274 C P. Doda Hawk/War203-204199257-27 AG:0A+s删购1mA0(队A()5AC(8别,(d5B+C(努8C.P. Do&n. LA. Hawk/ Wear 203-204 (1997) 267-277 Fig. 5. Wear surfaces following abrasion agains4 ALO,: (0 Al,O, + SiC.; and (g) 99.5% AI,O,. Si,N.-a: (b) Si,N,-A+SiC: (c, Si,N.-9: (d) Si,N.-B + Sic,: