H2O2 solution in hydrochloric acid (etchant no. 22 according to Bhavar et al. (2017): 100 ml HCl + 0.5 ml H2O2 (30%)). |
Promising results: the ability to distinguish grains based on the shade of their colors. Intense etching of melt boundaries and lack of etching of grain boundaries prevents their precise determination. |
a |
H2O2 solution in hydrochloric acid (ref. no. 22 according to Bhavar et al. (2017): 100 ml HCl + 0.5 ml H2O2 (30 %)) – electrolytic at 4 V. |
Intensive etching of melt boundaries, grain boundaries invisible. |
b |
Kalling’s etchant 1 and 2. |
Etching effects were not obtained. |
- |
10% aqueous solution of oxalic acid – electrolytic etching at 6 V |
Etching of melt boundaries, grain boundaries invisible. |
c |
38% aqueous solution of hydrochloric acid. |
A 10-minute etching first extracted the boundaries of the melts. A 3-hour etching revealed grains, but there is difficulty in precisely defining their boundaries. |
d |
60 ml HNO3 + 40 ml H2O solution (ref. no. 219 according to Bhavar et al., 2017) – electrolytic etching at 1 V. |
Promising results for observations with polarized light (the ability to distinguish grains based on the shade of their colors). Intense etching of melt boundaries and lack of etching of grain boundaries prevents their precise determination. |
e, f |
Berach’s etchant III with the addition of sodium pyrosulfate (1 g per 100 ml). |
No apparent etching effects were obtained. |
|
Nital 2% (etchant no. 74 according to Kundra, 2023) – electrolytic etching at 8 V. |
Etched melt boundaries in the first place, no etching of grain boundaries. Inability to distinguish between grains. |
g |
solution of 6.5 ml HCl + 1.5 ml HNO3 + 1.8 g CH3COOH + 1.17 ml H2O. |
Promising results for observations with polarized light (the ability to distinguish grains based on the shade of their colors). Intense etching of melt boundaries and lack of etching of grain boundaries prevents their precise determination. |
h |