Potassium Tungsten Bronze

Introduction

Potassium tungsten bronze(KxWO₃) has crystalline structure for hexagonal （0.18≤x≤0.33）and tetragonal（0.40≤x≤0.59）, it has super conductive property which shows charge density waves. Color of KxWO₃ changes with value of x. When x increases, it turns from dark blue(x=0.20) to purple(x=0.60).

Below is the SEM for KxWO3 when x=0.26，0.33，0.50，0.58:

Preparation

1.Mix K₂WO₄(dehydrate K₂WO₄•2H₂O under 200℃ for 2 hours) and WO3 for mole rate 1:7, weigh 2g and mix them up.
2.Configurate stainless ball mill (Ø6 mm) by weight rate 20:1, put mixing material into stainless steel milling container, sealing with cap and draw out the air, then inflating with Ar. Mill it on planetary ball mill for 10h (rotary speed 450r/min).
3. Press and cut the material under 20MPa, then put it into quartz tube, vacuumizing and then packing.
4.Put quartz tube into high temperature rotary and heat to 800 ℃ and 750 ℃, cool it down to room temperature.