title: Formability and mechanical properties of porous titanium produced by a moldless process.
abstract: Tailor-made porous titanium implants show great promise in both orthopedic and dental applications. However, traditional powder metallurgical processes require a high-cost mold, making them economically unviable for producing unique devices. In this study, a mixture of titanium powder and an inlay wax binder was developed for moldless forming and sintering. The formability of the mixture, the dimensional changes after sintering, and the physical and mechanical properties of the sintered porous titanium were evaluated. A 90:10 wt % mixture of Ti powder and wax binder was created manually at 70°C. After debindering, the specimen was sintered in Ar at 1100°C without any mold for 1, 5, and 10 h. The shrinkage, porosity, absorption ratio, bending and compressive strength, and elastic modulus were measured. The bending strength (135-356 MPa), compression strength (178-1226 MPa), and elastic modulus (24-54 GPa) increased with sintering time; the shrinkage also increased, whereas the porosity (from 37.1 to 29.7%) and absorption ratio decreased. The high formability of the binder/metal powder mixture presents a clear advantage for fabricating tailor-made bone and hard tissue substitution units. Moreover, the sintered compacts showed high strength and an elastic modulus comparable to that of cortical bone.
authors.affiliation: Department of Oral and Maxillofacial Prosthodontics and Oral Implantology, Institute of Health Biosciences, The University of Tokushima, Tokushima, Japan.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Naito
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Bae
authors.forename: Yoritoki
authors.initials: Y
authors.lastname: Tomotake
authors.forename: Kenichi
authors.initials: K
authors.lastname: Hamada
authors.forename: Kenzo
authors.initials: K
authors.lastname: Asaoka
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ichikawa
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D019245:Compressive Strength; D015921:Dental Implants; D055119:Elastic Modulus; D006801:Humans; D008422:Materials Testing; D008669:Metallurgy / Q000379:methods; D016062:Porosity; D019736:Prostheses and Implants; D014025:Titanium / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D015921:Dental Implants; D014025:Titanium
keywords: elastic modulus; moldless process; porosity; shrinkage; strength