for the high-speed, dry shaping of difficult exposed surfaces of wood and aluminium, for example on automobile dashboards. The wear, friction, and electrical properties of DLC make it an appealing material for medical applications. DLC has proved to have excellent bio-compatibility as well. This has enabled many medical procedures, such as Percutaneous coronary intervention employing brachytherapy to benefit from the unique electrical properties of DLC. At low voltages and low temperatures electrodes coated with DLC can emit enough electrons to be arranged into disposable, micro-X-ray tubes as small as the radioactive seeds that are introduced into arteries or tumors in conventional brachytherapy. The same dose of prescribed radiation can be applied from the inside, out with the additional possibility to switch on and off the radiation in the prescribed pattern for the X-rays being used. DLC has proved to be an excellent coating to prolong the life of and reduce complications with replacement hip joints and artificial knees. It also has been successfully applied to coronary artery stents, reducing the incidence of thrombosis. The implantable human heart pump can be considered the ultimate biomedical application where DLC coating is used on blood contacting surfaces of the key components of the device. Environmental benefits of durable products The increase in lifetime of articles coated with DLC that wear out because of abrasion can be described by the formula f = (g)µ, where g is a number that characterizes the type of DLC, the type of abrasion, the substrate material and μ is the thickness of the DLC coating in μm. For "low-impact" abrasion (pistons in cylinders, impellers in pumps for sandy liquids, etc.), g for pure ta-C on 304 stainless steel is 66. This means that one-μm thickness (that is ≈5% of the thickness of a human hair-end) would increase service lifetime for the article it coated from a week to over a year and two-μm thickness would increase it from a week to 85 years. These are measured values; though in the case of the 2 μm coating the lifetime was extrapolated from the last time the sample was evaluated until the testing apparatus itself wore out. There are environmental arguments that a sustainable economy ought to encourage products to be engineered for durability—in other words, to have planned durability (the opposite of planned obsolescence). Currently there are about 100 outsource vendors of DLC coatings that are loaded with amounts