Abstract
Calcium phosphate materials such as hydroxyapatite (HA) have biocompatible properties that can promote osteogenesis or new bone formation. Thermal spraying is an economical and effective process for coating the hydroxyapatite onto metal. It has been reported that plasma spraying changes the degree of crystallinity as well as the phase composition of the HA. This article reports the preparation and characterization of HA powders and coatings by two thermal spray processes (plasma and combustion flame) and suggests that the state of the starting powder adversely affects the coating characteristics. The raw HA powders are synthesized through a chemical reaction involving calcium hydroxide and orthophosphoric acid. Phase analysis using an X- ray diffractometer revealed that the synthesized powder consists of predominantly the HA phase. Calcined and crushed HA powders of various size ranges were fed into the plasma jet to produce HA coatings on metallic substrates. In addition, some HA powders were sprayed into distilled water by plasma spraying and combustion flame spraying to study powder melting characteristics. Other samples were plasma sprayed onto a solid rotating target to study atomization and impact behavior. The morphology of the rapidly solidified powders and thermal sprayed coatings were examined by scanning electron microscopy (SEM). An X- ray sedimentation particle size analyzer, laser diffraction particle size analyzer, and image analyzer performed the particle size analysis. Preliminary results indicate that particle cohesion, size range, and thermal treatment in the plasma affect the phase and structure of the as- sprayed coating, and some post- spray treatment may be necessary to produce a dense and adherent coating with the desired biocompatible properties.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
M. Jarcho, Calcium Phosphate Ceramics as Hard Tissue Prosthetics,Clin. Orthop.,Vol. 157,1981,p259–278
J.C. Ricci, J.M. Spivak, H. Alexander, N.C. Blumenthal, and J.R. Parson,Bull. Hosp. Joint Diseases Orthop. Inst.,Vol. 2,1989, p 178–191
H.W. Dennison, K. DeGroot, P.Ch. Makkes, A. Van den Hoof, and P.J. Klopper, Tissue Response to Dense Apatite Implants in Rats,J. Biomed. Mater. Res., Vol 14,1980, p 713–721
C.C. Berndt, G.N. Haddad, A.J.D. Farmer, and K.A. Gross, Thermal Spraying for Bioceramic Applications,Mater. Forum, Vol 14,1990, p 161–173
D.H. Kohn and P. Du neyne, Materials for Bone and Joint Replacement,Materials Science and Technology, Vol 14, D.F. Willam, Ed., VHC Publishers, 1992, p 66–70
M. Jarcho, C.H. Bolen, M.B. Thoma, J. Bobich, J.F. Kay, and R.H. Doremus, Hydroxyapatite Synthesis and Characterization in Dense Polycrystalline Form,Mater. Sci. II, 1976, p 2027–2035
H.H. Douglas, Overview of Problems Surrounding the Plasma Spraying of Hydroxyapatite Coatings,Thermal Spray Research and Applications, T.F. Bernecki, Ed., ASM International, Materials Park, OH, 1990, p 419–423
L. Katz, Calcium Phosphates and Apatites,Encyclopedia of Medical and Dental Materials, D.F. Williams, Ed., Pergamon Press, 1990, p 87–95
S.D. Cook, K.A. Thomas, J.F. Kay, and M. Jacho, Hydroxyapatite Coated Titanium for Orthopaedic Implant Applications,Clin. Ortho. Rel. Res., Vol 232,1988, p 225–243
P. Ducheyne, L.L. Hench, A. Kagan, M. Martens, A. Bursens, and J.C. Mulier, Effect of Hydroxyapatite Impregnation on Skeletal Bonding of Porous Coated Implants,J. Biomed Mater, Res., Vol 14,1980, p 225–237
D.P. Rivera, J. Fox, A.K. Skipor, R.M. Urban, and J.O. Galante, Calcium Phosphate-Coated Porous Titanium Implant for Enhanced Skeletal Fixation,J. Biomed. Mater. Res.,Vol 22,1988, p 191–202
S.D. Cook, K.A. Thomas, J.F. Kay, and M. Jacho, Hydroxyapatite-Coated Porous Ti for Use as an Orthopaedic Biological Attachment System,Clin. Ortho. Rel. Res., Vol 230,1988, p 303–312
J.L. Berry, J.M. Geiger, J.M. Moran, J.S. Skraba, and A.S. Greenwald, Use of Tricalcium Phosphate for Electrical Stimulation to Enhance Bone Porous Implant Interface,J. Biomed. Mater. Res., Vol 20,1986, p65–77
K.A. Gross, Surface Modification of Prosthesis, M. Eng. Thesis,Monash University, Australia, 1990
K.A. Khor, Production of Fine Metal and Ceramic Powders by the Plasma Melt and Rapid Solidification (PMRS) Process,J. Mater. Proc. Tech., Vol 29 (No. 1-3), 1992, p 267–281
R. McPherson, The Relationship Between the Mechanism on Formation, Microstructure and Properties,Thin Solid Film, Vol 83, 1981, p 297–381
J.G.C. Wolke, J.M.A. De Blieck-Hogervorst, W.J.A. Dhert, C.P.A.T. Klein, and K. de Groot, Studies on the Thermal Spraying of Apatite Bioceramics,J. Thermal Spray Technol.,Vol. 1 (No. 1), 1992,p75–82
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Khor, K.A., Cheang, P. Characterization of thermal sprayed hydroxyapatite powders and coatings. JTST 3, 45–50 (1994). https://doi.org/10.1007/BF02648998
Issue Date:
DOI: https://doi.org/10.1007/BF02648998