Chemical etching of AlF3-based glasses

In this work, two multi component etches have been identified for the purpo se of etching aluminium fluoride based [AIF(3)-M(II)F-2-xPO(3), M = Mg, Ca, Ba, Sr] fibre samples to improve their mechanical strength. Optimum workin g ;compositions are (i) 0.4 M AlCl3. 6H(2)O/1M HCl and (ii) (by volume) 50% HF (48%)/30% HNO3 (68%)/20% H2O with 3M H3BO3 dissolved. Both yield fibres of improved strength and quality, although the former etch performs better . Furthermore, an etch procedure has been developed for the aluminium chlor ide mixture which enables increased strength fibre to be pulled in a contro lled and reproducible manner. (C) 1999 Elsevier Science B.V. All rights res erved.