ENCYCLOPÉDIE DE LA RECHERCHE SUR L’ALUMINIUM AU QUÉBEC 2013 | Page 56

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NOUVEAUX PRODUITS ET MATÉRIAUX À BASE D'ALUMINIUM
NEW ALUMINIUM BASED PRODUCTS AND MATERIALS
RÉSISTANCE À L’USURE DE REVÊTEMENTS COMPOSITES
À BASE D’ALUMINE DE FER/CARBURE DE TITANE
WEAR RESISTANCE OF IRON ALUMINIDE/TITANIUM
CARBIDE COMPOSITE COATINGS
Auteur 1, Author2
1
2

1. Introduction

Aluminide coatings are attractive alternatives to improve tribological behavior of
hydroelectric power generation equipment in which wear has significant impact on
operating and maintenance costs, as well as efficiency. In addition, iron aluminide
intermetallics have been recently identified as potential coatings for steel substrates
in sulfidation and corrosion resistant applications [1, 2]. However, limited room
temperature ductility (˂ 5%) and poor wear resistance at room temperature [3] have
been the principal obstacles to their acceptance in many applications. Incorporation
of hard ceramic particles in iron aluminide matrix is reported to alleviate these
problems. Recent studies [3, 4] have demonstrated that incorporation of hard ceramic
particles may also improve the tribological properties of iron aluminide coatings.
Thus, in many applications under aggressive environments, the use of an iron
aluminide coating reinforced with ceramics could be a promising method.
Thermal spray processes, especially high-velocity oxy-fuel (HVOF) technique is
capable of depositing iron aluminide coatings. It has been reported that iron
aluminide coatings obtained by HVOF are characterized with high relative density
and adequate adhesion to substrate [5-7]. The wear resistance of HVOF iron
aluminide coatings is reported to be increased due to the higher hardness of the
coatings [7].
The main objectives of this work is to characterize the abrasion and sliding wear
behavior of iron aluminide coatings reinforced with TiC particles.

2. Methodology
Ball Milling for 12 h:
 Fe3Al
 Graphite
 Titanium

department and Institution 2.

Fig. 4 shows the friction coefficient (µ) plots of Fe-Al/TiC composite coatings as a function of sliding distance for a
constant applied load of 5 N and a sliding speed of 0.05 m/s. As it is shown, the friction behavior of both 30 mol% TiC and
50 mol% TiC composite coatings are quite similar. There is an initial rise in µ followed by a decrease and a steady state
plateau for both coatings. The initial rise in µ has been explained to be the result of high adhesive contact between the
counterpart and the coating surface [6, 8]. However, the values of µ seems to be different for the two coatings (about 0.7
for the coating with 30 mol% Ti+C and about 0.6 for the coating with 50 mol% Ti+C).
Table 2 indicates the Vickers hardness and the
sliding wear rates of the coatings. It is seen that
Vickers hardness and wear resistance of the
coatings increases with increasing TiC content
from 30 mol% to 50 mol%. Carbide particles
protruding from the coating surface are believed to
be more efficient for bearing the load than the FeAl matrix. This brings about an affective reduction
in micro-plowing and micro-cutting caused by the
WC counterpart, and consequently higher wear
resistance (lower wear rate). A wider and deeper
wear track profile in the coating with lower content
of TiC particles can be observed in Fig. 5.

Fig..4. Coefficient of Friction of Fe-Al/TiC coatings and the
substrate.

Fig.5. Wear track profiles of
Fe-Al coatings with (a) 30
mol% and (b) 50 mol%
Ti+C.

Heat Treatment
@ 1000 ºC for 1 h

XRD Verification

Département et Institution 1

HVOF
Projection
Table 2. Vickers Hardness and Sliding Wear Rates

Spray Nozzle

Fig.1.
Schematic of
an HVOF torch

Sliding Wear Rate, K
(mm3N-1m-1)

Fe3Al/30 mol% TiC

10.1

6.8*10-6

12.7

3.1*10-6

The mass loss for two coatings as a function of
abrasion time is shown in Fig. 6. It is qu ]H