O Minho

In the wire bonding technique, a thin Au wire is interconnected with an Al layer on a Si chip. During energization heating at solid-state temperatures, however, brittle Au-Al compounds with high electrical resistivities are formed at the interconnection by the reactive diffusion between Au and Al. In order to examine the growth behavior of the Au-Al compounds, the kinetics of the reactive diffusion was experimentally observed using sandwich Al/Au/Al diffusion couples. The diffusion couple was pr

To examine growth behavior of α-CoSn3 at solid-state temperatures, kinetics of reactive diffusion between Co and Sn was experimentally observed using sandwich Sn/Co/Sn diffusion couples prepared by a diffusion bonding technique. The diffusion couples were isothermally annealed in the temperature range of 433–473 K for various times up to 744 h. Owing to annealing, an intermetallic layer consisting of CoSn3 was formed at the original interface in the diffusion couple. The mean thickness of the in

The study investigated the growth kinetics and rate-controlling processes of intermetallic layers formed at the interface between Cu and eutectic Sn-Bi alloys with Ag or Ni addition at solid-state temperatures. Isothermal sections of the equilibrium phase diagram were calculated to understand phase stability at the interface. The thicknesses of the intermetallic layers were plotted against annealing time, and a power function equation with an exponent slightly smaller than 0.25 described their r

This study investigates the microstructural evolution and growth behavior of intermetallic compound (IMC) layers in the Cu/(Sn-yAg, y = 0.29–2.00 wt%) system during isothermal aging within the temperature range of 433–473 K. Through systematic variations in Ag content, aging temperature, and time, the fundamental mechanisms governing IMC formation and growth in Cu/(Sn–Ag) solder joints are elucidated. The results demonstrate that IMC growth kinetics follow a power-law relationship, with IMC laye

The kinetics of reactive diffusion in the Co/Zn system was experimentally examined at solid-state temperatures. In this experiment, sandwich Zn/Co/Zn diffusion couples were prepared by a diffusion bonding technique, and then isothermally annealed in the temperature range of 523-573 K for various times up to 211 h. Owing to annealing, an intermetallic layer consisting of the , 1 and 2 phases was formed at the original interface in the diffusion couple, where the thickness is much smaller for the

This study elucidates the formation of distinct phases, such as intermetallic compounds (IMCs), and the evolution of Kirkendall voids. We not only observed the emergence of polycrystalline IMC layers and distinct diffusion-induced recrystallization (DIR) regions using various experimental methods but also quantified the elusive Kirkendall vacancy fraction by an extended numerical model. Experiments revealed the formation of polycrystalline layers with Ni4W and a distinct DIR region. Irregularly

This study delves into the intricate interaction between multi-walled carbon nanotubes (MWCNTs) and the Sn–Ag–Cu solder system, highlighting its relevance in lead-free soldering applications. Reflow and isothermal aging induce the formation of intermetallic layers at the joint interface, including Cu6Sn5, Cu3Sn, and irregularly shaped Ag3Sn particles. The addition of MWCNTs leads to the flattening of Cu6Sn5 grains, restraining their growth and potentially improving mechanical strength. Notably,

This study explores the growth behavior and rate-controlling processes of intermetallic compounds at Ag/Zn diffusion couple interfaces. Through experimental observations and quantitative analysis, we identify three distinct intermetallic compounds: β-AgZn, γ-Ag 5 Zn 8 , and ε-AgZn 3 . We analyze the kinetics of intermetallic compound growth to elucidate the mechanisms governing thickness growth in terms of interdiffusion and interface reactions. The rate-controlling process varies with temperatu

This study focuses on the practical relevance of the Al-Ag bonding interface in electronic device fabrication, particularly in wire bonding, which is crucial for enhancing component reliability and performance. Experiments involved Al/Ag/Al diffusion couples, annealed at 703 K, revealing two stable intermediate phases, μ and δ. Characterizing the intermediate phases’ compositions and concentration profiles exposed a vital transition at the δ-Al interface. We used high-voltage electron microscopy

The fabrication of Ti-Mg composite biomaterials was investigated using spark plasma sintering (SPS) with varying Mg contents and sintering pressures. The effects of powder mixing, Mg addition, and sintering pressure on the microstructure and mechanical properties of the composite materials were systematically analyzed. Uniform dispersion of Mg within the Ti matrix was achieved, confirming the efficacy of ethanol-assisted ball milling for consistent mixing. The Young’s modulus of the composite ma