This review deals with the basis and novel trends in electrochromism, describing the basic aspects and methodologies employed for the construction and analyses of different modified electrodes. The work presents the classic materials used for the construction of electrochromic electrodes, such as WO3 and a view on the basic concepts of chromaticity as a useful approach for analyzing colorimetric results. The report also addresses how the incorporation of nanomaterials and the consequent novel modification of electrodes have furthered this area of science, producing electrochromic electrodes with high performance, high efficiency and low response times.

Ligas de metal duro (WC/Co) são geralmente processadas pelas técnicas da metalurgia do pó, que compreende mistura dos pós elementares, compactação e sinterização por fase líquida, com ou sem a posterior prensagem isostática a quente (HIP). Uma nova rota de processamento de metal duro é aqui apresentada, chamada de altas pressões e altas temperaturas (HPHT). Neste trabalho foi estudada a sinterização da liga WC/10% pesoCo a 5GPa, nas temperaturas de 1200, 1300, e 1400ºC, para os tempos de 1 e 2 minutos. Os melhores resultados obtidos foram: densidade =95,6%, dureza HV45 =10GPa e tenacidade à fratura K Ic=11MPa.m½.

Hardmetal is usually processed by the conventional powder technology techniques: mix of WC + Co powders, compacting, and liquid phase sintering. A new method to process hardmetal parts are described here. Parts of WC/10%wt Co were processed by using high pressure and high temperature sintering. It was used the pressure of 5GPa, temperatures of 1200, 1300, and 1400ºC, and times of 1and 2 minutes of sintering. The best results was density =95,5%, hardness HV45 =10GPa and fracture toughness of K Ic =11MPa.m½.