**2.4.3 Optimized sample**

After performing experiments designed by Taguchi method and analysing results with Winrobust software the optimized sample was provided using the following condition: pH = 2.5, T = 65°C, C = 40 g/lit, t = 7 h, R = 200 r.p.m .

The XRD pattern of this sample shows the hydroxide phase before calcination and Casiterite SnO2 phase after that.

According to SEM results, SnO2 particles are coated on mica flakes almost regularly and uniformly (figure 2.13-a). According to the laser beam diffraction technique the mean particle size of pigments is about 65 micron. The density of this pigment is 3.3 g/cm3 and the lightness and reflective percent are 97% and 89% respectively in which case these amounts of l\* and R are equal to the Winborust software results. Consequently choosing to use the Taguchi method and L16 algorithm is correct for this work.

Ceramic Coatings for Pigments 255

(a)

(b) (c)

Fig. 2.15. Microscopic image of optimized sample, (a) SEM, (b) and (c) light microscopy


Table 2.5 shows the results of Goniospectrophotometery of the optimized sample. Figure 2.14 shows the amount of optimized sample reflection from different angle views.

Table 2.5. R results of goniospectrophotometery of optimized sample

Fig. 2.14. Amount of optimized sample reflection from different angle views

According to table 2.5 and figure 2.14 parameters l\* and R in the different angle views have different values, and also these values are higher in smaller angle views. Therefore the optimized sample has lightness and reflection [2.21, 2.22]. In addition since the maximum value of reflection is in the range of yellow light wavelength (570-600 nm), the pigment is yellow. So it is possible to say that the optimized pigment is gold pearlescent pigment.

Figure 2.15 shows the microscopic image of the optimized sample. As can be seen from Fig. 2.14 and Fig. 2.15, most of mica flakes coated with SnO2 have a golden colour. However, in this sample, flakes with other colors can be seen as well, which might be due to different thickness of coating on the mica flakes.

Table 2.5 shows the results of Goniospectrophotometery of the optimized sample. Figure

a\* 0.81 0.74 0.73 0.67

b\* 13.04 14.20 14.34 13.78

l\* 96.76 87.57 87.03 86.99

R 570 nm 0.89 0.64 0.56 0.55

Table 2.5. R results of goniospectrophotometery of optimized sample

Fig. 2.14. Amount of optimized sample reflection from different angle views

thickness of coating on the mica flakes.

According to table 2.5 and figure 2.14 parameters l\* and R in the different angle views have different values, and also these values are higher in smaller angle views. Therefore the optimized sample has lightness and reflection [2.21, 2.22]. In addition since the maximum value of reflection is in the range of yellow light wavelength (570-600 nm), the pigment is yellow. So it is possible to say that the optimized pigment is gold pearlescent pigment.

Figure 2.15 shows the microscopic image of the optimized sample. As can be seen from Fig. 2.14 and Fig. 2.15, most of mica flakes coated with SnO2 have a golden colour. However, in this sample, flakes with other colors can be seen as well, which might be due to different

Angle view

20° 45° 75° 110°

2.14 shows the amount of optimized sample reflection from different angle views.

Colorimetery parameters

Fig. 2.15. Microscopic image of optimized sample, (a) SEM, (b) and (c) light microscopy

Ceramic Coatings for Pigments 257

[2.3] K.Othmer, "Encyclopedia of Chemical Technology", 3rd ed., 17, J.Wiley & sons,

[2.4] G. Taguchi and S. Konishi, Taguchi methods, orthogonal arrays and linear graphs, tools for quality engineering, American Supplier Institute, Dearborn, MI (1987) p. 35-38. [2.5] G. Taguchi, Taguchi on robust technology development methods, ASME Press, New

[2.6] Phillip J. Ross, Taguchi Technique for quality engineering, McGraw-Hill, New York

[2.7] K. Roy Ranjit, A Primer on Taguchi method, Van Nostrad Rainhold, New York

[2.8] J. Paulo Davim, An experimental study of tribological behaviour of the brass/steel pair,

[2.9] J. Paulo Davim, Design optimization of cutting parameters for turning metal matrix

[2.10] Genechi Taguchi, "System of Experimental Design" Vol. 1, 1987, KRAUS International

[2.11] Yeow Nam Ng, Don Black, Khanh Luu, "Taguchi Methods", 1995, Curtin University

[2.12] T. Junru, Sh. Lazhen, F. Xian song, H. Wenxiang, "Preparation of Nanometer – Sized

[2.15] H.R.Castro, B.S.Murad, D.Gouvea, "Influence of the Acid-Basic Character of Oxide

[2.17] Xiong Y, Zhou X, Hu L. Study on the process of the ultrafine α-FeOOH synthesis by

[2.18] K. Matsui, M. Ohgai, "Formation Mechanism of Hydrous Zirconia Particle

[2.20] K.Chang, etal, "A Method for Preparing a Pearlescency Pigment", U.S. Patent. APPL.

[2.21] H.M.Smith, "High Performance Pigment", Chapter 7, Wiley- VCH, Weinheim,

[2.22] L.M. Greenteain, "Pigment Handbook", Vol. 1, Chapter III-D-d-2, John Wiley & Sons

[2.13] J. P. Jolivet, "Metal Oxide Chemistry and Synthesis", John Wiley & Sons, (2002). [2.14] M. Yamamoto, A. Ando, "Pearlescent Pigment, and Paint Composition, Cosmetic

[2.16] Miller HA. Optical property of pearl pigment GFR. Farbe lack 1987; 12:93.

[2.19] M.R. Porten, "Hand book of Surfactan", Chapter 4, Chapter 8, Hall (1994).

composites based on the orthogonal arrays, J Mater Process Technol 132 (2003), p.

(1-x) SnO2. xsb2O3 Conductive Pigment Powders and the Hydrolysis Behavior of

Material, Ink and Plastics Blended with the New Pearlescent Pigment", U.S. Patent

Surfaces in Dispersants Effectiveness" Ceramics International 30 (2004) 2215-

dripping method. Journal of East china university of science and technology 1996;

Produced by Hydrolysis of ZrCL2 Solution, Kinetics Study for Nucleation and Crystal Growth Processes of Primary Particle", J. Am. Ceram. Soc. 84: 2203-2313

[2.2] S. Hanchisu, "Nacreou Pigments", Prog. Org. Coat. 3:191-220 (1975).

J Mater Process Technol 100 (2000), p273-279.

Handout Notes for Computer Aided Engineering.

Urea", Dyes and pigments 61 (2004) 31-38.

NewYork, 1978-1984, PP. 78-838.

York, NY (1993) p. 1-40.

(1988).

(1990).

340-344.

Publication.

5741 355 (1998).

2221.

22(5): 541-7.

20040096579 (2004).

Germany, (2002).

NewYork (1998).

(2001).
