mgo na 2 o k 2 o caf 2 al 2 o 3 sio 2 cao fe 2 o 3 mno mno 2 zno c sro pbo bao tio 2 and zro 2 in order to enhance the sinterability strength and porosity thereof and other properties where the hydroxyapatite is used as a composite material with a polymeric material the polymeric material may be selected from resins having a relatively low toxicity for example polyethylene polypropylene polymethyl methacrylate polyurethanes polyesters abs resins fluorine contained resins polycarbonates polysulfone epoxy resins silicones diallyl phthalate resins and furan resins on the other hand the methods of preparation of the ceramic material include a so called sintering method in which the raw material is sintered singly or on a substrate such as a metal plastics or ceramics and vapor deposition methods such as a plasma spray coating method an ion beam deposition method and a vacuum evaporation method in which the raw material is plasma sprayed on a substrate such as a metal or ceramics for example the single sintered material is generally obtained by compress molding a raw material comprising hydroxyapatite tricalcium phosphate or tetracalcium phosphate in a mold or a rubber press under a pressure of approximately 500 to 3 000 kg cm 2 to obtain a compact having a desired shape and then subjecting the compact to a sintering treatment at a temperature of approximately 700 u00b0 c to 1 300 u00b0 c for further details of other methods of preparation and the material composition reference will be made to the following publications japanese unexamined patent publication kokai nos 51 40400 52 64199 52 82893 52 142707 52 147606 52 149895 53 28997 53 75209 53 111000 53 118411 53 144194 53 110999 54 94512 54.