Biomaterial Database

Pyrolytic carbon indentation crack morphology. 1996

J L Ely, and J Stupka, and A D Haubold

Medical Carbon Research Institute, Austin, Texas 78754, USA.

In studying fatigue and fracture behavior of brittle materials, Vickers diamond indentation cracks are often used. Many of the studies of indentation cracks use crack system models such as the radial-median crack or Palmqvist crack. These systems are also used to study small crack growth in brittle materials, and have been studied for pyrolytic carbon. However, the true morphology of these cracks in pyrolytic carbon coatings on graphite substrates have not been described. This study examined Vickers diamond and spherical ball indentation cracks in pyrolytic carbon coatings using several techniques, including serial metallographic cross sections, indentation fracture in bending, acoustic emission, and residual surface indentation scanning. The crack systems developed using these techniques were not typical of either radial median or Palmqvist systems. The morphology is unique to this material, possibly because of the coating thickness limitations. Given the difference in crack system, the application of standard indentation crack equations in studying fracture mechanics, especially for small cracks, must be questioned.

UI	MeSH Term	Description	Entries
D008422	Materials Testing	The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility.	Biocompatibility Testing,Biocompatible Materials Testing,Hemocompatibility Testing,Testing, Biocompatible Materials,Testing, Hemocompatible Materials,Hemocompatibility Testings,Hemocompatible Materials Testing,Materials Testing, Biocompatible,Materials Testing, Hemocompatible,Testing, Biocompatibility,Testing, Hemocompatibility,Testing, Materials,Testings, Biocompatibility
D008857	Microscopy, Interference	The science and application of a double-beam transmission interference microscope in which the illuminating light beam is split into two paths. One beam passes through the specimen while the other beam reflects off a reference mirror before joining and interfering with the other. The observed optical path difference between the two beams can be measured and used to discriminate minute differences in thickness and refraction of non-stained transparent specimens, such as living cells in culture.	Interferometry, Microscopic,Microinterferometry,Microscopy, Differential Interference Contrast,Microscopy, Interference Reflection,Microscopy, Nomarski Interference Contrast,Interference Microscopy,Interference Reflection Microscopy,Microscopic Interferometry,Reflection Microscopy, Interference
D011474	Prosthesis Design	The plan and delineation of prostheses in general or a specific prosthesis.	Design, Prosthesis,Designs, Prosthesis,Prosthesis Designs
D011475	Prosthesis Failure	Malfunction of implantation shunts, valves, etc., and prosthesis loosening, migration, and breaking.	Prosthesis Loosening,Prosthesis Durability,Prosthesis Migration,Prosthesis Survival,Durabilities, Prosthesis,Durability, Prosthesis,Failure, Prosthesis,Failures, Prosthesis,Loosening, Prosthesis,Loosenings, Prosthesis,Migration, Prosthesis,Migrations, Prosthesis,Prosthesis Durabilities,Prosthesis Failures,Prosthesis Loosenings,Prosthesis Migrations,Prosthesis Survivals,Survival, Prosthesis,Survivals, Prosthesis
D002244	Carbon	A nonmetallic element with atomic symbol C, atomic number 6, and atomic weight [12.0096; 12.0116]. It may occur as several different allotropes including DIAMOND; CHARCOAL; and GRAPHITE; and as SOOT from incompletely burned fuel.	Carbon-12,Vitreous Carbon,Carbon 12,Carbon, Vitreous
D006350	Heart Valve Prosthesis	A device that substitutes for a heart valve. It may be composed of biological material (BIOPROSTHESIS) and/or synthetic material.	Prosthesis, Heart Valve,Cardiac Valve Prosthesis,Cardiac Valve Prostheses,Heart Valve Prostheses,Prostheses, Cardiac Valve,Prostheses, Heart Valve,Prosthesis, Cardiac Valve,Valve Prostheses, Cardiac,Valve Prostheses, Heart,Valve Prosthesis, Cardiac,Valve Prosthesis, Heart
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013314	Stress, Mechanical	A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.	Mechanical Stress,Mechanical Stresses,Stresses, Mechanical
D016474	Weight-Bearing	The physical state of supporting an applied load. This often refers to the weight-bearing bones or joints that support the body's weight, especially those in the spine, hip, knee, and foot.	Load-Bearing,Axial Loading,Loadbearing,Weightbearing,Axial Loadings,Load Bearing,Weight Bearing