Zirconia balls

The basic process of mechanical alloying is illustrated in Figure 3.2. The starting materials usually used are oxides. Powders with typical surface area in the range of 10-50 m -g are placed in a high-energy vibratory ball mill in the stoichiometric amount to contain Ce,. M 02 (0 < x < 0.9), This mill is equipped with zirconia balls and vials made of stabilized-zirconia. 

Commonly used types of grinding media are carbon steel, stainless steel, chrome steel, tungsten carbide, ceramic, or zirconia. Ball mills produce up to 50 ton/hr of powder substantially passing a 200-mesh screen. Temperature control can be achieved by the use of jacketed ball mills through which a heat transfer fluid is circulated. 

When sufficient wet materials was collected, it was freeze-dried, ground in a zirconia ball mill and sieved to pass 125 pm apertures. The resulting powder was collected in a mixing drum and homogenised by continuous rotation under dry Ar over two weeks. Cleaned brown glass bottles were filled with approximately 5 g of material and closed with screw caps and plastic inserts. A PTFE-ball was added to facilitate later re-homogenisation in case segregation would occur. 

C. Piconi, G Maccauro, L. Pilloni, W. Burger, F. Muratori, and H. G Richter. On the fracture of zirconia ball head. J. Mater Science. Mater Med, 17, 289-300 (2006). 

The brown powder was first ball milled with high purity zirconia balls for 12 h at a rotational speed of 200 rpm, in isopropyl alcohol with 3 wt% polyethylene glycol. The ball milled mixture was dispersed supersonically for 30 min and then dried by using a rotary evaporator. The dried powder was further calcined at different temperatures for 2 h. Rnally, the calcined powders were ball milled for second time with zirconia balls for 12 h in isopropyl alcohol. The milled powders were dried and then sintered by using SPS, with graphite dies with an inner diameter of 15 mm at 50 MPa uniaxial pressure. The temperature was increased to 600 °C within 10 min, from where and onwards the pressure was increased to 100 MPa. The samples were sintered at 1200-1350 °C for 5 min at a heating rate of 100 °C min. ... 

The dried gel was thermally treated at 900 °C for 4 h in air and wet milled in acetone media for 24 h using high-purity zirconia balls. The powder was again... 

Liao YS, McKellop H, Lu Z, Campbell P, Benya P. The effect of frictional heating and forced cooling on the serum lubricant and wear of UHMW polyethylene cups against cobalt-chromium and zirconia balls. Biomaterials 2003 24(18) 3047-59. 

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