Kinetics displacement deposition

The kinetics and mechanisms of the displacement deposition of Cu on a Zn substrate in alkaline media was studied by Massee and Piron (5). They determined that at the beginning of the deposition process, the rate is controlled by activation. The activation control mechanism changes to diffusion control when the copper covers enough of the Zn surface to facilitate further deposition of copper. This double mechanism can explain the kinetic behavior of the deposition process. 

The book is divided into 18 chapters, presented in a logical and practical order as follows. After a brief introduction (Chapter 1) comes the discussion of ionic solutions (Chapter 2), followed by the subjects of metal surfaces (Chapter 3) and metal solution interphases (Chapter 4). Electrode potential, deposition kinetics, and thin-fihn nucleation are the themes of the next three chapters (5-7). Next come electroless and displacement-type depositions (Chapter 8 and 9), followed by the chapters dealing with the effects of additives and the science and technology of alloy deposition... 

Ni3C decomposition is included in this class on the basis of Doremieux s conclusion [669] that the slow step is the combination of carbon atoms on reactant surfaces. The reaction (543—613 K) obeyed first-order [eqn. (15)] kinetics. The rate was not significantly different in nitrogen and, unlike the hydrides and nitrides, the mobile lattice constituent was not volatilized but deposited as amorphous carbon. The mechanism suggested is that carbon diffuses from within the structure to a surface where combination occurs. When carbon concentration within the crystal has been decreased sufficiently, nuclei of nickel metal are formed and thereafter reaction proceeds through boundary displacement. 

Ultraviolet radiation, 797 Undeipotential deposition, 1121, 1313 alloy formation during, 1316 causes of, 1315 definition, 1313 displacement potential, 1316 kinetics of, 1316 lead deposition, 1313 one-dimensional phase formation in, 1316 scanning tunneling microscopy used to study, 1313, 1315... 

There are four types of fundamental subjects involved in the process represented by Eq. (1.1) (1) metal-solution interface as the locus of the deposition process, (2) kinetics and mechanism of the deposition process, (3) nucleation and growth processes of the metal lattice (M a[tice), and (4) structure and properties of the deposits. The material in this book is arranged according to these four fundamental issues. We start by considering the basic components of an electrochemical cell for deposition in the first three chapters. Chapter 2 treats water and ionic solutions Chapter 3, metal and metal surfaces and Chapter 4, the metal-solution interface. In Chapter 5 we discuss the potential difference across an interface. Chapter 6 contains presentation of the kinetics and mechanisms of electrodeposition. Nucleation and growth of thin films and formation of the bulk phase are treated in Chapter 7. Electroless deposition and deposition by displacement are the subject of Chapters 8 and 9, respectively. Chapter 10 contains discussion on the effects of additives in the deposition and nucleation and growth processes. Simultaneous deposition of two or more metals, alloy deposition, is discussed in Chapter 11. The manner in which... 

In the autocatalytic deposition of Ni, Co, and Fe, different kinetic behavior is observed. For example, Ni is the most easily deposited by autocatalytic deposition with the common reducing agents in the acidic and alkaline conditions. Cobalt is usually deposited in alkaline solutions and with great difficulty in acidic solutions. Fe is deposited with a great difficulty, frequently with the help of small currents, resulting from displacement reactions of more electronegative metals. 

This method is also referred to as the miscible-displacement or continuous-flow method. In this method a thin disk of dispersed solid phase is deposited on a porous membrane and placed in a holder. A pump is used to maintain a constant flow velocity of solution through the thin disk and a fraction collector is used to collect effluent aliquots. A diagram of the basic experimental setup is shown in Fig. 2-6. A thin disk is used in an attempt to minimize diffusion resistances in the solid phase. Disk thickness, disk hydraulic conductivity, and membrane permeability determine the range of flow velocities that are achievable. Dispersion of the solid phase is necessary so that the transit time for a solute molecule is the same at all points in the disk. However, the presence of varying particle sizes and hence pore sizes may produce nonuniform solute transit times (Skopp and McCallister, 1986). This is more likely to occur with whole soils than with clay-sized particles of soil constituents. Typically, 1- or 2-g samples are used in kinetic studies on soils with the thin disk method, but disk thicknesses have not been measured. In their study of the kinetics of phosphate and silicate retention by goethite, Miller et al. (1989) estimated the thickness of the goethite disk to be 80 /xm. 

Influence of the kinetics on surface morphology of copper deposited via galvanic displacement was investigated by Annamalai and Murr [5]. Deposition of copper was performed from the acidic Cu(II) solution on iron substrate. An increase in the Cu(II) concentration from 0.5 to 5 g/L led to a decrease in the rate of copper deposition. 

Based on the results from Karavasteva [7], it seems that the kinetics and consequently the surface morphology of the deposited copper via the galvanic displacement reaction onto zinc, iron, and aluminum are strongly influenced by... 

If the field of nanotechnology is aimed to grow in the future where metallic nanoparticles find realistic applications, both galvanic displacement and electroless deposition with reducing agents open a tremendous window for future studies of the kinetics and mechanisms of these processes. This approach could lead to the successful production of desired sizes and shapes of the required nanoparticles. 

---