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.