Chemical lap polishing of PbTe and Pb1−xSnxTe crystals

Chemical lap polishing of PbTe and Pb_1−xSn_x Te crystals is investigated. A mixture of potassium hexacyanoferrate (III), sodium hydroxide, glycerol and water is used as a polish. The effect of various parameters of the process on the quality of the surface and on the rate of material removal is studied. The quality of the surface is strongly is strongly affected by the composition of the polish. The roughness increases with rising sodium hydroxide concentration but decreases with rising glycerol concentration. If the molar ratio of sodium hydroxide and potassium hexacyanoferrate (III) exceeds the value 0.5 etch figures are formed. The rate of material removal largely depends on the velocity of the relative movement between specimen and cloth, the rate of supply of polishing solution and on the concentration of sodium hydroxide.