Mechanical testing of plasma-sprayed ceramic coatings on metal substrates: Interfacial fracture toughness and tensile bond strength

1991 ◽  
Vol 26 (19) ◽  
pp. 5383-5395 ◽  
Author(s):  
M. J. Filiaggi ◽  
R. M. Pilliar
Keyword(s):  
Fracture Toughness ◽  
Bond Strength ◽  
Mechanical Testing ◽  
Interfacial Fracture ◽  
Ceramic Coatings ◽  
Tensile Bond Strength ◽  
Interfacial Fracture Toughness ◽  
Metal Substrates ◽  
Plasma Sprayed

Correlative analysis of cement–dentin interfaces using an interfacial fracture toughness and micro-tensile bond strength approach

2016 ◽  
Vol 32 (12) ◽  
pp. 1575-1585 ◽  
Author(s):  
Evelise M. Souza ◽  
Jan De Munck ◽  
Pong Pongprueksa ◽  
Annelies Van Ende ◽  
Bart Van Meerbeek
Keyword(s):  
Fracture Toughness ◽  
Bond Strength ◽  
Interfacial Fracture ◽  
Tensile Bond Strength ◽  
Interfacial Fracture Toughness ◽  
Correlative Analysis

Interfacial Fracture Toughness of a Plasma Sprayed Hydroxyapatite Coating Used for Orthopedic Implants

1998 ◽  
Vol 550 ◽  
Author(s):  
Y. Sugimura ◽  
M. Spector
Keyword(s):  
Fracture Toughness ◽  
Elastic Modulus ◽  
Adhesion Strength ◽  
Unit Area ◽  
Interfacial Fracture ◽  
Orthopedic Implants ◽  
New Method ◽  
Aqueous Environment ◽  
Interfacial Fracture Toughness ◽  
Plasma Sprayed

AbstractThis study introduces a new method for evaluating the adhesion strength of a coating on a substrate. The interfacial fracture toughness, Γi is used to assess the work per unit area required to separate an interface. Γi is measured for the as-received specimens of hydroxyapatite plasma sprayed on Ti-6A1-4V substrate. Calculation of the interfacial fracture toughness requires that the elastic modulus of the coating to be known. The Young's modulus of the plasma sprayed hydroxyapatite is assessed using a bend test. The effect of aqueous environment on the interfacial fracture toughness is also investigated.

The Effect of Conical Indenter Shape on TBC Interfacial Toughness Measurements

2007 ◽  
Author(s):  
Q. Ma ◽  
J. L. Beuth ◽  
G. H. Meier ◽  
F. S. Pettit
Keyword(s):  
Fracture Toughness ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Interfacial Fracture ◽  
Ceramic Coatings ◽  
Metallic Substrate ◽  
Interfacial Stress ◽  
Thermal Barrier ◽  
Interfacial Fracture Toughness

Thermal barrier coatings (TBCs) are thin ceramic coatings used to insulate gas turbine hot section components. The degradation of interfacial fracture toughness between the coating and the metallic substrate is a key concern for TBC systems. Previous research by the authors has explored the use of conical (Brale) indentation to measure the interfacial fracture toughness of electron beam physical vapor deposition (EB-PVD) TBCs. However, indentation using a standard 120° Brale indenter can fail to yield an ideal debond size for accurate measurement for poorly adhered coatings subjected to long-term thermal exposures, or for as-processed coatings that are well-adhered to the metallic substrate. These limitations of existing conical indentation tests have lead to the study of different shapes of indenters to obtain optimal debond sizes. In this paper, the differences in measuring the interfacial fracture toughness in thermal barrier coating systems due to indentation by rigid cones with various tip angles, namely, 60°, 90°, 120°, and 150° are addressed. Interfacial stress intensity factor distributions, i.e., curves of the interfacial stress intensity factor (K) vs. normalized radial distance (R/a), are obtained through numerical simulations coupled with thin film fracture mechanics relations. Results from experimental studies on an exposed EB-PVD TBC specimen are presented. The goal of this work is to obtain larger debond sizes for high toughness specimens and smaller debond sizes for low toughness specimens, while maintaining an adequate indentation depth.

Interfacial Fracture Toughness Measurement of Thick Ceramic Coatings by Indentation

2005 ◽  
Vol 290 ◽  
pp. 183-190 ◽  
Author(s):  
Marion Bartsch ◽  
Iulian Mircea ◽  
Jens Suffner ◽  
Bernd Baufeld
Keyword(s):  
Fracture Toughness ◽  
Cross Sections ◽  
Interfacial Fracture ◽  
Ceramic Coatings ◽  
Test Method ◽  
Propagation Path ◽  
Material System ◽  
Coating System ◽  
Interfacial Fracture Toughness ◽  
Adhesive Properties

The basic requirement for the use of a ceramic coating is sufficient adhesion to its substrate. A measure of the adhesive properties of a coating is the interfacial fracture toughness. The test method applicable for interfacial fracture toughness measurements depends on the mechanical properties of the material system and the geometry of the test piece. In this work, indentation methods have been evaluated for the estimation of the fracture toughness of ceramic thermal barrier coatings on metallic substrates. Coatings of 100 to 300 µm thickness were applied by electron beam – physical vapour deposition. The performed test types were Vickers indentation at the interface of polished cross sections of the coating system and Rockwell indentation with a brale C indenter, penetrating the coating perpendicular to the surface. Both tests generate delamination, in which the delamination crack length corresponds to the interfacial fracture toughness. Fracture surfaces and cross sections of the fractured coatings were investigated by optical and scanning electron microscope. Determined fracture toughness values are discussed with respect to the loading conditions in the test and the fracture process – i.e. interaction between indenter and coating system and the crack propagation path.

Mechanical and Chemical Characterization of a Metal-Bioceramic Interface

1989 ◽  
Vol 153 ◽  
Author(s):  
Mark J. Filiaggi ◽  
N. A. Coombs ◽  
R.M. Pilliar
Keyword(s):  
Fracture Toughness ◽  
High Resolution ◽  
Bond Strength ◽  
Chemical Characterization ◽  
Interfacial Fracture ◽  
Adhesive Bond ◽  
Interfacial Fracture Toughness ◽  
Implant Fixation ◽  
Resolution Electron

AbstractPlasma sprayed Hydroxyapatite (HA) coatings are applied to metal prostheses to allow for implant fixation through chemical bonding of the coating with surrounding bone tissue. Without a well-adhering coating, this fixation is threatened. Thus, a thorough characterization of the metal / ceramic interface is necessary. This study used a novel composite short bar interfacial fracture toughness technique with high resolution electron spectroscopic imaging to examine Ti-6AI-4V plasma spray coated with 100μm of HA. For this system, an interfacial fracture toughness value of 1.31 +/− 0.08 MPa·m1/2 was obtained, with a corresponding tensile adhesive bond strength of 6.7 +/− 1.5 MPa. High resolution ESI revealed distinct phosphorous segregation to the interface and diffusion into the underlying titanium. A 24-hour post-heat treatment at 960°C greatly increased the bond strength at this interface. Observations from ESI suggested that this effect may be due to enhanced diffusion of both phosphorous and calcium into the metal substrate.

Sign in / Sign up

Export Citation Format

Share Document