COMUNICAÇÃO TÉCNICA
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Nº 170936
Lead-free glass frit for automotive application
Cátia Fredericci
H. Fellegara
A.P. Abreu
A.L. Molisani
H.N. Yoshimura
Trabalho apresentado no
Brazilian Symposium on Glass
and Related Materials, 9.,
Curitiba, 2012. Slide da
apresentação.
A série “Comunicação Técnica” compreende trabalhos elaborados por técnicos do IPT, apresentados em
eventos, publicados em revistas especializadas ou quando seu conteúdo apresentar relevância pública.
___________________________________________________________________________________________________
Instituto de Pesquisas Tecnológicas do Estado de São Paulo
S/A - IPT
Av. Prof. Almeida Prado, 532 | Cidade Universitária ou
Caixa Postal 0141 | CEP 01064-970
São Paulo | SP | Brasil | CEP 05508-901
Tel 11 3767 4374/4000 | Fax 11 3767-4099
www.ipt.br
Lead-free glass frit for automotive application
Fredericci,
(1)
C. ,
(2)
H. ,
(3)
Abreu Molisani,
(1)
A.L.
(4)
Yoshimura,H.N.
Fellegara
A.P.
,
(1) Instituto de Pesquisas Tecnológicas do Estado de São Paulo - IPT
(2) Ticon – Tintas Condutivas Ltda
(3) Raw Materials
(4) Universidade Federal do ABC (UFABC)
[email protected]
1 ABSTRACT
In the light of recent health and environmental restrictions and concerns, the use of PbO and CdO
is largely avoided whenever possible. Several frits that fuse at low temperature and present low
toxicity, containing Bi2O3, SiO2, and B2O3 have been developed as lead-free frits for automotive
application. Many studies have been published about lead free glass frit; however, few publications
have been made regarding the refractory used to melt them. In this work it was analyzed the glass
formation in the system Bi2O3-SiO2-B2O3-TiO2 melted in electrocast mullite and electrocast
alumina-zirconia-silica (AZS) refractory. The glass was melted at 1250oC/5h and quenched in
water. The resulting frit was analyzed by X ray diffraction (XRD), X ray fluorescence (XRF) and
differential thermal analyses. The refractories were cut and their cross sections were analyzed by
scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results of
XRD shown that the frit was vitreous and presents glass transition temperature and crystallizes at
about 480oC and 615oC, respectively. The electrocast AZS refractory was more adequate than the
electrocast mullite for melting the glass studied.
Figure 2. (a) and (b) SEM micrographs of the interface glass-mullite refractory, (c) and (d) EDS
spectra of the points listed in (b).
2 MATERIALS AND METHODS
- The commercial refractories indicated in Table 1 were cut using a diamond saw to
approximately 50x50x73 mm3.
-Cylindrical holes were made in the central region with dimensions of 25 mm diameter by 50 mm
deep.
-The glass composition listed in Table 1 was put on the crucible, was heated at 1250 oC for 5 h and
quenched in water.
-The resulting frit was analyzed by X ray fluorescence (XRF).
-The refractories were cut and their cross sections were analyzed by scanning electron microscopy
(SEM) and energy dispersive spectroscopy (EDS).
Table 1. Refractory materials used for melting the glass.
Figure 3. (a) SEM micrograph of the interface glass-AZS refractory, (b), (c), (d), (e), (f) , (g) EDS
spectra of the points listed in (a).
3.2 X Ray Fluorescence Spectroscopy
Table 2. Nominal glass composition (wt%)
Table 2. Glass composition (wt%) after melting in AZS refractory.
3 RESULTS
4 CONCLUSION
3.1 Microstructural Analysis
The best refractory tested for melting the bismuth based glass was the AZS. The composition of the
glass after melting showed a little contamination of ZrO2 and Al2O3, but did not compromise the
properties of the frit. It is a potential lead free material to be used in formulation of enamels for the
formation of black band on rear windows of cars.
glass
refractory
Figure 1. Photographs of refractories after melting the glass at 1250 oC/5h.
KNOWLEDGMENTS
C. Fredericci thanks CNPq for funding (P. 313242/2009-7).