Devitrification and dilatometric properties of low Tg unleaded silicate glasses

• Candidate lead free glass enamels have been sought within the glass system described in general terms by the mole fractions 0·25R 2O.0·16(R'O, R2"O3). 0·59SiO2 where R=Li, Na, K; R'=Ba, Zn and R"=B, Bi. Glass compositions containing high mole fractions of Li2O were found to devitrify when they were heated to temperatures up to 530°C typical for the procedure used when fusing enamels to tableware glasses. The devitrification characteristics are complex and several peaks atributed to crystallisation were found by DSC characterisation. The thermal expansion coefficient(α) within the system ranges from 11-14×10-6 K-1 and the glass transition temperatures(Tg) between 410-460°C. The measured data could be fitted to the chemical composition by multiple regression analysis with a general equation of the form:(α, Tg)=K(α/T g)+Σ(cR×fR) in which K is a constant, c is the oxide mole fraction and f is an oxide specific factor. The statistical analysis correlation coefficients(r2) were around 0·9.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

Nyckelord

Chemical engineering

Enamels

Lithium

Regression analysis

Silicates

Kemiteknik

Glasteknologi

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)