Amorphous boron coatings produced with vacuum arc deposition technology

Abstract

In principle, boron (B) as a material has many excellent surface properties, including corrosion resistance, very high hardness, refractory properties, and a strong tendency to bond with most substrates. The potential technological benefits of the material have not been realized, because it is difficult to deposit it as coatings. B is difficult to evaporate, does not sputter well, and cannot be thermally sprayed. In this article, first successful deposition results from a robust system, based on the vacuum (cathodic) arc technology, are reported. Adherent coatings have been produced on 1100 Al, CP–Ti, Ti–6Al–4V, 316 SS, hard chrome plate, and 52 100 steel. Composition and thickness analyses have been performed by Rutherford backscattering spectroscopy. Hardness (H) and modules (E) have been evaluated by nanoindentation. The coatings are very pure and have properties characteristic of B suboxides. A microhardness of up to 27 GPa has been measured on a 400-nm-thick film deposited on 52 100 steel, with a corresponding modulus of 180 GPa. This gives a very high value for the H/E ratio, a figure-of-merit for impact resistance of the film. A number of applications are contemplated, including corrosion/abrasion protection for die-casting dies and improved wear resistance for biomedical implants.

Biocompatibility testing of simulated total joint arthoplasty articulation debris

“…Boron is similar to carbon in that it has a capacity to form stable covalently bonded atomic level networks and lubricating properties similar to graphite 1. In principle, B as a structural material has many excellent surface properties, including corrosion resistance, high hardness, stable high temperature properties for processing, and a strong tendency to bond with most substrates at elevated temperatures 2–4…”

“…1 In principle, B as a structural material has many excellent surface properties, including corrosion resistance, high hardness, stable high temperature properties for processing, and a strong tendency to bond with most substrates at elevated temperatures. [2][3][4] All types of total joint arthoplasty (TJA) and especially human temporomandiblular joint (TMJ) replacement has shown to be more challenging, complicated and has shorter lifetimes comparing to hip and knee joint replacements. This is because of the complexity of the TMJ that has a unique sliding/rotating articulation motion; and a critical anatomical location with a little bone for fixation that is proximal to the eye, the ear, major nerves, and blood supplies, and the brain.…”

Some Applications of Cathodic Arc Coatings

“…Several concepts are used to utilize boron in a cathodic arc process: (i) using a conducting boron-containing sintered compound or alloy cathode [44,45], (ii) heating a boron cathode to become sufficiently conducting (T 4 8008C) [46,47,48], (iii) get boron from a boroncontaining gas or vapor (reactive deposition), or (iv) combine arc deposition with other techniques such as sputtering.…”

Amorphous boron suboxide

“…Amorphous boron oxide (BO x ) films including B 6 O can be produced using distinctive experimental techniques such as evaporation, cathodic arc deposition, and radio frequency magnetron sputtering . These experimental studies mainly focused the mechanical properties of the thin films and proposed that an increase in O concentration and a decrease film density lead to a decrease in the mechanical properties.…”