pass through a 32 u03bcm sieve polishing effectiveness 2 96 mg cm2 min 10 6 kg ceriumhydrate treo content 55 ceo 2 treo 98 are suspended in 30 liter of water followed by addition of 4 8 kg of zr oh 4 zro 2 content 32 and 1 98 liter of hf 40 w w after addition of the compounds the mixture is stirred over a period for 3 hrs at a temperature between 40 50 u00b0 c and the solid is separated by filtration the filtered solid is washed with 1 liter water and the resulting wet cake dried at 150 u00b0 c over a period of 24 hrs the dried material is calcined in a muffle furnace at 950 u00b0 c furnace temp over a period of 8 hrs the calcined product is grounded in a jet mill producing a polishing composition having the following characteristics loi 0 35 ceo 2 72 zro 2 18 4 f 1 7 peaks at 2 theta degrees 24 0 28 1 29 8 38 4 47 8 59 4 69 8 79 4 particle size d50 1 76 u03bcm less than 0 03 would not pass through a 32 u03bcm sieve polishing effectiveness 2 86 mg.