Tellurite And Fluorotellurite Glasses For Active And Passive

7. Surface properties; MDO 258
etchants used in this study, with molarity for HCl (the number of moles of acid / alkali
per litre of solution), and molality (number of moles of acid / alkali per kg of solvent, i.e.
water), calculated from the grade (weight %) of acid / alkali.
Table (7.1): Etchants used in this study.
Etchant
Chemical
formula
Source
Grade2 /
wt. % / mol.l -1
Molality /
mol.kg -1
Sodium hydroxide NaOH Fisher 50.0 - 25.0
Sulphuric acid H2SO4 ″ 50.0 - 10.2
Hydrochloric acid HCl ″ 30.5 12.0 -
Hydrofluoric acid HF ″ 50.0 - 50.0
Nitric acid HNO3 ″ 70.0 - 37.0
Ortho-phosphoric acid H3PO4 ″ 85.0 - 57.8
Glacial acetic acid CH3COOH ″ 99.8 - 8309.2
Molarity 3
Optical microscopy was performed using a Nikon Optiphot with a Nikon DMX1200F
digital camera. Scales on the micrographs were digitally created using a micrograph of a
graticule at the same magnification as the sample micrograph.
7.1.3. Ion exchange
7.1.3.1. Method and instrumentation
Glasses melted at Nottingham University (see chapter 3) were sent to Prof. G. Rigini’s
group at CNR in Florence, Italy. These glasses, were polished flat and parallel on
2 Residual was water
3 At standard temperature and pressure