Progress in surface treatment II : special topic volume with invited peer reviewed papers only

225 Pages·2013·17.34 MB·English

by  Nahed El Mahallawy, Mingxing Zhang

Progress in
Surface Treatment II
Edited by
Nahed El Mahallawy
Mingxing Zhang
Progress in Surface Treatment II
Special topic volume with invited peer reviewed papers only
Edited by
Nahed El Mahallawy and Mingxing Zhang
Copyright  2013 Trans Tech Publications Ltd, Switzerland

All rights reserved. No part of the contents of this publication may be reproduced or
transmitted in any form or by any means without the written permission of the
publisher.

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Volume 533 of
Key Engineering Materials
ISSN print 1013-9826
ISSN cd 1662-9809
ISSN web 1662-9795

Full text available online at http://www.scientific.net

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Preface

There is always a big demand on mechanical components where the surface is exposed to
corrosion, wear or heat or other environmental conditions. Special properties may also be
required on the surface and are not present in the substrate material such as a thermal or
electrical conductivity and magnetic properties which find applications in electronic circuits ,
in semiconductors , in polymer, glass or ceramic materials. For solar energy applications, a
reflecting surface is needed for concentrating the solar energy and a solar absorber surface
with selective coating is needed with high absorptivity and minimum emissivity. For high
temperature applications, a thermal barrier layer on the surface of alloy steel will reduce the
heat effect and extends the life of the components such as turbine blades. For parts exposed to
relative motion such as gears and shafts, a wear resistant layer on a tough substrate is
required. Surface appearance and decorative aspects also find a wide range of applications.
For biomedical applications, the surface of the component should be biocompatible, corrosion
and wear resistant. Hence, surface treatment or surface modification is a major emerging
manufacturing technology for a wide range of applications.

Surface treatment excluding painting, includes surface hardening, surface alloying, surface
coating and hybrid processes. Due to the importance of the surface treatment, a first volume
appeared in 2008 and this is the second volume in which the emerging technologies and
applications are presented. It is the purpose of this special volume in surface treatment to
present some review of the progress in most popular modern surface treatment technologies
and applications for structural materials, therefore enable material scientists and engineers to
select suitable materials and techniques for their research and for their applications. It
contains papers on emerging technologies for deposition of metal or composite powder such
as thin film coating, cold spray, surface nano technology, cladding, pack cementation, high
velocity thermal spray, functional plasma spray, supersonic flame spray and others.

The guest editors would like to thank all authors for their significant contributions to this
special volume.

Prof. Dr. Nahed El Mahallawy Dr Mingxing Zhang
Ain Shams University, Cairo The University of Queensland
Egypt Australia
Table of Contents
Preface
Review on Recent Research and Development of Cold Spray Technologies
Q. Wang and M.X. Zhang 1
Cold Spraying of Titanium: A Review of Bonding Mechanisms, Microstructure and
Properties
T. Hussain 53
Application of Supersonic Flame Spraying for Next Generation Cylinder Liner Coatings
A. Manzat, A. Killinger and R. Gadow 91
High Velocity Thermal Spraying of Powders and Suspensions Containing Micron,
Submicron and Nanoparticles for Functional Coatings
A. Killinger and R. Gadow 99
Overview on Developed Functional Plasma Sprayed Coatings on Glass and Glass Ceramic
Substrates
M. Floristán, A. Killinger and R. Gadow 115
Advanced Ceramic / Metal Polymer Multilayered Coatings for Industrial Applications
A. Rempp, M. Widmann, A. Killinger and R. Gadow 133
Microstructure and High-Temperature Oxidation-Resistant Performance of Several Silicide
Coatings on Nb-Ti-Si Based Alloy Prepared by Pack Cementation Process
J. Li and X.P. Guo 145
Recent Studies on Coating of some Magnesium Alloys; Anodizing, Electroless Coating and
Hot Press Cladding
N. El Mahallawy and M. Harhash 167
Development of Bioactive Hydroxyapatite Coatings on Titanium Alloys
A. Carradò 183
Characterization and Tribological Performance of Cu-Based Intermetallic Layers
J. Joseph and D.M. Fabijanic 195
Characterisation of Interfacial Adhesion of Thin Film/Substrate Systems Using Indentation-
Induced Delamination: A Focused Review
M.Y. Lu, H.T. Xie and H. Huang 201
© (2013) Trans Tech Publications, Switzerland
doi:10.4028/www.scientific.net/KEM.533.1
Review on Recent Research and Development of Cold Spray
Technologies
Qiang Wang 1, 2, a, Ming-Xing Zhang 1, 3, b
1Division of Materials, School of Mechanical and Mining Engineering, The University of
Queensland, St. Lucia, QLD 4072, Australia
2CAST Cooperative Research Centre, Australia
3ARC Centre of Excellence for Design in Light Metals, Australia
[email protected], [email protected]

Keywords: cold spray; coatings; rapid manufacturing; particle impact; bonding mechanism; nozzle
design

Abstract:
Cold spray (CS) is an emerging revolutionary technology for deposition of metal or composite
powders at a low temperature. High quality deposits can be produced without heating related
defects, such as oxidation, phase transformation and residual tensile stress due to the shrinkage
during fast cooling. The present contribution demonstrates the state of the art of CS process. Since
nozzle is a key component in the CS equipment to prompt the efficiency of particle acceleration, the
progress of its design is summarized. Major issues regarding to the successful adhesion of particles
and corresponding interaction with substrates and existing deposits are discussed, in terms of
numerical simulation and experimental observation. Current implemented CS applications are
presented, and potential industrial applications are discussed.
1. Introduction
The discovery of recent cold spray (CS) technology derived from the study of interaction behavior
of particles and immersed components during 1970s and 1980s. Scientists (Alkhimov et al) from
the Institute of Theoretical and Applied Mechanics of the Siberian Branch of Russian Academy of
Sciences (ITAM of RAS) exploited the phenomenon that deposition of solid particles onto the
surface was achieved when the velocity of impact was higher than certain critical value and named
it as CS [1-4]. The principle of CS process is illustrated in Fig. 1. A high pressure gas (helium,
nitrogen or air) is dispatched into two streams: one travels through powder feed unit to deliver
particles; another passes through a heater to gain high velocity. Eventually, two streams mix up in
pre-chamber of the De-Laval convergent-divergent nozzle. The temperature of particles is well
below the melting point. Particles with velocities of 300–1200 m/s are ejected towards a substrate
to form metallic or composite coatings in the solid state [5-8]. Because of the transformation of
high kinetic energy to strain energy, the impact between particles and substrate induces severe
plastic deformation at a high strain and strain-rate, which could break up the oxide layers and
allows impinging particles to bond with newly exposed oxide-free metal surface [9-12].
Subsequently, bonding between particles occurs in a similar way that resulting from extensive
plastic deformation upon impact, thus the coating is built up layer by layer.
2 Progress in Surface Treatment II
Compared with other thermal spraying techniques (for example, plasma spray, arc spray, flame
spray and HVOF [high velocity oxygen fuel] spray, and so on) that involves either complete or
partial melting of powder particles, CS can eliminate thermal defects, such as high residual stress
due to solidification shrinkage, high temperature oxidization, and potential damage of the substrate
caused by molten metal impact. Hence, CS is particularly suitable for coating of thermal-sensitive
materials, such as nanocrystalline and amorphous materials [13, 14], and for oxygen-sensitive and
low melting temperature materials, such as aluminum, magnesium and titanium alloys [7, 12, 15].
In recent years, adapting towards a trend for low temperature processes, CS has drawn increasing
attention in surface engineering and modification. Tremendous research and development have
been carried out. The present study dedicates to demonstrate state of the art of CS technology and
provide comprehensively updated information of CS research and development, in terms of gas
dynamic, bonding mechanism, generalization of spray windows and potential applications.

Fig. 1 Schematic of cold spray process.

2. Gas dynamic principle of two-phase flow model
Since cold spray is a gas powered method, the conditions of gas and geometries of nozzle, and the
interaction between these components become unique to determine the gas velocity, which later on
determines the particle velocity upon impacting the substrate. The particles traveling through the
nozzle interact with the gas to achieve critical velocity with necessary kinetic energy for successful
bonding. Fig. 2 shows a cross section of typical De-Laval convergent-divergent nozzle in cold gas
spray system. High pressure gas is fed into the back of the convergent section of the nozzle. In the
nozzle the gas flow can be accelerated or decelerated by changing the flow area [16, 17]. At the
throat of the nozzle, the gas reaches sonic condition. At the divergent section of the nozzle, the
acceleration of gas continues to achieve supersonic velocities. Due to the extreme expansion, the
temperature and pressure decrease from their original stagnation values.
Nahed El Mahallawy and Mingxing Zhang 3

Fig. 2 Schematic of a typical De-Laval convergent-divergent nozzle in cold gas dynamic spray
system. [18]

2.1 Isentropic gas flow model
Dykhuizen and Smith [16].developed a cold spray gas-flow model, which considers a typical
geometry of the converging-diverging nozzle (Fig. 2) and involves a number of assumptions and
simplifications such as: (a) the gas flow is assumed to be one dimensional and isentropic (adiabatic
and frictionless); (b) the gas is treated as a perfect (ideal) gas; and (c) the constant-pressure and the
constant-volume specific heats of the gas are assumed to be constant. The process gas is assumed
to originate from a large reservoir where the pressure is equal to the stagnation pressure (P ), the
o
temperature is the total temperature (T ), and the velocity is zero. Under simplified conditions, the
o
changes of status are related to the local Mach number (M) and the ratio of specific heats (γ):
T 1
o 1 M2 (1)
T 2
 1
p  1 
o 1 M2 (2)
p  2 

11
  1 
o 1 M2 (3)
  2 

Where ρ is the gas density. The value of γ is 1.66 for monatomic gas (helium) and 1.4 for diatomic
gas (nitrogen). Air is typically modeled as a diatomic gas because it is a mixture of nitrogen and
oxygen. The local gas velocity can be obtained from:
V M RT (4)
g
Where R is the specific gas constant. To correlate the conditions of each cross section along the
nozzle, the following relationship can be used:
4 Progress in Surface Treatment II
1
A 1  2  1 21
  1 M2 (5)
A* M 1 2 

Where A is the area of nozzle cross section, and superscript * refers to the throat of nozzle.
2.2 Particle acceleration model
After knowing the gas velocity and temperature, particle acceleration and particle heat transfer can
be calculated [19]. The particle acceleration can be equated to the drag force on the particle:
 
dV dV C A  V V 2
m p mV p  D p g g p (6)
dt p dx 2
So the ultimate particle velocity is equal to the gas velocity, and a longer nozzle will enable the
particle to come closer to the gas velocity (neglecting nozzle friction effects on the gas velocity).
Furthermore, the examination of Eqs. (1), (4) and (5) indicates that the gas velocity within the
nozzle depends on the total gas temperature and the nozzle geometry (i.e. the cross-sectional area at
a given axial distance x), but not on the gas pressure (under the condition of a constant drag
coefficient). However, the effect of pressure on the particle velocity is through the change in
density, which is linear. In fact, the initial drag force is linearly dependent on the gas pressure
(density). So the role of pressure is to create sufficient drag on the particle such that it attains the
gas velocity in a reasonable distance.
Initially, the spray particle velocity is small compared to the gas velocity (i.e. V « V ), Eq (6) can
p g
be rearranged to:
C A x
V V D p g (7)
p g m

Examination of the above equation shows that initially:
 
V  g , or V  g (8)
p m p D
p p
So the importance of gas density, particle density and particle size are evident. The particle velocity
is proportional to square root of gas density, and inversely to square root of particle density and size.
From Grujicic et al. [20], we can estimate the particle temperature as follows:
   dx
m C dT A h T T dt A h T T (9)
p p p p g p p g p V
p
Where C is the specific heat capacity of the particle, h is the convective heat transfer coefficient,
p
since by the chain rule dt=(1/V ) dx. A typical value of the convective heat transfer coefficient (h)
p
is 190 W/m2K. Perhaps it’s more useful to use the Nusselt number, because h varies with flow
conditions.
Helfritch and Champagne [21] get around this problem by suggesting a modified form of the above
equation. Instead of using a single h value they use the product of the Nusselt number and the
thermal conductivity of the gas, given by: