The influence of argon-ion etching is investigated for liquid-quenched high-T-c Bi1.6Pb0.4Sr2Ca2Cu3Ox. The argon-ion irradiation has no effect on the T-c value for a dose of 4.05 x 10(17) (ions mm(-2)). However, doses in excess of this level greatly decreases the T-c value. Therefore, a critical irradiation does value (D-c) to maintain a T-c value above 100 K is defined and determined. The D-c is about 4.94 x 10(17) (ions mm(-2)) for argon-ion irradiation at the low acceleration energy of 1 keV.