5 documents found, page 1 of 1
Influência da cristalização na dureza, módulo de elasticidade e tenacidade à fr...
Braun,S. E.; Mikowski,A.; Comin,A. N.; Thesing,L. A.; Soares,P.; Lepienski,C. M.Resumo O efeito da cristalização sobre as propriedades mecânicas (dureza, módulo de elasticidade e tenacidade à fratura por indentação) do vitrocerâmico dissilicato de lítio Li2O.2SiO2 foi investigado pela técnica de indentação (indentação instrumentada, microdurezas Vickers e Knoop). Os tratamentos térmicos para cristalização foram realizados em duas etapas: nucleação em 475 °C por 2, 5 e 10 h, e crescimento d...
Characteristics of austenitic stainless steel nitrided in a hybrid glow dischar...
Oliveira,R. M.; Ueda,M.; Silva,L. L. G.; Reuther,H.; Lepienski,C. M.A nitriding process based on two distinct nitrogen glow discharge modes, with sample temperatures ranging from 380 0C to 480 0C, was employed to treat the surface of austenitic stainless steel (SS 304). The temperature is controlled exclusively by switching the operation conditions of the discharges. First mode of operation is the conventional one, named cathodic, which runs at higher pressure values (1 mbar) i...
Mechanical properties of Ag-doped top-seeded melt-grown YBCO pellets
Foerster,C. E.; Lima,E.; Rodrigues Jr.,P.; Serbena,F. C.; Lepienski,C. M.; Cantão,M. P.; Jurelo,A. R.; Obradors,X.In the present work we report the mechanical properties of ca(b)-planes of Ag-doped top-seeded melt-grown YBaCuO (YBCO) pellets at different concentrations. Hardness and elastic modulus were obtained by instrumented indentation and fracture toughness by conventional Vickers indentation. Hardness profiles for both planes indicated values between 7-8 GPa at deep tip penetration. Significant differences in elastic...
Results from experiments on hybrid plasma immersion ion implantation/nitriding ...
Ueda,M.; Gomes,G. F.; Kostov,K. G.; Reuther,H.; Lepienski,C. M.; Soares Jr,P. C.; Takai,O.; Silva,M. M.To improve the performance of critical part components, new methods for surface strengthening are being developed with success, like plasma immersion ion implantation (PIII) and hybrid surface treatments mixing PIII and ion nitriding processes. A combination of high pressure (4 × 10¹Pa), moderate temperature (up to 450ºC) glow discharge nitriding with low pressure (8 × 10-2Pa) and low DC bias voltage ion nitrid...
Improvements of ultra-high molecular weight polyethylene mechanical properties ...
Marcondes,A. R.; Ueda,M.; Kostov,K. G.; Beloto,A. F.; Leite,N. F.; Gomes,G. F.; Lepienski,C. M.Nitrogen Plasma Immersion Ion Implantation (PIII) has been used to modify the surface chemical structure of Ultra High Molecular Weight Polyethylene (UHMWPE). Grinding and polishing processes based on abrasive papers and alumina pastes have been evaluated with regard to their results on the improvement of polymer surface roughness, which has shown to be of crucial importance for hardness characterization. Raman...