The evolution of electronic equipment in recent decades is experiencing a remarkable development. Due to increasing of consumption and also a very fast replacement rate due mainly to obsolescence, the amount of resulting electrical and electronic waste (WEEE) is increasing. The WEEE term includes all of electrical and electronic equipment starting from mobile phones, computers, video cameras to tv set, washing machines, refrigerators. In other words, all electrical and electronic equipment from a household, electronic equipment from automotive or industrial electronic components. Now in all worldwide it is estimated that WEEE represents about 5% of all municipal solid waste. The recovery process can be taken into account only if the cost of recovery is much lower than the value of the precious metals recovered from this. Regarding to waste disposal restrictions and strict environmental regulations, are needed economically viable and environmentally friendly technologies. The paper presents the results of laboratory experiments on the recovery of precious metals, especially gold, present in various electrical and electronic components. WEEE used in the experiments was used from mobile phones, computer motherboards, computerized microprocessors and various types of gold-plated contacts.

The automotive industry is one of the most important consumers of materials and especially metal materials. Competition in this area, technical progress and vehicle requirements require knowledge of the properties of materials, processing technologies that ensure operating requirements, reliability, and aesthetic requirements, with minimum costs. This work is part of modern trends to improve the surface layers of parts used mainly in the automotive industry and beyond. A nitrocarburizing study is presented on the tapered gears that make up the machine differential, as well as the optimization of the nitrocarburizing technology. The paper describes the objectives of nitrocarburizing, the materials used for this purpose, ending with the structures and properties obtained after nitrocarburizing.