Siliconcarbide Embedded Hybrid Nanocomposites as AbrasionResistant Coating

Osman Arslan • Ertugrul Arpac • Hikmet Sayılkan

Received: 27 December 2009 / Accepted: 2 April 2010 / Published online: 17 April 2010

� Springer Science+Business Media, LLC 2010

Abstract Siliconcarbide (SiC) ceramic powder incorpo-

rated inorganic–organic nanocomposites were prepared by

sol–gel spin coating method. Coating properties and abra-

sion resistance of the hybrid polymers were examined by

scanning electron microscopy (SEM), EDX analysis,

FT-IR spectroscopy, thermogravimetric differential ther-

mal analysis (TG-DTA). Mechanical tests like surface

static corrosion analysis, abrasion test, scratch-tape test,

adhesion test, chemical and solvent resistance, surface

hardness were performed in order to evaluate the coatings

for possible industrial applications. Prepared polymers

were applied onto the aluminium substrates. Results

revealed that industrially available SiC ceramic powder

incorporated inorganic–organic nanocomposites can be

prepared with an easy and controlled way using sol–gel

method and applied onto the aluminium surfaces by spin

coating without using primer solution and shows excellent

abrasion resistance.

Keywords Abrasion resistant coating � Sol–gel �Hybrid material � Ceramic particle

1 Introduction

Using sol–gel process different inorganic organic hybrid

nanocomposite materials can be prepared from an alk-

oxysilane and a metal alkoxide. This concept is based on

the unusual characteristics of sol–gel reaction for the syn-

thesis of novel materials [1–5]. Sol gel process allows the

introduction of an organic part into an inorganic network

with specific properties. By using different molecules or

precursors, functional materials such as coatings, fibers,

composite materials, aerogels and powders can be obtained

[6–13]. Key factor is the connection and compatibility

between precursors. While silicon alkoxides are not so

reactive in normal room conditions, other transition metal

alkoxides like Ti, Al, Zr, must be protected from the

humidity. Due to their low reactivity silicon alkoxides need

catalyst for controlling and accelerating the hydrolysis and

condensation reactions but on the other hand, transition

metal alkoxides and their derivatives must be used in their

complexed forms for the synthesis of glasses and other

functional materials. Chemical modification of the transi-

tion metal alkoxides with a chelating agent is used to

prevent the precipitation of moisture sensitive precursors

because of their mentioned high activity. After hydrolysis

and condensation reactions of chelated transition metal

alkoxides, controlled and homogeneous mixtures can be

obtained. b-ketoesters, b-diketones and carboxylic acids

are widely used as complexation ligands [14–16].

Sol–gel process gives an easy way for the incorporation

of nanoscaled sols in order to obtain homogeneously dis-

persed materials or coating solutions. Effects of these

nanoscale sols have been extensively investigated and

published [17–19]. Hydrolysis and condensation reactions

of certain precursors or in situ reactions in the matrice can

be used for the incorporation of the particles into the

This work dedicated to the honored memory of the Prof. Dr. Hikmet

Sayılkan who has passed away last year.

O. Arslan (&)

Inorganic and Material Chemistry Department, University

of Cologne, Greinstrasse 6, 30939 Cologne, Germany

e-mail: oarslan@uni-koeln.de

E. Arpac

Chemistry Department, Akdeniz University,

07070 Antalya, Turkey

H. Sayılkan

Department of Science, Inonu University,

44069 Malatya, Turkey

123

J Inorg Organomet Polym (2010) 20:284–292

DOI 10.1007/s10904-010-9360-y

matrices [20]. Stability of the particles are vitally important

in order to obtain required properties. Surface charges play

a very important role as the particles must be stabilised for

homogeneous materials. Surface modifiers can also be used

preferentially but neither surface charges nor surface

modifiers are perfect stabilizers.

Nanocomposites as coating material has been developed

from ORMOCERs (ORganically MOdified CERamics) in

many studies which show excellent abrasion resistance,

antifogging, antisoiling, hidrophobic, scratch resistance

properties [21]. In this study we are reporting abrasion

resistant coatings developed for Al surfaces using com-

mercially available ceramic powder (H.C. Starck UF 10

SiC) alternatively. Using both an organoalkoxysilane and a

chelated metal alkoxide a nanocomposite coating material

was prepared and applied onto Al substrates by spin

coating method. Incorporation of commercially available

ceramic powder SiC and its effects on nanocomposite

structure on Al surfaces were investigated. This study is

another report by our group concerning with the incorpo-

ration and coating properties of ceramic particles embed-

ded nanocomposites [22]. As widely known, abrasion

resistant coatings have been used to improve the hardness,

protection and scratch resistance of the different surfaces.

Especially Wilkes, Kasemann, and Schmidt [23–25] syn-

thesized new coating materials from silane-functionalised

precursors which show high resistance to chemicals,

scratching and abrasion. Wilkes prepared inorganic organic

hybrid coatings onto the polycarbonate surfaces from a

trifunctional amine and other alkoxides. Thermally cured

coatings were investigated by the Taber abrader but the

results were relatively poor according to the results pre-

sented here. Cycles were stopped around 200 and abrasion

evaluation was conducted. Additional use of transition

metal alkoxides provided novel coating materials but their

adhesion and abrasion resistance were unpredictable and in

some cases completely different from the desired point.

Schmidt and Nass used a transition metal alkoxide (like Zr

or Ti alkoxide) with an organically silicon alkoxide for

hybrid nanocomposite structures. They also added nano-

sized boehmite particles for increasing the abrasion resis-

tance. Thermally cured coatings shown good abrasion

resistance but abrasion tests were made by haze analysis

and abrasion cycles were only up to the 500. Adhesion of

the coatings were tested according to the standard test

technique which also presented here. Adhesion, scratch and

abrasion resistance were good but because the modified

conditions and different techniques used, nanocomposites

can be simply accepted as positive for the desired appli-

cations. Another important point is the transparency of the

applied coatings. Wilkes, Schmidt and Nass investigated

transparent coatings for contact lenses or organic surfaces

like PC substrates.

In our investigation transparency is not an aim and

decoratif applications are far beyond from the purpose.

Obtained method and coating material is a novel structure

which provided by an industrially available ceramic par-

ticle (SiC) and an alkoxide formulation. Excellent abrasion

resistance up to 1000 cycles proved easy to handle and

industrially applicable coatings can be obtained.

2 Experimental

2.1 Chemicals

For nanocomposite coating materials, commercially avail-

able 3-glycidyloxypropyl trimethoxy silane—this epox-

ysilane will be referred as GLYMO (Degussa)—was used

as matrice. Aluminium tri-seconder butoxide Al(OsBu)3

was purchased from Fluka and used as a co-reactant after

chelated with methyl acetoacetate (Fluka). Methyl aceto-

acetate was used as a complexing ligand for Al(OsBu)3 in

order to control its reactivity. SiC ceramic particles (H.C.

Starck SiC UF-10 Ø: 1.8 lm) were used to increase the

abrasion resistance of the nanocomposite coatings. Coating

solutions have been applied onto 100 9 100 mm Al sub-

strates (Assan aluminium industry, alloy 1050, 0.8 mm Al

plate) by spin coating method. HCl (Merck) and distilled

water were used to start the hydrolysis-condensation

reactions of epoxysilane. Tween 80 (Sigma–Aldrich) was

used for surface modification and stabilisation of SiC

ceramic particles to obtain high homogenity. While epox-

ysilane GLYMO provides surface modification for SiC

powders, Tween 80 has also big effect upon stabilisation of

powders. Coatings which were prepared accidently in the

absence of Tween 80 showed that SiC ceramic particles

tend to agglomeration in the coating solution and inho-

mogeneous coatings were obtained.

2.2 Preparation of Sols

To an Aluminium trisec-butoxide solution, equimolar

amount of methylacetoacetate (MAA) was added, drop-

wise. Then solution was stirred vigorously and cooled in

ice-bath to prevent overwarming. Because of the exother-

mic nature of the complexation reaction, solution should be

kept around room temperature. After complexation, solu-

tion cooled to the room temperature and stirring was car-

ried on. Aluminium complex structure (Fig. 1) allows us to

co-condensation with the epoxysilane leading to hybrid

compound.

3-Glycidyloxypropyl trimethoxy silane (GLYMO) was

prehydrolised with 0.1 M HCl per mole hydrolisable –OR

group and stirred at room temperature for 6–12 h. After

prehydrolysis a clear solution was obtained. During

J Inorg Organomet Polym (2010) 20:284–292 285

123

hydrolysis there was no observable difference. The initial

ratio between the OR/H2O was 3/1 at the beginning of the

hydrolysis. Then this ratio was converted to 1/1 by using

0.1 M HCl while particle dispersion was being carried on.

2.3 Preparation of Coating Solution

Prehydrolised epoxysilane (Fig. 2), SiC ceramic particles

(arranging ratios between 5%, 10%, 15%, 18%, 20%, 22%,

25%, 26%, 28%, 30%, 40% and 50%) (H.C. Starck UF 10)

and dispersing agent Tween 80 were mixed together in the

dispersion vessel and dispersion was started. To increase

the homogenity glass roller balls had also been added.

These glass roller balls improve the dispersion of ceramic

powder in the mixtıure. After half an hour additional HCl

solution required for the full hydrolysis-condensation of the

remaining –OR groups was added. Dispersion of these SiC

ceramic particles was carried on for 1.5–2 h with a

mechanical stirrer in the dispersion vessel (Yokes Machine

Industry, Varian 6000 model).

To observe the mixing rate, stirring speed ranged

between 1000 and 3000 rpm. After the glass balls have

been removed by filtration, chelated Al co-reactant was

added and the whole solution was stirred vigorously for

15–20 min. As a surfactant and antifoaming agent BYK-

306 around 6% (BYK-Chemie) and BYK-530 around 5%

(BYKChemie) were used. 10 9 10 Al plates were coated

using spin coating method (Fig. 3).

Every coating was performed within 10 s. Al plates

were rinsed before handling with 5% P3 Almeco solution

at 70 �C. 100 mm 9 100 mm Al plates were dipped into

this solution in an ultrasonic bath and kept there for 5 min.

Afterwards Al plates were washed with pure water and

dried in an oven. P3 Almeco solution is a detergent based

solution which is especially used for degreasing process.

Further rinsing with water provides extra cleaning alu-

minium surfaces for the coating procedure. During spin

coating process spin rates were changing between 750 and

1000 for each coating application. The coatings were

thermally cured at 160–175 �C for 15 min. After coating

Al plates, abrasion, adhesion, corrosion and scratch tests

were performed. Effects of the increasing amount of

ceramic powder and dispersion rate on the quality of

coatings were investigated. The surface characteristics

GLYMO/Al(OsBu)2HacacOMe/SiC UF-10 coating was

monitored using scanning electron microscopy (SEM,

JEOL 6360LV, EDS: Noran System Six). Whole reactions

were confirmed using FT-IR (Bruker Tensor 27) analysis.

Especially functional groups for polymerization were

detected before and after the reactions. The thermal prop-

erties of the coating was observed with thermal analysis

systems using powders prepared from same coating

Keto-Enol form

of

methylacetoacetate

Fig. 1 Complexation of

aluminium trisec-butoxide

O---

R

OH

R---O

OH

O

OOH

OHSi

Si O

O

O

OHSi

OO

OH

OHSi

Si

O

O

O

O

SiO

O

O

O

O

O

O

Si

OR

O

O

O

O

Si

OR

Si

CH3

CH3

CH3

OO

O

O

O Si

H2O, H+

-ROH,-H2O

Fig. 2 Prehydrolysis of GLYMO precursor (R = glycidyloxypropyl)

286 J Inorg Organomet Polym (2010) 20:284–292

123

formulation as a reference.(DTA/TGA, Schimadzu Sys-

tem-50 model thermal analyzer). Homogenity and final

structure properties were observed by EDX analysis.

Abrasion resistance was tested with a Taber Abraser (Taber

Industries) 5131 (CS 10F rolls, 5,4 N). Scratch resistance

of the coatings were determined with a Multi Cross Cutter

(Erichsen, type 295), which was pulled over coating with

different weights. Adhesion and scratch behaviour of the

coatings were determined with a lattice cut/tape test

(Erichsen, ASTM D 3359). Corrosion tests were performed

with a Erichsen Corrotherm 610 according to DIN 50021

standard test for 15 days. Durability of coatings against to

acid and base were tested with an Erichsen Static Corrosion

Tester 434 by contacting surfaces with acidic and basic

solutions.

3 Results and Discussion

3.1 FT-IR Analysis of Reactions

Epoxysilane hydrolysis first was conducted using 0,1 M

HCl solution. FT-IR analysis of the epoxysilane compound

shows that pure epoxysilane contains no silanol OH-groups

but after hydrolysis, peak around 3371 cm-1 clearly proves

formed silanol groups. Epoxy ring on the organic part was

analyzed by its specific FT-IR absorption. Peak at

906 cm-1 belongs to the epoxy rings stretching peak which

is still available after the first hydrolysis. Presumably

epoxy ring protonated but still in the closed form. Si–C

bond peak appears at between around 1073–900 cm-1 and

probably overlaps with the SiC ceramic powder peak.

Same observation can be seen in nanocomposite hybrid

structure formation (Fig. 4).

Al(OsBu)3/HacacOMe complex formation can be seen

clearly from the correspondent FT-IR spectra. Pure FT-IR

spectra of the methylacetoacetate (HacacOMe) ligand

shows 2t(C=O) stretching band around 1720 and

1710 cm-1 which shift after the complexation with

Al(OsBu)3. High reactivity of Al(OsBu)3 precursor toward

humidity causes small OH-groups in the 3300 cm-1 range

during FT-IR measurement which can be ignored but must

be noted. After modification, the bands of the stretching

vibrations t(C=O) and m(C=C) of the enolic forms of the

b-ketoesters at about 1611 and 1521 cm-1 were detected

(Fig. 5).

Particle embedded polymerization reaction was

observed by reacting mentioned precursors. As can be seen

Dispersant (Tween 80)

Epoxysilane(GLYMO) + HCl

Stirring(6-12 h)

Ceramic Powder addition(H.C.Starck SiC UF-10)

Roller glass balls

Complexing Ligant

Stirring-Cooling

Al (OsBu)3

Al (OsBu)2(HacacOMe) Complex

Dispersion (1-2 h)

Filtration +BYK 530 and BYK 306 addition

Stirring

Co-condensation

Spin Coating on Al

Thermal Curing (160-175 oC)

Fig. 3 Procedure for abrasion

resistant hybrid coatings

J Inorg Organomet Polym (2010) 20:284–292 287

123

silanol groups, epoxy ring and carbonyl groups peaks were

slowly disappeared with the increasing heat treatment

period proving suggested hybrid polymer structure forma-

tion. Nanocomposite structure shows great coating material

property and was applied onto the aluminium substrates by

spin coating method (Figs. 6, 7).

3.2 Thermal Properties

TG/DTA analysis provides useful information about the

heat character and limitations about the coatings. TG/DTA

analysis of the coating material were carried out in air from

0 to 950 �C. In Fig. 8a one can see the TGA analysis and in

Fig. 8b its DTA spectra. As can be seen from the TGA

spectra, there is a big weight loss in two steps namely to

around 300 �C (exactly 302 as can be detected from DTA)

and 500 �C until around 800 �C. Below 250 �C, the weight

loss is considered as the evaporation of water, thermal

decomposition and volatilization of some organic mole-

cules. Till 380 �C probably all other organic molecules are

removed. Between 380 and 500 �C weight loss can be

attributed to the beginning of further condensation of

polymeric networks. Groups such as Si–OH, Al–OH start

to further condensation and structures like Si–O–Si, or

Al–O–Si is formed. This formation continues until the

800 �C. After that point there is no remarkable loss in the

weight. Weight loss which can be attributed to this process

is 34%. Further condensation and another exothermic peak

at 500 �C occurs and weight loss is 6%. After that point

another loss is observed till 800 �C. This last loss is around

7%. Total weight loss is 47%. TG/DTA analysis of GLY-

MO/Al(OsBu)2HacacOMe/26%SiC UF-10 shows that

coating material has a good heat resistance up to 300 �C

which providing a big advantage in industrial applications.

3.3 Scanning Electron Microscopy (SEM)

Scanning electron microscopy (SEM) was used to observe

both powder dispersion behaviour of SiC particles in the

hybrid material and surface morphology of coating.

Because of the high conductivity of the Al substrate,

coating properties were investigated using carbon coated

glass plates. Cross sectional SEM pictures of the coating is

shown in Fig. 9. It is obvious that SiC ceramic powders are

highly dispersed in the matrix and the addition of SiC

particles can decrease shrinkage of sol–gel network

smoothly which corresponds to hard and homogeneous

materials. Cracks and holes seen were attributed the diffi-

culties arised during the cross sectional sample preparation

procedure.

3.4 Abrasion Resistance

Table 1 shows the abrasion test results of coatings con-

taining the different amounts of the ceramic particles.

These ceramic particles were incorporated according to the

non-volatile content of the matrix mixture. Simply the

05001000150020002500300035004000

906 cm-1

3371cm-1

1073 cm-1

a b

Fig. 4 FT-IR spectra for (a) pure GLYMO, (b) partly hydrolysed

GLYMO. (Color figure online)

05001000150020002500300035004000

Al(OsBu)2(acacOEt)

HacacOEt

Al(OsBu)3

1726 cm-1

1711 cm-1

1611 cm-1

1518 cm-1

Fig. 5 Al(OsBu)2(HacacOMe) complex formation. (Color figure

online)

0500100015002000250030003500

Cured hybrid polymer

1 min heat before heat

3338 cm-1

901 cm-1

1528 cm-1

Fig. 6 Hybrid inorganic–organic nanocomposite formation. (Color

figure online)

288 J Inorg Organomet Polym (2010) 20:284–292

123

weigh content of the whole coating formulation was taken

into consideration. According to the abrasion test results,

resistance against to abrasion can be increased by the

incorporation of the ceramic particles but after a certain

point this property begins to decrease which probably

depends on the carrying capacity of the matrix and the

Fig. 7 Structural model of

hybrid material. (Color figure

online)

Fig. 8 TGA and DTA plots of GLYMO/Al(OsBu)2HacacOMe/26%SiC UF-10. (Color figure online)

Fig. 9 Cross sectional SEM

images of GLYMO/

Al(OsBu)2HacacOMe/26%SiC

UF-10

J Inorg Organomet Polym (2010) 20:284–292 289

123

technique used. In order to obtain abrasion test results,

three different coating samples were tested at the same

time and an average value was taken. Same procedure was

followed to get the thickness measurements. Especially

thicker coatings were ignored which possibly mislead the

measurements to be taken and thickness of the coatings

were kept between the standards given. Coating properties

against to abrasion were improved remarkably. Although

non SiC incorporated coatings showed relatively poor

abrasion resistance (abrasion test cycles should have

stopped around 500–600 cycles) SiC embedded nano-

composite coatings abrasion resistance values were

remarkably high. Even 5% incorporation of SiC affected

the abrasion resistance characteristics in a positive manner.

Appearance of the inorganic–organic hybrid coatings were

colorless before the SiC ceramic particles incorporation. As

expected, natural pale yellow-brown color of the SiC

ceramic particles transmitted to the coatings. Naturally, this

yellow-brown color of the coatings were getting darker

with the increasing amount of the incorporated SiC ceramic

particles. Especially handling difficulties arised when

incorporation of the ceramic content increased up to 50%.

Figure 10 shows the graph of weight loss versus amount

of SiC ceramic powder in the hybrid coatings. 26% SiC

ceramic powder containing coating has the best abrasion

result, almost zero (0.3 mg) after subjected to 1000 cycles.

For comparing the abrasion resistance some other values

were also showed in the graph. According to the literature

we know that abrasion resistance of a produced nanocom-

posite from a polymer matrice and nanoparticle is depend

on the interaction of nanoparticles and matrice, tempera-

ture, dispersion rate and speed, particle amount embedded

and surface stabilization due to the ionic or polymeric

environment. Obtained results clearly show that abrasion

resistance of the coatings reach a maximum resistance at a

certain point. Because abrasion resistance of the coatings

depend on the particle–matrix interaction, homogeneity,

curing temperature and particle size as well which was

observed in our previous work, varying the particle amount

would be the reason for the different abrasion character of

the nanocomposite [22]. Among these parameters curing

temperature and particle size must be ignored because they

were all the same. Hence, particle matrice interaction or

inappropriate capping of the particles or local agglomera-

tion could be a reason for a nonlinear change in the abrasion

resistance. Additionally we observed that increasing cera-

mic particle amount causes local viscosity problems pre-

venting the homogenity of the coatings.

3.5 EDX Analysis

Hybrid coatings prepared by the sol–gel process generally

show novel properties. Silicates, aluminates or titanates

which were also connected to a carbon chain, built dense

networks by the polymerisation of this M–O bonds with

hydrolysis-condensation reactions. Additional polymerisa-

tion of the organic part which could be epoxy, unsaturated

Table 1 Results of Taber

abrasion tests%Particle Cycle Loss (±0.1 mg) Thickness (±2 lm) Adhesion Scratch

5 1000 9.2 16 GT/TT = 0 5B

10 1000 1.7 14 GT/TT = 0 5B

15 1000 2.1 17 GT/TT = 0 5B

18 1000 1.5 15 GT/TT = 0 5B

20 1000 3.5 17 GT/TT = 0 5B

22 1000 3.2 13 GT/TT = 0 5B

25 1000 1.7 14 GT/TT = 0 5B

26 1000 0.3 14 GT/TT = 0 5B

28 1000 2.1 15 GT/TT = 0 5B

30 1000 1.6 17 GT/TT = 0 5B

40 1000 4.5 15 GT/TT = 0 5B

50 1000 8.6 16 GT/TT = 0 5B

9,2

0,3

8,6

0

10

20

30

40

50

60

0 2 4 6 8 10

Weight Loss(mg)

Pow

der

Load

(%w

eigh

t)

Fig. 10 Weight loss versus increasing ceramic powder content.

(Color figure online)

290 J Inorg Organomet Polym (2010) 20:284–292

123

double bond or isocyanate groups can also be formed. In this

work organic part acting as polyethylene oxide chain which

was prepared from an epoxysilane. Microstructure of the

nanocomposite coating can be seen in Fig. 11. EDX analysis

and spectras of the 4 different regions of the nanocomposite

coating were shown and investigated. This analysis reveals a

big homogenity of the coating composition in different

regions. Every region comprises perfectly distributed silicon

content and supported with different amount of aluminium

and oxygen which could be attributed to different reaction

regions of the precursors. However Na peak arised in the

spectrum can be defined as unwanted Na diffusion from the

glass substrate through the coating which would lead to the

unstable durability of the nanocomposite coating (Fig. 12

and Table 2).

3.6 Adhesion Properties

The scratch and adhesion test was performed according to

the cross cut/tape test of the ASTM D 3359. In this test,

coated surfaces are scratched with the tool of the test to

form the small squares on (Cross hatched test) the surface.

Then the tape is adhered to the surface where those little

squares appear and pulled back strongly. If this process

forms big cracks or removes relatively high coating

material that would be attributed to the weakness of the

adhesion. Tests indicated that all coatings have the 5B

value as the test result for the scratch resistance. After

scratching the freshly coated surface, there were no disin-

tegrations, no wears and no coating material adhered to the

tape. The adhesion of the coatings on Al substrates were

also determined. GT/TT ratio of all coatings were excellent

mean that equal to zero. According to the test it is already

known that if adhesion is excellent GT/TT = 0 and if there

is no adhesion between substrate and coating material

GT/TT = 5. This graduation shows that all coatings have

excellent adhesion even the absence of a primer pre-

application.

Table 1 shows the all GT/TT adhesion and scratching

test values of the coatings. As seen in this table, each of

them are equal to zero which means perfect. This test

showed that these abrasion resistant coatings adhere to Al

surfaces without using any other material which help to

increase the adhesion level of coatings. This is really

important for industrial applications. Without using primer

(chemical compounds which increase surface functionality

and adhesion) these coatings can be applied onto the Al

surfaces to prevent abrasion, scratch and corrosion.

3.7 Corrosion Resistance

Corrosion tests of these nanocomposite coatings were

performed by spraying 5% NaCl solution to coated Al

surfaces under 1–1.5 atm. pressure. Nanocomposite coat-

ings were kept under these conditions for 15 days at 40 �C.

There was no negative effect on color, general appearance,

adhesion after the corrosion test. Surfaces which were

already subjected to humidity beside corrosion, did not

change their properties. This corrosion test provides us a

Fig. 11 Microstructure of the coating. (Color figure online)

Fig. 12 EDX analysis of different regions. (Color figure online)

Table 2 Elemental analysis of the four different coating regions

Compound concentration (%)

C Al Na Si O

Point 1 36.32 1.33 0.96 31.07 30.32

Point 2 44.59 0.73 31.57 23.11

Point 3 41.85 0.81 31.55 25.80

Point 4 38.81 1.72 31.51 27.95

J Inorg Organomet Polym (2010) 20:284–292 291

123

general corrosion character of the coatings concerning with

the surface protection. Surfaces did not change their ori-

ginal structure or any cracks, holes occurred. Even though

polarization curves or Electrochemical Impedance Spec-

troscopy (EIS) would provide more quantitative results,

evaluation of the corrosion behaviour of the ceramic

powder incorporated hybrid coatings on metals will be

another detailed investigation. Moreover non SiC ceramic

powder containing pure nanocomposite coatings seem

smoothly affected from this test. All the three blank sam-

ples exposed to this test have quite small white regions on

surface with loss of the clear appearance and relatively

blurry.

3.8 Chemical Durability

Durability of nanocomposite coatings against acids and

bases were tested. Each static corrosion tester 434 basically

contains each of pH 2 and pH 12 solutions in the one

specific test. Coated Al surfaces were placed between

solutions and supporter. These solutions were also heated

to 70 �C in a bath. During 1 h coating surfaces were kept in

contact with these solutions. SiC ceramic particle con-

taining hybrid nanocomposites did not show any negative

effect upon these test procedure meaning they are highly

resistant against to acidic and basic conditions. There were

any crack, hole or any other effect which proves coatings

were negatively effected. Figure 13 shows a simple picture

of this test apparatus. The same procedure was applied to

the non SiC containing pure hybrid coatings. Even though

the observation of smooth color changement on the contact

points it is really hard to specify remarkable differences

between two coating formulation. Still SiC incorporated

nanocomposite coatings could be easily defined acid and

base resistant.

4 Conclusion

Commercially SiC ceramic powders containing inorganic

organic hybrid coatings can be applied onto the Aluminium

substrates with spin coating method and these nanocom-

posite materials provide excellent abrasion, scratch and

corrosion resistance. Tests were revealed that thermal sta-

bilities of these coatings for the curing temperatures are

suitable for industrial applications as well. Inorganic–

organic hybrid polymerization could be monitored by

FT-IR analysis of the precursors. Besides chelated alu-

minium alkoxides can be used as a co-reactant to obtain

particle containing alumina-silicates. Obtained nanocom-

posite structures show desired mechanical character and

these coatings are also resistant to acidic and basic condi-

tions. Obtained results prove that high abrasion resistant

coatings can be prepared with a facile method and their

abrasion, adhesion, scratch properties are highly desirable.

Industrially available SiC ceramic particles is a promising

candidate for the desirable abrasion resistant coatings.

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4 coatings can be tested at the same time

Fig. 13 Static corrosion apparatus. (Color figure online)

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