New Trends in Decorative Coatings 2 $ ? 6 ?
ecorative coatings applied with D . . sputter ion plating processes have become a widely accepted application for vacuum technology. Although the deposition itself is only one important step among others, indusmal decorative applications require a reproducible and productive coating system. Leybold, as a system manufacturer, is featuring machines with a high level of up-time as well as an extraordinary sales service. In addition, such equipment is able to control all manufacturing steps including the choice of substrate material, the proper machining of it, the advisable heat treatment, the correct surface machining, the appropriate electroplating and the right precleaning. All these factors have an important influence, since a successful product does not depend solely on film properties. All system features required in the performance portfolio need to be fulfilled. In some circumstances, features required for a satisfactory coating can only be determined in extensive field tests.
Decorative properties and chemical composition of hard coatings
Transition metal compounds (nitrides, carbides, etc.) find increasing use as decorative coatings combining intensive colours, high wear resistance and good corrosion resistance. While golden TiN and dark-grey TiC are limited in their colour variation, the addition of a second metal or a second metalloid widens the spectrum of decorative colours, e.g. to dark blue with (Ti, Al)N. In the search for new colours, a number of nitrides of binary IVa metal-based alloys were deposited by reactive magnetron sputtering. The correlation between colour and stoichiometry was determined by surface analytical methods. Proper selection of the process parameters (target composition, N2 flow rate, etc.) results in coatings with different colours exceeding the conventional spectrum of decorative coatings.
Percussion marks on bone surfaces as a new diagnostic of hominid behaviour
Since stone tool cut marks and carnivore tooth marks were first described systematically on Plio-Pleistocene archaeological bone1,2, bone surface modification has played a prominent role in interpreting early archaeological site formation and hominid behaviour3–15. Here we introduce a new class of bone surface modification, which we call percussion marks. Percussion marks were produced during experimental breakage of marrow bones, and occur as pits or grooves impressed on a bone's surface by natural protrusions on the granitic hammerstone and anvil used. Although percussion marks can superficially mimic carnivore tooth marks, they nonetheless are closely associated with hammerstone impact notches and show consistent micromorphological features which distinguish them from tooth marks and other classes of bone surface modification. Given indications of prehistoric hammer-stone breakage of marrow bones1,7, an awareness of percussion marks is critical for accurately identifying the biological agents of bone modification at archaeological sites and provides a new diagnostic of carcass processing by hominids.