusivity of Ge.

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We describe a novel means for the production of atomically-bonded thin films of a wide range of materials. The technique is a plasma and ion beam method involving synthesis of the desired surface film by plasma deposition and the simultaneous atomic mixing of the film into the substrate by low energy ion implantation from the surrounding plasma. Vacuum-arc-produced metal plasma is used for the metallic component of the film and gases can be added to form compound films. Multiple plasma generators can be used, and films of single metals, alloys, ceramics and multilayers can be formed. By repetitively pulse biasing the substrate during plasma deposition, the growing film is subjected to energetic ion bombardment, and direct and recoil ion implantation is induced. The depositing film is thereby atomically mixed to the substrate as it is formed. The films are atomically smooth, can be anywhere from a few monolayers to microns in thickness, and the interface or mixed transition zone can be tailored. Here we outline the basic plasma physics of the method and describe a number of novel surfaces which have been formed with excellent properties.

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