The document discusses the development of non-toxic pigment mixtures to enhance the anticorrosion efficiency of coatings. It aims to replace toxic chromates and lead pigments. The document introduces various types of anticorrosive pigments and their mechanisms of corrosion protection. It also discusses the synthesis of zinc ferrite nanoparticles via a precipitation method and their use in an anticorrosive paint formulation. Testing of the paint samples found that the zinc ferrite-based paint provided excellent resistance to water and salt water. The nanopigments allow for enhanced properties and better anticorrosion performance compared to conventional pigments.

1. Presented by:-
Mayur Khandait
B.Tech Surface coating technology
LIT Nagpur
Major project seminar on

2.  The aim of pigment mixtures development is to enhance the
anticorrosion efficiency of non-toxic pigments and shift its
efficiency closer to the old, toxic chromate and lead pigments.
 To replace the use of toxic pigment such as chromates and lead
pigments.

3. INTRODUCATION

4.  Pigments Are Insoluble, Fine Particle Size Materials Which Confer
On A Paint Its Color And Opacity and imparts anti-corrosion
properties.
 The Pigments Are Used In Paint Formulation To Carry Out One Or
More Of The Following Tasks
I. To Provide Color
II. To Hide Substrates And Obliterate Previous Colors
III. To Improve The Strength Of The Paint Film
IV. To Improve The Adhesion Of The Paint Film
V. To Reduce Gloss
VI. To Reduce Cost

5.  All pigments should be insoluble in the medium in which they
are used, chemically inert, free of soluble Salts and unaffected by
normal temperatures.
 It should be easily wetted for proper dispersion, Nontoxic, non-
corrosive and have low oil-absorption characteristics.
 They should be durable and fast to light as possible.

6.  In general the following properties of the pigments are
important in selecting a pigment for any particular product.
a) Hiding power
b) Tinting strength
c) Refractive index
d) Light fastness
f) Particle size and shape
g) Resistance to corrosion and Temperature

7.  Since the nanoparticles are very smaller in nature it will used in every
process to show its better performance.
 Size of nanoparticles are smaller to wave length of visible light.
 One of the most critical characteristics of nanoparticles is their very
high surface to volume ratio.
 Nanoparticles improve many of desired properties like chemical and
heat resistance, reduction in weight and opacity.
 Nano-pigments does not show hiding power.

8.  Main problem in using nanoparticles for coating purpose is dispersion
and stability of nanoparticles. Agglomeration may take place because of
high surface energy possessed by nanoparticles due to their large
surface area.
 Pigments may lose their colour on reducing their size to nano level and
hence will lose their opacity.
 their small size and large surface area can lead to particle-particle
aggregation,
making physical handling of nanoparticles difficult in liquid and dry
forms.

9.  Studies have shown that nano-particles of zinc ferrite and their effects
in shape affect the anticorrosive properties. The particle size and form
(structure) has a large effect on mechanical properties, permeability of
the film to water vapor and efficiency in protection against corrosion.
There is a connection between the size of the spherical particle and the
anticorrosive efficiency, the smaller the particle size the better is the
corrosion protection of the coating.

10.  The process of destruction of metals & its alloys by chemical &
electrochemical attack through its environment starting from its
surface is called as CORROSION.
 E.g. Rusting of iron: Fe2O3.2H2O, Reddish brown color rust.
 Generally metal undergo corrosion & convert into oxides,
hydroxide, carbonates, Sulphides etc.

11.  Anticorrosive pigments may be classified by their mode of action
 Active Pigments
 Barrier Pigments
 Sacrificial Pigments

12.  Active pigments: These pigments interact chemically, either directly or
via intermediates with the metal substrate to reduce the rate of
corrosion and make the metal surface passive termed as passivation.
 Barrier pigments: Barrier pigments act by physically reinforcing the
barrier properties of the paint film, which means that they reduce the
permeability of the paint film to agents that support corrosion. they are
chemically inert and are said to being active or passive. The barrier
effect can be achieved, for example, by using pigments with a platelet-
like or lamellar particle shape.

13.  Sacrificial pigments:
Sacrificial pigments are a special group of active pigments. They
are metallic pigments, which act by cathodic protection when
applied to ferrous substrates, Such pigments must contain a metal
that is higher in the electromotive series of metals than the metal of
the substrate to be protected.
Under corrosive conditions, the sacrificial pigment, being more
reactive than the substrate, becomes the anode in an
electrochemical corrosion cell in which the substrate is the cathode
this is the meaning of the term cathode protection.

14. EXPERIMENTAL WORK
AND RESULT

15. General Methods of Pigment Manufacturing
Precipitation
Filtration
Drying Calcination

16. ZnCl2+ 2FeCl3+ 8NaOH ZnFe2O4+ 4H2O +
8NaCl
Taking 10% solution of each species
So 1 mole of zinc chloride along with 2 moles of ferric chloride
reacts with 8 moles of NaOH which means 136.28 grams of zinc
chloride along with 540 grams of ferric chloride reacts with 320
grams of NaOH.

17. RAW MATERIALS AMOUNT (gm/100ml) 10% solution
Ferric chloride 16.1
Zinc chloride 13.62
Sodium hydroxide 32
RAW MATERIALS AMOUNT (gm/100ml) 10% solution
Ferric chloride 32.2
Zinc chloride 13.62
Sodium hydroxide 32
For 1:1 mole Ratio
For 1:2 mole Ratio

18.  The required quantities of zinc chloride (ZnCl2) and iron chloride
(FeCl3) solution are mixed in a stoichiometric proportion. The
precursors were added in H2O and mixed homogeneously to yield a
uniform mixture of precursor at 80 °C for 40 min. Then, aqueous
hydroxide sodium solution (NaOH) is added drop wise.
 The reaction temperature is controlled at 100 °C. All samples were
washing at several times with water and ethanol to remove the soluble
salt, and finally drying at 70 °C overnight. The dried samples were
subsequently annealed at 500 °C for 8h to get the desired nanoparticles

20. Paint
formulation
Sample 1 Sample 2
Nano Zinc-fernrite 2.5 2.5
TiO2 3 3
Epoxy Resin 25 25
Whiting 2 2
Toluene 10 10
Butanol 5 5
Amine 5 5

21. Test Sample 1 Sample 1
Finish smooth smooth
Viscosity 42 sec 42 sec
S.G 1.1 1.1
% solid 65 65
Surface dry 5 min 5 min
Hard dry 15 min 15 min
DFT 60 µm 60 µm
Flexibility Pass Pass
Adhesion test Pass Pass
Impact Test Pass at 80 cm Pass at 80 cm

22. Sample Salt spray (72 hrs) Humidity (72 hrs)
S1 pass Fair
S2 pass Good

26. CONCLUSION

27.  The process is economical as the temperature requires in
conventional method is 1000C and it can be done at lab scale.
 Nano Zinc ferrite based paint posses better anticorrosive properties.
 It provides excellent resistance to water and salt water, so it can be
best used as a primer in various coatings.
 Samples S1 & S2 posse’s good mechanical properties such as
scratch hardness, flexibility and adhesion.

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29. THANK
YOU