A Study of Hydroxyapatite Coating on Porous Ti Compact by Electrostatic Spray Deposition

Abstract

Coatings of hydroxyapatite (HA) on the porous-surfaced Ti compact have been conducted by electrostatic spray deposition (EDS). The precursor solution for the HA coating by ESD was prepared by mixing nano-scaled HA powder with ethyl alcohol. As-deposited HA films on the substrate were heat-treated (400 ~ 900 °C) and their physical characteristics were investigated by Scanning Electronic Microscopy (SEM), X-ray Diffractometer (XRD), and X-ray Photoelectronic Spectroscopy (XPS). As-deposited HA films were consisted of HA particles which were uniformly distributed on the Ti substrate, showing a porous structure. By heat treatment, HA particles were agglomerated each other and melted to form a highly dense and homogeneous coating layer consisted of equiaxed nano-scaled grains. HA coatings on the porous-surfaced Ti compact consisted of highly crystalline apatite phase with the Ca/P ratio of about 1.67 were successfully obtained by using ESD.

Calcium orthophosphate deposits: Preparation, properties and biomedical applications

“…The obtained solutions were pumped, quickly mixed prior the nozzle and electrostatically sprayed onto a substrate, while the substrate itself might be heated to 300 -450 °C [637][638][639][640][641][642]. Except solutions, CaPO 4 powders might be suspended in alcohols and the obtained suspensions are electrosprayed [643][644][645][646][647][648][649]. Among them, the solution approach allows putting down of the thinner deposits than the suspension approach.…”

There Are over 60 Ways to Produce Biocompatible Calcium Orthophosphate (CaPO4) Deposits on Various Substrates

“…The resulting solution is pumped, rapidly stirred in front of a nozzle and electrostatically sprayed onto the substrate, which can be heated up to 300-450 • C [719][720][721][722][723][724]. Besides solutions, CaPO 4 powder can also be suspended in alcohol and the resulting suspension electrosprayed [725][726][727][728][729]. Of these, the solution method allows the deposition of finer precipitates compared to the suspension method.…”

“…Since ESD can take place at room temperature, thermally unstable compounds can also be deposited. As seen in Figure 26, electrostatically sputtered CaPO 4 deposits can be porous [723][724][725][726]729,730]. However, after deposition, the substrate can be calcined at high temperatures.…”

Design of advanced one-step hydroxyapatite coatings for biomedical applications using the electrostatic spray deposition

“…In light of the deficiencies of plasma spraying, alternative techniques are being developed for depositing thin HAP-based coatings, including sol-gel deposition [23], dip coating, electrochemical deposition [24,25], RF magnetron sputtering deposition [26,27], Pulsed Laser Deposition (PLD) [28] and Hot Isostatic Pressing (HIP) [29,30]. Among these methods, the Electrostatic Spray Deposition technique (ESD) has been reported as a promising low-temperature deposition technique for producing CaP coatings [31][32][33][34][35][36][37], which may eliminate some of the problems associated with the plasma-spraying process. The preparation of CaP coatings by ESD has been reported using H3PO4 as a P(V) precursor [31][32][33].…”

“…Amorphous as-deposited CaP coatings were obtained, but additional heat treatment was required for improving the mechanical properties of the coatings [33]. ESD has also been used to shape HAP coatings from spraying a suspension based on HAP nanostructured powders [34][35][36][37]. However, this procedure although in one step has drawbacks, such as the instability of the suspension, compositional homogeneity, and thus the reproducibility of the deposition.…”