Ligas Sn-Ag-Sb: análise da solidificação e do cenário mercadológico
The use of lead-containing alloys (Pb) in electronic microcomponents is a technological and environmental issue that requires urgent and attention. In this context, the development of new alloys with similar or superior properties to Pb-containing alloys is an alternative. Furthermore, the Fourth...
Na minha lista:
| Autor principal: | |
|---|---|
| Outros Autores: | |
| Formato: | Dissertação |
| Idioma: | pt_BR |
| Publicado em: |
Universidade Federal do Rio Grande do Norte
|
| Assuntos: | |
| Endereço do item: | https://repositorio.ufrn.br/handle/123456789/54679 |
| Tags: |
Adicionar Tag
Sem tags, seja o primeiro a adicionar uma tag!
|
| Resumo: | The use of lead-containing alloys (Pb) in electronic microcomponents is a technological and
environmental issue that requires urgent and attention. In this context, the development of
new alloys with similar or superior properties to Pb-containing alloys is an alternative.
Furthermore, the Fourth Industrial Revolution brought new production possibilities, with the
creation of new materials improving properties such as lightweight, better mechanical
properties, adaptability and with recyclability characteristics. The 4.0 paradigm demands
eco-friendly solutions and the new lead-free alloys are the best alternatives to meet this
new window of opportunity. The Sn-Ag alloys have promising properties such as good
mechanical strength and creep resistance, but they have low toughness, problems with
silver segregation and low wetting on metallic substrates. In this context, the present study
aims to analyze the effect of antimony (Sb) additions (0.2 and 2.0% in weight) on the
microstructure, thermal parameters of solidification (cooling rate-ṪL and growth rate-VL),
phase transformation temperatures, macrosegregation, mechanical properties and fracture
modes in the hypoeutectic Sn-2.0wt.%Ag alloy directionally solidified under transient
conditions. The microstructural and mechanical characterization occurred through the use
of techniques such as Optical Microscopy (OM), Scanning Electron Microscopy (SEM), XRay Fluorescence (FRX), X-Ray Diffraction (XRD) and Vickers microhardness.
Thermodynamic calculations were performed by Thermocalc software, in order to study the
evolution of phase fractions and solidification paths. In addition, an analysis of the market
scenario in which the Sn-Ag-Sb alloys are inserted was carried out, through prospects on
the Espacenet platform and desk research. The microstructures of Sn-Ag-Sb alloys are
completely dendritic with an Sn-rich matrix (β-Sn) surrounded by a eutectic mixture, βSn+Ag3Sn+SbSn. The Sb additions promoted a microstructural refinement and a slight
increase in liquidus and solidus temperatures, when compared to the binary alloy Sn2wt.%Ag. Ag exhibited a constant and higher than nominal macrosegregation profile, while
Sb changed from a constant profile to an inverse type with increasing Sb content. The
Ag3Sn intermetallic displayed two morphologies, fibrous and spherical, with prevalence of
the latter for ṪL>5.10 °C/s and 2.90 °C/s for the alloys with 0.2wt.%Sb and 2wt.%Sb,
respectively. Sb promoted an increase in the Vickers microhardness of both Sn-Ag-Sb
alloys, with a higher value for the 2wt.%Sb content. In the market context, Sn-Ag-Sb alloys
have high potential for application in nanotechnology, autonomous robots and artificial
intelligence. |
|---|