[A fundamental study of the fabrication of a medical prosthesis by slip casting (author's transl)].

Abstract

Sintered 316 L stainless steel, made by slip casting, was studied in the present work for its potential use as a medical prosthesis. The physical and mechanical properties were scrutinized to determine characteristics of the specimens. Corrosion tests were conducted in boiling 5% H2SO4. Microstructures of the specimens were examined. The samples were implanted for 31 days in the dorsolateral subcutaneous site of living rats. The results were as follows. The shrinkage during heating varied from 10.3 to 33.0%, the relative density from 0.41 to 0.78, and porosity from 20.4 to 58.2%. Tensile strength varied from 2.3 to 24.6 kg/mm2, yield strength from 2.8 to 11.6 kg/mm2, elastic modulus from 1 075 to 7 400 kg/mm2, elongation from 9.1 to 19%, hardness of Brinell scale from 7.5 to 53.1. Mechanical properties as mentioned above decreased with increasing porosity. Pore size distribution varied 4.4 to 44 mu. Both Si and ferrite, or either of the two were observed in the matrix of austenite. Corrosion resistance were effected greatly by the porosity. Blood vessels, fibroblasts, fibrous tissues were found surrounding the sintered specimens and in the interior pores. No degeneration or necrosis were noted. Based on the tentative findings of the present studies, I can say that sintered stainless steel have a potential for medical application.