title: Mechanical and thermal properties of hot pressed CoCrMo-porcelain composites developed for prosthetic dentistry.
abstract: In this study, mechanical and thermal properties of CoCrMo-porcelain composites for dental restorations have been evaluated. These metal-ceramic composites were produced by powder metallurgy and hot pressing techniques from the mixtures of metal and ceramic powders with different volume fractions. Young's moduli and the coefficient of thermal expansion of materials were evaluated by dynamic mechanical analysis (DMA) and dilatometry (DIL) tests, respectively. The strength in flexion and shear was measured with a universal test machine and hardness with a respective tester. The microstructures and fracture surfaces were inspected by the means of optical microscopy and Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS). Shear strength, Flexural strength and Young' moduli of ceramic and metal-matrix composites were found to increase with higher metal particles content. The DMA tests performed at different frequencies showed no frequency-dependent features of the materials studied, indicating no viscoelastic behavior. The fracture surfaces analysis suggests the load-transfer mechanism be possibly responsible for this behavior, as the differences in CTE are low enough to cause significant thermal stresses in these materials. The results might be included in a materials properties database for further use for design and optimization of dental restorations.
authors.affiliation: Center for Mechanical and Materials Technologies, Universidade do Minho, Campus de Azurém, 4800-058 Guimarães, Portugal; Departamento de Engenharia de Materiais, Universidade Federal do Rio Grande do Norte (UFRN), 59072-970 Natal/RN, Brazil. Electronic address: brunohenriques@dem.uminho.pt.
authors.forename: B
authors.initials: B
authors.lastname: Henriques
authors.affiliation: Department of Materials Science and Engineering, School of Chemical Technology, Aalto University Foundation, 00076 Aalto, Espoo, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Gasik
authors.affiliation: Center for Mechanical and Materials Technologies, Universidade do Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
authors.forename: J C M
authors.initials: JC
authors.lastname: Souza
authors.affiliation: Departamento de Engenharia de Materiais, Universidade Federal do Rio Grande do Norte (UFRN), 59072-970 Natal/RN, Brazil.
authors.forename: R M
authors.initials: RM
authors.lastname: Nascimento
authors.affiliation: Center for Mechanical and Materials Technologies, Universidade do Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
authors.forename: D
authors.initials: D
authors.lastname: Soares
authors.affiliation: Center for Mechanical and Materials Technologies, Universidade do Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
authors.forename: F S
authors.initials: FS
authors.lastname: Silva
mesh_terms: D003776:Dental Porcelain / Q000737:chemistry*; D017266:Dental Prosthesis; D055119:Elastic Modulus; D006358:Hot Temperature; D008422:Materials Testing; D055595:Mechanical Phenomena; D033081:Shear Strength; D013499:Surface Properties; D014800:Vitallium / Q000737:chemistry*
chemical_list: D003776:Dental Porcelain; D014800:Vitallium
keywords: CoCrMo alloy; Composite; Mechanical properties; Porcelain; Powder metallurgy; Thermal properties