Despite the AISI 304 stainless steel has high corrosion/oxidation resistance, its tribological properties are poor, being one of the barriers for use in severe wear applications. Thus, there is a wide field for studying technologies that aim to increase the surface hardness and wear resistance of this material. In this work, hardness and wear resistance for AISI 304 stainless steel submitted to the thermochemical treatment by low temperature plasma carburizing (LTPC) in a fixed gas mixture composition of 93% H 2 and 7% CH 4 are presented. Through the evaluation of the carburizing layers, it was possible to observe a substantial improvement in tribological properties after all temperature and time of treatment. This improvement is directly related to the increase of the process variables; among them temperature has a stronger influence on the wear resistance obtained using LTPC process.

ResumoO presente trabalho avaliou a influência do tratamento térmico na recristalização do compósito formado por hidroxiapatita (HA) e titânia (TiO2) aplicado à liga Ti-6Al-4V através do processo plasma spray. As fases e o grau de cristalinidade do revestimento foram observados por difração de raios X. Já a integridade e o mecanismo de formação do revestimento foram avaliados por microscopia óptica. A adição da titânia à hidroxiapatita produziu um revestimento uniforme e isento de trincas. Quanto às fases formadas observou-se que após aspersão térmica a plasma spray ocorreu a formação de fase amorfa de fosfato de cálcio e de rutilo. Entretanto após o tratamento térmico a 750 ºC ocorreu à recristalização da hidroxiapatita com a presença da fase -TCP e rutilo.Palavras chaves: aspersão térmica, revestimentos bioativos, hidroxiapatita-titânia. IntroduçãoNa aspersão térmica durante a interação partícula- Materiais e métodosO presente trabalho foi realizado em parceria entre o laboratório de plasma spray do

In this work, a ternary composite of epoxy filled with ND and MS was produced for abrasive applications. Surfactants (oleic acid (OA), sodium dodecyl sulfate (SDS) and Triton TX-100 (TX-100)) were used to improve the particle dispersion and, consequently, the composite properties. The elastic modulus increased up to 76% for the sample with 1 wt% ND and 5 wt% ND using TX-100 (1ND5MS-TX100). Regardless of the filler concentration, the particles did not modify the thermal degradation behavior of the epoxy. Thermogravimetric (TGA) and dynamic mechanical (DMA) analyses suggest a strong particle-matrix interface, also evidenced in scanning electron microscope (SEM) micrographs. The composites presented superior tribological performance. 1ND5MS-TX100 presented a wear rate of 2.19 x 10 -3 mm 3 .Nm -1 , 61.3% lower than the epoxy. Also, all composites significantly reduced the roughness of the marble, being proportional to the abrasives concentration. Overall, composites with TX-100 presented improved wear behavior.